unofficial mirror of emacs-devel@gnu.org 
 help / color / mirror / code / Atom feed
blob d9fef345212451072dbe2484c5551df542ed74dc 204273 bytes (raw)
name: src/dispnew.c 	 # note: path name is non-authoritative(*)

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
4857
4858
4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
4910
4911
4912
4913
4914
4915
4916
4917
4918
4919
4920
4921
4922
4923
4924
4925
4926
4927
4928
4929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
4946
4947
4948
4949
4950
4951
4952
4953
4954
4955
4956
4957
4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
4993
4994
4995
4996
4997
4998
4999
5000
5001
5002
5003
5004
5005
5006
5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
5091
5092
5093
5094
5095
5096
5097
5098
5099
5100
5101
5102
5103
5104
5105
5106
5107
5108
5109
5110
5111
5112
5113
5114
5115
5116
5117
5118
5119
5120
5121
5122
5123
5124
5125
5126
5127
5128
5129
5130
5131
5132
5133
5134
5135
5136
5137
5138
5139
5140
5141
5142
5143
5144
5145
5146
5147
5148
5149
5150
5151
5152
5153
5154
5155
5156
5157
5158
5159
5160
5161
5162
5163
5164
5165
5166
5167
5168
5169
5170
5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
5188
5189
5190
5191
5192
5193
5194
5195
5196
5197
5198
5199
5200
5201
5202
5203
5204
5205
5206
5207
5208
5209
5210
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220
5221
5222
5223
5224
5225
5226
5227
5228
5229
5230
5231
5232
5233
5234
5235
5236
5237
5238
5239
5240
5241
5242
5243
5244
5245
5246
5247
5248
5249
5250
5251
5252
5253
5254
5255
5256
5257
5258
5259
5260
5261
5262
5263
5264
5265
5266
5267
5268
5269
5270
5271
5272
5273
5274
5275
5276
5277
5278
5279
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
5300
5301
5302
5303
5304
5305
5306
5307
5308
5309
5310
5311
5312
5313
5314
5315
5316
5317
5318
5319
5320
5321
5322
5323
5324
5325
5326
5327
5328
5329
5330
5331
5332
5333
5334
5335
5336
5337
5338
5339
5340
5341
5342
5343
5344
5345
5346
5347
5348
5349
5350
5351
5352
5353
5354
5355
5356
5357
5358
5359
5360
5361
5362
5363
5364
5365
5366
5367
5368
5369
5370
5371
5372
5373
5374
5375
5376
5377
5378
5379
5380
5381
5382
5383
5384
5385
5386
5387
5388
5389
5390
5391
5392
5393
5394
5395
5396
5397
5398
5399
5400
5401
5402
5403
5404
5405
5406
5407
5408
5409
5410
5411
5412
5413
5414
5415
5416
5417
5418
5419
5420
5421
5422
5423
5424
5425
5426
5427
5428
5429
5430
5431
5432
5433
5434
5435
5436
5437
5438
5439
5440
5441
5442
5443
5444
5445
5446
5447
5448
5449
5450
5451
5452
5453
5454
5455
5456
5457
5458
5459
5460
5461
5462
5463
5464
5465
5466
5467
5468
5469
5470
5471
5472
5473
5474
5475
5476
5477
5478
5479
5480
5481
5482
5483
5484
5485
5486
5487
5488
5489
5490
5491
5492
5493
5494
5495
5496
5497
5498
5499
5500
5501
5502
5503
5504
5505
5506
5507
5508
5509
5510
5511
5512
5513
5514
5515
5516
5517
5518
5519
5520
5521
5522
5523
5524
5525
5526
5527
5528
5529
5530
5531
5532
5533
5534
5535
5536
5537
5538
5539
5540
5541
5542
5543
5544
5545
5546
5547
5548
5549
5550
5551
5552
5553
5554
5555
5556
5557
5558
5559
5560
5561
5562
5563
5564
5565
5566
5567
5568
5569
5570
5571
5572
5573
5574
5575
5576
5577
5578
5579
5580
5581
5582
5583
5584
5585
5586
5587
5588
5589
5590
5591
5592
5593
5594
5595
5596
5597
5598
5599
5600
5601
5602
5603
5604
5605
5606
5607
5608
5609
5610
5611
5612
5613
5614
5615
5616
5617
5618
5619
5620
5621
5622
5623
5624
5625
5626
5627
5628
5629
5630
5631
5632
5633
5634
5635
5636
5637
5638
5639
5640
5641
5642
5643
5644
5645
5646
5647
5648
5649
5650
5651
5652
5653
5654
5655
5656
5657
5658
5659
5660
5661
5662
5663
5664
5665
5666
5667
5668
5669
5670
5671
5672
5673
5674
5675
5676
5677
5678
5679
5680
5681
5682
5683
5684
5685
5686
5687
5688
5689
5690
5691
5692
5693
5694
5695
5696
5697
5698
5699
5700
5701
5702
5703
5704
5705
5706
5707
5708
5709
5710
5711
5712
5713
5714
5715
5716
5717
5718
5719
5720
5721
5722
5723
5724
5725
5726
5727
5728
5729
5730
5731
5732
5733
5734
5735
5736
5737
5738
5739
5740
5741
5742
5743
5744
5745
5746
5747
5748
5749
5750
5751
5752
5753
5754
5755
5756
5757
5758
5759
5760
5761
5762
5763
5764
5765
5766
5767
5768
5769
5770
5771
5772
5773
5774
5775
5776
5777
5778
5779
5780
5781
5782
5783
5784
5785
5786
5787
5788
5789
5790
5791
5792
5793
5794
5795
5796
5797
5798
5799
5800
5801
5802
5803
5804
5805
5806
5807
5808
5809
5810
5811
5812
5813
5814
5815
5816
5817
5818
5819
5820
5821
5822
5823
5824
5825
5826
5827
5828
5829
5830
5831
5832
5833
5834
5835
5836
5837
5838
5839
5840
5841
5842
5843
5844
5845
5846
5847
5848
5849
5850
5851
5852
5853
5854
5855
5856
5857
5858
5859
5860
5861
5862
5863
5864
5865
5866
5867
5868
5869
5870
5871
5872
5873
5874
5875
5876
5877
5878
5879
5880
5881
5882
5883
5884
5885
5886
5887
5888
5889
5890
5891
5892
5893
5894
5895
5896
5897
5898
5899
5900
5901
5902
5903
5904
5905
5906
5907
5908
5909
5910
5911
5912
5913
5914
5915
5916
5917
5918
5919
5920
5921
5922
5923
5924
5925
5926
5927
5928
5929
5930
5931
5932
5933
5934
5935
5936
5937
5938
5939
5940
5941
5942
5943
5944
5945
5946
5947
5948
5949
5950
5951
5952
5953
5954
5955
5956
5957
5958
5959
5960
5961
5962
5963
5964
5965
5966
5967
5968
5969
5970
5971
5972
5973
5974
5975
5976
5977
5978
5979
5980
5981
5982
5983
5984
5985
5986
5987
5988
5989
5990
5991
5992
5993
5994
5995
5996
5997
5998
5999
6000
6001
6002
6003
6004
6005
6006
6007
6008
6009
6010
6011
6012
6013
6014
6015
6016
6017
6018
6019
6020
6021
6022
6023
6024
6025
6026
6027
6028
6029
6030
6031
6032
6033
6034
6035
6036
6037
6038
6039
6040
6041
6042
6043
6044
6045
6046
6047
6048
6049
6050
6051
6052
6053
6054
6055
6056
6057
6058
6059
6060
6061
6062
6063
6064
6065
6066
6067
6068
6069
6070
6071
6072
6073
6074
6075
6076
6077
6078
6079
6080
6081
6082
6083
6084
6085
6086
6087
6088
6089
6090
6091
6092
6093
6094
6095
6096
6097
6098
6099
6100
6101
6102
6103
6104
6105
6106
6107
6108
6109
6110
6111
6112
6113
6114
6115
6116
6117
6118
6119
6120
6121
6122
6123
6124
6125
6126
6127
6128
6129
6130
6131
6132
6133
6134
6135
6136
6137
6138
6139
6140
6141
6142
6143
6144
6145
6146
6147
6148
6149
6150
6151
6152
6153
6154
6155
6156
6157
6158
6159
6160
6161
6162
6163
6164
6165
6166
6167
6168
6169
6170
6171
6172
6173
6174
6175
6176
6177
6178
6179
6180
6181
6182
6183
6184
6185
6186
6187
6188
6189
6190
6191
6192
6193
6194
6195
6196
6197
6198
6199
6200
6201
6202
6203
6204
6205
6206
6207
6208
6209
6210
6211
6212
6213
6214
6215
6216
6217
6218
6219
6220
6221
6222
6223
6224
6225
6226
6227
6228
6229
6230
6231
6232
6233
6234
6235
6236
6237
6238
6239
6240
6241
6242
6243
6244
6245
6246
6247
6248
6249
6250
6251
6252
6253
6254
6255
6256
6257
6258
6259
6260
6261
6262
6263
6264
6265
6266
6267
6268
6269
6270
6271
6272
6273
6274
6275
6276
6277
6278
6279
6280
6281
6282
6283
6284
6285
6286
6287
6288
6289
6290
6291
6292
6293
6294
6295
6296
6297
6298
6299
6300
6301
6302
6303
6304
6305
6306
6307
6308
6309
6310
6311
6312
6313
6314
6315
6316
6317
6318
6319
6320
6321
6322
6323
6324
6325
6326
6327
6328
6329
6330
6331
6332
6333
6334
6335
6336
6337
6338
6339
6340
6341
6342
6343
6344
6345
6346
6347
6348
6349
6350
6351
6352
6353
6354
6355
6356
6357
6358
6359
6360
6361
6362
6363
6364
6365
6366
6367
6368
6369
6370
6371
6372
6373
6374
6375
6376
6377
6378
6379
6380
6381
6382
6383
6384
6385
6386
6387
6388
6389
6390
6391
6392
6393
6394
6395
6396
6397
6398
6399
6400
6401
6402
6403
6404
6405
6406
6407
6408
6409
6410
6411
6412
6413
6414
6415
6416
6417
6418
6419
6420
6421
6422
6423
6424
6425
6426
6427
6428
6429
6430
6431
6432
6433
6434
6435
6436
6437
6438
6439
6440
6441
6442
6443
6444
6445
6446
6447
6448
6449
6450
6451
6452
6453
6454
6455
6456
6457
6458
6459
6460
6461
6462
6463
6464
6465
6466
6467
6468
6469
6470
6471
6472
6473
6474
6475
6476
6477
6478
6479
6480
6481
6482
6483
6484
6485
6486
6487
6488
6489
6490
6491
6492
6493
6494
6495
6496
6497
6498
6499
6500
6501
6502
6503
6504
6505
6506
6507
6508
6509
6510
6511
6512
6513
6514
6515
6516
6517
6518
6519
6520
6521
6522
6523
6524
6525
6526
6527
6528
6529
6530
6531
6532
6533
6534
6535
6536
6537
6538
6539
6540
6541
6542
6543
6544
6545
6546
6547
6548
6549
6550
6551
6552
6553
6554
6555
6556
6557
6558
6559
6560
6561
6562
6563
6564
6565
6566
6567
6568
6569
6570
6571
6572
6573
6574
6575
6576
6577
6578
6579
6580
6581
6582
6583
6584
6585
6586
6587
6588
6589
6590
6591
6592
6593
6594
6595
6596
6597
6598
6599
6600
6601
6602
6603
6604
6605
6606
6607
6608
6609
6610
6611
6612
6613
6614
6615
6616
6617
6618
6619
6620
6621
6622
 
/* Updating of data structures for redisplay.

Copyright (C) 1985-1988, 1993-1995, 1997-2020 Free Software Foundation,
Inc.

This file is part of GNU Emacs.

GNU Emacs is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */

#include <config.h>

#include "sysstdio.h"
#include <stdlib.h>
#include <unistd.h>

#include "lisp.h"
#include "ptr-bounds.h"
#include "termchar.h"
/* cm.h must come after dispextern.h on Windows.  */
#include "dispextern.h"
#include "cm.h"
#include "buffer.h"
#include "keyboard.h"
#include "frame.h"
#include "termhooks.h"
#include "window.h"
#include "commands.h"
#include "disptab.h"
#include "blockinput.h"
#include "syssignal.h"
#include "systime.h"
#include "tparam.h"
#include "xwidget.h"
#include "pdumper.h"

#ifdef HAVE_WINDOW_SYSTEM
#include TERM_HEADER
#endif /* HAVE_WINDOW_SYSTEM */

#include <errno.h>

#include <fpending.h>

#ifdef WINDOWSNT
#include "w32.h"
#endif
\f
/* Structure to pass dimensions around.  Used for character bounding
   boxes, glyph matrix dimensions and alike.  */

struct dim
{
  int width;
  int height;
};

\f
/* Function prototypes.  */

static void update_frame_line (struct frame *, int, bool);
static int required_matrix_height (struct window *);
static int required_matrix_width (struct window *);
static void increment_row_positions (struct glyph_row *, ptrdiff_t, ptrdiff_t);
static void build_frame_matrix_from_window_tree (struct glyph_matrix *,
                                                 struct window *);
static void build_frame_matrix_from_leaf_window (struct glyph_matrix *,
                                                 struct window *);
static void adjust_decode_mode_spec_buffer (struct frame *);
static void fill_up_glyph_row_with_spaces (struct glyph_row *);
static void clear_window_matrices (struct window *, bool);
static void fill_up_glyph_row_area_with_spaces (struct glyph_row *, int);
static int scrolling_window (struct window *, int);
static bool update_window_line (struct window *, int, bool *);
static void mirror_make_current (struct window *, int);
#ifdef GLYPH_DEBUG
static void check_matrix_pointers (struct glyph_matrix *,
                                   struct glyph_matrix *);
#endif
static void mirror_line_dance (struct window *, int, int, int *, char *);
static bool update_window_tree (struct window *, bool);
static bool update_window (struct window *, bool);
static bool update_frame_1 (struct frame *, bool, bool, bool, bool);
static bool scrolling (struct frame *);
static void set_window_cursor_after_update (struct window *);
static void adjust_frame_glyphs_for_window_redisplay (struct frame *);
static void adjust_frame_glyphs_for_frame_redisplay (struct frame *);
static void set_window_update_flags (struct window *w, bool on_p);

/* True means last display completed.  False means it was preempted.  */

bool display_completed;

/* True means SIGWINCH happened when not safe.  */

static bool delayed_size_change;

/* A glyph for a space.  */

struct glyph space_glyph;

#if defined GLYPH_DEBUG && defined ENABLE_CHECKING

/* Counts of allocated structures.  These counts serve to diagnose
   memory leaks and double frees.  */

static int glyph_matrix_count;
static int glyph_pool_count;

#endif /* GLYPH_DEBUG and ENABLE_CHECKING */

/* If non-null, the frame whose frame matrices are manipulated.  If
   null, window matrices are worked on.  */

static struct frame *frame_matrix_frame;

/* Convert vpos and hpos from frame to window and vice versa.
   This may only be used for terminal frames.  */

#ifdef GLYPH_DEBUG

static int window_to_frame_vpos (struct window *, int);
static int window_to_frame_hpos (struct window *, int);
#define WINDOW_TO_FRAME_VPOS(W, VPOS) window_to_frame_vpos ((W), (VPOS))
#define WINDOW_TO_FRAME_HPOS(W, HPOS) window_to_frame_hpos ((W), (HPOS))

/* One element of the ring buffer containing redisplay history
   information.  */

struct redisplay_history
{
  char trace[512 + 100];
};

/* The size of the history buffer.  */

#define REDISPLAY_HISTORY_SIZE	30

/* The redisplay history buffer.  */

static struct redisplay_history redisplay_history[REDISPLAY_HISTORY_SIZE];

/* Next free entry in redisplay_history.  */

static int history_idx;

/* A tick that's incremented each time something is added to the
   history.  */

static uintmax_t history_tick;
\f
/* Add to the redisplay history how window W has been displayed.
   MSG is a trace containing the information how W's glyph matrix
   has been constructed.  PAUSED_P means that the update
   has been interrupted for pending input.  */

static void
add_window_display_history (struct window *w, const char *msg, bool paused_p)
{
  char *buf;
  void *ptr = w;

  if (history_idx >= REDISPLAY_HISTORY_SIZE)
    history_idx = 0;
  buf = redisplay_history[history_idx].trace;
  ++history_idx;

  snprintf (buf, sizeof redisplay_history[0].trace,
	    "%"PRIuMAX": window %p (%s)%s\n%s",
	    history_tick++,
	    ptr,
	    ((BUFFERP (w->contents)
	      && STRINGP (BVAR (XBUFFER (w->contents), name)))
	     ? SSDATA (BVAR (XBUFFER (w->contents), name))
	     : "???"),
	    paused_p ? " ***paused***" : "",
	    msg);
}


/* Add to the redisplay history that frame F has been displayed.
   PAUSED_P means that the update has been interrupted for
   pending input.  */

static void
add_frame_display_history (struct frame *f, bool paused_p)
{
  char *buf;
  void *ptr = f;

  if (history_idx >= REDISPLAY_HISTORY_SIZE)
    history_idx = 0;
  buf = redisplay_history[history_idx].trace;
  ++history_idx;

  sprintf (buf, "%"PRIuMAX": update frame %p%s",
	   history_tick++,
	   ptr, paused_p ? " ***paused***" : "");
}


DEFUN ("dump-redisplay-history", Fdump_redisplay_history,
       Sdump_redisplay_history, 0, 0, "",
       doc: /* Dump redisplay history to stderr.  */)
  (void)
{
  int i;

  for (i = history_idx - 1; i != history_idx; --i)
    {
      if (i < 0)
	i = REDISPLAY_HISTORY_SIZE - 1;
      fprintf (stderr, "%s\n", redisplay_history[i].trace);
    }

  return Qnil;
}


#else /* not GLYPH_DEBUG */

#define WINDOW_TO_FRAME_VPOS(W, VPOS) ((VPOS) + WINDOW_TOP_EDGE_LINE (W))
#define WINDOW_TO_FRAME_HPOS(W, HPOS) ((HPOS) + WINDOW_LEFT_EDGE_COL (W))

#endif /* GLYPH_DEBUG */


#if defined PROFILING && !HAVE___EXECUTABLE_START
/* This function comes first in the Emacs executable and is used only
   to estimate the text start for profiling.  */
void
__executable_start (void)
{
  emacs_abort ();
}
#endif
\f
/***********************************************************************
			    Glyph Matrices
 ***********************************************************************/

/* Allocate and return a glyph_matrix structure.  POOL is the glyph
   pool from which memory for the matrix should be allocated, or null
   for window-based redisplay where no glyph pools are used.  The
   member `pool' of the glyph matrix structure returned is set to
   POOL, the structure is otherwise zeroed.  */

static struct glyph_matrix *
new_glyph_matrix (struct glyph_pool *pool)
{
  struct glyph_matrix *result = xzalloc (sizeof *result);

#if defined GLYPH_DEBUG && defined ENABLE_CHECKING
  /* Increment number of allocated matrices.  This count is used
     to detect memory leaks.  */
  ++glyph_matrix_count;
#endif

  /* Set pool and return.  */
  result->pool = pool;
  return result;
}


/* Free glyph matrix MATRIX.  Passing in a null MATRIX is allowed.

   If GLYPH_DEBUG and ENABLE_CHECKING are in effect, the global counter
   glyph_matrix_count is decremented when a matrix is freed.  If the count
   gets negative, more structures were freed than allocated, i.e. one matrix
   was freed more than once or a bogus pointer was passed to this function.

   If MATRIX->pool is null, this means that the matrix manages its own
   glyph memory---this is done for matrices on X frames.  Freeing the
   matrix also frees the glyph memory in this case.  */

static void
free_glyph_matrix (struct glyph_matrix *matrix)
{
  if (matrix)
    {
      int i;

#if defined GLYPH_DEBUG && defined ENABLE_CHECKING
      /* Detect the case that more matrices are freed than were
	 allocated.  */
      --glyph_matrix_count;
      eassert (glyph_matrix_count >= 0);
#endif

      /* Free glyph memory if MATRIX owns it.  */
      if (matrix->pool == NULL)
	for (i = 0; i < matrix->rows_allocated; ++i)
	  xfree (matrix->rows[i].glyphs[LEFT_MARGIN_AREA]);

      /* Free row structures and the matrix itself.  */
      xfree (matrix->rows);
      xfree (matrix);
    }
}


/* Return the number of glyphs to reserve for a marginal area of
   window W.  TOTAL_GLYPHS is the number of glyphs in a complete
   display line of window W.  MARGIN gives the width of the marginal
   area in canonical character units.  */

static int
margin_glyphs_to_reserve (struct window *w, int total_glyphs, int margin)
{
  if (margin > 0)
    {
      int width = w->total_cols;
      double d = max (0, margin);
      d = min (width / 2 - 1, d);
      /* Since MARGIN is positive, we cannot possibly have less than
	 one glyph for the marginal area.  */
      return max (1, (int) ((double) total_glyphs / width * d));
    }
  return 0;
}

/* Return true if ROW's hash value is correct.
   Optimized away if ENABLE_CHECKING is not defined.  */

static bool
verify_row_hash (struct glyph_row *row)
{
  return row->hash == row_hash (row);
}

/* Adjust glyph matrix MATRIX on window W or on a frame to changed
   window sizes.

   W is null if the function is called for a frame glyph matrix.
   Otherwise it is the window MATRIX is a member of.  X and Y are the
   indices of the first column and row of MATRIX within the frame
   matrix, if such a matrix exists.  They are zero for purely
   window-based redisplay.  DIM is the needed size of the matrix.

   In window-based redisplay, where no frame matrices exist, glyph
   matrices manage their own glyph storage.  Otherwise, they allocate
   storage from a common frame glyph pool which can be found in
   MATRIX->pool.

   The reason for this memory management strategy is to avoid complete
   frame redraws if possible.  When we allocate from a common pool, a
   change of the location or size of a sub-matrix within the pool
   requires a complete redisplay of the frame because we cannot easily
   make sure that the current matrices of all windows still agree with
   what is displayed on the screen.  While this is usually fast, it
   leads to screen flickering.  */

static void
adjust_glyph_matrix (struct window *w, struct glyph_matrix *matrix, int x, int y, struct dim dim)
{
  int i;
  int new_rows;
  bool marginal_areas_changed_p = 0;
  bool tab_line_changed_p = 0;
  bool tab_line_p = 0;
  bool header_line_changed_p = 0;
  bool header_line_p = 0;
  int left = -1, right = -1;
  int window_width = -1, window_height = -1;

  /* See if W had a header line that has disappeared now, or vice versa.
     Get W's size.  */
  if (w)
    {
      window_box (w, ANY_AREA, 0, 0, &window_width, &window_height);

      tab_line_p = window_wants_tab_line (w);
      tab_line_changed_p = tab_line_p != matrix->tab_line_p;

      header_line_p = window_wants_header_line (w);
      header_line_changed_p = header_line_p != matrix->header_line_p;
    }
  matrix->tab_line_p = tab_line_p;
  matrix->header_line_p = header_line_p;

  /* If POOL is null, MATRIX is a window matrix for window-based redisplay.
     Do nothing if MATRIX' size, position, vscroll, and marginal areas
     haven't changed.  This optimization is important because preserving
     the matrix means preventing redisplay.  */
  eassume (w != NULL || matrix->pool != NULL);
  if (matrix->pool == NULL)
    {
      left = margin_glyphs_to_reserve (w, dim.width, w->left_margin_cols);
      right = margin_glyphs_to_reserve (w, dim.width, w->right_margin_cols);
      eassert (left >= 0 && right >= 0);
      marginal_areas_changed_p = (left != matrix->left_margin_glyphs
				  || right != matrix->right_margin_glyphs);

      if (!marginal_areas_changed_p
	  && !XFRAME (w->frame)->fonts_changed
	  && !tab_line_changed_p
	  && !header_line_changed_p
	  && matrix->window_pixel_left == WINDOW_LEFT_PIXEL_EDGE (w)
	  && matrix->window_pixel_top == WINDOW_TOP_PIXEL_EDGE (w)
	  && matrix->window_height == window_height
	  && matrix->window_vscroll == (w->vscroll + w->vpixoffset)
	  && matrix->window_width == window_width)
	return;
    }

  /* Enlarge MATRIX->rows if necessary.  New rows are cleared.  */
  if (matrix->rows_allocated < dim.height)
    {
      int old_alloc = matrix->rows_allocated;
      new_rows = dim.height - matrix->rows_allocated;
      matrix->rows = xpalloc (matrix->rows, &matrix->rows_allocated,
			      new_rows, INT_MAX, sizeof *matrix->rows);
      memset (matrix->rows + old_alloc, 0,
	      (matrix->rows_allocated - old_alloc) * sizeof *matrix->rows);
    }
  else
    new_rows = 0;

  /* If POOL is not null, MATRIX is a frame matrix or a window matrix
     on a frame not using window-based redisplay.  Set up pointers for
     each row into the glyph pool.  */
  if (matrix->pool)
    {
      eassert (matrix->pool->glyphs);

      if (w)
	{
	  left = margin_glyphs_to_reserve (w, dim.width,
					   w->left_margin_cols);
	  right = margin_glyphs_to_reserve (w, dim.width,
					    w->right_margin_cols);
	}
      else
	left = right = 0;

      for (i = 0; i < dim.height; ++i)
	{
	  struct glyph_row *row = &matrix->rows[i];

	  row->glyphs[LEFT_MARGIN_AREA]
	    = (matrix->pool->glyphs
	       + (y + i) * matrix->pool->ncolumns
	       + x);

	  if (w == NULL
	      || (row == matrix->rows + dim.height - 1
		  && window_wants_mode_line (w))
	      || (row == matrix->rows && matrix->tab_line_p)
	      || (row == matrix->rows
		  && !matrix->tab_line_p && matrix->header_line_p)
	      || (row == (matrix->rows + 1)
		  && matrix->tab_line_p && matrix->header_line_p))
	    {
	      row->glyphs[TEXT_AREA]
		= row->glyphs[LEFT_MARGIN_AREA];
	      row->glyphs[RIGHT_MARGIN_AREA]
		= row->glyphs[TEXT_AREA] + dim.width;
	      row->glyphs[LAST_AREA]
		= row->glyphs[RIGHT_MARGIN_AREA];
	    }
	  else
	    {
	      row->glyphs[TEXT_AREA]
		= row->glyphs[LEFT_MARGIN_AREA] + left;
	      row->glyphs[RIGHT_MARGIN_AREA]
		= row->glyphs[TEXT_AREA] + dim.width - left - right;
	      row->glyphs[LAST_AREA]
		= row->glyphs[LEFT_MARGIN_AREA] + dim.width;
	    }
	}

      matrix->left_margin_glyphs = left;
      matrix->right_margin_glyphs = right;
    }
  else
    {
      /* If MATRIX->pool is null, MATRIX is responsible for managing
	 its own memory.  It is a window matrix for window-based redisplay.
	 Allocate glyph memory from the heap.  */
      if (dim.width > matrix->matrix_w
	  || new_rows
	  || tab_line_changed_p
	  || header_line_changed_p
	  || marginal_areas_changed_p)
	{
	  struct glyph_row *row = matrix->rows;
	  struct glyph_row *end = row + matrix->rows_allocated;

	  while (row < end)
	    {
	      row->glyphs[LEFT_MARGIN_AREA]
		= xnrealloc (row->glyphs[LEFT_MARGIN_AREA],
			     dim.width, sizeof (struct glyph));

	      /* The mode line, if displayed, never has marginal areas.  */
	      if ((row == matrix->rows + dim.height - 1
		   && !(w && window_wants_mode_line (w)))
		  || (row == matrix->rows && matrix->tab_line_p)
		  || (row == matrix->rows
		      && !matrix->tab_line_p && matrix->header_line_p)
		  || (row == (matrix->rows + 1)
		      && matrix->tab_line_p && matrix->header_line_p))
		{
		  row->glyphs[TEXT_AREA]
		    = row->glyphs[LEFT_MARGIN_AREA];
		  row->glyphs[RIGHT_MARGIN_AREA]
		    = row->glyphs[TEXT_AREA] + dim.width;
		  row->glyphs[LAST_AREA]
		    = row->glyphs[RIGHT_MARGIN_AREA];
		}
	      else
		{
		  row->glyphs[TEXT_AREA]
		    = row->glyphs[LEFT_MARGIN_AREA] + left;
		  row->glyphs[RIGHT_MARGIN_AREA]
		    = row->glyphs[TEXT_AREA] + dim.width - left - right;
		  row->glyphs[LAST_AREA]
		    = row->glyphs[LEFT_MARGIN_AREA] + dim.width;
		}
	      ++row;
	    }
	}

      eassert (left >= 0 && right >= 0);
      matrix->left_margin_glyphs = left;
      matrix->right_margin_glyphs = right;

      /* If we are resizing a window, make sure the previous mode-line
	 row of the window's current matrix is no longer marked as such.  */
      if (w && matrix == w->current_matrix
	  && matrix->nrows > 0
	  && dim.height != matrix->nrows
	  && matrix->nrows <= matrix->rows_allocated)
	MATRIX_MODE_LINE_ROW (matrix)->mode_line_p = false;
    }

  /* Number of rows to be used by MATRIX.  */
  matrix->nrows = dim.height;
  eassert (matrix->nrows >= 0);

  if (w)
    {
      if (matrix == w->current_matrix)
	{
	  /* Mark rows in a current matrix of a window as not having
	     valid contents.  It's important to not do this for
	     desired matrices.  When Emacs starts, it may already be
	     building desired matrices when this function runs.  */
	  if (window_width < 0)
	    window_width = window_box_width (w, -1);

	  /* Optimize the case that only the height has changed (C-x 2,
	     upper window).  Invalidate all rows that are no longer part
	     of the window.  */
	  if (!marginal_areas_changed_p
	      && !tab_line_changed_p
	      && !header_line_changed_p
	      && new_rows == 0
	      && dim.width == matrix->matrix_w
	      && matrix->window_pixel_left == WINDOW_LEFT_PIXEL_EDGE (w)
	      && matrix->window_pixel_top == WINDOW_TOP_PIXEL_EDGE (w)
	      && matrix->window_width == window_width)
	    {
	      /* Find the last row in the window.  */
	      for (i = 0; i < matrix->nrows && matrix->rows[i].enabled_p; ++i)
		if (MATRIX_ROW_BOTTOM_Y (matrix->rows + i) >= window_height)
		  {
		    ++i;
		    break;
		  }

	      /* Window end is invalid, if inside of the rows that
		 are invalidated below.  */
	      if (w->window_end_vpos >= i)
		w->window_end_valid = 0;

	      while (i < matrix->nrows)
		matrix->rows[i++].enabled_p = false;
	    }
	  else
	    {
	      for (i = 0; i < matrix->nrows; ++i)
		matrix->rows[i].enabled_p = false;
	    }
	  /* We've disabled the mode-line row, so force redrawing of
	     the mode line, if any, since otherwise it will remain
	     disabled in the current matrix, and expose events won't
	     redraw it.  */
	  if (window_wants_mode_line (w))
	    w->update_mode_line = 1;
	}
      else if (matrix == w->desired_matrix)
	{
	  /* Rows in desired matrices always have to be cleared;
	     redisplay expects this is the case when it runs, so it
	     had better be the case when we adjust matrices between
	     redisplays.  */
	  for (i = 0; i < matrix->nrows; ++i)
	    matrix->rows[i].enabled_p = false;
	}
    }


  /* Remember last values to be able to optimize frame redraws.  */
  matrix->matrix_x = x;
  matrix->matrix_y = y;
  matrix->matrix_w = dim.width;
  matrix->matrix_h = dim.height;

  /* Record the top y location and height of W at the time the matrix
     was last adjusted.  This is used to optimize redisplay above.  */
  if (w)
    {
      matrix->window_pixel_left = WINDOW_LEFT_PIXEL_EDGE (w);
      matrix->window_pixel_top = WINDOW_TOP_PIXEL_EDGE (w);
      matrix->window_height = window_height;
      matrix->window_width = window_width;
      matrix->window_vscroll = w->vscroll + w->vpixoffset;
    }
}


/* Reverse the contents of rows in MATRIX between START and END.  The
   contents of the row at END - 1 end up at START, END - 2 at START +
   1 etc.  This is part of the implementation of rotate_matrix (see
   below).  */

static void
reverse_rows (struct glyph_matrix *matrix, int start, int end)
{
  int i, j;

  for (i = start, j = end - 1; i < j; ++i, --j)
    {
      /* Non-ISO HP/UX compiler doesn't like auto struct
	 initialization.  */
      struct glyph_row temp;
      temp = matrix->rows[i];
      matrix->rows[i] = matrix->rows[j];
      matrix->rows[j] = temp;
    }
}


/* Rotate the contents of rows in MATRIX in the range FIRST .. LAST -
   1 by BY positions.  BY < 0 means rotate left, i.e. towards lower
   indices.  (Note: this does not copy glyphs, only glyph pointers in
   row structures are moved around).

   The algorithm used for rotating the vector was, I believe, first
   described by Kernighan.  See the vector R as consisting of two
   sub-vectors AB, where A has length BY for BY >= 0.  The result
   after rotating is then BA.  Reverse both sub-vectors to get ArBr
   and reverse the result to get (ArBr)r which is BA.  Similar for
   rotating right.  */

void
rotate_matrix (struct glyph_matrix *matrix, int first, int last, int by)
{
  if (by < 0)
    {
      /* Up (rotate left, i.e. towards lower indices).  */
      by = -by;
      reverse_rows (matrix, first, first + by);
      reverse_rows (matrix, first + by, last);
      reverse_rows (matrix, first, last);
    }
  else if (by > 0)
    {
      /* Down (rotate right, i.e. towards higher indices).  */
      reverse_rows (matrix, last - by, last);
      reverse_rows (matrix, first, last - by);
      reverse_rows (matrix, first, last);
    }
}


/* Increment buffer positions in glyph rows of MATRIX.  Do it for rows
   with indices START <= index < END.  Increment positions by DELTA/
   DELTA_BYTES.  */

void
increment_matrix_positions (struct glyph_matrix *matrix, int start, int end,
			    ptrdiff_t delta, ptrdiff_t delta_bytes)
{
  /* Check that START and END are reasonable values.  */
  eassert (start >= 0 && start <= matrix->nrows);
  eassert (end >= 0 && end <= matrix->nrows);
  eassert (start <= end);

  for (; start < end; ++start)
    increment_row_positions (matrix->rows + start, delta, delta_bytes);
}


/* Clear the enable_p flags in a range of rows in glyph matrix MATRIX.
   START and END are the row indices of the first and last + 1 row to clear.  */

void
clear_glyph_matrix_rows (struct glyph_matrix *matrix, int start, int end)
{
  eassert (start <= end);
  eassert (start >= 0 && (start < matrix->nrows
			  /* matrix->nrows can be 0 for the initial frame.  */
			  || (matrix->nrows == 0)));
  eassert (end >= 0 && end <= matrix->nrows);

  for (; start < end; ++start)
    matrix->rows[start].enabled_p = false;
}


/* Clear MATRIX.

   Empty all rows in MATRIX by clearing their enabled_p flags.
   The function prepare_desired_row will eventually really clear a row
   when it sees one with a false enabled_p flag.

   Reset update hints to default values.  The only update hint
   currently present is the flag MATRIX->no_scrolling_p.  */

void
clear_glyph_matrix (struct glyph_matrix *matrix)
{
  if (matrix)
    {
      clear_glyph_matrix_rows (matrix, 0, matrix->nrows);
      matrix->no_scrolling_p = 0;
    }
}


/* Shift part of the glyph matrix MATRIX of window W up or down.
   Increment y-positions in glyph rows between START and END by DY,
   and recompute their visible height.  */

void
shift_glyph_matrix (struct window *w, struct glyph_matrix *matrix, int start, int end, int dy)
{
  int min_y, max_y;

  eassert (start <= end);
  eassert (start >= 0 && start < matrix->nrows);
  eassert (end >= 0 && end <= matrix->nrows);

  min_y = WINDOW_TAB_LINE_HEIGHT (w) + WINDOW_HEADER_LINE_HEIGHT (w);
  max_y = WINDOW_BOX_HEIGHT_NO_MODE_LINE (w);

  for (; start < end; ++start)
    {
      struct glyph_row *row = &matrix->rows[start];

      row->y += dy;
      row->visible_height = row->height;

      if (row->y < min_y)
	row->visible_height -= min_y - row->y;
      if (row->y + row->height > max_y)
	row->visible_height -= row->y + row->height - max_y;
      if (row->fringe_bitmap_periodic_p)
	row->redraw_fringe_bitmaps_p = 1;
    }
}


/* Mark all rows in current matrices of frame F as invalid.  Marking
   invalid is done by setting enabled_p to zero for all rows in a
   current matrix.  */

void
clear_current_matrices (register struct frame *f)
{
  /* Clear frame current matrix, if we have one.  */
  if (f->current_matrix)
    clear_glyph_matrix (f->current_matrix);

#if defined (HAVE_X_WINDOWS) && ! defined (USE_X_TOOLKIT) && ! defined (USE_GTK)
  /* Clear the matrix of the menu bar window, if such a window exists.
     The menu bar window is currently used to display menus on X when
     no toolkit support is compiled in.  */
  if (WINDOWP (f->menu_bar_window))
    clear_glyph_matrix (XWINDOW (f->menu_bar_window)->current_matrix);
#endif

#if defined (HAVE_WINDOW_SYSTEM)
  /* Clear the matrix of the tab-bar window, if any.  */
  if (WINDOWP (f->tab_bar_window))
    clear_glyph_matrix (XWINDOW (f->tab_bar_window)->current_matrix);
#endif

#if defined (HAVE_WINDOW_SYSTEM) && ! defined (HAVE_EXT_TOOL_BAR)
  /* Clear the matrix of the tool-bar window, if any.  */
  if (WINDOWP (f->tool_bar_window))
    clear_glyph_matrix (XWINDOW (f->tool_bar_window)->current_matrix);
#endif

  /* Clear current window matrices.  */
  eassert (WINDOWP (FRAME_ROOT_WINDOW (f)));
  clear_window_matrices (XWINDOW (FRAME_ROOT_WINDOW (f)), 0);
}


/* Clear out all display lines of F for a coming redisplay.  */

void
clear_desired_matrices (register struct frame *f)
{
  if (f->desired_matrix)
    clear_glyph_matrix (f->desired_matrix);

#if defined (HAVE_X_WINDOWS) && ! defined (USE_X_TOOLKIT) && ! defined (USE_GTK)
  if (WINDOWP (f->menu_bar_window))
    clear_glyph_matrix (XWINDOW (f->menu_bar_window)->desired_matrix);
#endif

#if defined (HAVE_WINDOW_SYSTEM)
  if (WINDOWP (f->tab_bar_window))
    clear_glyph_matrix (XWINDOW (f->tab_bar_window)->desired_matrix);
#endif

#if defined (HAVE_WINDOW_SYSTEM) && ! defined (HAVE_EXT_TOOL_BAR)
  if (WINDOWP (f->tool_bar_window))
    clear_glyph_matrix (XWINDOW (f->tool_bar_window)->desired_matrix);
#endif

  /* Do it for window matrices.  */
  eassert (WINDOWP (FRAME_ROOT_WINDOW (f)));
  clear_window_matrices (XWINDOW (FRAME_ROOT_WINDOW (f)), 1);
}


/* Clear matrices in window tree rooted in W.  If DESIRED_P,
   clear desired matrices, otherwise clear current matrices.  */

static void
clear_window_matrices (struct window *w, bool desired_p)
{
  while (w)
    {
      if (WINDOWP (w->contents))
	clear_window_matrices (XWINDOW (w->contents), desired_p);
      else
	{
	  if (desired_p)
	    clear_glyph_matrix (w->desired_matrix);
	  else
	    {
	      clear_glyph_matrix (w->current_matrix);
	      w->window_end_valid = 0;
	    }
	}

      w = NILP (w->next) ? 0 : XWINDOW (w->next);
    }
}


\f
/***********************************************************************
			      Glyph Rows

      See dispextern.h for an overall explanation of glyph rows.
 ***********************************************************************/

/* Clear glyph row ROW.  NOTE: this code relies on the current
   layout of `glyphs' and `used' fields of `struct glyph_row'.  */

void
clear_glyph_row (struct glyph_row *row)
{
  enum { off = offsetof (struct glyph_row, used) };

  /* Zero everything except pointers in `glyphs'.  */
  memset (row->used, 0, sizeof *row - off);
}


/* Make ROW an empty, enabled row of canonical character height,
   in window W starting at y-position Y.  */

void
blank_row (struct window *w, struct glyph_row *row, int y)
{
  int min_y, max_y;

  min_y = WINDOW_TAB_LINE_HEIGHT (w) + WINDOW_HEADER_LINE_HEIGHT (w);
  max_y = WINDOW_BOX_HEIGHT_NO_MODE_LINE (w);

  clear_glyph_row (row);
  row->y = y;
  row->ascent = row->phys_ascent = 0;
  row->height = row->phys_height = FRAME_LINE_HEIGHT (XFRAME (w->frame));
  row->visible_height = row->height;

  if (row->y < min_y)
    row->visible_height -= min_y - row->y;
  if (row->y + row->height > max_y)
    row->visible_height -= row->y + row->height - max_y;

  row->enabled_p = true;
}


/* Increment buffer positions in glyph row ROW.  DELTA and DELTA_BYTES
   are the amounts by which to change positions.  Note that the first
   glyph of the text area of a row can have a buffer position even if
   the used count of the text area is zero.  Such rows display line
   ends.  */

static void
increment_row_positions (struct glyph_row *row,
			 ptrdiff_t delta, ptrdiff_t delta_bytes)
{
  int area, i;

  /* Increment start and end positions.  */
  MATRIX_ROW_START_CHARPOS (row) += delta;
  MATRIX_ROW_START_BYTEPOS (row) += delta_bytes;
  MATRIX_ROW_END_CHARPOS (row) += delta;
  MATRIX_ROW_END_BYTEPOS (row) += delta_bytes;
  CHARPOS (row->start.pos) += delta;
  BYTEPOS (row->start.pos) += delta_bytes;
  CHARPOS (row->end.pos) += delta;
  BYTEPOS (row->end.pos) += delta_bytes;

  if (!row->enabled_p)
    return;

  /* Increment positions in glyphs.  */
  for (area = 0; area < LAST_AREA; ++area)
    for (i = 0; i < row->used[area]; ++i)
      if (BUFFERP (row->glyphs[area][i].object)
	  && row->glyphs[area][i].charpos > 0)
	row->glyphs[area][i].charpos += delta;

  /* Capture the case of rows displaying a line end.  */
  if (row->used[TEXT_AREA] == 0
      && MATRIX_ROW_DISPLAYS_TEXT_P (row))
    row->glyphs[TEXT_AREA]->charpos += delta;
}


#if 0
/* Swap glyphs between two glyph rows A and B.  This exchanges glyph
   contents, i.e. glyph structure contents are exchanged between A and
   B without changing glyph pointers in A and B.  */

static void
swap_glyphs_in_rows (struct glyph_row *a, struct glyph_row *b)
{
  int area;

  for (area = 0; area < LAST_AREA; ++area)
    {
      /* Number of glyphs to swap.  */
      int max_used = max (a->used[area], b->used[area]);

      /* Start of glyphs in area of row A.  */
      struct glyph *glyph_a = a->glyphs[area];

      /* End + 1 of glyphs in area of row A.  */
      struct glyph *glyph_a_end = a->glyphs[max_used];

      /* Start of glyphs in area of row B.  */
      struct glyph *glyph_b = b->glyphs[area];

      while (glyph_a < glyph_a_end)
	{
	  /* Non-ISO HP/UX compiler doesn't like auto struct
             initialization.  */
	  struct glyph temp;
	  temp = *glyph_a;
	  *glyph_a = *glyph_b;
	  *glyph_b = temp;
	  ++glyph_a;
	  ++glyph_b;
	}
    }
}

#endif /* 0 */

/* Exchange pointers to glyph memory between glyph rows A and B.  Also
   exchange the used[] array and the hash values of the rows, because
   these should all go together for the row's hash value to be
   correct.  */

static void
swap_glyph_pointers (struct glyph_row *a, struct glyph_row *b)
{
  int i;
  unsigned hash_tem = a->hash;

  for (i = 0; i < LAST_AREA + 1; ++i)
    {
      struct glyph *temp = a->glyphs[i];

      a->glyphs[i] = b->glyphs[i];
      b->glyphs[i] = temp;
      if (i < LAST_AREA)
	{
	  short used_tem = a->used[i];

	  a->used[i] = b->used[i];
	  b->used[i] = used_tem;
	}
    }
  a->hash = b->hash;
  b->hash = hash_tem;
}


/* Copy glyph row structure FROM to glyph row structure TO, except that
   glyph pointers, the `used' counts, and the hash values in the structures
   are left unchanged.  NOTE: this code relies on the current layout of
   `glyphs', `used', `hash' and `x' fields of `struct glyph_row'.  */

static void
copy_row_except_pointers (struct glyph_row *to, struct glyph_row *from)
{
  enum { off = offsetof (struct glyph_row, x) };

  memcpy (&to->x, &from->x, sizeof *to - off);
}


/* Assign glyph row FROM to glyph row TO.  This works like a structure
   assignment TO = FROM, except that glyph pointers are not copied but
   exchanged between TO and FROM.  Pointers must be exchanged to avoid
   a memory leak.  */

static void
assign_row (struct glyph_row *to, struct glyph_row *from)
{
  swap_glyph_pointers (to, from);
  copy_row_except_pointers (to, from);
}


/* Test whether the glyph memory of the glyph row WINDOW_ROW, which is
   a row in a window matrix, is a slice of the glyph memory of the
   glyph row FRAME_ROW which is a row in a frame glyph matrix.  Value
   is true if the glyph memory of WINDOW_ROW is part of the glyph
   memory of FRAME_ROW.  */

#ifdef GLYPH_DEBUG

static bool
glyph_row_slice_p (struct glyph_row *window_row, struct glyph_row *frame_row)
{
  struct glyph *window_glyph_start = window_row->glyphs[0];
  struct glyph *frame_glyph_start = frame_row->glyphs[0];
  struct glyph *frame_glyph_end = frame_row->glyphs[LAST_AREA];

  return (frame_glyph_start <= window_glyph_start
	  && window_glyph_start < frame_glyph_end);
}

#endif /* GLYPH_DEBUG */

#if 0

/* Find the row in the window glyph matrix WINDOW_MATRIX being a slice
   of ROW in the frame matrix FRAME_MATRIX.  Value is null if no row
   in WINDOW_MATRIX is found satisfying the condition.  */

static struct glyph_row *
find_glyph_row_slice (struct glyph_matrix *window_matrix,
		      struct glyph_matrix *frame_matrix, int row)
{
  int i;

  eassert (row >= 0 && row < frame_matrix->nrows);

  for (i = 0; i < window_matrix->nrows; ++i)
    if (glyph_row_slice_p (window_matrix->rows + i,
			   frame_matrix->rows + row))
      break;

  return i < window_matrix->nrows ? window_matrix->rows + i : 0;
}

#endif /* 0 */

/* Prepare ROW for display in windows W.  Desired rows are cleared
   lazily, i.e. they are only marked as to be cleared by setting their
   enabled_p flag to zero.  When a row is to be displayed, a prior
   call to this function really clears it.  In addition, this function
   makes sure the marginal areas of ROW are in sync with the window's
   display margins.  MODE_LINE_P non-zero means we are preparing a
   glyph row for tab/header line or mode line.  */

void
prepare_desired_row (struct window *w, struct glyph_row *row, bool mode_line_p)
{
  if (!row->enabled_p)
    {
      bool rp = row->reversed_p;

      clear_glyph_row (row);
      row->enabled_p = true;
      row->reversed_p = rp;
    }
  if (mode_line_p)
    {
      /* Mode and header/tab lines, if displayed, never have marginal
	 areas.  If we are called with MODE_LINE_P non-zero, we are
	 displaying the mode/header/tab line in this window, and so the
	 marginal areas of this glyph row should be eliminated.  This
	 is needed when the mode/header/tab line is switched on in a
	 window that has display margins.  */
      if (w->left_margin_cols > 0)
	row->glyphs[TEXT_AREA] = row->glyphs[LEFT_MARGIN_AREA];
      if (w->right_margin_cols > 0)
	row->glyphs[RIGHT_MARGIN_AREA] = row->glyphs[LAST_AREA];
    }
  else
    {
      /* The real number of glyphs reserved for the margins is
	 recorded in the glyph matrix, and can be different from
	 window's left_margin_cols and right_margin_cols; see
	 margin_glyphs_to_reserve for when that happens.  */
      int left = w->desired_matrix->left_margin_glyphs;
      int right = w->desired_matrix->right_margin_glyphs;

      /* Make sure the marginal areas of this row are in sync with
	 what the window wants, when the row actually displays text
	 and not tab/header/mode line.  */
      if (w->left_margin_cols > 0
	  && (left != row->glyphs[TEXT_AREA] - row->glyphs[LEFT_MARGIN_AREA]))
	row->glyphs[TEXT_AREA] = row->glyphs[LEFT_MARGIN_AREA] + left;
      if (w->right_margin_cols > 0
	  && (right != row->glyphs[LAST_AREA] - row->glyphs[RIGHT_MARGIN_AREA]))
	row->glyphs[RIGHT_MARGIN_AREA] = row->glyphs[LAST_AREA] - right;
    }
}


/* Return a hash code for glyph row ROW, which may
   be from current or desired matrix of frame F.  */

static unsigned
line_hash_code (struct frame *f, struct glyph_row *row)
{
  unsigned hash = 0;

  if (row->enabled_p)
    {
      struct glyph *glyph = row->glyphs[TEXT_AREA];
      struct glyph *end = glyph + row->used[TEXT_AREA];

      while (glyph < end)
	{
	  int c = glyph->u.ch;
	  int face_id = glyph->face_id;
	  if (FRAME_MUST_WRITE_SPACES (f))
	    c -= SPACEGLYPH;
	  hash = (((hash << 4) + (hash >> 24)) & 0x0fffffff) + c;
	  hash = (((hash << 4) + (hash >> 24)) & 0x0fffffff) + face_id;
	  ++glyph;
	}

      if (hash == 0)
	hash = 1;
    }

  return hash;
}


/* Return the cost of drawing line VPOS in MATRIX, which may
   be current or desired matrix of frame F.  The cost equals
   the number of characters in the line.  If must_write_spaces
   is zero, leading and trailing spaces are ignored.  */

static int
line_draw_cost (struct frame *f, struct glyph_matrix *matrix, int vpos)
{
  struct glyph_row *row = matrix->rows + vpos;
  struct glyph *beg = row->glyphs[TEXT_AREA];
  struct glyph *end = beg + row->used[TEXT_AREA];
  int len;
  Lisp_Object *glyph_table_base = GLYPH_TABLE_BASE;
  ptrdiff_t glyph_table_len = GLYPH_TABLE_LENGTH;

  /* Ignore trailing and leading spaces if we can.  */
  if (!FRAME_MUST_WRITE_SPACES (f))
    {
      /* Skip from the end over trailing spaces.  */
      while (end > beg && CHAR_GLYPH_SPACE_P (*(end - 1)))
	--end;

      /* All blank line.  */
      if (end == beg)
	return 0;

      /* Skip over leading spaces.  */
      while (CHAR_GLYPH_SPACE_P (*beg))
	++beg;
    }

  /* If we don't have a glyph-table, each glyph is one character,
     so return the number of glyphs.  */
  if (glyph_table_base == 0)
    len = end - beg;
  else
    {
      /* Otherwise, scan the glyphs and accumulate their total length
	 in LEN.  */
      len = 0;
      while (beg < end)
	{
	  GLYPH g;

	  SET_GLYPH_FROM_CHAR_GLYPH (g, *beg);

	  if (GLYPH_INVALID_P (g)
	      || GLYPH_SIMPLE_P (glyph_table_base, glyph_table_len, g))
	    len += 1;
	  else
	    len += GLYPH_LENGTH (glyph_table_base, g);

	  ++beg;
	}
    }

  return len;
}


/* Return true if the glyph rows A and B have equal contents.
   MOUSE_FACE_P means compare the mouse_face_p flags of A and B, too.  */

static bool
row_equal_p (struct glyph_row *a, struct glyph_row *b, bool mouse_face_p)
{
  eassert (verify_row_hash (a));
  eassert (verify_row_hash (b));

  if (a == b)
    return 1;
  else if (a->hash != b->hash)
    return 0;
  else
    {
      struct glyph *a_glyph, *b_glyph, *a_end;
      int area;

      if (mouse_face_p && a->mouse_face_p != b->mouse_face_p)
	return 0;

      /* Compare glyphs.  */
      for (area = LEFT_MARGIN_AREA; area < LAST_AREA; ++area)
	{
	  if (a->used[area] != b->used[area])
	    return 0;

	  a_glyph = a->glyphs[area];
	  a_end = a_glyph + a->used[area];
	  b_glyph = b->glyphs[area];

	  while (a_glyph < a_end
		 && GLYPH_EQUAL_P (a_glyph, b_glyph))
	    ++a_glyph, ++b_glyph;

	  if (a_glyph != a_end)
	    return 0;
	}

      if (a->fill_line_p != b->fill_line_p
	  || a->cursor_in_fringe_p != b->cursor_in_fringe_p
	  || a->left_fringe_bitmap != b->left_fringe_bitmap
	  || a->left_fringe_face_id != b->left_fringe_face_id
	  || a->left_fringe_offset != b->left_fringe_offset
	  || a->right_fringe_bitmap != b->right_fringe_bitmap
	  || a->right_fringe_face_id != b->right_fringe_face_id
	  || a->right_fringe_offset != b->right_fringe_offset
	  || a->fringe_bitmap_periodic_p != b->fringe_bitmap_periodic_p
	  || a->overlay_arrow_bitmap != b->overlay_arrow_bitmap
	  || a->exact_window_width_line_p != b->exact_window_width_line_p
	  || a->overlapped_p != b->overlapped_p
	  || (MATRIX_ROW_CONTINUATION_LINE_P (a)
	      != MATRIX_ROW_CONTINUATION_LINE_P (b))
	  || a->reversed_p != b->reversed_p
	  /* Different partially visible characters on left margin.  */
	  || a->x != b->x
	  /* Different height.  */
	  || a->ascent != b->ascent
	  || a->phys_ascent != b->phys_ascent
	  || a->phys_height != b->phys_height
	  || a->visible_height != b->visible_height)
	return 0;
    }

  return 1;
}


\f
/***********************************************************************
			      Glyph Pool

     See dispextern.h for an overall explanation of glyph pools.
 ***********************************************************************/

/* Allocate a glyph_pool structure.  The structure returned is initialized
   with zeros.  If GLYPH_DEBUG and ENABLE_CHECKING are in effect, the global
   variable glyph_pool_count is incremented for each pool allocated.  */

static struct glyph_pool * ATTRIBUTE_MALLOC
new_glyph_pool (void)
{
  struct glyph_pool *result = xzalloc (sizeof *result);

#if defined GLYPH_DEBUG && defined ENABLE_CHECKING
  /* For memory leak and double deletion checking.  */
  ++glyph_pool_count;
#endif

  return result;
}


/* Free a glyph_pool structure POOL.  The function may be called with
   a null POOL pointer.  If GLYPH_DEBUG and ENABLE_CHECKING are in effect,
   global variable glyph_pool_count is decremented with every pool structure
   freed.  If this count gets negative, more structures were freed than
   allocated, i.e. one structure must have been freed more than once or
   a bogus pointer was passed to free_glyph_pool.  */

static void
free_glyph_pool (struct glyph_pool *pool)
{
  if (pool)
    {
#if defined GLYPH_DEBUG && defined ENABLE_CHECKING
      /* More freed than allocated?  */
      --glyph_pool_count;
      eassert (glyph_pool_count >= 0);
#endif
      xfree (pool->glyphs);
      xfree (pool);
    }
}


/* Enlarge a glyph pool POOL.  MATRIX_DIM gives the number of rows and
   columns we need.  This function never shrinks a pool.  The only
   case in which this would make sense, would be when a frame's size
   is changed from a large value to a smaller one.  But, if someone
   does it once, we can expect that he will do it again.

   Return true if the pool changed in a way which makes
   re-adjusting window glyph matrices necessary.  */

static bool
realloc_glyph_pool (struct glyph_pool *pool, struct dim matrix_dim)
{
  ptrdiff_t needed;
  bool changed_p;

  changed_p = (pool->glyphs == 0
	       || matrix_dim.height != pool->nrows
	       || matrix_dim.width != pool->ncolumns);

  /* Enlarge the glyph pool.  */
  if (INT_MULTIPLY_WRAPV (matrix_dim.height, matrix_dim.width, &needed))
    memory_full (SIZE_MAX);
  if (needed > pool->nglyphs)
    {
      ptrdiff_t old_nglyphs = pool->nglyphs;
      pool->glyphs = xpalloc (pool->glyphs, &pool->nglyphs,
			      needed - old_nglyphs, -1, sizeof *pool->glyphs);
      memclear (pool->glyphs + old_nglyphs,
		(pool->nglyphs - old_nglyphs) * sizeof *pool->glyphs);
    }

  /* Remember the number of rows and columns because (a) we use them
     to do sanity checks, and (b) the number of columns determines
     where rows in the frame matrix start---this must be available to
     determine pointers to rows of window sub-matrices.  */
  pool->nrows = matrix_dim.height;
  pool->ncolumns = matrix_dim.width;

  return changed_p;
}


\f
/***********************************************************************
			      Debug Code
 ***********************************************************************/

#ifdef GLYPH_DEBUG


/* Flush standard output.  This is sometimes useful to call from the debugger.
   XXX Maybe this should be changed to flush the current terminal instead of
   stdout.
*/

void flush_stdout (void) EXTERNALLY_VISIBLE;

void
flush_stdout (void)
{
  fflush (stdout);
}


/* Check that no glyph pointers have been lost in MATRIX.  If a
   pointer has been lost, e.g. by using a structure assignment between
   rows, at least one pointer must occur more than once in the rows of
   MATRIX.  */

void
check_matrix_pointer_lossage (struct glyph_matrix *matrix)
{
  int i, j;

  for (i = 0; i < matrix->nrows; ++i)
    for (j = 0; j < matrix->nrows; ++j)
      eassert (i == j
	       || (matrix->rows[i].glyphs[TEXT_AREA]
		   != matrix->rows[j].glyphs[TEXT_AREA]));
}


/* Get a pointer to glyph row ROW in MATRIX, with bounds checks.  */

struct glyph_row *
matrix_row (struct glyph_matrix *matrix, int row)
{
  eassert (matrix && matrix->rows);
  eassert (row >= 0 && row < matrix->nrows);

  /* That's really too slow for normal testing because this function
     is called almost everywhere.  Although---it's still astonishingly
     fast, so it is valuable to have for debugging purposes.  */
#if 0
  check_matrix_pointer_lossage (matrix);
#endif

  return matrix->rows + row;
}


#if 0 /* This function makes invalid assumptions when text is
	 partially invisible.  But it might come handy for debugging
	 nevertheless.  */

/* Check invariants that must hold for an up to date current matrix of
   window W.  */

static void
check_matrix_invariants (struct window *w)
{
  struct glyph_matrix *matrix = w->current_matrix;
  int yb = window_text_bottom_y (w);
  struct glyph_row *row = matrix->rows;
  struct glyph_row *last_text_row = NULL;
  struct buffer *saved = current_buffer;
  struct buffer *buffer = XBUFFER (w->contents);
  int c;

  /* This can sometimes happen for a fresh window.  */
  if (matrix->nrows < 2)
    return;

  set_buffer_temp (buffer);

  /* Note: last row is always reserved for the mode line.  */
  while (MATRIX_ROW_DISPLAYS_TEXT_P (row)
	 && MATRIX_ROW_BOTTOM_Y (row) < yb)
    {
      struct glyph_row *next = row + 1;

      if (MATRIX_ROW_DISPLAYS_TEXT_P (row))
	last_text_row = row;

      /* Check that character and byte positions are in sync.  */
      eassert (MATRIX_ROW_START_BYTEPOS (row)
	       == CHAR_TO_BYTE (MATRIX_ROW_START_CHARPOS (row)));
      eassert (BYTEPOS (row->start.pos)
	       == CHAR_TO_BYTE (CHARPOS (row->start.pos)));

      /* CHAR_TO_BYTE aborts when invoked for a position > Z.  We can
	 have such a position temporarily in case of a minibuffer
	 displaying something like `[Sole completion]' at its end.  */
      if (MATRIX_ROW_END_CHARPOS (row) < BUF_ZV (current_buffer))
	{
	  eassert (MATRIX_ROW_END_BYTEPOS (row)
		   == CHAR_TO_BYTE (MATRIX_ROW_END_CHARPOS (row)));
	  eassert (BYTEPOS (row->end.pos)
		   == CHAR_TO_BYTE (CHARPOS (row->end.pos)));
	}

      /* Check that end position of `row' is equal to start position
	 of next row.  */
      if (next->enabled_p && MATRIX_ROW_DISPLAYS_TEXT_P (next))
	{
	  eassert (MATRIX_ROW_END_CHARPOS (row)
		   == MATRIX_ROW_START_CHARPOS (next));
	  eassert (MATRIX_ROW_END_BYTEPOS (row)
		   == MATRIX_ROW_START_BYTEPOS (next));
	  eassert (CHARPOS (row->end.pos) == CHARPOS (next->start.pos));
	  eassert (BYTEPOS (row->end.pos) == BYTEPOS (next->start.pos));
	}
      row = next;
    }

  eassert (w->current_matrix->nrows == w->desired_matrix->nrows);
  eassert (w->desired_matrix->rows != NULL);
  set_buffer_temp (saved);
}

#endif /* 0  */

#endif /* GLYPH_DEBUG */


\f
/**********************************************************************
		 Allocating/ Adjusting Glyph Matrices
 **********************************************************************/

/* Allocate glyph matrices over a window tree for a frame-based
   redisplay

   X and Y are column/row within the frame glyph matrix where
   sub-matrices for the window tree rooted at WINDOW must be
   allocated.  DIM_ONLY_P means that the caller of this
   function is only interested in the result matrix dimension, and
   matrix adjustments should not be performed.

   The function returns the total width/height of the sub-matrices of
   the window tree.  If called on a frame root window, the computation
   will take the mini-buffer window into account.

   *WINDOW_CHANGE_FLAGS is set to a bit mask with bits

   NEW_LEAF_MATRIX set if any window in the tree did not have a
   glyph matrices yet, and

   CHANGED_LEAF_MATRIX set if the dimension or location of a matrix of
   any window in the tree will be changed or have been changed (see
   DIM_ONLY_P)

   *WINDOW_CHANGE_FLAGS must be initialized by the caller of this
   function.

   Windows are arranged into chains of windows on the same level
   through the next fields of window structures.  Such a level can be
   either a sequence of horizontally adjacent windows from left to
   right, or a sequence of vertically adjacent windows from top to
   bottom.  Each window in a horizontal sequence can be either a leaf
   window or a vertical sequence; a window in a vertical sequence can
   be either a leaf or a horizontal sequence.  All windows in a
   horizontal sequence have the same height, and all windows in a
   vertical sequence have the same width.

   This function uses, for historical reasons, a more general
   algorithm to determine glyph matrix dimensions that would be
   necessary.

   The matrix height of a horizontal sequence is determined by the
   maximum height of any matrix in the sequence.  The matrix width of
   a horizontal sequence is computed by adding up matrix widths of
   windows in the sequence.

   |<------- result width ------->|
   +---------+----------+---------+ ---
   |         |		|	  |  |
   |         |		|	  |
   +---------+		|	  |  result height
	     |		+---------+
	     |		|            |
	     +----------+	    ---

   The matrix width of a vertical sequence is the maximum matrix width
   of any window in the sequence.  Its height is computed by adding up
   matrix heights of windows in the sequence.

   |<---- result width -->|
   +---------+		    ---
   |         |               |
   |         |               |
   +---------+--+            |
   |		|            |
   |		|	     result height
   |		|
   +------------+---------+  |
   |			  |  |
   |			  |  |
   +------------+---------+ ---  */

/* Bit indicating that a new matrix will be allocated or has been
   allocated.  */

#define NEW_LEAF_MATRIX		(1 << 0)

/* Bit indicating that a matrix will or has changed its location or
   size.  */

#define CHANGED_LEAF_MATRIX	(1 << 1)

static struct dim
allocate_matrices_for_frame_redisplay (Lisp_Object window, int x, int y,
				       bool dim_only_p, int *window_change_flags)
{
  struct frame *f = XFRAME (WINDOW_FRAME (XWINDOW (window)));
  int x0 = x, y0 = y;
  int wmax = 0, hmax = 0;
  struct dim total;
  struct dim dim;
  struct window *w;
  bool in_horz_combination_p;

  /* What combination is WINDOW part of?  Compute this once since the
     result is the same for all windows in the `next' chain.  The
     special case of a root window (parent equal to nil) is treated
     like a vertical combination because a root window's `next'
     points to the mini-buffer window, if any, which is arranged
     vertically below other windows.  */
  in_horz_combination_p
    = (!NILP (XWINDOW (window)->parent)
       && WINDOW_HORIZONTAL_COMBINATION_P (XWINDOW (XWINDOW (window)->parent)));

  /* For WINDOW and all windows on the same level.  */
  do
    {
      w = XWINDOW (window);

      /* Get the dimension of the window sub-matrix for W, depending
	 on whether this is a combination or a leaf window.  */
      if (WINDOWP (w->contents))
	dim = allocate_matrices_for_frame_redisplay (w->contents, x, y,
						     dim_only_p,
						     window_change_flags);
      else
	{
	  /* If not already done, allocate sub-matrix structures.  */
	  if (w->desired_matrix == NULL)
	    {
	      w->desired_matrix = new_glyph_matrix (f->desired_pool);
	      w->current_matrix = new_glyph_matrix (f->current_pool);
	      *window_change_flags |= NEW_LEAF_MATRIX;
	    }

	  /* Width and height MUST be chosen so that there are no
	     holes in the frame matrix.  */
	  dim.width = required_matrix_width (w);
	  dim.height = required_matrix_height (w);

	  /* Will matrix be re-allocated?  */
	  if (x != w->desired_matrix->matrix_x
	      || y != w->desired_matrix->matrix_y
	      || dim.width != w->desired_matrix->matrix_w
	      || dim.height != w->desired_matrix->matrix_h
	      || (margin_glyphs_to_reserve (w, dim.width,
					    w->left_margin_cols)
		  != w->desired_matrix->left_margin_glyphs)
	      || (margin_glyphs_to_reserve (w, dim.width,
					    w->right_margin_cols)
		  != w->desired_matrix->right_margin_glyphs))
	    *window_change_flags |= CHANGED_LEAF_MATRIX;

	  /* Actually change matrices, if allowed.  Do not consider
	     CHANGED_LEAF_MATRIX computed above here because the pool
	     may have been changed which we don't know here.  We trust
	     that we only will be called with DIM_ONLY_P when
	     necessary.  */
	  if (!dim_only_p)
	    {
	      adjust_glyph_matrix (w, w->desired_matrix, x, y, dim);
	      adjust_glyph_matrix (w, w->current_matrix, x, y, dim);
	    }
	}

      /* If we are part of a horizontal combination, advance x for
	 windows to the right of W; otherwise advance y for windows
	 below W.  */
      if (in_horz_combination_p)
	x += dim.width;
      else
        y += dim.height;

      /* Remember maximum glyph matrix dimensions.  */
      wmax = max (wmax, dim.width);
      hmax = max (hmax, dim.height);

      /* Next window on same level.  */
      window = w->next;
    }
  while (!NILP (window));

  /* Set `total' to the total glyph matrix dimension of this window
     level.  In a vertical combination, the width is the width of the
     widest window; the height is the y we finally reached, corrected
     by the y we started with.  In a horizontal combination, the total
     height is the height of the tallest window, and the width is the
     x we finally reached, corrected by the x we started with.  */
  if (in_horz_combination_p)
    {
      total.width = x - x0;
      total.height = hmax;
    }
  else
    {
      total.width = wmax;
      total.height = y - y0;
    }

  return total;
}


/* Return the required height of glyph matrices for window W.  */

static int
required_matrix_height (struct window *w)
{
#ifdef HAVE_WINDOW_SYSTEM
  struct frame *f = XFRAME (w->frame);

  if (FRAME_WINDOW_P (f))
    {
      /* https://lists.gnu.org/r/emacs-devel/2015-11/msg00194.html  */
      int ch_height = max (FRAME_SMALLEST_FONT_HEIGHT (f), 1);
      int window_pixel_height = window_box_height (w) + eabs (w->vscroll)
	+ eabs (w->vpixoffset);

      return (((window_pixel_height + ch_height - 1)
	       / ch_height) * w->nrows_scale_factor
	      /* One partially visible line at the top and
		 bottom of the window.  */
	      + 2
	      /* 3 for tab, header and mode line.  */
	      + 3);
    }
#endif /* HAVE_WINDOW_SYSTEM */

  return WINDOW_TOTAL_LINES (w);
}


/* Return the required width of glyph matrices for window W.  */

static int
required_matrix_width (struct window *w)
{
#ifdef HAVE_WINDOW_SYSTEM
  struct frame *f = XFRAME (w->frame);
  if (FRAME_WINDOW_P (f))
    {
      /* https://lists.gnu.org/r/emacs-devel/2015-11/msg00194.html  */
      int ch_width = max (FRAME_SMALLEST_CHAR_WIDTH (f), 1);

      /* Compute number of glyphs needed in a glyph row.  */
      return (((WINDOW_PIXEL_WIDTH (w) + ch_width - 1)
	       / ch_width) * w->ncols_scale_factor
	      /* 2 partially visible columns in the text area.  */
	      + 2
	      /* One partially visible column at the right
		 edge of each marginal area.  */
	      + 1 + 1);
    }
#endif /* HAVE_WINDOW_SYSTEM */

  return w->total_cols;
}


/* Allocate window matrices for window-based redisplay.  W is the
   window whose matrices must be allocated/reallocated.  */

static void
allocate_matrices_for_window_redisplay (struct window *w)
{
  while (w)
    {
      if (WINDOWP (w->contents))
	allocate_matrices_for_window_redisplay (XWINDOW (w->contents));
      else
	{
	  /* W is a leaf window.  */
	  struct dim dim;

	  /* If matrices are not yet allocated, allocate them now.  */
	  if (w->desired_matrix == NULL)
	    {
	      w->desired_matrix = new_glyph_matrix (NULL);
	      w->current_matrix = new_glyph_matrix (NULL);
	    }

	  dim.width = required_matrix_width (w);
	  dim.height = required_matrix_height (w);
	  adjust_glyph_matrix (w, w->desired_matrix, 0, 0, dim);
	  adjust_glyph_matrix (w, w->current_matrix, 0, 0, dim);
	}

      w = NILP (w->next) ? NULL : XWINDOW (w->next);
    }
}

/* Allocate/reallocate glyph matrices of a single frame F.
   This function must be called when a new frame is created,
   its size changes, or its window configuration changes.  */

void
adjust_frame_glyphs (struct frame *f)
{
  /* Block input so that expose events and other events that access
     glyph matrices are not processed while we are changing them.  */
  block_input ();

  if (FRAME_WINDOW_P (f))
    adjust_frame_glyphs_for_window_redisplay (f);
  else
    adjust_frame_glyphs_for_frame_redisplay (f);

  /* Don't forget the buffer for decode_mode_spec.  */
  adjust_decode_mode_spec_buffer (f);

  f->glyphs_initialized_p = 1;

  unblock_input ();
}

/* Return true if any window in the tree has nonzero window margins.  See
   the hack at the end of adjust_frame_glyphs_for_frame_redisplay.  */
static bool
showing_window_margins_p (struct window *w)
{
  while (w)
    {
      if (WINDOWP (w->contents))
	{
	  if (showing_window_margins_p (XWINDOW (w->contents)))
	    return 1;
	}
      else if (w->left_margin_cols > 0 || w->right_margin_cols > 0)
	return 1;

      w = NILP (w->next) ? 0 : XWINDOW (w->next);
    }
  return 0;
}


/* In the window tree with root W, build current matrices of leaf
   windows from the frame's current matrix.  */

static void
fake_current_matrices (Lisp_Object window)
{
  struct window *w;

  for (; !NILP (window); window = w->next)
    {
      w = XWINDOW (window);

      if (WINDOWP (w->contents))
	fake_current_matrices (w->contents);
      else
	{
	  int i;
	  struct frame *f = XFRAME (w->frame);
	  struct glyph_matrix *m = w->current_matrix;
	  struct glyph_matrix *fm = f->current_matrix;

	  eassert (m->matrix_h == WINDOW_TOTAL_LINES (w));
	  eassert (m->matrix_w == WINDOW_TOTAL_COLS (w));

	  for (i = 0; i < m->matrix_h; ++i)
	    {
	      struct glyph_row *r = m->rows + i;
	      struct glyph_row *fr = fm->rows + i + WINDOW_TOP_EDGE_LINE (w);

	      eassert (r->glyphs[TEXT_AREA] >= fr->glyphs[TEXT_AREA]
		       && r->glyphs[LAST_AREA] <= fr->glyphs[LAST_AREA]);

	      r->enabled_p = fr->enabled_p;
	      if (r->enabled_p)
		{
		  r->used[LEFT_MARGIN_AREA] = m->left_margin_glyphs;
		  r->used[RIGHT_MARGIN_AREA] = m->right_margin_glyphs;
		  r->used[TEXT_AREA] = (m->matrix_w
					- r->used[LEFT_MARGIN_AREA]
					- r->used[RIGHT_MARGIN_AREA]);
		  r->mode_line_p = 0;
		  r->tab_line_p = 0;
		}
	    }
	}
    }
}


/* Save away the contents of frame F's current frame matrix.  Value is
   a glyph matrix holding the contents of F's current frame matrix.  */

static struct glyph_matrix *
save_current_matrix (struct frame *f)
{
  int i;
  struct glyph_matrix *saved = xzalloc (sizeof *saved);
  saved->nrows = f->current_matrix->nrows;
  saved->rows = xzalloc (saved->nrows * sizeof *saved->rows);

  for (i = 0; i < saved->nrows; ++i)
    {
      struct glyph_row *from = f->current_matrix->rows + i;
      struct glyph_row *to = saved->rows + i;
      ptrdiff_t nbytes = from->used[TEXT_AREA] * sizeof (struct glyph);

      to->glyphs[TEXT_AREA] = xmalloc (nbytes);
      memcpy (to->glyphs[TEXT_AREA], from->glyphs[TEXT_AREA], nbytes);
      to->used[TEXT_AREA] = from->used[TEXT_AREA];
      to->enabled_p = from->enabled_p;
      to->hash = from->hash;
      if (from->used[LEFT_MARGIN_AREA])
	{
	  nbytes = from->used[LEFT_MARGIN_AREA] * sizeof (struct glyph);
	  to->glyphs[LEFT_MARGIN_AREA] = xmalloc (nbytes);
	  memcpy (to->glyphs[LEFT_MARGIN_AREA],
		  from->glyphs[LEFT_MARGIN_AREA], nbytes);
	  to->used[LEFT_MARGIN_AREA] = from->used[LEFT_MARGIN_AREA];
	}
      if (from->used[RIGHT_MARGIN_AREA])
	{
	  nbytes = from->used[RIGHT_MARGIN_AREA] * sizeof (struct glyph);
	  to->glyphs[RIGHT_MARGIN_AREA] = xmalloc (nbytes);
	  memcpy (to->glyphs[RIGHT_MARGIN_AREA],
		  from->glyphs[RIGHT_MARGIN_AREA], nbytes);
	  to->used[RIGHT_MARGIN_AREA] = from->used[RIGHT_MARGIN_AREA];
	}
    }

  return saved;
}


/* Restore the contents of frame F's current frame matrix from SAVED,
   and free memory associated with SAVED.  */

static void
restore_current_matrix (struct frame *f, struct glyph_matrix *saved)
{
  int i;

  for (i = 0; i < saved->nrows; ++i)
    {
      struct glyph_row *from = saved->rows + i;
      struct glyph_row *to = f->current_matrix->rows + i;
      ptrdiff_t nbytes = from->used[TEXT_AREA] * sizeof (struct glyph);

      memcpy (to->glyphs[TEXT_AREA], from->glyphs[TEXT_AREA], nbytes);
      to->used[TEXT_AREA] = from->used[TEXT_AREA];
      xfree (from->glyphs[TEXT_AREA]);
      nbytes = from->used[LEFT_MARGIN_AREA] * sizeof (struct glyph);
      if (nbytes)
	{
	  memcpy (to->glyphs[LEFT_MARGIN_AREA],
		  from->glyphs[LEFT_MARGIN_AREA], nbytes);
	  to->used[LEFT_MARGIN_AREA] = from->used[LEFT_MARGIN_AREA];
	  xfree (from->glyphs[LEFT_MARGIN_AREA]);
	}
      else
	to->used[LEFT_MARGIN_AREA] = 0;
      nbytes = from->used[RIGHT_MARGIN_AREA] * sizeof (struct glyph);
      if (nbytes)
	{
	  memcpy (to->glyphs[RIGHT_MARGIN_AREA],
		  from->glyphs[RIGHT_MARGIN_AREA], nbytes);
	  to->used[RIGHT_MARGIN_AREA] = from->used[RIGHT_MARGIN_AREA];
	  xfree (from->glyphs[RIGHT_MARGIN_AREA]);
	}
      else
	to->used[RIGHT_MARGIN_AREA] = 0;
    }

  xfree (saved->rows);
  xfree (saved);
}



/* Allocate/reallocate glyph matrices of a single frame F for
   frame-based redisplay.  */

static void
adjust_frame_glyphs_for_frame_redisplay (struct frame *f)
{
  struct dim matrix_dim;
  bool pool_changed_p;
  int window_change_flags;
  int top_window_y;

  if (!FRAME_LIVE_P (f))
    return;

  top_window_y = FRAME_TOP_MARGIN (f);

  /* Allocate glyph pool structures if not already done.  */
  if (f->desired_pool == NULL)
    {
      f->desired_pool = new_glyph_pool ();
      f->current_pool = new_glyph_pool ();
    }

  /* Allocate frames matrix structures if needed.  */
  if (f->desired_matrix == NULL)
    {
      f->desired_matrix = new_glyph_matrix (f->desired_pool);
      f->current_matrix = new_glyph_matrix (f->current_pool);
    }

  /* Compute window glyph matrices.  (This takes the mini-buffer
     window into account).  The result is the size of the frame glyph
     matrix needed.  The variable window_change_flags is set to a bit
     mask indicating whether new matrices will be allocated or
     existing matrices change their size or location within the frame
     matrix.  */
  window_change_flags = 0;
  matrix_dim
    = allocate_matrices_for_frame_redisplay (FRAME_ROOT_WINDOW (f),
					     0, top_window_y,
					     1,
					     &window_change_flags);

  /* Add in menu bar lines, if any.  */
  matrix_dim.height += top_window_y;

  /* Enlarge pools as necessary.  */
  pool_changed_p = realloc_glyph_pool (f->desired_pool, matrix_dim);
  realloc_glyph_pool (f->current_pool, matrix_dim);

  /* Set up glyph pointers within window matrices.  Do this only if
     absolutely necessary since it requires a frame redraw.  */
  if (pool_changed_p || window_change_flags)
    {
      /* Do it for window matrices.  */
      allocate_matrices_for_frame_redisplay (FRAME_ROOT_WINDOW (f),
					     0, top_window_y, 0,
					     &window_change_flags);

      /* Size of frame matrices must equal size of frame.  Note
	 that we are called for X frames with window widths NOT equal
	 to the frame width (from CHANGE_FRAME_SIZE_1).  */
      if (matrix_dim.width != FRAME_TOTAL_COLS (f)
	  || matrix_dim.height != FRAME_TOTAL_LINES (f))
	{
	  /* We have reallocated the frame's glyph pools, but didn't
	     update the glyph pointers in the frame's glyph matrices
	     to use the reallocated pools (that happens below, in the
	     call to adjust_glyph_matrix).  Set the frame's garbaged
	     flag, so that when we are called again from
	     redisplay_internal, we don't erroneously call
	     save_current_matrix, because it will use the wrong glyph
	     pointers, and will most probably crash.  */
	  if (!FRAME_WINDOW_P (f) && pool_changed_p)
	    SET_FRAME_GARBAGED (f);
	  return;
	}

      eassert (matrix_dim.width == FRAME_TOTAL_COLS (f)
	       && matrix_dim.height == FRAME_TOTAL_LINES (f));

      /* Pointers to glyph memory in glyph rows are exchanged during
	 the update phase of redisplay, which means in general that a
	 frame's current matrix consists of pointers into both the
	 desired and current glyph pool of the frame.  Adjusting a
	 matrix sets the frame matrix up so that pointers are all into
	 the same pool.  If we want to preserve glyph contents of the
	 current matrix over a call to adjust_glyph_matrix, we must
	 make a copy of the current glyphs, and restore the current
	 matrix' contents from that copy.  */
      if (display_completed
	  && !FRAME_GARBAGED_P (f)
	  && matrix_dim.width == f->current_matrix->matrix_w
	  && matrix_dim.height == f->current_matrix->matrix_h
	  /* For some reason, the frame glyph matrix gets corrupted if
	     any of the windows contain margins.  I haven't been able
	     to hunt down the reason, but for the moment this prevents
	     the problem from manifesting. -- cyd  */
	  && !showing_window_margins_p (XWINDOW (FRAME_ROOT_WINDOW (f))))
	{
	  struct glyph_matrix *copy = save_current_matrix (f);
	  adjust_glyph_matrix (NULL, f->desired_matrix, 0, 0, matrix_dim);
	  adjust_glyph_matrix (NULL, f->current_matrix, 0, 0, matrix_dim);
	  restore_current_matrix (f, copy);
	  fake_current_matrices (FRAME_ROOT_WINDOW (f));
	}
      else
	{
	  adjust_glyph_matrix (NULL, f->desired_matrix, 0, 0, matrix_dim);
	  adjust_glyph_matrix (NULL, f->current_matrix, 0, 0, matrix_dim);
	  SET_FRAME_GARBAGED (f);
	}
    }
}


/* Allocate/reallocate glyph matrices of a single frame F for
   window-based redisplay.  */

static void
adjust_frame_glyphs_for_window_redisplay (struct frame *f)
{
  eassert (FRAME_WINDOW_P (f) && FRAME_LIVE_P (f));

  /* Allocate/reallocate window matrices.  */
  allocate_matrices_for_window_redisplay (XWINDOW (FRAME_ROOT_WINDOW (f)));

#if defined (HAVE_X_WINDOWS) && ! defined (USE_X_TOOLKIT) && ! defined (USE_GTK)
  /* Allocate/ reallocate matrices of the dummy window used to display
     the menu bar under X when no X toolkit support is available.  */
  {
    /* Allocate a dummy window if not already done.  */
    struct window *w;
    if (NILP (f->menu_bar_window))
      {
	Lisp_Object frame;
	fset_menu_bar_window (f, make_window ());
	w = XWINDOW (f->menu_bar_window);
	XSETFRAME (frame, f);
	wset_frame (w, frame);
	w->pseudo_window_p = 1;
      }
    else
      w = XWINDOW (f->menu_bar_window);

    /* Set window dimensions to frame dimensions and allocate or
       adjust glyph matrices of W.  */
    w->pixel_left = 0;
    w->left_col = 0;
    w->pixel_top = 0;
    w->top_line = 0;
    w->pixel_width = (FRAME_PIXEL_WIDTH (f)
		      - 2 * FRAME_INTERNAL_BORDER_WIDTH (f));
    w->total_cols = FRAME_TOTAL_COLS (f);
    w->pixel_height = FRAME_MENU_BAR_HEIGHT (f);
    w->total_lines = FRAME_MENU_BAR_LINES (f);
    allocate_matrices_for_window_redisplay (w);
  }
#endif

#if defined (HAVE_WINDOW_SYSTEM)
  {
    /* Allocate/ reallocate matrices of the tab bar window.  If we
       don't have a tab bar window yet, make one.  */
    struct window *w;
    if (NILP (f->tab_bar_window))
      {
	Lisp_Object frame;
	fset_tab_bar_window (f, make_window ());
	w = XWINDOW (f->tab_bar_window);
	XSETFRAME (frame, f);
	wset_frame (w, frame);
	w->pseudo_window_p = 1;
      }
    else
      w = XWINDOW (f->tab_bar_window);

    w->pixel_left = 0;
    w->left_col = 0;
    w->pixel_top = FRAME_MENU_BAR_HEIGHT (f)
      + (!NILP (Vtab_bar_position) ? FRAME_TOOL_BAR_HEIGHT (f) : 0);
    w->top_line = FRAME_MENU_BAR_LINES (f)
      + (!NILP (Vtab_bar_position) ? FRAME_TOOL_BAR_LINES (f) : 0);
    w->total_cols = FRAME_TOTAL_COLS (f);
    w->pixel_width = (FRAME_PIXEL_WIDTH (f)
		       - 2 * FRAME_INTERNAL_BORDER_WIDTH (f));
    w->total_lines = FRAME_TAB_BAR_LINES (f);
    w->pixel_height = FRAME_TAB_BAR_HEIGHT (f);
    allocate_matrices_for_window_redisplay (w);
  }
#endif

#if defined (HAVE_WINDOW_SYSTEM) && ! defined (HAVE_EXT_TOOL_BAR)
  {
    /* Allocate/ reallocate matrices of the tool bar window.  If we
       don't have a tool bar window yet, make one.  */
    struct window *w;
    if (NILP (f->tool_bar_window))
      {
	Lisp_Object frame;
	fset_tool_bar_window (f, make_window ());
	w = XWINDOW (f->tool_bar_window);
	XSETFRAME (frame, f);
	wset_frame (w, frame);
	w->pseudo_window_p = 1;
      }
    else
      w = XWINDOW (f->tool_bar_window);

    w->pixel_left = 0;
    w->left_col = 0;
    w->pixel_top = FRAME_MENU_BAR_HEIGHT (f)
      + (NILP (Vtab_bar_position) ? FRAME_TAB_BAR_HEIGHT (f) : 0);
    w->top_line = FRAME_MENU_BAR_LINES (f)
      + (NILP (Vtab_bar_position) ? FRAME_TAB_BAR_LINES (f) : 0);
    w->total_cols = FRAME_TOTAL_COLS (f);
    w->pixel_width = (FRAME_PIXEL_WIDTH (f)
		       - 2 * FRAME_INTERNAL_BORDER_WIDTH (f));
    w->total_lines = FRAME_TOOL_BAR_LINES (f);
    w->pixel_height = FRAME_TOOL_BAR_HEIGHT (f);
    allocate_matrices_for_window_redisplay (w);
  }
#endif
}


/* Re-allocate buffer for decode_mode_spec on frame F.  */

static void
adjust_decode_mode_spec_buffer (struct frame *f)
{
  int frame_message_buf_size = FRAME_MESSAGE_BUF_SIZE (f);

  eassert (frame_message_buf_size >= 0);
  f->decode_mode_spec_buffer = xrealloc (f->decode_mode_spec_buffer,
					 frame_message_buf_size + 1);
}


\f
/**********************************************************************
			Freeing Glyph Matrices
 **********************************************************************/

/* Free glyph memory for a frame F.  F may be null.  This function can
   be called for the same frame more than once.  The root window of
   F may be nil when this function is called.  This is the case when
   the function is called when F is destroyed.  */

void
free_glyphs (struct frame *f)
{
  if (f && f->glyphs_initialized_p)
    {
      /* Block interrupt input so that we don't get surprised by an X
         event while we're in an inconsistent state.  */
      block_input ();
      f->glyphs_initialized_p = 0;

      /* Release window sub-matrices.  */
      if (!NILP (f->root_window))
        free_window_matrices (XWINDOW (f->root_window));

#if defined (HAVE_X_WINDOWS) && ! defined (USE_X_TOOLKIT) && ! defined (USE_GTK)
      /* Free the dummy window for menu bars without X toolkit and its
	 glyph matrices.  */
      if (!NILP (f->menu_bar_window))
	{
	  struct window *w = XWINDOW (f->menu_bar_window);
	  free_glyph_matrix (w->desired_matrix);
	  free_glyph_matrix (w->current_matrix);
	  w->desired_matrix = w->current_matrix = NULL;
	  fset_menu_bar_window (f, Qnil);
	}
#endif

#if defined (HAVE_WINDOW_SYSTEM)
      /* Free the tab bar window and its glyph matrices.  */
      if (!NILP (f->tab_bar_window))
	{
	  struct window *w = XWINDOW (f->tab_bar_window);
	  free_glyph_matrix (w->desired_matrix);
	  free_glyph_matrix (w->current_matrix);
	  w->desired_matrix = w->current_matrix = NULL;
	  fset_tab_bar_window (f, Qnil);
	}
#endif

#if defined (HAVE_WINDOW_SYSTEM) && ! defined (HAVE_EXT_TOOL_BAR)
      /* Free the tool bar window and its glyph matrices.  */
      if (!NILP (f->tool_bar_window))
	{
	  struct window *w = XWINDOW (f->tool_bar_window);
	  free_glyph_matrix (w->desired_matrix);
	  free_glyph_matrix (w->current_matrix);
	  w->desired_matrix = w->current_matrix = NULL;
	  fset_tool_bar_window (f, Qnil);
	}
#endif

      /* Release frame glyph matrices.  Reset fields to zero in
	 case we are called a second time.  */
      if (f->desired_matrix)
	{
	  free_glyph_matrix (f->desired_matrix);
	  free_glyph_matrix (f->current_matrix);
	  f->desired_matrix = f->current_matrix = NULL;
	}

      /* Release glyph pools.  */
      if (f->desired_pool)
	{
	  free_glyph_pool (f->desired_pool);
	  free_glyph_pool (f->current_pool);
	  f->desired_pool = f->current_pool = NULL;
	}

      unblock_input ();
    }
}


/* Free glyph sub-matrices in the window tree rooted at W.  This
   function may be called with a null pointer, and it may be called on
   the same tree more than once.  */

void
free_window_matrices (struct window *w)
{
  while (w)
    {
      if (WINDOWP (w->contents))
	free_window_matrices (XWINDOW (w->contents));
      else
	{
	  /* This is a leaf window.  Free its memory and reset fields
	     to zero in case this function is called a second time for
	     W.  */
	  free_glyph_matrix (w->current_matrix);
	  free_glyph_matrix (w->desired_matrix);
	  w->current_matrix = w->desired_matrix = NULL;
	}

      /* Next window on same level.  */
      w = NILP (w->next) ? 0 : XWINDOW (w->next);
    }
}


/* Check glyph memory leaks.  This function is called from
   shut_down_emacs.  Note that frames are not destroyed when Emacs
   exits.  We therefore free all glyph memory for all active frames
   explicitly and check that nothing is left allocated.  */

void
check_glyph_memory (void)
{
  Lisp_Object tail, frame;

  /* Free glyph memory for all frames.  */
  FOR_EACH_FRAME (tail, frame)
    free_glyphs (XFRAME (frame));

#if defined GLYPH_DEBUG && defined ENABLE_CHECKING
  /* Check that nothing is left allocated.  */
  eassert (glyph_matrix_count == 0);
  eassert (glyph_pool_count == 0);
#endif
}


\f
/**********************************************************************
		       Building a Frame Matrix
 **********************************************************************/

/* Most of the redisplay code works on glyph matrices attached to
   windows.  This is a good solution most of the time, but it is not
   suitable for terminal code.  Terminal output functions cannot rely
   on being able to set an arbitrary terminal window.  Instead they
   must be provided with a view of the whole frame, i.e. the whole
   screen.  We build such a view by constructing a frame matrix from
   window matrices in this section.

   Windows that must be updated have their must_be_updated_p flag set.
   For all such windows, their desired matrix is made part of the
   desired frame matrix.  For other windows, their current matrix is
   made part of the desired frame matrix.

   +-----------------+----------------+
   |     desired     |   desired      |
   |                 |                |
   +-----------------+----------------+
   |               current            |
   |                                  |
   +----------------------------------+

   Desired window matrices can be made part of the frame matrix in a
   cheap way: We exploit the fact that the desired frame matrix and
   desired window matrices share their glyph memory.  This is not
   possible for current window matrices.  Their glyphs are copied to
   the desired frame matrix.  The latter is equivalent to
   preserve_other_columns in the old redisplay.

   Used glyphs counters for frame matrix rows are the result of adding
   up glyph lengths of the window matrices.  A line in the frame
   matrix is enabled, if a corresponding line in a window matrix is
   enabled.

   After building the desired frame matrix, it will be passed to
   terminal code, which will manipulate both the desired and current
   frame matrix.  Changes applied to the frame's current matrix have
   to be visible in current window matrices afterwards, of course.

   This problem is solved like this:

   1. Window and frame matrices share glyphs.  Window matrices are
   constructed in a way that their glyph contents ARE the glyph
   contents needed in a frame matrix.  Thus, any modification of
   glyphs done in terminal code will be reflected in window matrices
   automatically.

   2. Exchanges of rows in a frame matrix done by terminal code are
   intercepted by hook functions so that corresponding row operations
   on window matrices can be performed.  This is necessary because we
   use pointers to glyphs in glyph row structures.  To satisfy the
   assumption of point 1 above that glyphs are updated implicitly in
   window matrices when they are manipulated via the frame matrix,
   window and frame matrix must of course agree where to find the
   glyphs for their rows.  Possible manipulations that must be
   mirrored are assignments of rows of the desired frame matrix to the
   current frame matrix and scrolling the current frame matrix.  */

/* Build frame F's desired matrix from window matrices.  Only windows
   which have the flag must_be_updated_p set have to be updated.  Menu
   bar lines of a frame are not covered by window matrices, so make
   sure not to touch them in this function.  */

static void
build_frame_matrix (struct frame *f)
{
  int i;

  /* F must have a frame matrix when this function is called.  */
  eassert (!FRAME_WINDOW_P (f));

  /* Clear all rows in the frame matrix covered by window matrices.
     Menu bar lines are not covered by windows.  */
  for (i = FRAME_TOP_MARGIN (f); i < f->desired_matrix->nrows; ++i)
    clear_glyph_row (MATRIX_ROW (f->desired_matrix, i));

  /* Build the matrix by walking the window tree.  */
  build_frame_matrix_from_window_tree (f->desired_matrix,
				       XWINDOW (FRAME_ROOT_WINDOW (f)));
}


/* Walk a window tree, building a frame matrix MATRIX from window
   matrices.  W is the root of a window tree.  */

static void
build_frame_matrix_from_window_tree (struct glyph_matrix *matrix, struct window *w)
{
  while (w)
    {
      if (WINDOWP (w->contents))
	build_frame_matrix_from_window_tree (matrix, XWINDOW (w->contents));
      else
	build_frame_matrix_from_leaf_window (matrix, w);

      w = NILP (w->next) ? 0 : XWINDOW (w->next);
    }
}


/* Add a window's matrix to a frame matrix.  FRAME_MATRIX is the
   desired frame matrix built.  W is a leaf window whose desired or
   current matrix is to be added to FRAME_MATRIX.  W's flag
   must_be_updated_p determines which matrix it contributes to
   FRAME_MATRIX.  If W->must_be_updated_p, W's desired matrix
   is added to FRAME_MATRIX, otherwise W's current matrix is added.
   Adding a desired matrix means setting up used counters and such in
   frame rows, while adding a current window matrix to FRAME_MATRIX
   means copying glyphs.  The latter case corresponds to
   preserve_other_columns in the old redisplay.  */

static void
build_frame_matrix_from_leaf_window (struct glyph_matrix *frame_matrix, struct window *w)
{
  struct glyph_matrix *window_matrix;
  int window_y, frame_y;
  /* If non-zero, a glyph to insert at the right border of W.  */
  GLYPH right_border_glyph;

  SET_GLYPH_FROM_CHAR (right_border_glyph, 0);

  /* Set window_matrix to the matrix we have to add to FRAME_MATRIX.  */
  if (w->must_be_updated_p)
    {
      window_matrix = w->desired_matrix;

      /* Decide whether we want to add a vertical border glyph.  */
      if (!WINDOW_RIGHTMOST_P (w))
	{
	  struct Lisp_Char_Table *dp = window_display_table (w);
	  Lisp_Object gc;

	  SET_GLYPH_FROM_CHAR (right_border_glyph, '|');
	  if (dp
	      && (gc = DISP_BORDER_GLYPH (dp), GLYPH_CODE_P (gc)))
	    {
	      SET_GLYPH_FROM_GLYPH_CODE (right_border_glyph, gc);
	      spec_glyph_lookup_face (w, &right_border_glyph);
	    }

	  if (GLYPH_FACE (right_border_glyph) <= 0)
	    SET_GLYPH_FACE (right_border_glyph, VERTICAL_BORDER_FACE_ID);
	}
    }
  else
    window_matrix = w->current_matrix;

  /* For all rows in the window matrix and corresponding rows in the
     frame matrix.  */
  window_y = 0;
  frame_y = window_matrix->matrix_y;
  while (window_y < window_matrix->nrows)
    {
      struct glyph_row *frame_row = frame_matrix->rows + frame_y;
      struct glyph_row *window_row = window_matrix->rows + window_y;
      bool current_row_p = window_matrix == w->current_matrix;

      /* Fill up the frame row with spaces up to the left margin of the
	 window row.  */
      fill_up_frame_row_with_spaces (frame_row, window_matrix->matrix_x);

      /* Fill up areas in the window matrix row with spaces.  */
      fill_up_glyph_row_with_spaces (window_row);

      /* If only part of W's desired matrix has been built, and
         window_row wasn't displayed, use the corresponding current
         row instead.  */
      if (window_matrix == w->desired_matrix
	  && !window_row->enabled_p)
	{
	  window_row = w->current_matrix->rows + window_y;
	  current_row_p = 1;
	}

      if (current_row_p)
	{
	  /* Copy window row to frame row.  */
	  memcpy (frame_row->glyphs[TEXT_AREA] + window_matrix->matrix_x,
		  window_row->glyphs[0],
		  window_matrix->matrix_w * sizeof (struct glyph));
	}
      else
	{
	  eassert (window_row->enabled_p);

	  /* Only when a desired row has been displayed, we want
	     the corresponding frame row to be updated.  */
	  frame_row->enabled_p = true;

          /* Maybe insert a vertical border between horizontally adjacent
	     windows.  */
          if (GLYPH_CHAR (right_border_glyph) != 0)
	    {
              struct glyph *border = window_row->glyphs[LAST_AREA] - 1;
	      SET_CHAR_GLYPH_FROM_GLYPH (*border, right_border_glyph);
	    }

#ifdef GLYPH_DEBUG
	  /* Window row window_y must be a slice of frame row
	     frame_y.  */
	  eassert (glyph_row_slice_p (window_row, frame_row));

	  /* If rows are in sync, we don't have to copy glyphs because
	     frame and window share glyphs.  */

	  strcpy (w->current_matrix->method, w->desired_matrix->method);
	  add_window_display_history (w, w->current_matrix->method, 0);
#endif
	}

      /* Set number of used glyphs in the frame matrix.  Since we fill
         up with spaces, and visit leaf windows from left to right it
         can be done simply.  */
      frame_row->used[TEXT_AREA]
	= window_matrix->matrix_x + window_matrix->matrix_w;

      /* Next row.  */
      ++window_y;
      ++frame_y;
    }
}

/* Given a user-specified glyph, possibly including a Lisp-level face
   ID, return a glyph that has a realized face ID.
   This is used for glyphs displayed specially and not part of the text;
   for instance, vertical separators, truncation markers, etc.  */

void
spec_glyph_lookup_face (struct window *w, GLYPH *glyph)
{
  int lface_id = GLYPH_FACE (*glyph);
  /* Convert the glyph's specified face to a realized (cache) face.  */
  if (lface_id > 0)
    {
      int face_id = merge_faces (w, Qt, lface_id, DEFAULT_FACE_ID);
      SET_GLYPH_FACE (*glyph, face_id);
    }
}

/* Add spaces to a glyph row ROW in a window matrix.

   Each row has the form:

   +---------+-----------------------------+------------+
   | left    |	text			   | right	|
   +---------+-----------------------------+------------+

   Left and right marginal areas are optional.  This function adds
   spaces to areas so that there are no empty holes between areas.
   In other words:  If the right area is not empty, the text area
   is filled up with spaces up to the right area.   If the text area
   is not empty, the left area is filled up.

   To be called for frame-based redisplay, only.  */

static void
fill_up_glyph_row_with_spaces (struct glyph_row *row)
{
  fill_up_glyph_row_area_with_spaces (row, LEFT_MARGIN_AREA);
  fill_up_glyph_row_area_with_spaces (row, TEXT_AREA);
  fill_up_glyph_row_area_with_spaces (row, RIGHT_MARGIN_AREA);
}


/* Fill area AREA of glyph row ROW with spaces.  To be called for
   frame-based redisplay only.  */

static void
fill_up_glyph_row_area_with_spaces (struct glyph_row *row, int area)
{
  if (row->glyphs[area] < row->glyphs[area + 1])
    {
      struct glyph *end = row->glyphs[area + 1];
      struct glyph *text = row->glyphs[area] + row->used[area];

      while (text < end)
	*text++ = space_glyph;
      row->used[area] = text - row->glyphs[area];
    }
}


/* Add spaces to the end of ROW in a frame matrix until index UPTO is
   reached.  In frame matrices only one area, TEXT_AREA, is used.  */

void
fill_up_frame_row_with_spaces (struct glyph_row *row, int upto)
{
  int i = row->used[TEXT_AREA];
  struct glyph *glyph = row->glyphs[TEXT_AREA];

  while (i < upto)
    glyph[i++] = space_glyph;

  row->used[TEXT_AREA] = i;
}


\f
/**********************************************************************
      Mirroring operations on frame matrices in window matrices
 **********************************************************************/

/* Set frame being updated via frame-based redisplay to F.  This
   function must be called before updates to make explicit that we are
   working on frame matrices or not.  */

static void
set_frame_matrix_frame (struct frame *f)
{
  frame_matrix_frame = f;
}


/* Make sure glyph row ROW in CURRENT_MATRIX is up to date.
   DESIRED_MATRIX is the desired matrix corresponding to
   CURRENT_MATRIX.  The update is done by exchanging glyph pointers
   between rows in CURRENT_MATRIX and DESIRED_MATRIX.  If
   frame_matrix_frame is non-null, this indicates that the exchange is
   done in frame matrices, and that we have to perform analogous
   operations in window matrices of frame_matrix_frame.  */

static void
make_current (struct glyph_matrix *desired_matrix, struct glyph_matrix *current_matrix, int row)
{
  struct glyph_row *current_row = MATRIX_ROW (current_matrix, row);
  struct glyph_row *desired_row = MATRIX_ROW (desired_matrix, row);
  bool mouse_face_p = current_row->mouse_face_p;

  /* Do current_row = desired_row.  This exchanges glyph pointers
     between both rows, and does a structure assignment otherwise.  */
  assign_row (current_row, desired_row);

  /* Enable current_row to mark it as valid.  */
  current_row->enabled_p = true;
  current_row->mouse_face_p = mouse_face_p;

  /* If we are called on frame matrices, perform analogous operations
     for window matrices.  */
  if (frame_matrix_frame)
    mirror_make_current (XWINDOW (frame_matrix_frame->root_window), row);
}


/* W is the root of a window tree.  FRAME_ROW is the index of a row in
   W's frame which has been made current (by swapping pointers between
   current and desired matrix).  Perform analogous operations in the
   matrices of leaf windows in the window tree rooted at W.  */

static void
mirror_make_current (struct window *w, int frame_row)
{
  while (w)
    {
      if (WINDOWP (w->contents))
 	mirror_make_current (XWINDOW (w->contents), frame_row);
      else
	{
	  /* Row relative to window W.  Don't use FRAME_TO_WINDOW_VPOS
	     here because the checks performed in debug mode there
	     will not allow the conversion.  */
	  int row = frame_row - w->desired_matrix->matrix_y;

	  /* If FRAME_ROW is within W, assign the desired row to the
	     current row (exchanging glyph pointers).  */
	  if (row >= 0 && row < w->desired_matrix->matrix_h)
	    {
	      struct glyph_row *current_row
		= MATRIX_ROW (w->current_matrix, row);
	      struct glyph_row *desired_row
		= MATRIX_ROW (w->desired_matrix, row);

	      if (desired_row->enabled_p)
		assign_row (current_row, desired_row);
	      else
		swap_glyph_pointers (desired_row, current_row);
	      current_row->enabled_p = true;

	      /* Set the Y coordinate of the mode/header line's row.
		 It is needed in draw_row_with_mouse_face to find the
		 screen coordinates.  (Window-based redisplay sets
		 this in update_window, but no one seems to do that
		 for frame-based redisplay.)  */
	      if (current_row->mode_line_p)
		current_row->y = row;
	    }
	}

      w = NILP (w->next) ? 0 : XWINDOW (w->next);
    }
}


/* Perform row dance after scrolling.  We are working on the range of
   lines UNCHANGED_AT_TOP + 1 to UNCHANGED_AT_TOP + NLINES (not
   including) in MATRIX.  COPY_FROM is a vector containing, for each
   row I in the range 0 <= I < NLINES, the index of the original line
   to move to I.  This index is relative to the row range, i.e. 0 <=
   index < NLINES.  RETAINED_P is a vector containing zero for each
   row 0 <= I < NLINES which is empty.

   This function is called from do_scrolling and do_direct_scrolling.  */

void
mirrored_line_dance (struct glyph_matrix *matrix, int unchanged_at_top, int nlines,
		     int *copy_from, char *retained_p)
{
  /* A copy of original rows.  */
  struct glyph_row *old_rows;

  /* Rows to assign to.  */
  struct glyph_row *new_rows = MATRIX_ROW (matrix, unchanged_at_top);

  int i;

  /* Make a copy of the original rows.  */
  USE_SAFE_ALLOCA;
  SAFE_NALLOCA (old_rows, 1, nlines);
  memcpy (old_rows, new_rows, nlines * sizeof *old_rows);

  /* Assign new rows, maybe clear lines.  */
  for (i = 0; i < nlines; ++i)
    {
      bool enabled_before_p = new_rows[i].enabled_p;

      eassert (i + unchanged_at_top < matrix->nrows);
      eassert (unchanged_at_top + copy_from[i] < matrix->nrows);
      new_rows[i] = old_rows[copy_from[i]];
      new_rows[i].enabled_p = enabled_before_p;

      /* RETAINED_P is zero for empty lines.  */
      if (!retained_p[copy_from[i]])
	new_rows[i].enabled_p = false;
    }

  /* Do the same for window matrices, if MATRIX is a frame matrix.  */
  if (frame_matrix_frame)
    mirror_line_dance (XWINDOW (frame_matrix_frame->root_window),
		       unchanged_at_top, nlines, copy_from, retained_p);

  SAFE_FREE ();
}


/* Synchronize glyph pointers in the current matrix of window W with
   the current frame matrix.  */

static void
sync_window_with_frame_matrix_rows (struct window *w)
{
  struct frame *f = XFRAME (w->frame);
  struct glyph_row *window_row, *window_row_end, *frame_row;
  int left, right, x, width;

  /* Preconditions: W must be a live window on a tty frame.  */
  eassert (BUFFERP (w->contents));
  eassert (!FRAME_WINDOW_P (f));

  left = margin_glyphs_to_reserve (w, 1, w->left_margin_cols);
  right = margin_glyphs_to_reserve (w, 1, w->right_margin_cols);
  x = w->current_matrix->matrix_x;
  width = w->current_matrix->matrix_w;

  window_row = w->current_matrix->rows;
  window_row_end = window_row + w->current_matrix->nrows;
  frame_row = f->current_matrix->rows + WINDOW_TOP_EDGE_LINE (w);

  for (; window_row < window_row_end; ++window_row, ++frame_row)
    {
      window_row->glyphs[LEFT_MARGIN_AREA]
	= frame_row->glyphs[0] + x;
      window_row->glyphs[TEXT_AREA]
	= window_row->glyphs[LEFT_MARGIN_AREA] + left;
      window_row->glyphs[LAST_AREA]
	= window_row->glyphs[LEFT_MARGIN_AREA] + width;
      window_row->glyphs[RIGHT_MARGIN_AREA]
	= window_row->glyphs[LAST_AREA] - right;
    }
}


/* Return the window in the window tree rooted in W containing frame
   row ROW.  Value is null if none is found.  */

static struct window *
frame_row_to_window (struct window *w, int row)
{
  struct window *found = NULL;

  while (w && !found)
    {
      if (WINDOWP (w->contents))
 	found = frame_row_to_window (XWINDOW (w->contents), row);
      else if (row >= WINDOW_TOP_EDGE_LINE (w)
	       && row < WINDOW_BOTTOM_EDGE_LINE (w))
	found = w;

      w = NILP (w->next) ? 0 : XWINDOW (w->next);
    }

  return found;
}


/* Perform a line dance in the window tree rooted at W, after
   scrolling a frame matrix in mirrored_line_dance.

   We are working on the range of lines UNCHANGED_AT_TOP + 1 to
   UNCHANGED_AT_TOP + NLINES (not including) in W's frame matrix.
   COPY_FROM is a vector containing, for each row I in the range 0 <=
   I < NLINES, the index of the original line to move to I.  This
   index is relative to the row range, i.e. 0 <= index < NLINES.
   RETAINED_P is a vector containing zero for each row 0 <= I < NLINES
   which is empty.  */

static void
mirror_line_dance (struct window *w, int unchanged_at_top, int nlines, int *copy_from, char *retained_p)
{
  while (w)
    {
      if (WINDOWP (w->contents))
	mirror_line_dance (XWINDOW (w->contents), unchanged_at_top,
			   nlines, copy_from, retained_p);
      else
	{
	  /* W is a leaf window, and we are working on its current
	     matrix m.  */
	  struct glyph_matrix *m = w->current_matrix;
	  int i;
	  bool sync_p = 0;
	  struct glyph_row *old_rows;

	  /* Make a copy of the original rows of matrix m.  */
	  USE_SAFE_ALLOCA;
	  SAFE_NALLOCA (old_rows, 1, m->nrows);
	  memcpy (old_rows, m->rows, m->nrows * sizeof *old_rows);

	  for (i = 0; i < nlines; ++i)
	    {
	      /* Frame relative line assigned to.  */
	      int frame_to = i + unchanged_at_top;

	      /* Frame relative line assigned.  */
	      int frame_from = copy_from[i] + unchanged_at_top;

	      /* Window relative line assigned to.  */
	      int window_to = frame_to - m->matrix_y;

	      /* Window relative line assigned.  */
	      int window_from = frame_from - m->matrix_y;

	      /* Is assigned line inside window?  */
	      bool from_inside_window_p
		= window_from >= 0 && window_from < m->matrix_h;

	      /* Is assigned to line inside window?  */
	      bool to_inside_window_p
		= window_to >= 0 && window_to < m->matrix_h;

	      if (from_inside_window_p && to_inside_window_p)
		{
		  /* Do the assignment.  The enabled_p flag is saved
		     over the assignment because the old redisplay did
		     that.  */
		  bool enabled_before_p = m->rows[window_to].enabled_p;
		  m->rows[window_to] = old_rows[window_from];
		  m->rows[window_to].enabled_p = enabled_before_p;

		  /* If frame line is empty, window line is empty, too.  */
		  if (!retained_p[copy_from[i]])
		    m->rows[window_to].enabled_p = false;
		}
	      else if (to_inside_window_p)
		{
		  /* A copy between windows.  This is an infrequent
		     case not worth optimizing.  */
		  struct frame *f = XFRAME (w->frame);
		  struct window *root = XWINDOW (FRAME_ROOT_WINDOW (f));
		  struct window *w2;
		  struct glyph_matrix *m2;
		  int m2_from;

		  w2 = frame_row_to_window (root, frame_from);
		  /* ttn@surf.glug.org: when enabling menu bar using `emacs
		     -nw', FROM_FRAME sometimes has no associated window.
		     This check avoids a segfault if W2 is null.  */
		  if (w2)
		    {
		      m2 = w2->current_matrix;
		      m2_from = frame_from - m2->matrix_y;
		      copy_row_except_pointers (m->rows + window_to,
						m2->rows + m2_from);

		      /* If frame line is empty, window line is empty, too.  */
		      if (!retained_p[copy_from[i]])
			m->rows[window_to].enabled_p = false;
		    }
		  sync_p = 1;
		}
	      else if (from_inside_window_p)
		sync_p = 1;
	    }

	  /* If there was a copy between windows, make sure glyph
	     pointers are in sync with the frame matrix.  */
	  if (sync_p)
	    sync_window_with_frame_matrix_rows (w);

	  /* Check that no pointers are lost.  */
	  CHECK_MATRIX (m);

	  SAFE_FREE ();
	}

      /* Next window on same level.  */
      w = NILP (w->next) ? 0 : XWINDOW (w->next);
    }
}


#ifdef GLYPH_DEBUG

/* Check that window and frame matrices agree about their
   understanding where glyphs of the rows are to find.  For each
   window in the window tree rooted at W, check that rows in the
   matrices of leaf window agree with their frame matrices about
   glyph pointers.  */

static void
check_window_matrix_pointers (struct window *w)
{
  while (w)
    {
      if (WINDOWP (w->contents))
	check_window_matrix_pointers (XWINDOW (w->contents));
      else
	{
	  struct frame *f = XFRAME (w->frame);
	  check_matrix_pointers (w->desired_matrix, f->desired_matrix);
	  check_matrix_pointers (w->current_matrix, f->current_matrix);
	}

      w = NILP (w->next) ? 0 : XWINDOW (w->next);
    }
}


/* Check that window rows are slices of frame rows.  WINDOW_MATRIX is
   a window and FRAME_MATRIX is the corresponding frame matrix.  For
   each row in WINDOW_MATRIX check that it's a slice of the
   corresponding frame row.  If it isn't, abort.  */

static void
check_matrix_pointers (struct glyph_matrix *window_matrix,
		       struct glyph_matrix *frame_matrix)
{
  /* Row number in WINDOW_MATRIX.  */
  int i = 0;

  /* Row number corresponding to I in FRAME_MATRIX.  */
  int j = window_matrix->matrix_y;

  /* For all rows check that the row in the window matrix is a
     slice of the row in the frame matrix.  If it isn't we didn't
     mirror an operation on the frame matrix correctly.  */
  while (i < window_matrix->nrows)
    {
      if (!glyph_row_slice_p (window_matrix->rows + i,
			      frame_matrix->rows + j))
        emacs_abort ();
      ++i, ++j;
    }
}

#endif /* GLYPH_DEBUG */


\f
/**********************************************************************
		      VPOS and HPOS translations
 **********************************************************************/

#ifdef GLYPH_DEBUG

/* Translate vertical position VPOS which is relative to window W to a
   vertical position relative to W's frame.  */

static int
window_to_frame_vpos (struct window *w, int vpos)
{
  eassert (!FRAME_WINDOW_P (XFRAME (w->frame)));
  eassert (vpos >= 0 && vpos <= w->desired_matrix->nrows);
  vpos += WINDOW_TOP_EDGE_LINE (w);
  eassert (vpos >= 0 && vpos <= FRAME_TOTAL_LINES (XFRAME (w->frame)));
  return vpos;
}


/* Translate horizontal position HPOS which is relative to window W to
   a horizontal position relative to W's frame.  */

static int
window_to_frame_hpos (struct window *w, int hpos)
{
  eassert (!FRAME_WINDOW_P (XFRAME (w->frame)));
  hpos += WINDOW_LEFT_EDGE_COL (w);
  return hpos;
}

#endif /* GLYPH_DEBUG */


\f
/**********************************************************************
			    Redrawing Frames
 **********************************************************************/

/* Redraw frame F.  */

void
redraw_frame (struct frame *f)
{
  /* Error if F has no glyphs.  */
  eassert (f->glyphs_initialized_p);
  update_begin (f);
  if (FRAME_MSDOS_P (f))
    FRAME_TERMINAL (f)->set_terminal_modes_hook (FRAME_TERMINAL (f));
  clear_frame (f);
  clear_current_matrices (f);
  update_end (f);
  fset_redisplay (f);
  /* Mark all windows as inaccurate, so that every window will have
     its redisplay done.  */
  mark_window_display_accurate (FRAME_ROOT_WINDOW (f), 0);
  set_window_update_flags (XWINDOW (FRAME_ROOT_WINDOW (f)), true);
  f->garbaged = false;
}

DEFUN ("redraw-frame", Fredraw_frame, Sredraw_frame, 0, 1, 0,
       doc: /* Clear frame FRAME and output again what is supposed to appear on it.
If FRAME is omitted or nil, the selected frame is used.  */)
  (Lisp_Object frame)
{
  redraw_frame (decode_live_frame (frame));
  return Qnil;
}

DEFUN ("redraw-display", Fredraw_display, Sredraw_display, 0, 0, "",
       doc: /* Clear and redisplay all visible frames.  */)
  (void)
{
  Lisp_Object tail, frame;

  FOR_EACH_FRAME (tail, frame)
    if (FRAME_VISIBLE_P (XFRAME (frame)))
      redraw_frame (XFRAME (frame));

  return Qnil;
}


\f
/***********************************************************************
			     Frame Update
 ***********************************************************************/

/* Update frame F based on the data in desired matrices.

   If FORCE_P, don't let redisplay be stopped by detecting pending input.
   If INHIBIT_HAIRY_ID_P, don't try scrolling.

   Value is true if redisplay was stopped due to pending input.  */

bool
update_frame (struct frame *f, bool force_p, bool inhibit_hairy_id_p)
{
  /* True means display has been paused because of pending input.  */
  bool paused_p;
  struct window *root_window = XWINDOW (f->root_window);

  if (redisplay_dont_pause)
    force_p = true;
  else if (!force_p && detect_input_pending_ignore_squeezables ())
    {
      paused_p = true;
      goto do_pause;
    }

  if (FRAME_WINDOW_P (f))
    {
      /* We are working on window matrix basis.  All windows whose
	 flag must_be_updated_p is set have to be updated.  */

      /* Record that we are not working on frame matrices.  */
      set_frame_matrix_frame (NULL);

      /* Update all windows in the window tree of F, maybe stopping
	 when pending input is detected.  */
      update_begin (f);

#if defined (HAVE_X_WINDOWS) && ! defined (USE_X_TOOLKIT) && ! defined (USE_GTK)
      /* Update the menu bar on X frames that don't have toolkit
	 support.  */
      if (WINDOWP (f->menu_bar_window))
	update_window (XWINDOW (f->menu_bar_window), true);
#endif

#if defined (HAVE_WINDOW_SYSTEM)
      /* Update the tab-bar window, if present.  */
      if (WINDOWP (f->tab_bar_window))
	{
	  struct window *w = XWINDOW (f->tab_bar_window);

	  /* Update tab-bar window.  */
	  if (w->must_be_updated_p)
	    {
	      Lisp_Object tem;

	      update_window (w, true);
	      w->must_be_updated_p = false;

	      /* Swap tab-bar strings.  We swap because we want to
		 reuse strings.  */
	      tem = f->current_tab_bar_string;
	      fset_current_tab_bar_string (f, f->desired_tab_bar_string);
	      fset_desired_tab_bar_string (f, tem);
	    }
	}
#endif

#if defined (HAVE_WINDOW_SYSTEM) && ! defined (HAVE_EXT_TOOL_BAR)
      /* Update the tool-bar window, if present.  */
      if (WINDOWP (f->tool_bar_window))
	{
	  struct window *w = XWINDOW (f->tool_bar_window);

	  /* Update tool-bar window.  */
	  if (w->must_be_updated_p)
	    {
	      Lisp_Object tem;

	      update_window (w, true);
	      w->must_be_updated_p = false;

	      /* Swap tool-bar strings.  We swap because we want to
		 reuse strings.  */
	      tem = f->current_tool_bar_string;
	      fset_current_tool_bar_string (f, f->desired_tool_bar_string);
	      fset_desired_tool_bar_string (f, tem);
	    }
	}
#endif

      /* Update windows.  */
      paused_p = update_window_tree (root_window, force_p);
      update_end (f);
    }
  else
    {
      /* We are working on frame matrix basis.  Set the frame on whose
	 frame matrix we operate.  */
      set_frame_matrix_frame (f);

      /* Build F's desired matrix from window matrices.  */
      build_frame_matrix (f);

      /* Update the display.  */
      update_begin (f);
      paused_p = update_frame_1 (f, force_p, inhibit_hairy_id_p, 1, false);
      update_end (f);

      if (FRAME_TERMCAP_P (f) || FRAME_MSDOS_P (f))
        {
          if (FRAME_TTY (f)->termscript)
	    fflush (FRAME_TTY (f)->termscript);
	  if (FRAME_TERMCAP_P (f))
	    fflush (FRAME_TTY (f)->output);
        }

      /* Check window matrices for lost pointers.  */
#ifdef GLYPH_DEBUG
      check_window_matrix_pointers (root_window);
      add_frame_display_history (f, paused_p);
#endif
    }

 do_pause:
  /* Reset flags indicating that a window should be updated.  */
  set_window_update_flags (root_window, false);

  display_completed = !paused_p;
  return paused_p;
}

/* Update a TTY frame F that has a menu dropped down over some of its
   glyphs.  This is like the second part of update_frame, but it
   doesn't call build_frame_matrix, because we already have the
   desired matrix prepared, and don't want it to be overwritten by the
   text of the normal display.

   ROW and COL, if non-negative, are the row and column of the TTY
   frame where to position the cursor after the frame update is
   complete.  Negative values mean ask update_frame_1 to position the
   cursor "normally", i.e. at point in the selected window.  */
void
update_frame_with_menu (struct frame *f, int row, int col)
{
  struct window *root_window = XWINDOW (f->root_window);
  bool paused_p, cursor_at_point_p;

  eassert (FRAME_TERMCAP_P (f));

  /* We are working on frame matrix basis.  Set the frame on whose
     frame matrix we operate.  */
  set_frame_matrix_frame (f);

  /* Update the display.  */
  update_begin (f);
  cursor_at_point_p = !(row >= 0 && col >= 0);
  /* Force update_frame_1 not to stop due to pending input, and not
     try scrolling.  */
  paused_p = update_frame_1 (f, 1, 1, cursor_at_point_p, true);
  /* ROW and COL tell us where in the menu to position the cursor, so
     that screen readers know the active region on the screen.  */
  if (!cursor_at_point_p)
    cursor_to (f, row, col);
  update_end (f);

  if (FRAME_TTY (f)->termscript)
    fflush (FRAME_TTY (f)->termscript);
  fflush (FRAME_TTY (f)->output);
  /* Check window matrices for lost pointers.  */
#if GLYPH_DEBUG
#if 0
      /* We cannot possibly survive the matrix pointers check, since
	 we have overwritten parts of the frame glyph matrix without
	 making any updates to the window matrices.  */
  check_window_matrix_pointers (root_window);
#endif
  add_frame_display_history (f, paused_p);
#endif

  /* Reset flags indicating that a window should be updated.  */
  set_window_update_flags (root_window, false);
  display_completed = !paused_p;
}

\f
/************************************************************************
			 Window-based updates
 ************************************************************************/

/* Perform updates in window tree rooted at W.
   If FORCE_P, don't stop updating if input is pending.  */

static bool
update_window_tree (struct window *w, bool force_p)
{
  bool paused_p = 0;

  while (w && !paused_p)
    {
      if (WINDOWP (w->contents))
	paused_p |= update_window_tree (XWINDOW (w->contents), force_p);
      else if (w->must_be_updated_p)
	paused_p |= update_window (w, force_p);

      w = NILP (w->next) ? 0 : XWINDOW (w->next);
    }

  return paused_p;
}


/* Update window W if its flag must_be_updated_p is set.
   If FORCE_P, don't stop updating if input is pending.  */

void
update_single_window (struct window *w)
{
  if (w->must_be_updated_p)
    {
      struct frame *f = XFRAME (WINDOW_FRAME (w));

      /* Record that this is not a frame-based redisplay.  */
      set_frame_matrix_frame (NULL);

      /* Update W.  */
      update_begin (f);
      update_window (w, true);
      update_end (f);

      /* Reset flag in W.  */
      w->must_be_updated_p = false;
    }
}

#ifdef HAVE_WINDOW_SYSTEM

/* Redraw lines from the current matrix of window W that are
   overlapped by other rows.  YB is bottom-most y-position in W.  */

static void
redraw_overlapped_rows (struct window *w, int yb)
{
  int i;
  struct frame *f = XFRAME (WINDOW_FRAME (w));

  /* If rows overlapping others have been changed, the rows being
     overlapped have to be redrawn.  This won't draw lines that have
     already been drawn in update_window_line because overlapped_p in
     desired rows is 0, so after row assignment overlapped_p in
     current rows is 0.  */
  for (i = 0; i < w->current_matrix->nrows; ++i)
    {
      struct glyph_row *row = w->current_matrix->rows + i;

      if (!row->enabled_p)
	break;
      else if (row->mode_line_p)
	continue;

      if (row->overlapped_p)
	{
	  enum glyph_row_area area;

	  for (area = LEFT_MARGIN_AREA; area < LAST_AREA; ++area)
	    {
	      output_cursor_to (w, i, 0, row->y,
				area == TEXT_AREA ? row->x : 0);
	      if (row->used[area])
		FRAME_RIF (f)->write_glyphs (w, row, row->glyphs[area],
                                             area, row->used[area]);
	      FRAME_RIF (f)->clear_end_of_line (w, row, area, -1);
	    }

	  row->overlapped_p = 0;
	}

      if (MATRIX_ROW_BOTTOM_Y (row) >= yb)
	break;
    }
}


/* Redraw lines from the current matrix of window W that overlap
   others.  YB is bottom-most y-position in W.  */

static void
redraw_overlapping_rows (struct window *w, int yb)
{
  int i, bottom_y;
  struct glyph_row *row;
  struct redisplay_interface *rif = FRAME_RIF (XFRAME (WINDOW_FRAME (w)));

  for (i = 0; i < w->current_matrix->nrows; ++i)
    {
      row = w->current_matrix->rows + i;

      if (!row->enabled_p)
	break;
      else if (row->mode_line_p)
	continue;

      bottom_y = MATRIX_ROW_BOTTOM_Y (row);

      if (row->overlapping_p)
	{
	  int overlaps = 0;

	  if (MATRIX_ROW_OVERLAPS_PRED_P (row) && i > 0
	      && !MATRIX_ROW (w->current_matrix, i - 1)->overlapped_p)
	    overlaps |= OVERLAPS_PRED;
	  if (MATRIX_ROW_OVERLAPS_SUCC_P (row) && bottom_y < yb
	      && !MATRIX_ROW (w->current_matrix, i + 1)->overlapped_p)
	    overlaps |= OVERLAPS_SUCC;

	  if (overlaps)
	    {
	      if (row->used[LEFT_MARGIN_AREA])
		rif->fix_overlapping_area (w, row, LEFT_MARGIN_AREA, overlaps);

	      if (row->used[TEXT_AREA])
		rif->fix_overlapping_area (w, row, TEXT_AREA, overlaps);

	      if (row->used[RIGHT_MARGIN_AREA])
		rif->fix_overlapping_area (w, row, RIGHT_MARGIN_AREA, overlaps);

	      /* Record in neighbor rows that ROW overwrites part of
		 their display.  */
	      if (overlaps & OVERLAPS_PRED)
		MATRIX_ROW (w->current_matrix, i - 1)->overlapped_p = 1;
	      if (overlaps & OVERLAPS_SUCC)
		MATRIX_ROW (w->current_matrix, i + 1)->overlapped_p = 1;
	    }
	}

      if (bottom_y >= yb)
	break;
    }
}

#endif /* HAVE_WINDOW_SYSTEM */


#if defined GLYPH_DEBUG && 0

/* Check that no row in the current matrix of window W is enabled
   which is below what's displayed in the window.  */

static void
check_current_matrix_flags (struct window *w)
{
  bool last_seen_p = 0;
  int i, yb = window_text_bottom_y (w);

  for (i = 0; i < w->current_matrix->nrows - 1; ++i)
    {
      struct glyph_row *row = MATRIX_ROW (w->current_matrix, i);
      if (!last_seen_p && MATRIX_ROW_BOTTOM_Y (row) >= yb)
	last_seen_p = 1;
      else if (last_seen_p && row->enabled_p)
	emacs_abort ();
    }
}

#endif /* GLYPH_DEBUG */


/* Update display of window W.
   If FORCE_P, don't stop updating when input is pending.  */

static bool
update_window (struct window *w, bool force_p)
{
  struct glyph_matrix *desired_matrix = w->desired_matrix;
  bool paused_p;
  int preempt_count = clip_to_bounds (1, baud_rate / 2400 + 1, INT_MAX);
#ifdef HAVE_WINDOW_SYSTEM
  struct redisplay_interface *rif = FRAME_RIF (XFRAME (WINDOW_FRAME (w)));
#endif
#ifdef GLYPH_DEBUG
  /* Check that W's frame doesn't have glyph matrices.  */
  eassert (FRAME_WINDOW_P (XFRAME (WINDOW_FRAME (w))));
#endif

  /* Check pending input the first time so that we can quickly return.  */
  if (!force_p)
    detect_input_pending_ignore_squeezables ();

  /* If forced to complete the update, no input is pending, or we are
     tracking the mouse, do the update.  */
  if (force_p || !input_pending || !NILP (track_mouse))
    {
      struct glyph_row *row, *end;
      struct glyph_row *mode_line_row;
      struct glyph_row *tab_line_row;
      struct glyph_row *header_line_row;
      int yb;
      bool changed_p = 0, mouse_face_overwritten_p = 0;
      int n_updated = 0;

#ifdef HAVE_WINDOW_SYSTEM
      gui_update_window_begin (w);
#endif
      yb = window_text_bottom_y (w);
      row = MATRIX_ROW (desired_matrix, 0);
      end = MATRIX_MODE_LINE_ROW (desired_matrix);

      /* Take note of the tab line, if there is one.  We will
	 update it below, after updating all of the window's lines.  */
      if (row->mode_line_p && row->tab_line_p)
	{
	  tab_line_row = row;
	  ++row;
	}
      else
	tab_line_row = NULL;

      /* Take note of the header line, if there is one.  We will
	 update it below, after updating all of the window's lines.  */
      if (row->mode_line_p)
	{
	  header_line_row = row;
	  ++row;
	}
      else
	header_line_row = NULL;

      /* Update the mode line, if necessary.  */
      mode_line_row = MATRIX_MODE_LINE_ROW (desired_matrix);
      if (mode_line_row->mode_line_p && mode_line_row->enabled_p)
	{
	  mode_line_row->y = yb + WINDOW_SCROLL_BAR_AREA_HEIGHT (w);
	  update_window_line (w, MATRIX_ROW_VPOS (mode_line_row,
						  desired_matrix),
			      &mouse_face_overwritten_p);
	}

      /* Find first enabled row.  Optimizations in redisplay_internal
	 may lead to an update with only one row enabled.  There may
	 be also completely empty matrices.  */
      while (row < end && !row->enabled_p)
	++row;

      /* Try reusing part of the display by copying.  */
      if (row < end && !desired_matrix->no_scrolling_p)
	{
	  int rc = scrolling_window (w, (tab_line_row != NULL ? 1 : 0)
				     + (header_line_row != NULL ? 1 : 0));
	  if (rc < 0)
	    {
	      /* All rows were found to be equal.  */
	      paused_p = 0;
	      goto set_cursor;
	    }
	  else if (rc > 0)
	    {
	      /* We've scrolled the display.  */
	      force_p = 1;
	      changed_p = 1;
	    }
	}

      /* Update the rest of the lines.  */
      for (; row < end && (force_p || !input_pending); ++row)
	/* scrolling_window resets the enabled_p flag of the rows it
	   reuses from current_matrix.  */
	if (row->enabled_p)
	  {
	    int vpos = MATRIX_ROW_VPOS (row, desired_matrix);
	    int i;

	    /* We'll have to play a little bit with when to
	       detect_input_pending.  If it's done too often,
	       scrolling large windows with repeated scroll-up
	       commands will too quickly pause redisplay.  */
	    if (!force_p && ++n_updated % preempt_count == 0)
	      detect_input_pending_ignore_squeezables ();
	    changed_p |= update_window_line (w, vpos,
					     &mouse_face_overwritten_p);

	    /* Mark all rows below the last visible one in the current
	       matrix as invalid.  This is necessary because of
	       variable line heights.  Consider the case of three
	       successive redisplays, where the first displays 5
	       lines, the second 3 lines, and the third 5 lines again.
	       If the second redisplay wouldn't mark rows in the
	       current matrix invalid, the third redisplay might be
	       tempted to optimize redisplay based on lines displayed
	       in the first redisplay.  */
	    if (MATRIX_ROW_BOTTOM_Y (row) >= yb)
	      for (i = vpos + 1; i < w->current_matrix->nrows - 1; ++i)
		SET_MATRIX_ROW_ENABLED_P (w->current_matrix, i, false);
	  }

      /* Was display preempted?  */
      paused_p = row < end;

    set_cursor:

      /* Update the tab line after scrolling because a new tab
	 line would otherwise overwrite lines at the top of the window
	 that can be scrolled.  */
      if (tab_line_row && tab_line_row->enabled_p)
	{
	  tab_line_row->y = 0;
	  update_window_line (w, 0, &mouse_face_overwritten_p);
	}

      /* Update the header line after scrolling because a new header
	 line would otherwise overwrite lines at the top of the window
	 that can be scrolled.  */
      if (header_line_row && header_line_row->enabled_p)
	{
	  header_line_row->y = tab_line_row ? CURRENT_TAB_LINE_HEIGHT (w) : 0;
	  update_window_line (w, tab_line_row ? 1 : 0, &mouse_face_overwritten_p);
	}

      /* Fix the appearance of overlapping/overlapped rows.  */
      if (!paused_p && !w->pseudo_window_p)
	{
#ifdef HAVE_WINDOW_SYSTEM
	  if (changed_p && rif->fix_overlapping_area)
	    {
	      redraw_overlapped_rows (w, yb);
	      redraw_overlapping_rows (w, yb);
	    }
#endif

	  /* Make cursor visible at cursor position of W.  */
	  set_window_cursor_after_update (w);

#if 0 /* Check that current matrix invariants are satisfied.  This is
	 for debugging only.  See the comment of check_matrix_invariants.  */
	  IF_DEBUG (check_matrix_invariants (w));
#endif
	}

#ifdef GLYPH_DEBUG
      /* Remember the redisplay method used to display the matrix.  */
      strcpy (w->current_matrix->method, w->desired_matrix->method);
#endif

#ifdef HAVE_WINDOW_SYSTEM
      update_window_fringes (w, 0);

      /* End the update of window W.  Don't set the cursor if we
         paused updating the display because in this case,
         set_window_cursor_after_update hasn't been called, and
         W->output_cursor doesn't contain the cursor location.  */
      gui_update_window_end (w, !paused_p, mouse_face_overwritten_p);
#endif
      /* If the update wasn't interrupted, this window has been
	 completely updated.  */
      if (!paused_p)
	w->must_be_updated_p = false;
    }
  else
    paused_p = 1;

#ifdef GLYPH_DEBUG
  /* check_current_matrix_flags (w); */
  add_window_display_history (w, w->current_matrix->method, paused_p);
#endif

  xwidget_end_redisplay (w, w->current_matrix);
  clear_glyph_matrix (desired_matrix);

  return paused_p;
}

#ifdef HAVE_WINDOW_SYSTEM

/* Start update of window W.  */

void
gui_update_window_begin (struct window *w)
{
  struct frame *f = XFRAME (WINDOW_FRAME (w));
  Mouse_HLInfo *hlinfo = MOUSE_HL_INFO (f);

  block_input ();

  if (FRAME_RIF (f)->update_window_begin_hook)
    FRAME_RIF (f)->update_window_begin_hook (w);

  w->output_cursor = w->cursor;

  if (f == hlinfo->mouse_face_mouse_frame)
    {
      /* Don't do highlighting for mouse motion during the update.  */
      hlinfo->mouse_face_defer = true;

      /* If the frame needs to be redrawn, simply forget about any
	 prior mouse highlighting.  */
      if (FRAME_GARBAGED_P (f))
	hlinfo->mouse_face_window = Qnil;
    }

  unblock_input ();
}

/* End update of window W.

   Draw vertical borders between horizontally adjacent windows, and
   display W's cursor if CURSOR_ON_P is non-zero.

   MOUSE_FACE_OVERWRITTEN_P non-zero means that some row containing
   glyphs in mouse-face were overwritten.  In that case we have to
   make sure that the mouse-highlight is properly redrawn.  */
void
gui_update_window_end (struct window *w, bool cursor_on_p,
                       bool mouse_face_overwritten_p)
{
  struct frame *f = XFRAME (WINDOW_FRAME (w));

  /* Pseudo windows don't have cursors, so don't display them here.  */
  if (!w->pseudo_window_p)
    {
      block_input ();

      if (cursor_on_p)
	display_and_set_cursor (w, true,
				w->output_cursor.hpos, w->output_cursor.vpos,
				w->output_cursor.x, w->output_cursor.y);

      if (draw_window_fringes (w, true))
	{
	  if (WINDOW_RIGHT_DIVIDER_WIDTH (w))
	    gui_draw_right_divider (w);
	  else
	    gui_draw_vertical_border (w);
	}
      unblock_input ();
    }

  /* If a row with mouse-face was overwritten, arrange for
     frame_up_to_date_hook to redisplay the mouse highlight.  */
  if (mouse_face_overwritten_p)
    {
      Mouse_HLInfo *hlinfo = MOUSE_HL_INFO (f);

      hlinfo->mouse_face_beg_row = hlinfo->mouse_face_beg_col = -1;
      hlinfo->mouse_face_end_row = hlinfo->mouse_face_end_col = -1;
      hlinfo->mouse_face_window = Qnil;
    }

  if (FRAME_RIF (f)->update_window_end_hook)
    FRAME_RIF (f)->update_window_end_hook (w,
                                           cursor_on_p,
                                           mouse_face_overwritten_p);
}

#endif /* HAVE_WINDOW_SYSTEM  */

/* Update the display of area AREA in window W, row number VPOS.
   AREA can be either LEFT_MARGIN_AREA or RIGHT_MARGIN_AREA.  */

static void
update_marginal_area (struct window *w, struct glyph_row *updated_row,
		      enum glyph_row_area area, int vpos)
{
  struct glyph_row *desired_row = MATRIX_ROW (w->desired_matrix, vpos);
  struct redisplay_interface *rif = FRAME_RIF (XFRAME (WINDOW_FRAME (w)));

  /* Set cursor to start of glyphs, write them, and clear to the end
     of the area.  I don't think that something more sophisticated is
     necessary here, since marginal areas will not be the default.  */
  output_cursor_to (w, vpos, 0, desired_row->y, 0);
  if (desired_row->used[area])
    rif->write_glyphs (w, updated_row, desired_row->glyphs[area],
		       area, desired_row->used[area]);
  rif->clear_end_of_line (w, updated_row, area, -1);
}


/* Update the display of the text area of row VPOS in window W.
   Value is true if display has changed.  */

static bool
update_text_area (struct window *w, struct glyph_row *updated_row, int vpos)
{
  struct glyph_row *current_row = MATRIX_ROW (w->current_matrix, vpos);
  struct glyph_row *desired_row = MATRIX_ROW (w->desired_matrix, vpos);
  struct redisplay_interface *rif = FRAME_RIF (XFRAME (WINDOW_FRAME (w)));
  bool changed_p = 0;

  /* If rows are at different X or Y, or rows have different height,
     or the current row is marked invalid, write the entire line.  */
  if (!current_row->enabled_p
      || desired_row->y != current_row->y
      || desired_row->ascent != current_row->ascent
      || desired_row->phys_ascent != current_row->phys_ascent
      || desired_row->phys_height != current_row->phys_height
      || desired_row->visible_height != current_row->visible_height
      || current_row->overlapped_p
      /* This next line is necessary for correctly redrawing
	 mouse-face areas after scrolling and other operations.
	 However, it causes excessive flickering when mouse is moved
	 across the mode line.  Luckily, turning it off for the mode
	 line doesn't seem to hurt anything. -- cyd.
         But it is still needed for the header line. -- kfs.  */
      || (current_row->mouse_face_p
	  && !(current_row->mode_line_p && vpos > 0))
      || current_row->x != desired_row->x)
    {
      output_cursor_to (w, vpos, 0, desired_row->y, desired_row->x);

      if (desired_row->used[TEXT_AREA])
	rif->write_glyphs (w, updated_row, desired_row->glyphs[TEXT_AREA],
			   TEXT_AREA, desired_row->used[TEXT_AREA]);

      /* Clear to end of window.  */
      rif->clear_end_of_line (w, updated_row, TEXT_AREA, -1);
      changed_p = 1;

      /* This erases the cursor.  We do this here because
         notice_overwritten_cursor cannot easily check this, which
         might indicate that the whole functionality of
         notice_overwritten_cursor would better be implemented here.
         On the other hand, we need notice_overwritten_cursor as long
         as mouse highlighting is done asynchronously outside of
         redisplay.  */
      if (vpos == w->phys_cursor.vpos)
	w->phys_cursor_on_p = 0;
    }
  else
    {
      int stop, i, x;
      struct glyph *current_glyph = current_row->glyphs[TEXT_AREA];
      struct glyph *desired_glyph = desired_row->glyphs[TEXT_AREA];
      bool overlapping_glyphs_p = current_row->contains_overlapping_glyphs_p;
      int desired_stop_pos = desired_row->used[TEXT_AREA];
      bool abort_skipping = 0;

      /* If the desired row extends its face to the text area end, and
	 unless the current row also does so at the same position,
	 make sure we write at least one glyph, so that the face
	 extension actually takes place.  */
      if (MATRIX_ROW_EXTENDS_FACE_P (desired_row)
	  && (desired_stop_pos < current_row->used[TEXT_AREA]
	      || (desired_stop_pos == current_row->used[TEXT_AREA]
		  && !MATRIX_ROW_EXTENDS_FACE_P (current_row))))
	--desired_stop_pos;

      stop = min (current_row->used[TEXT_AREA], desired_stop_pos);
      i = 0;
      x = desired_row->x;

      /* Loop over glyphs that current and desired row may have
	 in common.  */
      while (i < stop)
	{
	  bool can_skip_p = !abort_skipping;

	  /* Skip over glyphs that both rows have in common.  These
	     don't have to be written.  We can't skip if the last
	     current glyph overlaps the glyph to its right.  For
	     example, consider a current row of `if ' with the `f' in
	     Courier bold so that it overlaps the ` ' to its right.
	     If the desired row is ` ', we would skip over the space
	     after the `if' and there would remain a pixel from the
	     `f' on the screen.  */
	  if (overlapping_glyphs_p && i > 0)
	    {
	      struct glyph *glyph = &current_row->glyphs[TEXT_AREA][i - 1];
	      int left, right;

	      rif->get_glyph_overhangs (glyph, XFRAME (w->frame),
					&left, &right);
	      can_skip_p = (right == 0 && !abort_skipping);
	    }

	  if (can_skip_p)
	    {
	      int start_hpos = i;

	      while (i < stop
		     && GLYPH_EQUAL_P (desired_glyph, current_glyph))
		{
		  x += desired_glyph->pixel_width;
		  ++desired_glyph, ++current_glyph, ++i;
		}

	      /* Consider the case that the current row contains "xxx
		 ppp ggg" in italic Courier font, and the desired row
		 is "xxx ggg".  The character `p' has lbearing, `g'
		 has not.  The loop above will stop in front of the
		 first `p' in the current row.  If we would start
		 writing glyphs there, we wouldn't erase the lbearing
		 of the `p'.  The rest of the lbearing problem is then
		 taken care of by draw_glyphs.  */
	      if (overlapping_glyphs_p
		  && i > 0
		  && i < current_row->used[TEXT_AREA]
		  && (current_row->used[TEXT_AREA]
		      != desired_row->used[TEXT_AREA]))
		{
		  int left, right;

		  rif->get_glyph_overhangs (current_glyph,
					    XFRAME (w->frame),
					    &left, &right);
		  while (left > 0 && i > 0)
		    {
		      --i, --desired_glyph, --current_glyph;
		      x -= desired_glyph->pixel_width;
		      left -= desired_glyph->pixel_width;
		    }

		  /* Abort the skipping algorithm if we end up before
		     our starting point, to avoid looping (bug#1070).
		     This can happen when the lbearing is larger than
		     the pixel width.  */
		  abort_skipping = (i < start_hpos);
		}
	    }

	  /* Try to avoid writing the entire rest of the desired row
	     by looking for a resync point.  This mainly prevents
	     mode line flickering in the case the mode line is in
	     fixed-pitch font, which it usually will be.  */
	  if (i < desired_row->used[TEXT_AREA])
	    {
	      int start_x = x, start_hpos = i;
	      struct glyph *start = desired_glyph;
	      int current_x = x;
	      bool skip_first_p = !can_skip_p;

	      /* Find the next glyph that's equal again.  */
	      while (i < stop
		     && (skip_first_p
			 || !GLYPH_EQUAL_P (desired_glyph, current_glyph))
		     && x == current_x)
		{
		  x += desired_glyph->pixel_width;
		  current_x += current_glyph->pixel_width;
		  ++desired_glyph, ++current_glyph, ++i;
		  skip_first_p = 0;
		}

	      if (i == start_hpos || x != current_x)
		{
		  i = start_hpos;
		  x = start_x;
		  desired_glyph = start;
		  break;
		}

	      output_cursor_to (w, vpos, start_hpos, desired_row->y, start_x);
	      rif->write_glyphs (w, updated_row, start,
				 TEXT_AREA, i - start_hpos);
	      changed_p = 1;
	    }
	}

      /* Write the rest.  */
      if (i < desired_row->used[TEXT_AREA])
	{
	  output_cursor_to (w, vpos, i, desired_row->y, x);
	  rif->write_glyphs (w, updated_row, desired_glyph,
			     TEXT_AREA, desired_row->used[TEXT_AREA] - i);
	  changed_p = 1;
	}

      /* Maybe clear to end of line.  */
      if (MATRIX_ROW_EXTENDS_FACE_P (desired_row))
	{
	  /* If new row extends to the end of the text area, nothing
	     has to be cleared, if and only if we did a write_glyphs
	     above.  This is made sure by setting desired_stop_pos
	     appropriately above.  */
	  eassert (i < desired_row->used[TEXT_AREA]
		   || ((desired_row->used[TEXT_AREA]
			== current_row->used[TEXT_AREA])
		       && MATRIX_ROW_EXTENDS_FACE_P (current_row)));
	}
      else if (MATRIX_ROW_EXTENDS_FACE_P (current_row))
	{
	  /* If old row extends to the end of the text area, clear.  */
	  if (i >= desired_row->used[TEXT_AREA])
	    output_cursor_to (w, vpos, i, desired_row->y,
			      desired_row->pixel_width);
	  rif->clear_end_of_line (w, updated_row, TEXT_AREA, -1);
	  changed_p = 1;
	}
      else if (desired_row->pixel_width < current_row->pixel_width)
	{
	  /* Otherwise clear to the end of the old row.  Everything
	     after that position should be clear already.  */
	  int xlim;

	  if (i >= desired_row->used[TEXT_AREA])
	    output_cursor_to (w, vpos, i, desired_row->y,
			      desired_row->pixel_width);

	  /* If cursor is displayed at the end of the line, make sure
	     it's cleared.  Nowadays we don't have a phys_cursor_glyph
	     with which to erase the cursor (because this method
	     doesn't work with lbearing/rbearing), so we must do it
	     this way.  */
	  if (vpos == w->phys_cursor.vpos
	      && (desired_row->reversed_p
		  ? (w->phys_cursor.hpos < 0)
		  : (w->phys_cursor.hpos >= desired_row->used[TEXT_AREA])))
	    {
	      w->phys_cursor_on_p = 0;
	      xlim = -1;
	    }
	  else
	    xlim = current_row->pixel_width;
	  rif->clear_end_of_line (w, updated_row, TEXT_AREA, xlim);
	  changed_p = 1;
	}
    }

  return changed_p;
}


/* Update row VPOS in window W.  Value is true if display has been changed.  */

static bool
update_window_line (struct window *w, int vpos, bool *mouse_face_overwritten_p)
{
  struct glyph_row *current_row = MATRIX_ROW (w->current_matrix, vpos);
  struct glyph_row *desired_row = MATRIX_ROW (w->desired_matrix, vpos);
  struct redisplay_interface *rif = FRAME_RIF (XFRAME (WINDOW_FRAME (w)));
  bool changed_p = 0;

  /* A row can be completely invisible in case a desired matrix was
     built with a vscroll and then make_cursor_line_fully_visible shifts
     the matrix.  Make sure to make such rows current anyway, since
     we need the correct y-position, for example, in the current matrix.  */
  if (desired_row->mode_line_p
      || desired_row->visible_height > 0)
    {
      eassert (desired_row->enabled_p);

      /* Update display of the left margin area, if there is one.  */
      if (!desired_row->full_width_p && w->left_margin_cols > 0)
	{
	  changed_p = 1;
	  update_marginal_area (w, desired_row, LEFT_MARGIN_AREA, vpos);
	  /* Setting this flag will ensure the vertical border, if
	     any, between this window and the one on its left will be
	     redrawn.  This is necessary because updating the left
	     margin area can potentially draw over the border.  */
	  current_row->redraw_fringe_bitmaps_p = 1;
	}

      /* Update the display of the text area.  */
      if (update_text_area (w, desired_row, vpos))
	{
	  changed_p = 1;
	  if (current_row->mouse_face_p)
	    *mouse_face_overwritten_p = 1;
	}

      /* Update display of the right margin area, if there is one.  */
      if (!desired_row->full_width_p && w->right_margin_cols > 0)
	{
	  changed_p = 1;
	  update_marginal_area (w, desired_row, RIGHT_MARGIN_AREA, vpos);
	}

      /* Draw truncation marks etc.  */
      if (!current_row->enabled_p
	  || desired_row->y != current_row->y
	  || desired_row->visible_height != current_row->visible_height
	  || desired_row->cursor_in_fringe_p != current_row->cursor_in_fringe_p
	  || desired_row->overlay_arrow_bitmap != current_row->overlay_arrow_bitmap
	  || current_row->redraw_fringe_bitmaps_p
	  || desired_row->mode_line_p != current_row->mode_line_p
	  || desired_row->exact_window_width_line_p != current_row->exact_window_width_line_p
	  || (MATRIX_ROW_CONTINUATION_LINE_P (desired_row)
	      != MATRIX_ROW_CONTINUATION_LINE_P (current_row)))
	rif->after_update_window_line_hook (w, desired_row);
    }

  /* Update current_row from desired_row.  */
  make_current (w->desired_matrix, w->current_matrix, vpos);
  return changed_p;
}


/* Set the cursor after an update of window W.  This function may only
   be called from update_window.  */

static void
set_window_cursor_after_update (struct window *w)
{
  struct frame *f = XFRAME (w->frame);
  int cx, cy, vpos, hpos;

  /* Not intended for frame matrix updates.  */
  eassert (FRAME_WINDOW_P (f));

  if (cursor_in_echo_area
      && !NILP (echo_area_buffer[0])
      /* If we are showing a message instead of the mini-buffer,
	 show the cursor for the message instead.  */
      && XWINDOW (minibuf_window) == w
      && EQ (minibuf_window, echo_area_window)
      /* These cases apply only to the frame that contains
	 the active mini-buffer window.  */
      && FRAME_HAS_MINIBUF_P (f)
      && EQ (FRAME_MINIBUF_WINDOW (f), echo_area_window))
    {
      cx = cy = vpos = hpos = 0;

      /* If the mini-buffer is several lines high, find the last
	 line that has any text on it.  Note: either all lines
	 are enabled or none.  Otherwise we wouldn't be able to
	 determine Y.  */
      struct glyph_row *last_row = NULL;
      int yb = window_text_bottom_y (w);

      for (struct glyph_row *row = w->current_matrix->rows;
	   row->enabled_p && (!last_row || MATRIX_ROW_BOTTOM_Y (row) <= yb);
	   row++)
	if (row->used[TEXT_AREA] && row->glyphs[TEXT_AREA][0].charpos >= 0)
	  last_row = row;

      if (last_row)
	{
	  struct glyph *start = last_row->glyphs[TEXT_AREA];
	  struct glyph *last = start + last_row->used[TEXT_AREA] - 1;

	  while (last > start && last->charpos < 0)
	    --last;

	  for (struct glyph *glyph = start; glyph < last; glyph++)
	    {
	      cx += glyph->pixel_width;
	      hpos++;
	    }

	  cy = last_row->y;
	  vpos = MATRIX_ROW_VPOS (last_row, w->current_matrix);
	}
    }
  else
    {
      cx = w->cursor.x;
      cy = w->cursor.y;
      hpos = w->cursor.hpos;
      vpos = w->cursor.vpos;
    }

  /* Window cursor can be out of sync for horizontally split windows.
     Horizontal position is -1 when cursor is on the left fringe.   */
  hpos = clip_to_bounds (-1, hpos, w->current_matrix->matrix_w - 1);
  vpos = clip_to_bounds (0, vpos, w->current_matrix->nrows - 1);
  output_cursor_to (w, vpos, hpos, cy, cx);
}


/* Set WINDOW->must_be_updated_p to ON_P for all windows in
   the window tree rooted at W.  */

static void
set_window_update_flags (struct window *w, bool on_p)
{
  while (w)
    {
      if (WINDOWP (w->contents))
	set_window_update_flags (XWINDOW (w->contents), on_p);
      else
	w->must_be_updated_p = on_p;

      w = NILP (w->next) ? 0 : XWINDOW (w->next);
    }
}


\f
/***********************************************************************
			Window-Based Scrolling
 ***********************************************************************/

/* Structure describing rows in scrolling_window.  */

struct row_entry
{
  /* Number of occurrences of this row in desired and current matrix.  */
  int old_uses, new_uses;

  /* Vpos of row in new matrix.  */
  int new_line_number;

  /* Bucket index of this row_entry in the hash table row_table.  */
  ptrdiff_t bucket;

  /* The row described by this entry.  */
  struct glyph_row *row;

  /* Hash collision chain.  */
  struct row_entry *next;
};

/* A pool to allocate row_entry structures from, and the size of the
   pool.  The pool is reallocated in scrolling_window when we find
   that we need a larger one.  */

static struct row_entry *row_entry_pool;
static ptrdiff_t row_entry_pool_size;

/* Index of next free entry in row_entry_pool.  */

static ptrdiff_t row_entry_idx;

/* The hash table used during scrolling, and the table's size.  This
   table is used to quickly identify equal rows in the desired and
   current matrix.  */

static struct row_entry **row_table;
static ptrdiff_t row_table_size;

/* Vectors of pointers to row_entry structures belonging to the
   current and desired matrix, and the size of the vectors.  */

static struct row_entry **old_lines, **new_lines;
static ptrdiff_t old_lines_size, new_lines_size;

/* A pool to allocate run structures from, and its size.  */

static struct run *run_pool;
static ptrdiff_t runs_size;

/* A vector of runs of lines found during scrolling.  */

static struct run **runs;

/* Add glyph row ROW to the scrolling hash table.  */

static struct row_entry *
add_row_entry (struct glyph_row *row)
{
  struct row_entry *entry;
  ptrdiff_t i = row->hash % row_table_size;

  entry = row_table[i];
  eassert (entry || verify_row_hash (row));
  while (entry && !row_equal_p (entry->row, row, 1))
    entry = entry->next;

  if (entry == NULL)
    {
      entry = row_entry_pool + row_entry_idx++;
      entry->row = row;
      entry->old_uses = entry->new_uses = 0;
      entry->new_line_number = 0;
      entry->bucket = i;
      entry->next = row_table[i];
      row_table[i] = entry;
    }

  return entry;
}


/* Try to reuse part of the current display of W by scrolling lines.
   HEADER_LINE_P means W has a header line.

   The algorithm is taken from Communications of the ACM, Apr78 "A
   Technique for Isolating Differences Between Files."  It should take
   O(N) time.

   A short outline of the steps of the algorithm

   1. Skip lines equal at the start and end of both matrices.

   2. Enter rows in the current and desired matrix into a symbol
   table, counting how often they appear in both matrices.

   3. Rows that appear exactly once in both matrices serve as anchors,
   i.e. we assume that such lines are likely to have been moved.

   4. Starting from anchor lines, extend regions to be scrolled both
   forward and backward.

   Value is

   -1	if all rows were found to be equal.
   0	to indicate that we did not scroll the display, or
   1	if we did scroll.  */

static int
scrolling_window (struct window *w, int tab_line_p)
{
  struct glyph_matrix *desired_matrix = w->desired_matrix;
  struct glyph_matrix *current_matrix = w->current_matrix;
  int yb = window_text_bottom_y (w);
  ptrdiff_t i;
  int j, first_old, first_new, last_old, last_new;
  int nruns, run_idx;
  ptrdiff_t n;
  struct row_entry *entry;
  struct redisplay_interface *rif = FRAME_RIF (XFRAME (WINDOW_FRAME (w)));

  /* Skip over rows equal at the start.  */
  for (i = tab_line_p; i < current_matrix->nrows - 1; ++i)
    {
      struct glyph_row *d = MATRIX_ROW (desired_matrix, i);
      struct glyph_row *c = MATRIX_ROW (current_matrix, i);

      if (c->enabled_p
	  && d->enabled_p
	  && !d->redraw_fringe_bitmaps_p
	  && c->y == d->y
	  && MATRIX_ROW_BOTTOM_Y (c) <= yb
	  && MATRIX_ROW_BOTTOM_Y (d) <= yb
	  && row_equal_p (c, d, 1))
	{
	  assign_row (c, d);
	  d->enabled_p = false;
	}
      else
	break;
    }

#ifdef HAVE_XWIDGETS
  /* Currently this seems needed to detect xwidget movement reliably.
     This is most probably because an xwidget glyph is represented in
     struct glyph's 'union u' by a pointer to a struct, which takes 8
     bytes in 64-bit builds, and thus the comparison of u.val values
     done by GLYPH_EQUAL_P doesn't work reliably, since it assumes the
     size of the union is 4 bytes.  FIXME.  */
    return 0;
#endif

  /* Can't scroll the display of w32 GUI frames when position of point
     is indicated by the system caret, because scrolling the display
     will then "copy" the pixels used by the caret.  */
#ifdef HAVE_NTGUI
  if (w32_use_visible_system_caret)
    return 0;
#endif

  /* Give up if some rows in the desired matrix are not enabled.  */
  if (! MATRIX_ROW_ENABLED_P (desired_matrix, i))
    return -1;

  first_old = first_new = i;

  /* Set last_new to the index + 1 of the row that reaches the
     bottom boundary in the desired matrix.  Give up if we find a
     disabled row before we reach the bottom boundary.  */
  i = first_new + 1;
  while (i < desired_matrix->nrows - 1)
    {
      int bottom;

      if (! MATRIX_ROW_ENABLED_P (desired_matrix, i))
	return 0;
      bottom = MATRIX_ROW_BOTTOM_Y (MATRIX_ROW (desired_matrix, i));
      if (bottom <= yb)
	++i;
      if (bottom >= yb)
	break;
    }

  last_new = i;

  /* Set last_old to the index + 1 of the row that reaches the bottom
     boundary in the current matrix.  We don't look at the enabled
     flag here because we plan to reuse part of the display even if
     other parts are disabled.  */
  i = first_old + 1;
  while (i < current_matrix->nrows - 1)
    {
      int bottom = MATRIX_ROW_BOTTOM_Y (MATRIX_ROW (current_matrix, i));
      if (bottom <= yb)
	++i;
      if (bottom >= yb)
	break;
    }

  last_old = i;

  /* Skip over rows equal at the bottom.  */
  i = last_new;
  j = last_old;
  while (i - 1 > first_new
         && j - 1 > first_old
         && MATRIX_ROW_ENABLED_P (current_matrix, j - 1)
	 && (MATRIX_ROW (current_matrix, j - 1)->y
	     == MATRIX_ROW (desired_matrix, i - 1)->y)
	 && !MATRIX_ROW (desired_matrix, i - 1)->redraw_fringe_bitmaps_p
         && row_equal_p (MATRIX_ROW (desired_matrix, i - 1),
                         MATRIX_ROW (current_matrix, j - 1), 1))
    --i, --j;
  last_new = i;
  last_old = j;

  /* Nothing to do if all rows are equal.  */
  if (last_new == first_new)
    return 0;

  /* Check for integer overflow in size calculation.

     If next_almost_prime checks (N) for divisibility by 2..10, then
     it can return at most N + 10, e.g., next_almost_prime (1) == 11.
     So, set next_almost_prime_increment_max to 10.

     It's just a coincidence that next_almost_prime_increment_max ==
     NEXT_ALMOST_PRIME_LIMIT - 1.  If NEXT_ALMOST_PRIME_LIMIT were
     13, then next_almost_prime_increment_max would be 14, e.g.,
     because next_almost_prime (113) would be 127.  */
  {
    verify (NEXT_ALMOST_PRIME_LIMIT == 11);
    enum { next_almost_prime_increment_max = 10 };
    ptrdiff_t row_table_max =
      (min (PTRDIFF_MAX, SIZE_MAX) / (3 * sizeof *row_table)
       - next_almost_prime_increment_max);
    ptrdiff_t current_nrows_max = row_table_max - desired_matrix->nrows;
    if (current_nrows_max < current_matrix->nrows)
      memory_full (SIZE_MAX);
  }

  /* Reallocate vectors, tables etc. if necessary.  */

  if (current_matrix->nrows > old_lines_size)
    old_lines = xpalloc (old_lines, &old_lines_size,
			 current_matrix->nrows - old_lines_size,
			 INT_MAX, sizeof *old_lines);

  if (desired_matrix->nrows > new_lines_size)
    new_lines = xpalloc (new_lines, &new_lines_size,
			 desired_matrix->nrows - new_lines_size,
			 INT_MAX, sizeof *new_lines);

  n = desired_matrix->nrows;
  n += current_matrix->nrows;
  if (row_table_size < 3 * n)
    {
      ptrdiff_t size = next_almost_prime (3 * n);
      row_table = xnrealloc (row_table, size, sizeof *row_table);
      row_table_size = size;
      memset (row_table, 0, size * sizeof *row_table);
    }

  if (n > row_entry_pool_size)
    row_entry_pool = xpalloc (row_entry_pool, &row_entry_pool_size,
			      n - row_entry_pool_size,
			      -1, sizeof *row_entry_pool);

  if (desired_matrix->nrows > runs_size)
    {
      runs = xnrealloc (runs, desired_matrix->nrows, sizeof *runs);
      run_pool = xnrealloc (run_pool, desired_matrix->nrows, sizeof *run_pool);
      runs_size = desired_matrix->nrows;
    }

  nruns = run_idx = 0;
  row_entry_idx = 0;

  /* Add rows from the current and desired matrix to the hash table
     row_hash_table to be able to find equal ones quickly.  */

  for (i = first_old; i < last_old; ++i)
    {
      if (MATRIX_ROW_ENABLED_P (current_matrix, i))
	{
	  entry = add_row_entry (MATRIX_ROW (current_matrix, i));
	  old_lines[i] = entry;
	  ++entry->old_uses;
	}
      else
	old_lines[i] = NULL;
    }

  for (i = first_new; i < last_new; ++i)
    {
      eassert (MATRIX_ROW_ENABLED_P (desired_matrix, i));
      entry = add_row_entry (MATRIX_ROW (desired_matrix, i));
      ++entry->new_uses;
      entry->new_line_number = i;
      new_lines[i] = entry;
    }

  /* Identify moves based on lines that are unique and equal
     in both matrices.  */
  for (i = first_old; i < last_old;)
    if (old_lines[i]
	&& old_lines[i]->old_uses == 1
        && old_lines[i]->new_uses == 1)
      {
	int p, q;
	int new_line = old_lines[i]->new_line_number;
	struct run *run = run_pool + run_idx++;

	/* Record move.  */
	run->current_vpos = i;
	run->current_y = MATRIX_ROW (current_matrix, i)->y;
	run->desired_vpos = new_line;
	run->desired_y = MATRIX_ROW (desired_matrix, new_line)->y;
	run->nrows = 1;
	run->height = MATRIX_ROW (current_matrix, i)->height;

	/* Extend backward.  */
	p = i - 1;
	q = new_line - 1;
	while (p > first_old
	       && q > first_new
	       && old_lines[p] == new_lines[q])
	  {
	    int h = MATRIX_ROW (current_matrix, p)->height;
	    --run->current_vpos;
	    --run->desired_vpos;
	    ++run->nrows;
	    run->height += h;
	    run->desired_y -= h;
	    run->current_y -= h;
	    --p, --q;
	  }

	/* Extend forward.  */
	p = i + 1;
	q = new_line + 1;
	while (p < last_old
	       && q < last_new
	       && old_lines[p] == new_lines[q])
	  {
	    int h = MATRIX_ROW (current_matrix, p)->height;
	    ++run->nrows;
	    run->height += h;
	    ++p, ++q;
	  }

	/* Insert run into list of all runs.  Order runs by copied
	   pixel lines.  Note that we record runs that don't have to
	   be copied because they are already in place.  This is done
	   because we can avoid calling update_window_line in this
	   case.  */
	for (p = 0; p < nruns && runs[p]->height > run->height; ++p)
	  ;
	for (q = nruns; q > p; --q)
	  runs[q] = runs[q - 1];
	runs[p] = run;
	++nruns;

	i += run->nrows;
      }
    else
      ++i;

  /* Do the moves.  Do it in a way that we don't overwrite something
     we want to copy later on.  This is not solvable in general
     because there is only one display and we don't have a way to
     exchange areas on this display.  Example:

          +-----------+       +-----------+
          |     A     |       |     B     |
          +-----------+  -->  +-----------+
          |     B     |       |     A     |
          +-----------+       +-----------+

     Instead, prefer bigger moves, and invalidate moves that would
     copy from where we copied to.  */

  for (i = 0; i < nruns; ++i)
    if (runs[i]->nrows > 0)
      {
	struct run *r = runs[i];

	/* Copy on the display.  */
	if (r->current_y != r->desired_y)
	  {
	    rif->clear_window_mouse_face (w);
	    rif->scroll_run_hook (w, r);
	  }

	/* Truncate runs that copy to where we copied to, and
	   invalidate runs that copy from where we copied to.  */
	for (j = nruns - 1; j > i; --j)
	  {
	    struct run *p = runs[j];
	    bool truncated_p = 0;

	    if (p->nrows > 0
		&& p->desired_y < r->desired_y + r->height
		&& p->desired_y + p->height > r->desired_y)
	      {
		if (p->desired_y < r->desired_y)
		  {
		    p->nrows = r->desired_vpos - p->desired_vpos;
		    p->height = r->desired_y - p->desired_y;
		    truncated_p = 1;
		  }
		else
		  {
		    int nrows_copied = (r->desired_vpos + r->nrows
					- p->desired_vpos);

		    if (p->nrows <= nrows_copied)
		      p->nrows = 0;
		    else
		      {
			int height_copied = (r->desired_y + r->height
					     - p->desired_y);

			p->current_vpos += nrows_copied;
			p->desired_vpos += nrows_copied;
			p->nrows -= nrows_copied;
			p->current_y += height_copied;
			p->desired_y += height_copied;
			p->height -= height_copied;
			truncated_p = 1;
		      }
		  }
	      }

	    if (r->current_y != r->desired_y
		/* The condition below is equivalent to
		   ((p->current_y >= r->desired_y
		     && p->current_y < r->desired_y + r->height)
		    || (p->current_y + p->height > r->desired_y
			&& (p->current_y + p->height
			    <= r->desired_y + r->height)))
		   because we have 0 < p->height <= r->height.  */
		&& p->current_y < r->desired_y + r->height
		&& p->current_y + p->height > r->desired_y)
	      p->nrows = 0;

	    /* Reorder runs by copied pixel lines if truncated.  */
	    if (truncated_p && p->nrows > 0)
	      {
		int k = nruns - 1;

		while (runs[k]->nrows == 0 || runs[k]->height < p->height)
		  k--;
		memmove (runs + j, runs + j + 1, (k - j) * sizeof (*runs));
		runs[k] = p;
	      }
	  }

	/* Assign matrix rows.  */
	for (j = 0; j < r->nrows; ++j)
	  {
	    struct glyph_row *from, *to;
	    bool to_overlapped_p;

	    to = MATRIX_ROW (current_matrix, r->desired_vpos + j);
	    from = MATRIX_ROW (desired_matrix, r->desired_vpos + j);
	    to_overlapped_p = to->overlapped_p;
	    from->redraw_fringe_bitmaps_p = from->fringe_bitmap_periodic_p;
	    assign_row (to, from);
	    /* The above `assign_row' actually does swap, so if we had
	       an overlap in the copy destination of two runs, then
	       the second run would assign a previously disabled bogus
	       row.  But thanks to the truncation code in the
	       preceding for-loop, we no longer have such an overlap,
	       and thus the assigned row should always be enabled.  */
	    eassert (to->enabled_p);
	    from->enabled_p = false;
	    to->overlapped_p = to_overlapped_p;
	  }
      }

  /* Clear the hash table, for the next time.  */
  for (i = 0; i < row_entry_idx; ++i)
    row_table[row_entry_pool[i].bucket] = NULL;

  /* Value is 1 to indicate that we scrolled the display.  */
  return nruns > 0;
}


\f
/************************************************************************
			 Frame-Based Updates
 ************************************************************************/

/* Update the desired frame matrix of frame F.

   FORCE_P means that the update should not be stopped by pending input.
   INHIBIT_ID_P means that scrolling by insert/delete should not be tried.
   SET_CURSOR_P false means do not set cursor at point in selected window.

   Value is true if update was stopped due to pending input.  */

static bool
update_frame_1 (struct frame *f, bool force_p, bool inhibit_id_p,
		bool set_cursor_p, bool updating_menu_p)
{
  /* Frame matrices to work on.  */
  struct glyph_matrix *current_matrix = f->current_matrix;
  struct glyph_matrix *desired_matrix = f->desired_matrix;
  int i;
  bool pause_p;
  int preempt_count = clip_to_bounds (1, baud_rate / 2400 + 1, INT_MAX);

  eassert (current_matrix && desired_matrix);

  if (baud_rate != FRAME_COST_BAUD_RATE (f))
    calculate_costs (f);

  if (!force_p && detect_input_pending_ignore_squeezables ())
    {
      pause_p = 1;
      goto do_pause;
    }

  /* If we cannot insert/delete lines, it's no use trying it.  */
  if (!FRAME_LINE_INS_DEL_OK (f))
    inhibit_id_p = 1;

  /* See if any of the desired lines are enabled; don't compute for
     i/d line if just want cursor motion.  */
  for (i = 0; i < desired_matrix->nrows; i++)
    if (MATRIX_ROW_ENABLED_P (desired_matrix, i))
      break;

  /* Try doing i/d line, if not yet inhibited.  */
  if (!inhibit_id_p && i < desired_matrix->nrows)
    force_p |= scrolling (f);

  /* Update the individual lines as needed.  Do bottom line first.  */
  if (MATRIX_ROW_ENABLED_P (desired_matrix, desired_matrix->nrows - 1))
    update_frame_line (f, desired_matrix->nrows - 1, updating_menu_p);

  /* Now update the rest of the lines.  */
  for (i = 0; i < desired_matrix->nrows - 1 && (force_p || !input_pending); i++)
    {
      if (MATRIX_ROW_ENABLED_P (desired_matrix, i))
	{
	  if (FRAME_TERMCAP_P (f))
	    {
	      /* Flush out every so many lines.
		 Also flush out if likely to have more than 1k buffered
		 otherwise.   I'm told that some telnet connections get
		 really screwed by more than 1k output at once.  */
	      FILE *display_output = FRAME_TTY (f)->output;
	      if (display_output)
		{
		  ptrdiff_t outq = __fpending (display_output);
		  if (outq > 900
		      || (outq > 20 && ((i - 1) % preempt_count == 0)))
		    fflush (display_output);
		}
	    }

	  if (!force_p && (i - 1) % preempt_count == 0)
	    detect_input_pending_ignore_squeezables ();

	  update_frame_line (f, i, updating_menu_p);
	}
    }

  pause_p = 0 < i && i < FRAME_TOTAL_LINES (f) - 1;

  /* Now just clean up termcap drivers and set cursor, etc.  */
  if (!pause_p && set_cursor_p)
    {
      if ((cursor_in_echo_area
	   /* If we are showing a message instead of the mini-buffer,
	      show the cursor for the message instead of for the
	      (now hidden) mini-buffer contents.  */
	   || (EQ (minibuf_window, selected_window)
	       && EQ (minibuf_window, echo_area_window)
	       && !NILP (echo_area_buffer[0])))
	  /* These cases apply only to the frame that contains
	     the active mini-buffer window.  */
	  && FRAME_HAS_MINIBUF_P (f)
	  && EQ (FRAME_MINIBUF_WINDOW (f), echo_area_window))
	{
	  int top = WINDOW_TOP_EDGE_LINE (XWINDOW (FRAME_MINIBUF_WINDOW (f)));
	  int col;

	  /* Put cursor at the end of the prompt.  If the mini-buffer
	     is several lines high, find the last line that has
	     any text on it.  */
	  int row = FRAME_TOTAL_LINES (f);
	  do
	    {
	      row--;
	      col = 0;

	      if (MATRIX_ROW_ENABLED_P (current_matrix, row))
		{
		  /* Frame rows are filled up with spaces that
		     must be ignored here.  */
		  struct glyph_row *r = MATRIX_ROW (current_matrix, row);
		  struct glyph *start = r->glyphs[TEXT_AREA];

		  col = r->used[TEXT_AREA];
		  while (0 < col && start[col - 1].charpos < 0)
		    col--;
		}
	    }
	  while (row > top && col == 0);

	  /* Make sure COL is not out of range.  */
	  if (col >= FRAME_CURSOR_X_LIMIT (f))
	    {
	      /* If we have another row, advance cursor into it.  */
	      if (row < FRAME_TOTAL_LINES (f) - 1)
		{
		  col = FRAME_LEFT_SCROLL_BAR_COLS (f);
		  row++;
		}
	      /* Otherwise move it back in range.  */
	      else
		col = FRAME_CURSOR_X_LIMIT (f) - 1;
	    }

	  cursor_to (f, row, col);
	}
      else
	{
	  /* We have only one cursor on terminal frames.  Use it to
	     display the cursor of the selected window.  */
	  struct window *w = XWINDOW (FRAME_SELECTED_WINDOW (f));
	  if (w->cursor.vpos >= 0
	      /* The cursor vpos may be temporarily out of bounds
	         in the following situation:  There is one window,
		 with the cursor in the lower half of it.  The window
		 is split, and a message causes a redisplay before
	         a new cursor position has been computed.  */
	      && w->cursor.vpos < WINDOW_TOTAL_LINES (w))
	    {
	      int x = WINDOW_TO_FRAME_HPOS (w, w->cursor.hpos);
	      int y = WINDOW_TO_FRAME_VPOS (w, w->cursor.vpos);

	      x += max (0, w->left_margin_cols);
	      cursor_to (f, y, x);
	    }
	}
    }

 do_pause:

  clear_desired_matrices (f);
  return pause_p;
}


/* Do line insertions/deletions on frame F for frame-based redisplay.  */

static bool
scrolling (struct frame *frame)
{
  int unchanged_at_top, unchanged_at_bottom;
  int window_size;
  int changed_lines;
  int i;
  int height = FRAME_TOTAL_LINES (frame);
  int free_at_end_vpos = height;
  struct glyph_matrix *current_matrix = frame->current_matrix;
  struct glyph_matrix *desired_matrix = frame->desired_matrix;
  verify (sizeof (int) <= sizeof (unsigned));
  verify (alignof (unsigned) % alignof (int) == 0);
  unsigned *old_hash;
  USE_SAFE_ALLOCA;
  SAFE_NALLOCA (old_hash, 4, height);
  unsigned *new_hash = old_hash + height;
  int *draw_cost = (int *) (new_hash + height);
  int *old_draw_cost = draw_cost + height;
  old_hash = ptr_bounds_clip (old_hash, height * sizeof *old_hash);
  new_hash = ptr_bounds_clip (new_hash, height * sizeof *new_hash);
  draw_cost = ptr_bounds_clip (draw_cost, height * sizeof *draw_cost);
  old_draw_cost = ptr_bounds_clip (old_draw_cost,
				   height * sizeof *old_draw_cost);

  eassert (current_matrix);

  /* Compute hash codes of all the lines.  Also calculate number of
     changed lines, number of unchanged lines at the beginning, and
     number of unchanged lines at the end.  */
  changed_lines = 0;
  unchanged_at_top = 0;
  unchanged_at_bottom = height;
  for (i = 0; i < height; i++)
    {
      /* Give up on this scrolling if some old lines are not enabled.  */
      if (!MATRIX_ROW_ENABLED_P (current_matrix, i))
	{
	  SAFE_FREE ();
	  return false;
	}
      old_hash[i] = line_hash_code (frame, MATRIX_ROW (current_matrix, i));
      if (! MATRIX_ROW_ENABLED_P (desired_matrix, i))
	{
	  /* This line cannot be redrawn, so don't let scrolling mess it.  */
	  new_hash[i] = old_hash[i];
	  draw_cost[i] = SCROLL_INFINITY;
	}
      else
	{
	  new_hash[i] = line_hash_code (frame, MATRIX_ROW (desired_matrix, i));
	  draw_cost[i] = line_draw_cost (frame, desired_matrix, i);
	}

      if (old_hash[i] != new_hash[i])
	{
	  changed_lines++;
	  unchanged_at_bottom = height - i - 1;
	}
      else if (i == unchanged_at_top)
	unchanged_at_top++;
      old_draw_cost[i] = line_draw_cost (frame, current_matrix, i);
    }

  /* If changed lines are few, don't allow preemption, don't scroll.  */
  if ((!FRAME_SCROLL_REGION_OK (frame)
       && changed_lines < baud_rate / 2400)
      || unchanged_at_bottom == height)
    {
      SAFE_FREE ();
      return true;
    }

  window_size = (height - unchanged_at_top
		 - unchanged_at_bottom);

  if (FRAME_SCROLL_REGION_OK (frame))
    free_at_end_vpos -= unchanged_at_bottom;
  else if (FRAME_MEMORY_BELOW_FRAME (frame))
    free_at_end_vpos = -1;

  /* Do id/calc only if small window, or slow terminal, or many lines
     in common between current frame and desired frame.  But the
     window size must be at least 2.  */
  if ((FRAME_SCROLL_REGION_OK (frame)
       || window_size < 18 || baud_rate <= 2400
       || (window_size
	   < 10 * scrolling_max_lines_saved (unchanged_at_top,
					     height - unchanged_at_bottom,
					     old_hash, new_hash, draw_cost)))
      && 2 <= window_size)
    scrolling_1 (frame, window_size, unchanged_at_top, unchanged_at_bottom,
		 draw_cost + unchanged_at_top - 1,
		 old_draw_cost + unchanged_at_top - 1,
		 old_hash + unchanged_at_top - 1,
		 new_hash + unchanged_at_top - 1,
		 free_at_end_vpos - unchanged_at_top);

  SAFE_FREE ();
  return false;
}


/* Count the number of blanks at the start of the vector of glyphs R
   which is LEN glyphs long.  */

static int
count_blanks (struct glyph *r, int len)
{
  int i;

  for (i = 0; i < len; ++i)
    if (!CHAR_GLYPH_SPACE_P (r[i]))
      break;

  return i;
}


/* Count the number of glyphs in common at the start of the glyph
   vectors STR1 and STR2.  END1 is the end of STR1 and END2 is the end
   of STR2.  Value is the number of equal glyphs equal at the start.  */

static int
count_match (struct glyph *str1, struct glyph *end1, struct glyph *str2, struct glyph *end2)
{
  struct glyph *p1 = str1;
  struct glyph *p2 = str2;

  while (p1 < end1
	 && p2 < end2
	 && GLYPH_CHAR_AND_FACE_EQUAL_P (p1, p2))
    ++p1, ++p2;

  return p1 - str1;
}


/* Char insertion/deletion cost vector, from term.c */

#define char_ins_del_cost(f) (&char_ins_del_vector[FRAME_TOTAL_COLS ((f))])


/* Perform a frame-based update on line VPOS in frame FRAME.  */

static void
update_frame_line (struct frame *f, int vpos, bool updating_menu_p)
{
  struct glyph *obody, *nbody, *op1, *op2, *np1, *nend;
  int tem;
  int osp, nsp, begmatch, endmatch, olen, nlen;
  struct glyph_matrix *current_matrix = f->current_matrix;
  struct glyph_matrix *desired_matrix = f->desired_matrix;
  struct glyph_row *current_row = MATRIX_ROW (current_matrix, vpos);
  struct glyph_row *desired_row = MATRIX_ROW (desired_matrix, vpos);
  bool must_write_whole_line_p;
  bool write_spaces_p = FRAME_MUST_WRITE_SPACES (f);
  bool colored_spaces_p = (FACE_FROM_ID (f, DEFAULT_FACE_ID)->background
			   != FACE_TTY_DEFAULT_BG_COLOR);

  if (colored_spaces_p)
    write_spaces_p = 1;

  /* Current row not enabled means it has unknown contents.  We must
     write the whole desired line in that case.  */
  must_write_whole_line_p = !current_row->enabled_p;
  if (must_write_whole_line_p)
    {
      obody = 0;
      olen = 0;
    }
  else
    {
      obody = MATRIX_ROW_GLYPH_START (current_matrix, vpos);
      olen = current_row->used[TEXT_AREA];

      /* Ignore trailing spaces, if we can.  */
      if (!write_spaces_p)
	while (olen > 0 && CHAR_GLYPH_SPACE_P (obody[olen-1]))
	  olen--;
    }

  current_row->enabled_p = true;
  current_row->used[TEXT_AREA] = desired_row->used[TEXT_AREA];

  /* For some reason, cursor is sometimes moved behind our back when a
     frame with a TTY menu is redrawn.  Homing the cursor as below
     fixes that.  */
  if (updating_menu_p)
    cursor_to (f, 0, 0);

  /* If desired line is empty, just clear the line.  */
  if (!desired_row->enabled_p)
    {
      nlen = 0;
      goto just_erase;
    }

  nbody = desired_row->glyphs[TEXT_AREA];
  nlen = desired_row->used[TEXT_AREA];
  nend = nbody + nlen;

  /* If display line has unknown contents, write the whole line.  */
  if (must_write_whole_line_p)
    {
      /* Ignore spaces at the end, if we can.  */
      if (!write_spaces_p)
	while (nlen > 0 && CHAR_GLYPH_SPACE_P (nbody[nlen - 1]))
	  --nlen;

      /* Write the contents of the desired line.  */
      if (nlen)
	{
          cursor_to (f, vpos, 0);
	  write_glyphs (f, nbody, nlen);
	}

      /* Don't call clear_end_of_line if we already wrote the whole
	 line.  The cursor will not be at the right margin in that
	 case but in the line below.  */
      if (nlen < FRAME_TOTAL_COLS (f))
	{
	  cursor_to (f, vpos, nlen);
          clear_end_of_line (f, FRAME_TOTAL_COLS (f));
	}
      else
	/* Make sure we are in the right row, otherwise cursor movement
	   with cmgoto might use `ch' in the wrong row.  */
	cursor_to (f, vpos, 0);

      make_current (desired_matrix, current_matrix, vpos);
      return;
    }

  /* Pretend trailing spaces are not there at all,
     unless for one reason or another we must write all spaces.  */
  if (!write_spaces_p)
    while (nlen > 0 && CHAR_GLYPH_SPACE_P (nbody[nlen - 1]))
      nlen--;

  /* If there's no i/d char, quickly do the best we can without it.  */
  if (!FRAME_CHAR_INS_DEL_OK (f))
    {
      int i, j;

      /* Find the first glyph in desired row that doesn't agree with
	 a glyph in the current row, and write the rest from there on.  */
      for (i = 0; i < nlen; i++)
	{
	  if (i >= olen || !GLYPH_EQUAL_P (nbody + i, obody + i))
	    {
	      /* Find the end of the run of different glyphs.  */
	      j = i + 1;
	      while (j < nlen
		     && (j >= olen
			 || !GLYPH_EQUAL_P (nbody + j, obody + j)
			 || CHAR_GLYPH_PADDING_P (nbody[j])))
		++j;

	      /* Output this run of non-matching chars.  */
	      cursor_to (f, vpos, i);
	      write_glyphs (f, nbody + i, j - i);
	      i = j - 1;

	      /* Now find the next non-match.  */
	    }
	}

      /* Clear the rest of the line, or the non-clear part of it.  */
      if (olen > nlen)
	{
	  cursor_to (f, vpos, nlen);
	  clear_end_of_line (f, olen);
	}

      /* Make current row = desired row.  */
      make_current (desired_matrix, current_matrix, vpos);
      return;
    }

  /* Here when CHAR_INS_DEL_OK != 0, i.e. we can insert or delete
     characters in a row.  */

  if (!olen)
    {
      /* If current line is blank, skip over initial spaces, if
	 possible, and write the rest.  */
      if (write_spaces_p)
	nsp = 0;
      else
	nsp = count_blanks (nbody, nlen);

      if (nlen > nsp)
	{
	  cursor_to (f, vpos, nsp);
	  write_glyphs (f, nbody + nsp, nlen - nsp);
	}

      /* Exchange contents between current_frame and new_frame.  */
      make_current (desired_matrix, current_matrix, vpos);
      return;
    }

  /* Compute number of leading blanks in old and new contents.  */
  osp = count_blanks (obody, olen);
  nsp = (colored_spaces_p ? 0 : count_blanks (nbody, nlen));

  /* Compute number of matching chars starting with first non-blank.  */
  begmatch = count_match (obody + osp, obody + olen,
			  nbody + nsp, nbody + nlen);

  /* Spaces in new match implicit space past the end of old.  */
  /* A bug causing this to be a no-op was fixed in 18.29.  */
  if (!write_spaces_p && osp + begmatch == olen)
    {
      np1 = nbody + nsp;
      while (np1 + begmatch < nend && CHAR_GLYPH_SPACE_P (np1[begmatch]))
	++begmatch;
    }

  /* Avoid doing insert/delete char
     just cause number of leading spaces differs
     when the following text does not match.  */
  if (begmatch == 0 && osp != nsp)
    osp = nsp = min (osp, nsp);

  /* Find matching characters at end of line */
  op1 = obody + olen;
  np1 = nbody + nlen;
  op2 = op1 + begmatch - min (olen - osp, nlen - nsp);
  while (op1 > op2
	 && GLYPH_EQUAL_P (op1 - 1, np1 - 1))
    {
      op1--;
      np1--;
    }
  endmatch = obody + olen - op1;

  /* tem gets the distance to insert or delete.
     endmatch is how many characters we save by doing so.
     Is it worth it?  */

  tem = (nlen - nsp) - (olen - osp);
  if (endmatch && tem
      && (!FRAME_CHAR_INS_DEL_OK (f)
          || endmatch <= char_ins_del_cost (f)[tem]))
    endmatch = 0;

  /* nsp - osp is the distance to insert or delete.
     If that is nonzero, begmatch is known to be nonzero also.
     begmatch + endmatch is how much we save by doing the ins/del.
     Is it worth it?  */

  if (nsp != osp
      && (!FRAME_CHAR_INS_DEL_OK (f)
	  || begmatch + endmatch <= char_ins_del_cost (f)[nsp - osp]))
    {
      begmatch = 0;
      endmatch = 0;
      osp = nsp = min (osp, nsp);
    }

  /* Now go through the line, inserting, writing and
     deleting as appropriate.  */

  if (osp > nsp)
    {
      cursor_to (f, vpos, nsp);
      delete_glyphs (f, osp - nsp);
    }
  else if (nsp > osp)
    {
      /* If going to delete chars later in line
	 and insert earlier in the line,
	 must delete first to avoid losing data in the insert */
      if (endmatch && nlen < olen + nsp - osp)
	{
	  cursor_to (f, vpos, nlen - endmatch + osp - nsp);
	  delete_glyphs (f, olen + nsp - osp - nlen);
	  olen = nlen - (nsp - osp);
	}
      cursor_to (f, vpos, osp);
      insert_glyphs (f, 0, nsp - osp);
    }
  olen += nsp - osp;

  tem = nsp + begmatch + endmatch;
  if (nlen != tem || olen != tem)
    {
      if (!endmatch || nlen == olen)
	{
	  /* If new text being written reaches right margin, there is
	     no need to do clear-to-eol at the end of this function
	     (and it would not be safe, since cursor is not going to
	     be "at the margin" after the text is done).  */
	  if (nlen == FRAME_TOTAL_COLS (f))
	    olen = 0;

	  /* Function write_glyphs is prepared to do nothing
	     if passed a length <= 0.  Check it here to avoid
	     unnecessary cursor movement.  */
	  if (nlen - tem > 0)
	    {
	      cursor_to (f, vpos, nsp + begmatch);
	      write_glyphs (f, nbody + nsp + begmatch, nlen - tem);
	    }
	}
      else if (nlen > olen)
	{
	  /* Here, we used to have the following simple code:
	     ----------------------------------------
	     write_glyphs (nbody + nsp + begmatch, olen - tem);
	     insert_glyphs (nbody + nsp + begmatch + olen - tem, nlen - olen);
	     ----------------------------------------
	     but it doesn't work if nbody[nsp + begmatch + olen - tem]
	     is a padding glyph.  */
	  int out = olen - tem;	/* Columns to be overwritten originally.  */
	  int del;

	  cursor_to (f, vpos, nsp + begmatch);

	  /* Calculate columns we can actually overwrite.  */
	  while (CHAR_GLYPH_PADDING_P (nbody[nsp + begmatch + out]))
	    out--;
	  write_glyphs (f, nbody + nsp + begmatch, out);

	  /* If we left columns to be overwritten, we must delete them.  */
	  del = olen - tem - out;
	  if (del > 0)
	    delete_glyphs (f, del);

	  /* At last, we insert columns not yet written out.  */
	  insert_glyphs (f, nbody + nsp + begmatch + out, nlen - olen + del);
	  olen = nlen;
	}
      else if (olen > nlen)
	{
	  cursor_to (f, vpos, nsp + begmatch);
	  write_glyphs (f, nbody + nsp + begmatch, nlen - tem);
	  delete_glyphs (f, olen - nlen);
	  olen = nlen;
	}
    }

 just_erase:
  /* If any unerased characters remain after the new line, erase them.  */
  if (olen > nlen)
    {
      cursor_to (f, vpos, nlen);
      clear_end_of_line (f, olen);
    }

  /* Exchange contents between current_frame and new_frame.  */
  make_current (desired_matrix, current_matrix, vpos);
}


\f
/***********************************************************************
		   X/Y Position -> Buffer Position
 ***********************************************************************/

/* Determine what's under window-relative pixel position (*X, *Y).
   Return the object (string or buffer) that's there.
   Return in *POS the position in that object.
   Adjust *X and *Y to character positions.
   If an image is shown at the specified position, return
   in *OBJECT its image-spec.
   Return in *DX and *DY the pixel coordinates of the click,
   relative to the top left corner of object, or relative to
   the top left corner of the character glyph at (*X, *Y)
   if the object at (*X, *Y) is nil.
   Return WIDTH and HEIGHT of the object at (*X, *Y), or zero
   if the coordinates point to an empty area of the display.  */

Lisp_Object
buffer_posn_from_coords (struct window *w, int *x, int *y, struct display_pos *pos, Lisp_Object *object, int *dx, int *dy, int *width, int *height)
{
  struct it it;
  Lisp_Object old_current_buffer = Fcurrent_buffer ();
  struct text_pos startp;
  Lisp_Object string;
  struct glyph_row *row;
#ifdef HAVE_WINDOW_SYSTEM
  struct image *img = 0;
#endif
  int x0, x1, to_x, it_vpos;
  void *itdata = NULL;

  /* We used to set current_buffer directly here, but that does the
     wrong thing with `face-remapping-alist' (bug#2044).  */
  Fset_buffer (w->contents);
  itdata = bidi_shelve_cache ();
  CLIP_TEXT_POS_FROM_MARKER (startp, w->start);
  start_display (&it, w, startp);
  x0 = *x;

  /* First, move to the beginning of the row corresponding to *Y.  We
     need to be in that row to get the correct value of base paragraph
     direction for the text at (*X, *Y).  */
  move_it_to (&it, -1, 0, *y, -1, MOVE_TO_X | MOVE_TO_Y);

  /* TO_X is the pixel position that the iterator will compute for the
     glyph at *X.  */
  to_x = x0;
  if (it.bidi_it.paragraph_dir == R2L)
    /* For lines in an R2L paragraph, we need to mirror TO_X wrt the
       text area.  This is because the iterator, even in R2L
       paragraphs, delivers glyphs as if they started at the left
       margin of the window.  (When we actually produce glyphs for
       display, we reverse their order in PRODUCE_GLYPHS, but the
       iterator doesn't know about that.)  The following line adjusts
       the pixel position to the iterator geometry, which is what
       move_it_* routines use.  (The -1 is because in a window whose
       text-area width is W, the rightmost pixel position is W-1, and
       it should be mirrored into zero pixel position.)  */
    to_x = window_box_width (w, TEXT_AREA) - to_x - 1;

  /* We need to add it.first_visible_x because iterator positions
     include the hscroll. */
  to_x += it.first_visible_x;

  /* If we are hscrolling only the current line, and Y is at the line
     containing point, augment TO_X with the hscroll amount of the
     current line.  */
  if (it.line_wrap == TRUNCATE
      && EQ (automatic_hscrolling, Qcurrent_line) && IT_CHARPOS (it) < PT)
    {
      struct it it2 = it;
      void *it2data = bidi_shelve_cache ();
      it2.last_visible_x = 1000000;
      /* If the line at Y shows point, the call below to
	 move_it_in_display_line will succeed in reaching point.  */
      move_it_in_display_line (&it2, PT, -1, MOVE_TO_POS);
      if (IT_CHARPOS (it2) >= PT)
	{
	  to_x += (w->hscroll - w->min_hscroll) * FRAME_COLUMN_WIDTH (it.f);
	  /* We need to pretend the window is hscrolled, so that
	     move_it_in_display_line below will DTRT with TO_X.  */
	  it.first_visible_x += w->hscroll * FRAME_COLUMN_WIDTH (it.f);
	  it.last_visible_x += w->hscroll * FRAME_COLUMN_WIDTH (it.f);
	}
      bidi_unshelve_cache (it2data, 0);
    }

  /* Now move horizontally in the row to the glyph under *X.  Second
     argument is ZV to prevent move_it_in_display_line from matching
     based on buffer positions.  */
  move_it_in_display_line (&it, ZV, to_x, MOVE_TO_X);
  bidi_unshelve_cache (itdata, 0);

  Fset_buffer (old_current_buffer);

  *dx = to_x - it.current_x;
  *dy = *y - it.current_y;

  string = w->contents;
  if (STRINGP (it.string))
    string = it.string;
  *pos = it.current;
  if (it.what == IT_COMPOSITION
      && it.cmp_it.nchars > 1
      && it.cmp_it.reversed_p)
    {
      /* The current display element is a grapheme cluster in a
	 composition.  In that case, we need the position of the first
	 character of the cluster.  But, as it.cmp_it.reversed_p is 1,
	 it.current points to the last character of the cluster, thus
	 we must move back to the first character of the same
	 cluster.  */
      CHARPOS (pos->pos) -= it.cmp_it.nchars - 1;
      if (STRINGP (it.string))
	BYTEPOS (pos->pos) = string_char_to_byte (string, CHARPOS (pos->pos));
      else
	BYTEPOS (pos->pos) = buf_charpos_to_bytepos (XBUFFER (w->contents),
						     CHARPOS (pos->pos));
    }

#ifdef HAVE_WINDOW_SYSTEM
  if (it.what == IT_IMAGE)
    {
      /* Note that this ignores images that are fringe bitmaps,
	 because their image ID is zero, and so IMAGE_OPT_FROM_ID will
	 return NULL.  This is okay, since fringe bitmaps are not
	 displayed in the text area, and so are never the object we
	 are interested in.  */
      img = IMAGE_OPT_FROM_ID (it.f, it.image_id);
      if (img && !NILP (img->spec))
	*object = img->spec;
    }
#endif

  /* IT's vpos counts from the glyph row that includes the window's
     start position, i.e. it excludes the header-line row, but
     MATRIX_ROW includes the header-line row.  Adjust for a possible
     header-line row.  */
  it_vpos = it.vpos + window_wants_header_line (w)
    + window_wants_tab_line (w);
  if (it_vpos < w->current_matrix->nrows
      && (row = MATRIX_ROW (w->current_matrix, it_vpos),
	  row->enabled_p))
    {
      if (it.hpos < row->used[TEXT_AREA])
	{
	  struct glyph *glyph = row->glyphs[TEXT_AREA] + it.hpos;
#ifdef HAVE_WINDOW_SYSTEM
	  if (img)
	    {
	      *dy -= row->ascent - glyph->ascent;
	      *dx += glyph->slice.img.x;
	      *dy += glyph->slice.img.y;
	      /* Image slices positions are still relative to the entire image */
	      *width = img->width;
	      *height = img->height;
	    }
	  else
#endif
	    {
	      *width = glyph->pixel_width;
	      *height = glyph->ascent + glyph->descent;
	    }
	}
      else
	{
	  *width = 0;
	  *height = row->height;
	}
    }
  else
    {
      *width = *height = 0;
    }

  /* Add extra (default width) columns if clicked after EOL. */
  x1 = max (0, it.current_x + it.pixel_width);
  if (to_x > x1)
    it.hpos += (to_x - x1) / WINDOW_FRAME_COLUMN_WIDTH (w);

  *x = it.hpos;
  *y = it.vpos;

  return string;
}


/* Value is the string under window-relative coordinates X/Y in the
   mode line or header line (PART says which) of window W, or nil if none.
   *CHARPOS is set to the position in the string returned.  */

Lisp_Object
mode_line_string (struct window *w, enum window_part part,
		  int *x, int *y, ptrdiff_t *charpos, Lisp_Object *object,
		  int *dx, int *dy, int *width, int *height)
{
  struct glyph_row *row;
  struct glyph *glyph, *end;
  int x0, y0;
  Lisp_Object string = Qnil;

  if (part == ON_MODE_LINE)
    row = MATRIX_MODE_LINE_ROW (w->current_matrix);
  else if (part == ON_TAB_LINE)
    row = MATRIX_TAB_LINE_ROW (w->current_matrix);
  else
    row = MATRIX_HEADER_LINE_ROW (w->current_matrix);
  y0 = *y - row->y;
  *y = row - MATRIX_FIRST_TEXT_ROW (w->current_matrix);

  if (row->mode_line_p && row->enabled_p)
    {
      /* Find the glyph under X.  If we find one with a string object,
         it's the one we were looking for.  */
      glyph = row->glyphs[TEXT_AREA];
      end = glyph + row->used[TEXT_AREA];
      for (x0 = *x; glyph < end && x0 >= glyph->pixel_width; ++glyph)
	x0 -= glyph->pixel_width;
      *x = glyph - row->glyphs[TEXT_AREA];
      if (glyph < end)
	{
	  string = glyph->object;
	  *charpos = glyph->charpos;
	  *width = glyph->pixel_width;
	  *height = glyph->ascent + glyph->descent;
#ifdef HAVE_WINDOW_SYSTEM
	  if (glyph->type == IMAGE_GLYPH)
	    {
	      struct image *img;
	      img = IMAGE_OPT_FROM_ID (WINDOW_XFRAME (w), glyph->u.img_id);
	      if (img != NULL)
		*object = img->spec;
	      y0 -= row->ascent - glyph->ascent;
	    }
#endif
	}
      else
	{
	  /* Add extra (default width) columns if clicked after EOL. */
	  *x += x0 / WINDOW_FRAME_COLUMN_WIDTH (w);
	  *width = 0;
	  *height = row->height;
	}
    }
  else
    {
      *x = 0;
      x0 = 0;
      *width = *height = 0;
    }

  *dx = x0;
  *dy = y0;

  return string;
}


/* Value is the string under window-relative coordinates X/Y in either
   marginal area, or nil if none.  *CHARPOS is set to the position in
   the string returned.  */

Lisp_Object
marginal_area_string (struct window *w, enum window_part part,
		      int *x, int *y, ptrdiff_t *charpos, Lisp_Object *object,
		      int *dx, int *dy, int *width, int *height)
{
  struct glyph_row *row = w->current_matrix->rows;
  struct glyph *glyph, *end;
  int x0, y0, i, wy = *y;
  int area;
  Lisp_Object string = Qnil;

  if (part == ON_LEFT_MARGIN)
    area = LEFT_MARGIN_AREA;
  else if (part == ON_RIGHT_MARGIN)
    area = RIGHT_MARGIN_AREA;
  else
    emacs_abort ();

  for (i = 0; row->enabled_p && i < w->current_matrix->nrows; ++i, ++row)
    if (wy >= row->y && wy < MATRIX_ROW_BOTTOM_Y (row))
      break;
  y0 = *y - row->y;
  *y = row - MATRIX_FIRST_TEXT_ROW (w->current_matrix);

  if (row->enabled_p)
    {
      /* Find the glyph under X.  If we find one with a string object,
	 it's the one we were looking for.  */
      if (area == RIGHT_MARGIN_AREA)
	x0 = ((WINDOW_HAS_FRINGES_OUTSIDE_MARGINS (w)
	       ? WINDOW_LEFT_FRINGE_WIDTH (w)
	       : WINDOW_FRINGES_WIDTH (w))
	      + window_box_width (w, LEFT_MARGIN_AREA)
	      + window_box_width (w, TEXT_AREA));
      else
	x0 = (WINDOW_HAS_FRINGES_OUTSIDE_MARGINS (w)
	      ? WINDOW_LEFT_FRINGE_WIDTH (w)
	      : 0);

      glyph = row->glyphs[area];
      end = glyph + row->used[area];
      for (x0 = *x - x0; glyph < end && x0 >= glyph->pixel_width; ++glyph)
	x0 -= glyph->pixel_width;
      *x = glyph - row->glyphs[area];
      if (glyph < end)
	{
	  string = glyph->object;
	  *charpos = glyph->charpos;
	  *width = glyph->pixel_width;
	  *height = glyph->ascent + glyph->descent;
#ifdef HAVE_WINDOW_SYSTEM
	  if (glyph->type == IMAGE_GLYPH)
	    {
	      struct image *img;
	      img = IMAGE_OPT_FROM_ID (WINDOW_XFRAME (w), glyph->u.img_id);
	      if (img != NULL)
		*object = img->spec;
	      y0 -= row->ascent - glyph->ascent;
	      x0 += glyph->slice.img.x;
	      y0 += glyph->slice.img.y;
	    }
#endif
	}
      else
	{
	  /* Add extra (default width) columns if clicked after EOL. */
	  *x += x0 / WINDOW_FRAME_COLUMN_WIDTH (w);
	  *width = 0;
	  *height = row->height;
	}
    }
  else
    {
      x0 = 0;
      *x = 0;
      *width = *height = 0;
    }

  *dx = x0;
  *dy = y0;

  return string;
}


/***********************************************************************
			 Changing Frame Sizes
 ***********************************************************************/

#ifdef SIGWINCH

static void deliver_window_change_signal (int);

static void
handle_window_change_signal (int sig)
{
  int width, height;
  struct tty_display_info *tty;

  /* The frame size change obviously applies to a single
     termcap-controlled terminal, but we can't decide which.
     Therefore, we resize the frames corresponding to each tty.
  */
  for (tty = tty_list; tty; tty = tty->next) {

    if (! tty->term_initted)
      continue;

    /* Suspended tty frames have tty->input == NULL avoid trying to
       use it.  */
    if (!tty->input)
      continue;

    get_tty_size (fileno (tty->input), &width, &height);

    if (width > 5 && height > 2) {
      Lisp_Object tail, frame;

      FOR_EACH_FRAME (tail, frame)
        if (FRAME_TERMCAP_P (XFRAME (frame)) && FRAME_TTY (XFRAME (frame)) == tty)
          /* Record the new sizes, but don't reallocate the data
             structures now.  Let that be done later outside of the
             signal handler.  */
          change_frame_size (XFRAME (frame), width,
			     height - FRAME_MENU_BAR_LINES (XFRAME (frame))
			     - FRAME_TAB_BAR_LINES (XFRAME (frame)),
			     0, 1, 0, 0);
    }
  }
}

static void
deliver_window_change_signal (int sig)
{
  deliver_process_signal (sig, handle_window_change_signal);
}
#endif /* SIGWINCH */


/* Do any change in frame size that was requested by a signal.
   SAFE means this function is called from a place where it is
   safe to change frame sizes while a redisplay is in progress.  */

void
do_pending_window_change (bool safe)
{
  /* If window change signal handler should have run before, run it now.  */
  if (redisplaying_p && !safe)
    return;

  while (delayed_size_change)
    {
      Lisp_Object tail, frame;

      delayed_size_change = 0;

      FOR_EACH_FRAME (tail, frame)
	{
	  struct frame *f = XFRAME (frame);

	  if (f->new_height != 0 || f->new_width != 0)
	    change_frame_size (f, f->new_width, f->new_height,
			       0, 0, safe, f->new_pixelwise);
	}
    }
}


static void
change_frame_size_1 (struct frame *f, int new_width, int new_height,
		     bool pretend, bool delay, bool safe, bool pixelwise)
{
  /* If we can't deal with the change now, queue it for later.  */
  if (delay || (redisplaying_p && !safe))
    {
      f->new_width = new_width;
      f->new_height = new_height;
      f->new_pixelwise = pixelwise;
      delayed_size_change = 1;
    }
  else
    {
      /* This size-change overrides any pending one for this frame.  */
      f->new_height = 0;
      f->new_width = 0;
      f->new_pixelwise = 0;

      /* If an argument is zero, set it to the current value.  */
      if (pixelwise)
	{
	  new_width = (new_width <= 0) ? FRAME_TEXT_WIDTH (f) : new_width;
	  new_height = (new_height <= 0) ? FRAME_TEXT_HEIGHT (f) : new_height;
	}
      else
	{
	  new_width = (((new_width <= 0) ? FRAME_COLS (f) : new_width)
		       * FRAME_COLUMN_WIDTH (f));
	  new_height = (((new_height <= 0) ? FRAME_LINES (f) : new_height)
			* FRAME_LINE_HEIGHT (f));
	}

      /* Adjust frame size but make sure set_window_size_hook does not
	 get called.  */
      adjust_frame_size (f, new_width, new_height, 5, pretend,
			 Qchange_frame_size);
    }
}


/* Change text height/width of frame F.  Values may be given as zero to
   indicate that no change is needed.

   If DELAY, assume we're being called from a signal handler, and queue
   the change for later - perhaps the next redisplay.  Since this tries
   to resize windows, we can't call it from a signal handler.

   SAFE means this function is called from a place where it's safe to
   change frame sizes while a redisplay is in progress.  */
void
change_frame_size (struct frame *f, int new_width, int new_height,
		   bool pretend, bool delay, bool safe, bool pixelwise)
{
  Lisp_Object tail, frame;

  if (FRAME_MSDOS_P (f))
    {
      /* On MS-DOS, all frames use the same screen, so a change in
         size affects all frames.  Termcap now supports multiple
         ttys. */
      FOR_EACH_FRAME (tail, frame)
	if (! FRAME_WINDOW_P (XFRAME (frame)))
	  change_frame_size_1 (XFRAME (frame), new_width, new_height,
			       pretend, delay, safe, pixelwise);
    }
  else
    change_frame_size_1 (f, new_width, new_height, pretend, delay, safe,
			 pixelwise);
}
\f
/***********************************************************************
		   Terminal Related Lisp Functions
 ***********************************************************************/

DEFUN ("open-termscript", Fopen_termscript, Sopen_termscript,
       1, 1, "FOpen termscript file: ",
       doc: /* Start writing all terminal output to FILE as well as the terminal.
FILE = nil means just close any termscript file currently open.  */)
  (Lisp_Object file)
{
  struct tty_display_info *tty;

  if (! FRAME_TERMCAP_P (SELECTED_FRAME ())
      && ! FRAME_MSDOS_P (SELECTED_FRAME ()))
    error ("Current frame is not on a tty device");

  tty = CURTTY ();

  if (tty->termscript != 0)
    {
      block_input ();
      fclose (tty->termscript);
      tty->termscript = 0;
      unblock_input ();
    }

  if (! NILP (file))
    {
      file = Fexpand_file_name (file, Qnil);
      tty->termscript = emacs_fopen (SSDATA (file), "w");
      if (tty->termscript == 0)
	report_file_error ("Opening termscript", file);
    }
  return Qnil;
}


DEFUN ("send-string-to-terminal", Fsend_string_to_terminal,
       Ssend_string_to_terminal, 1, 2, 0,
       doc: /* Send STRING to the terminal without alteration.
Control characters in STRING will have terminal-dependent effects.

Optional parameter TERMINAL specifies the tty terminal device to use.
It may be a terminal object, a frame, or nil for the terminal used by
the currently selected frame.  In batch mode, STRING is sent to stdout
when TERMINAL is nil.  */)
  (Lisp_Object string, Lisp_Object terminal)
{
  struct terminal *t = decode_live_terminal (terminal);
  FILE *out;

  /* ??? Perhaps we should do something special for multibyte strings here.  */
  CHECK_STRING (string);
  block_input ();

  if (t->type == output_initial)
    out = stdout;
  else if (t->type != output_termcap && t->type != output_msdos_raw)
    error ("Device %d is not a termcap terminal device", t->id);
  else
    {
      struct tty_display_info *tty = t->display_info.tty;

      if (! tty->output)
	error ("Terminal is currently suspended");

      if (tty->termscript)
	{
	  fwrite (SDATA (string), 1, SBYTES (string), tty->termscript);
	  fflush (tty->termscript);
	}
      out = tty->output;
    }
  fwrite (SDATA (string), 1, SBYTES (string), out);
  fflush (out);
  unblock_input ();
  return Qnil;
}


DEFUN ("ding", Fding, Sding, 0, 1, 0,
       doc: /* Beep, or flash the screen.
Also, unless an argument is given,
terminate any keyboard macro currently executing.  */)
  (Lisp_Object arg)
{
  if (!NILP (arg))
    {
      if (noninteractive)
	putchar (07);
      else
	ring_bell (XFRAME (selected_frame));
    }
  else
    bitch_at_user ();

  return Qnil;
}

void
bitch_at_user (void)
{
  if (noninteractive)
    putchar (07);
  else if (!INTERACTIVE)  /* Stop executing a keyboard macro.  */
    {
      const char *msg
	= "Keyboard macro terminated by a command ringing the bell";
      Fsignal (Quser_error, list1 (build_string (msg)));
    }
  else
    ring_bell (XFRAME (selected_frame));
}


\f
/***********************************************************************
			  Sleeping, Waiting
 ***********************************************************************/

DEFUN ("sleep-for", Fsleep_for, Ssleep_for, 1, 2, 0,
       doc: /* Pause, without updating display, for SECONDS seconds.
SECONDS may be a floating-point value, meaning that you can wait for a
fraction of a second.  Optional second arg MILLISECONDS specifies an
additional wait period, in milliseconds; this is for backwards compatibility.
\(Not all operating systems support waiting for a fraction of a second.)  */)
  (Lisp_Object seconds, Lisp_Object milliseconds)
{
  double duration = extract_float (seconds);

  if (!NILP (milliseconds))
    {
      CHECK_FIXNUM (milliseconds);
      duration += XFIXNUM (milliseconds) / 1000.0;
    }

  if (duration > 0)
    {
      struct timespec t = dtotimespec (duration);
      struct timespec tend = timespec_add (current_timespec (), t);

      /* wait_reading_process_output returns as soon as it detects
	 output from any subprocess, so we wait in a loop until the
	 time expires.  */
      do {
	wait_reading_process_output (min (t.tv_sec, WAIT_READING_MAX),
				     t.tv_nsec, 0, 0, Qnil, NULL, 0);
	t = timespec_sub (tend, current_timespec ());
      } while (timespec_sign (t) > 0);
    }

  return Qnil;
}


/* This is just like wait_reading_process_output, except that
   it does redisplay.

   TIMEOUT is number of seconds to wait (float or integer),
   or t to wait forever.
   READING is true if reading input.
   If DISPLAY_OPTION is >0 display process output while waiting.
   If DISPLAY_OPTION is >1 perform an initial redisplay before waiting.
*/

Lisp_Object
sit_for (Lisp_Object timeout, bool reading, int display_option)
{
  intmax_t sec;
  int nsec;
  bool do_display = display_option > 0;

  swallow_events (do_display);

  if ((detect_input_pending_run_timers (do_display))
      || !NILP (Vexecuting_kbd_macro))
    return Qnil;

  if (display_option > 1)
    redisplay_preserve_echo_area (2);

  if (INTEGERP (timeout))
    {
      if (integer_to_intmax (timeout, &sec))
	{
	  if (sec <= 0)
	    return Qt;
	  sec = min (sec, WAIT_READING_MAX);
	}
      else
	{
	  if (NILP (Fnatnump (timeout)))
	    return Qt;
	  sec = WAIT_READING_MAX;
	}
      nsec = 0;
    }
  else if (FLOATP (timeout))
    {
      double seconds = XFLOAT_DATA (timeout);
      if (! (0 < seconds))
	return Qt;
      else
	{
	  struct timespec t = dtotimespec (seconds);
	  sec = min (t.tv_sec, WAIT_READING_MAX);
	  nsec = t.tv_nsec;
	}
    }
  else if (EQ (timeout, Qt))
    {
      sec = 0;
      nsec = 0;
    }
  else
    wrong_type_argument (Qnumberp, timeout);


#ifdef USABLE_SIGIO
  gobble_input ();
#endif

  wait_reading_process_output (sec, nsec, reading ? -1 : 1, do_display,
			       Qnil, NULL, 0);

  return detect_input_pending () ? Qnil : Qt;
}


DEFUN ("redisplay", Fredisplay, Sredisplay, 0, 1, 0,
       doc: /* Perform redisplay.
Optional arg FORCE, if non-nil, prevents redisplay from being
preempted by arriving input, even if `redisplay-dont-pause' is nil.
If `redisplay-dont-pause' is non-nil (the default), redisplay is never
preempted by arriving input, so FORCE does nothing.

Return t if redisplay was performed, nil if redisplay was preempted
immediately by pending input.  */)
  (Lisp_Object force)
{
  ptrdiff_t count;

  swallow_events (true);
  if ((detect_input_pending_run_timers (1)
       && NILP (force) && !redisplay_dont_pause)
      || !NILP (Vexecuting_kbd_macro))
    return Qnil;

  count = SPECPDL_INDEX ();
  if (!NILP (force) && !redisplay_dont_pause)
    specbind (Qredisplay_dont_pause, Qt);
  redisplay_preserve_echo_area (2);
  return unbind_to (count, Qt);
}


\f
/***********************************************************************
			 Other Lisp Functions
 ***********************************************************************/

/* A vector of size >= 2 * NFRAMES + 3 * NBUFFERS + 1, containing the
   session's frames, frame names, buffers, buffer-read-only flags, and
   buffer-modified-flags.  */

static Lisp_Object frame_and_buffer_state;


DEFUN ("frame-or-buffer-changed-p", Fframe_or_buffer_changed_p,
       Sframe_or_buffer_changed_p, 0, 1, 0,
       doc: /* Return non-nil if the frame and buffer state appears to have changed.
VARIABLE is a variable name whose value is either nil or a state vector
that will be updated to contain all frames and buffers,
aside from buffers whose names start with space,
along with the buffers' read-only and modified flags.  This allows a fast
check to see whether buffer menus might need to be recomputed.
If this function returns non-nil, it updates the internal vector to reflect
the current state.

If VARIABLE is nil, an internal variable is used.  Users should not
pass nil for VARIABLE.  */)
  (Lisp_Object variable)
{
  Lisp_Object state, tail, frame, buf;
  ptrdiff_t n, idx;

  if (! NILP (variable))
    {
      CHECK_SYMBOL (variable);
      state = Fsymbol_value (variable);
      if (! VECTORP (state))
	goto changed;
    }
  else
    state = frame_and_buffer_state;

  idx = 0;
  FOR_EACH_FRAME (tail, frame)
    {
      if (idx == ASIZE (state))
	goto changed;
      if (!EQ (AREF (state, idx++), frame))
	goto changed;
      if (idx == ASIZE (state))
	goto changed;
      if (!EQ (AREF (state, idx++), XFRAME (frame)->name))
	goto changed;
    }
  /* Check that the buffer info matches.  */
  FOR_EACH_LIVE_BUFFER (tail, buf)
    {
      /* Ignore buffers that aren't included in buffer lists.  */
      if (SREF (BVAR (XBUFFER (buf), name), 0) == ' ')
	continue;
      if (idx == ASIZE (state))
	goto changed;
      if (!EQ (AREF (state, idx++), buf))
	goto changed;
      if (idx == ASIZE (state))
	goto changed;
      if (!EQ (AREF (state, idx++), BVAR (XBUFFER (buf), read_only)))
	goto changed;
      if (idx == ASIZE (state))
	goto changed;
      if (!EQ (AREF (state, idx++), Fbuffer_modified_p (buf)))
	goto changed;
    }
  if (idx == ASIZE (state))
    goto changed;
  /* Detect deletion of a buffer at the end of the list.  */
  if (EQ (AREF (state, idx), Qlambda))
    return Qnil;

  /* Come here if we decide the data has changed.  */
 changed:
  /* Count the size we will need.
     Start with 1 so there is room for at least one lambda at the end.  */
  n = 1;
  FOR_EACH_FRAME (tail, frame)
    n += 2;
  FOR_EACH_LIVE_BUFFER (tail, buf)
    n += 3;
  /* Reallocate the vector if data has grown to need it,
     or if it has shrunk a lot.  */
  if (! VECTORP (state)
      || n > ASIZE (state)
      || n + 20 < ASIZE (state) / 2)
    /* Add 20 extra so we grow it less often.  */
    {
      state = make_vector (n + 20, Qlambda);
      if (! NILP (variable))
	Fset (variable, state);
      else
	frame_and_buffer_state = state;
    }

  /* Record the new data in the (possibly reallocated) vector.  */
  idx = 0;
  FOR_EACH_FRAME (tail, frame)
    {
      ASET (state, idx, frame);
      idx++;
      ASET (state, idx, XFRAME (frame)->name);
      idx++;
    }
  FOR_EACH_LIVE_BUFFER (tail, buf)
    {
      /* Ignore buffers that aren't included in buffer lists.  */
      if (SREF (BVAR (XBUFFER (buf), name), 0) == ' ')
	continue;
      ASET (state, idx, buf);
      idx++;
      ASET (state, idx, BVAR (XBUFFER (buf), read_only));
      idx++;
      ASET (state, idx, Fbuffer_modified_p (buf));
      idx++;
    }
  /* Fill up the vector with lambdas (always at least one).  */
  ASET (state, idx, Qlambda);
  idx++;
  while (idx < ASIZE (state))
    {
      ASET (state, idx, Qlambda);
      idx++;
    }
  /* Make sure we didn't overflow the vector.  */
  eassert (idx <= ASIZE (state));
  return Qt;
}


\f
/***********************************************************************
			    Initialization
***********************************************************************/

static void
init_faces_initial (void)
{
  /* For the initial frame, we don't have any way of knowing what
     are the foreground and background colors of the terminal.  */
  struct frame *sf = SELECTED_FRAME ();

  FRAME_FOREGROUND_PIXEL (sf) = FACE_TTY_DEFAULT_FG_COLOR;
  FRAME_BACKGROUND_PIXEL (sf) = FACE_TTY_DEFAULT_BG_COLOR;
  call0 (intern ("tty-set-up-initial-frame-faces"));
}

/* Initialization done when Emacs fork is started, before doing stty.
   Determine terminal type and set terminal_driver.  Then invoke its
   decoding routine to set up variables in the terminal package.  */

static void
init_display_interactive (void)
{
  char *terminal_type;

  /* Construct the space glyph.  */
  space_glyph.type = CHAR_GLYPH;
  SET_CHAR_GLYPH (space_glyph, ' ', DEFAULT_FACE_ID, 0);
  space_glyph.charpos = -1;

  inverse_video = 0;
  cursor_in_echo_area = false;

  /* Now is the time to initialize this; it's used by init_sys_modes
     during startup.  */
  Vinitial_window_system = Qnil;

  /* SIGWINCH needs to be handled no matter what display we start
     with.  Otherwise newly opened tty frames will not resize
     automatically. */
#ifdef SIGWINCH
  if (!will_dump_p ())
    {
      struct sigaction action;
      emacs_sigaction_init (&action, deliver_window_change_signal);
      sigaction (SIGWINCH, &action, 0);
    }
#endif /* SIGWINCH */

  /* If running as a daemon, no need to initialize any frames/terminal,
     except on Windows, where we at least want to initialize it.  */
  if (IS_DAEMON)
    {
      /* Pdump'ed Emacs doesn't record the initial frame from temacs,
	 so the non-basic faces realized for that frame in temacs
	 aren't in emacs.  This causes errors when users try to
	 customize those faces in their init file.  The call to
	 init_faces_initial will realize these faces now.  (Non-daemon
	 Emacs does this either near the end of this function or when
	 the GUI frame is created.)  */
      if (dumped_with_pdumper_p ())
        init_faces_initial ();
#ifndef WINDOWSNT
      return;
#endif
    }

  /* If the user wants to use a window system, we shouldn't bother
     initializing the terminal.  This is especially important when the
     terminal is so dumb that emacs gives up before and doesn't bother
     using the window system.

     If the DISPLAY environment variable is set and nonempty,
     try to use X, and if that fails output a line to stderr
     reporting that -nw will be simulated.  */

#ifdef HAVE_X_WINDOWS
  if (! inhibit_window_system && ! display_arg)
    {
      char *display;
      display = getenv ("DISPLAY");
      display_arg = (display != 0 && *display != 0);

      if (display_arg && !x_display_ok (display))
	{
	  fprintf (stderr, "Display %s unavailable, simulating -nw\n",
		   display);
	  inhibit_window_system = 1;
	}
    }

  if (!inhibit_window_system && display_arg)
    {
      Vinitial_window_system = Qx;
#ifdef HAVE_X11
      Vwindow_system_version = make_fixnum (11);
#endif
#ifdef USE_NCURSES
      /* In some versions of ncurses,
	 tputs crashes if we have not called tgetent.
	 So call tgetent.  */
      { char b[2044]; tgetent (b, "xterm");}
#endif
      return;
    }
#endif /* HAVE_X_WINDOWS */

#ifdef HAVE_NTGUI
  if (!inhibit_window_system)
    {
      Vinitial_window_system = Qw32;
      Vwindow_system_version = make_fixnum (1);
      return;
    }
#endif /* HAVE_NTGUI */

#ifdef HAVE_NS
  if (!inhibit_window_system && !will_dump_p ())
    {
      Vinitial_window_system = Qns;
      Vwindow_system_version = make_fixnum (10);
      return;
    }
#endif

#ifdef HAVE_PGTK
  if (!inhibit_window_system
#ifndef CANNOT_DUMP
     && initialized
#endif
      )
    {
      Vinitial_window_system = Qpgtk;
      Vwindow_system_version = make_fixnum (1);
      return;
    }
#endif

  /* If no window system has been specified, try to use the terminal.  */
  if (! isatty (STDIN_FILENO))
    fatal ("standard input is not a tty");

#ifdef WINDOWSNT
  terminal_type = (char *)"w32console";
#else
  terminal_type = getenv ("TERM");
#endif
  if (!terminal_type)
    {
      char const *msg
	= "Please set the environment variable TERM; see 'tset'.\n";
#ifdef HAVE_WINDOW_SYSTEM
      if (! inhibit_window_system)
	msg = ("Please set the environment variable DISPLAY or TERM; "
	       "see 'tset'.\n");
#endif /* HAVE_WINDOW_SYSTEM */
      fputs (msg, stderr);
      exit (1);
    }

  {
    struct terminal *t;
    struct frame *f = XFRAME (selected_frame);

    init_foreground_group ();

    /* Open a display on the controlling tty. */
    t = init_tty (0, terminal_type, 1); /* Errors are fatal. */

    /* Convert the initial frame to use the new display. */
    if (f->output_method != output_initial)
      emacs_abort ();
    f->output_method = t->type;
    f->terminal = t;

    t->reference_count++;
#ifdef MSDOS
    f->output_data.tty = &the_only_tty_output;
    f->output_data.tty->display_info = &the_only_display_info;
#else
    if (f->output_method == output_termcap)
      create_tty_output (f);
#endif
    t->display_info.tty->top_frame = selected_frame;
    change_frame_size (XFRAME (selected_frame),
                       FrameCols (t->display_info.tty),
                       FrameRows (t->display_info.tty)
		       - FRAME_MENU_BAR_LINES (f)
		       - FRAME_TAB_BAR_LINES (f), 0, 0, 1, 0);

    /* Delete the initial terminal. */
    if (--initial_terminal->reference_count == 0
        && initial_terminal->delete_terminal_hook)
      (*initial_terminal->delete_terminal_hook) (initial_terminal);

    /* Update frame parameters to reflect the new type. */
    AUTO_FRAME_ARG (tty_type_arg, Qtty_type, Ftty_type (selected_frame));
    Fmodify_frame_parameters (selected_frame, tty_type_arg);
    AUTO_FRAME_ARG (tty_arg, Qtty, (t->display_info.tty->name
				    ? build_string (t->display_info.tty->name)
				    : Qnil));
    Fmodify_frame_parameters (selected_frame, tty_arg);
  }

  {
    struct frame *sf = SELECTED_FRAME ();
    int width = FRAME_TOTAL_COLS (sf);
    int height = FRAME_TOTAL_LINES (sf);
    int area;

    /* If these sizes are so big they cause overflow, just ignore the
       change.  It's not clear what better we could do.  The rest of
       the code assumes that (width + 2) * height * sizeof (struct glyph)
       does not overflow and does not exceed PTRDIFF_MAX or SIZE_MAX.  */
    if (INT_ADD_WRAPV (width, 2, &area)
	|| INT_MULTIPLY_WRAPV (height, area, &area)
	|| min (PTRDIFF_MAX, SIZE_MAX) / sizeof (struct glyph) < area)
      fatal ("screen size %dx%d too big", width, height);
  }

  calculate_costs (XFRAME (selected_frame));

  /* Set up faces of the initial terminal frame.  */
  if (initialized && !noninteractive && NILP (Vinitial_window_system))
    init_faces_initial ();
}

void
init_display (void)
{
  if (noninteractive)
    {
      if (dumped_with_pdumper_p ())
        init_faces_initial ();
    }
  else
    init_display_interactive ();
}

\f
/***********************************************************************
			   Blinking cursor
 ***********************************************************************/

DEFUN ("internal-show-cursor", Finternal_show_cursor,
       Sinternal_show_cursor, 2, 2, 0,
       doc: /* Set the cursor-visibility flag of WINDOW to SHOW.
WINDOW nil means use the selected window.  SHOW non-nil means
show a cursor in WINDOW in the next redisplay.  SHOW nil means
don't show a cursor.  */)
  (Lisp_Object window, Lisp_Object show)
{
  /* Don't change cursor state while redisplaying.  This could confuse
     output routines.  */
  if (!redisplaying_p)
    decode_any_window (window)->cursor_off_p = NILP (show);
  return Qnil;
}


DEFUN ("internal-show-cursor-p", Finternal_show_cursor_p,
       Sinternal_show_cursor_p, 0, 1, 0,
       doc: /* Value is non-nil if next redisplay will display a cursor in WINDOW.
WINDOW nil or omitted means report on the selected window.  */)
  (Lisp_Object window)
{
  return decode_any_window (window)->cursor_off_p ? Qnil : Qt;
}
\f
/***********************************************************************
			    Initialization
 ***********************************************************************/

static void syms_of_display_for_pdumper (void);

void
syms_of_display (void)
{
  defsubr (&Sredraw_frame);
  defsubr (&Sredraw_display);
  defsubr (&Sframe_or_buffer_changed_p);
  defsubr (&Sopen_termscript);
  defsubr (&Sding);
  defsubr (&Sredisplay);
  defsubr (&Ssleep_for);
  defsubr (&Ssend_string_to_terminal);
  defsubr (&Sinternal_show_cursor);
  defsubr (&Sinternal_show_cursor_p);

#ifdef GLYPH_DEBUG
  defsubr (&Sdump_redisplay_history);
#endif

  frame_and_buffer_state = make_vector (20, Qlambda);
  staticpro (&frame_and_buffer_state);

  /* This is the "purpose" slot of a display table.  */
  DEFSYM (Qdisplay_table, "display-table");

  DEFSYM (Qredisplay_dont_pause, "redisplay-dont-pause");

  DEFVAR_INT ("baud-rate", baud_rate,
	      doc: /* The output baud rate of the terminal.
On most systems, changing this value will affect the amount of padding
and the other strategic decisions made during redisplay.  */);

  DEFVAR_BOOL ("inverse-video", inverse_video,
	       doc: /* Non-nil means invert the entire frame display.
This means everything is in inverse video which otherwise would not be.  */);

  DEFVAR_BOOL ("visible-bell", visible_bell,
	       doc: /* Non-nil means try to flash the frame to represent a bell.

See also `ring-bell-function'.  */);

  DEFVAR_BOOL ("no-redraw-on-reenter", no_redraw_on_reenter,
	       doc: /* Non-nil means no need to redraw entire frame after suspending.
A non-nil value is useful if the terminal can automatically preserve
Emacs's frame display when you reenter Emacs.
It is up to you to set this variable if your terminal can do that.  */);

  DEFVAR_LISP ("initial-window-system", Vinitial_window_system,
	       doc: /* Name of the window system that Emacs uses for the first frame.
The value is a symbol:
 nil for a termcap frame (a character-only terminal),
 `x' for an Emacs frame that is really an X window,
 `w32' for an Emacs frame that is a window on MS-Windows display,
 `ns' for an Emacs frame on a GNUstep or Macintosh Cocoa display,
 `pc' for a direct-write MS-DOS frame.

Use of this variable as a boolean is deprecated.  Instead,
use `display-graphic-p' or any of the other `display-*-p'
predicates which report frame's specific UI-related capabilities.  */);

  DEFVAR_KBOARD ("window-system", Vwindow_system,
		 doc: /* Name of window system through which the selected frame is displayed.
The value is a symbol:
 nil for a termcap frame (a character-only terminal),
 `x' for an Emacs frame that is really an X window,
 `w32' for an Emacs frame that is a window on MS-Windows display,
 `ns' for an Emacs frame on a GNUstep or Macintosh Cocoa display,
 `pc' for a direct-write MS-DOS frame.

Use of this variable as a boolean is deprecated.  Instead,
use `display-graphic-p' or any of the other `display-*-p'
predicates which report frame's specific UI-related capabilities.  */);

  DEFVAR_LISP ("window-system-version", Vwindow_system_version,
	       doc: /* The version number of the window system in use.
For X windows, this is 11.  */);

  DEFVAR_BOOL ("cursor-in-echo-area", cursor_in_echo_area,
	       doc: /* Non-nil means put cursor in minibuffer, at end of any message there.  */);

  DEFVAR_LISP ("glyph-table", Vglyph_table,
	       doc: /* Table defining how to output a glyph code to the frame.
If not nil, this is a vector indexed by glyph code to define the glyph.
Each element can be:
 integer: a glyph code which this glyph is an alias for.
 string: output this glyph using that string (not impl. in X windows).
 nil: this glyph mod 524288 is the code of a character to output,
    and this glyph / 524288 is the face number (see `face-id') to use
    while outputting it.  */);
  Vglyph_table = Qnil;

  DEFVAR_LISP ("standard-display-table", Vstandard_display_table,
	       doc: /* Display table to use for buffers that specify none.
It is also used for standard output and error streams.
See `buffer-display-table' for more information.  */);
  Vstandard_display_table = Qnil;

  DEFVAR_BOOL ("redisplay-dont-pause", redisplay_dont_pause,
	       doc: /* Nil means display update is paused when input is detected.  */);
  /* Contrary to expectations, a value of "false" can be detrimental to
     responsiveness since aborting a redisplay throws away some of the
     work already performed.  It's usually more efficient (and gives
     more prompt feedback to the user) to let the redisplay terminate,
     and just completely skip the next command's redisplay (which is
     done regardless of this setting if there's pending input at the
     beginning of the next redisplay).  */
  redisplay_dont_pause = true;

  DEFVAR_LISP ("tab-bar-position", Vtab_bar_position,
	       doc: /* Specify on which side from the tool bar the tab bar shall be.
Possible values are `t' (below the tool bar), `nil' (above the tool bar).
This option affects only builds where the tool bar is not external.  */);

  pdumper_do_now_and_after_load (syms_of_display_for_pdumper);
}

static void
syms_of_display_for_pdumper (void)
{
  Vinitial_window_system = Qnil;
  Vwindow_system_version = Qnil;
}

debug log:

solving d9fef34521 ...
found d9fef34521 in https://yhetil.org/emacs-devel/87zhaxjpea.fsf@yahoo.com/
found 5b6fa51a56 in https://git.savannah.gnu.org/cgit/emacs.git
preparing index
index prepared:
100644 5b6fa51a563f581cd9914f1aa2fffaab4dbddf95	src/dispnew.c

applying [1/1] https://yhetil.org/emacs-devel/87zhaxjpea.fsf@yahoo.com/
diff --git a/src/dispnew.c b/src/dispnew.c
index 5b6fa51a56..d9fef34521 100644

Checking patch src/dispnew.c...
Applied patch src/dispnew.c cleanly.

index at:
100644 d9fef345212451072dbe2484c5551df542ed74dc	src/dispnew.c

(*) Git path names are given by the tree(s) the blob belongs to.
    Blobs themselves have no identifier aside from the hash of its contents.^

Code repositories for project(s) associated with this public inbox

	https://git.savannah.gnu.org/cgit/emacs.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).