[PATCH 1/4] add date parser file from Keith

[Sebastian Spaeth <Sebastian@SSpaeth.de>]

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From: Keith Packard <keithp@keithp.com>

Here's some code which further improves date parsing by allowing lots of
date formats, including things like "today", "thisweek", ISO and US date
formats and month names. You can separate two dates with .. to make a
range, or you can just use the default range ("lastmonth" is everything
From the 1st of the previous month to the 1st of the current month).

Sebastian Spaeth removed 2 unneeded functions and silenced some unused variable warnings, but left the code otherwise as-is.
---
 lib/date.c |  414 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 414 insertions(+), 0 deletions(-)
 create mode 100644 lib/date.c

diff --git a/lib/date.c b/lib/date.c
new file mode 100644
index 0000000..805a1d9
--- /dev/null
+++ b/lib/date.c
@@ -0,0 +1,414 @@
+/*
+ * Copyright © 2009 Keith Packard <keithp@keithp.com>
+ *
+ * This program 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.
+ *
+ * This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include "notmuch.h"
+#include <time.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#define DAY	(24 * 60 * 60)
+
+static void
+today(struct tm *result, time_t after) {
+    time_t	t;
+
+    if (after)
+	t = after;
+    else
+	time(&t);
+    localtime_r(&t, result);
+    result->tm_sec = result->tm_min = result->tm_hour = 0;
+}
+
+static int parse_today(const char *text, time_t *first, time_t *last, time_t after) {
+    (void)after; /*disable unused paramter warning*/
+    if (strcasecmp(text, "today") == 0) {
+	struct tm n;
+	today(&n, 0);
+	*first = mktime(&n);
+	*last = *first + DAY;
+	return 0;
+    }
+    return 1;
+}
+
+static int parse_yesterday(const char *text, time_t *first, time_t *last, time_t after) {
+    if (strcasecmp(text, "yesterday") == 0) {
+	struct tm n;
+	today(&n, 0);
+	*last = mktime(&n);
+	*first = *last - DAY;
+	return 0;
+    }
+    return 1;
+    (void)after; /*disable unused paramter warning*/
+}
+
+static int parse_thisweek(const char *text, time_t *first, time_t *last, time_t after) {
+    if (strcasecmp(text, "thisweek") == 0) {
+	struct tm n;
+	today(&n, 0);
+	*first = mktime(&n) - (n.tm_wday * DAY);
+	*last = *first + DAY * 7;
+	return 0;
+    }
+    return 1;
+    (void)after; /*disable unused paramter warning*/
+}
+
+static int parse_lastweek(const char *text, time_t *first, time_t *last, time_t after) {
+    if (strcasecmp(text, "lastweek") == 0) {
+	struct tm n;
+	today(&n, 0);
+	*last = mktime(&n) - (n.tm_wday * DAY);
+	*first = *last - DAY * 7;
+	return 0;
+    }
+    return 1;
+    (void)after; /*disable unused paramter warning*/
+}
+
+static int parse_thismonth(const char *text, time_t *first, time_t *last, time_t after) {
+    if (strcasecmp(text, "thismonth") == 0) {
+	struct tm n;
+	today(&n, 0);
+	n.tm_mday = 1;
+	*first = mktime(&n);
+	if (n.tm_mon++ == 12) {
+	    n.tm_mon = 0;
+	    n.tm_year++;
+	}
+	*last = mktime(&n);
+	return 0;
+    }
+    return 1;
+    (void)after; /*disable unused paramter warning*/
+}
+
+static int parse_lastmonth(const char *text, time_t *first, time_t *last, time_t after) {
+    if (strcasecmp(text, "lastmonth") == 0) {
+	struct tm n;
+	today(&n, 0);
+	n.tm_mday = 1;
+	if (n.tm_mon == 0) {
+	    n.tm_year--;
+	    n.tm_mon = 11;
+	} else
+	    n.tm_mon--;
+	*first = mktime(&n);
+	if (n.tm_mon++ == 12) {
+	    n.tm_mon = 0;
+	    n.tm_year++;
+	}
+	*last = mktime(&n);
+	return 0;
+    }
+    return 1;
+    (void)after; /*disable unused paramter warning*/
+}
+
+static const char *months[12][2] = {
+    { "January", "Jan" },
+    { "February", "Feb" },
+    { "March", "Mar" },
+    { "April", "Apr" },
+    { "May", "May" },
+    { "June", "Jun" },
+    { "July", "Jul" },
+    { "August", "Aug" },
+    { "September", "Sep" },
+    { "October", "Oct" },
+    { "November", "Nov" },
+    { "December", "Dec" },
+};
+
+static int year(const char *text, int *y) {
+    char *end;
+    *y = strtol(text, &end, 10);
+    if (end == text)
+	return 1;
+    if (*end != '\0')
+	return 1;
+    if (*y < 1970 || *y > 2038)
+	return 1;
+    *y -= 1900;
+    return 0;
+}
+
+static int month(const char *text, int *m) {
+    char *end;
+    int i;
+    for (i = 0; i < 12; i++) {
+	if (strcasecmp(text, months[i][0]) == 0 ||
+	    strcasecmp(text, months[i][1]) == 0)
+	{
+	    *m = i;
+	    return 0;
+	}
+    }
+    *m = strtol(text, &end, 10);
+    if (end == text)
+	return 1;
+    if (*end != '\0')
+	return 1;
+    if (*m < 1 || *m > 12)
+	return 1;
+    *m -= 1;
+    return 0;
+}
+
+static int day(const char *text, int *d) {
+    char *end;
+    *d = strtol(text, &end, 10);
+    if (end == text)
+	return 1;
+    if (*end != '\0')
+	return 1;
+    if (*d < 1 || *d > 31)
+	return 1;
+    return 0;
+}
+
+/* month[-day] */
+static int parse_month(const char *text, time_t *first, time_t *last, time_t after) {
+    int		m = 0, d = 0;
+    int		i;
+    struct tm	n;
+    char	tmp[80];
+    char	*t;
+    char	*save;
+    char	*token;
+
+    if(strlen (text) >= sizeof (tmp))
+	return 1;
+    strcpy(tmp, text);
+
+    t = tmp;
+    save = NULL;
+    i = 0;
+    while ((token = strtok_r(t, "-", &save)) != NULL) {
+	i++;
+	switch(i) {
+	case 1:
+	    if (month(token, &m) != 0)
+		return 1;
+	    break;
+	case 2:
+	    if (day(token, &d) != 0)
+		return 1;
+	    break;
+	default:
+	    return 1;
+	}
+	t = NULL;
+    }
+    today(&n, after);
+    if (after) {
+	if (m < n.tm_mon)
+	    n.tm_year++;
+    } else {
+	if (m > n.tm_mon)
+	    n.tm_year--;
+    }
+    switch (i) {
+    case 1:
+	n.tm_mday = 1;
+	n.tm_mon = m;
+	*first = mktime(&n);
+	if (++n.tm_mon > 11) {
+	    n.tm_mon = 0;
+	    n.tm_year++;
+	}
+	*last = mktime(&n);
+	return 0;
+    case 2:
+	n.tm_mday = d;
+	n.tm_mon = m;
+	*first = mktime(&n);
+	*last = *first + DAY;
+	return 0;
+    }
+    return 1;
+}
+
+/* year[-month[-day]] */
+static int parse_iso(const char *text, time_t *first, time_t *last, time_t after) {
+    int		y = 0, m = 0, d = 0;
+    int		i;
+    struct tm	n;
+    char	tmp[80];
+    char	*t;
+    char	*save;
+    char	*token;
+
+    if(strlen (text) >= sizeof (tmp))
+	return 1;
+    strcpy(tmp, text);
+
+    t = tmp;
+    save = NULL;
+    i = 0;
+    while ((token = strtok_r(t, "-", &save)) != NULL) {
+	i++;
+	switch(i) {
+	case 1:
+	    if (year(token, &y) != 0)
+		return 1;
+	    break;
+	case 2:
+	    if (month(token, &m) != 0)
+		return 1;
+	    break;
+	case 3:
+	    if (day(token, &d) != 0)
+		return 1;
+	    break;
+	default:
+	    return 1;
+	}
+	t = NULL;
+    }
+    today(&n, 0);
+    switch (i) {
+    case 1:
+	n.tm_mday = 1;
+	n.tm_mon = 0;
+	n.tm_year = y;
+	*first = mktime(&n);
+	n.tm_year = y + 1;
+	*last = mktime(&n);
+	return 0;
+    case 2:
+	n.tm_mday = 1;
+	n.tm_mon = m;
+	n.tm_year = y;
+	*first = mktime(&n);
+	if (++n.tm_mon > 11) {
+	    n.tm_mon = 0;
+	    n.tm_year++;
+	}
+	*last = mktime(&n);
+	return 0;
+    case 3:
+	n.tm_mday = d;
+	n.tm_mon = m;
+	n.tm_year = y;
+	*first = mktime(&n);
+	*last = *first + DAY;
+	return 0;
+    }
+    return 1;
+    (void)after; /*disable unused paramter warning*/
+}
+
+/* month[/day[/year]] */
+static int parse_us(const char *text, time_t *first, time_t *last, time_t after) {
+    int		y = 0, m = 0, d = 0;
+    int		i;
+    struct tm	n;
+    char	tmp[80];
+    char	*t;
+    char	*save;
+    char	*token;
+
+    if(strlen (text) >= sizeof (tmp))
+	return 1;
+    strcpy(tmp, text);
+
+    t = tmp;
+    save = NULL;
+    i = 0;
+    while ((token = strtok_r(t, "/", &save)) != NULL) {
+	i++;
+	switch(i) {
+	case 1:
+	    if (month(token, &m) != 0)
+		return 1;
+	    break;
+	case 2:
+	    if (day(token, &d) != 0)
+		return 1;
+	    break;
+	case 3:
+	    if (year(token, &y) != 0)
+		return 1;
+	    break;
+	default:
+	    return 1;
+	}
+	t = NULL;
+    }
+    today(&n, after);
+    if (after) {
+	if (m < n.tm_mon)
+	    n.tm_year++;
+    } else {
+	if (m > n.tm_mon)
+	    n.tm_year--;
+    }
+    switch (i) {
+    case 1:
+	n.tm_mday = 1;
+	n.tm_mon = m;
+	*first = mktime(&n);
+	if (++n.tm_mon > 11) {
+	    n.tm_mon = 0;
+	    n.tm_year++;
+	}
+	*last = mktime(&n);
+	return 0;
+    case 2:
+	n.tm_mday = d;
+	n.tm_mon = m;
+	*first = mktime(&n);
+	*last = *first + DAY;
+	return 0;
+    case 3:
+	n.tm_mday = d;
+	n.tm_mon = m;
+	n.tm_year = y;
+	*first = mktime(&n);
+	*last = *first + DAY;
+	return 0;
+    }
+    return 1;
+}
+
+static int (*parsers[])(const char *text, time_t *first, time_t *last, time_t after) = {
+    parse_today,
+    parse_yesterday,
+    parse_thisweek,
+    parse_lastweek,
+    parse_thismonth,
+    parse_lastmonth,
+    parse_month,
+    parse_iso,
+    parse_us,
+    0,
+};
+
+notmuch_status_t
+notmuch_parse_date(const char *text, time_t *first, time_t *last, time_t after)
+{
+    int		i;
+    for (i = 0; parsers[i]; i++)
+	if (parsers[i](text, first, last, after) == 0)
+	    return NOTMUCH_STATUS_SUCCESS;
+    return NOTMUCH_STATUS_INVALID_DATE;
+}
-- 
1.6.3.3