Re: i18n/l10n summary

[Paul Eggert <eggert@cs.ucla.edu>]

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I wrote on 2017-06-04:
> Philipp Stephani wrote:
>> It's not hard to fix,
> 
> Thanks. However, on my platform those fixes slowed down a microbenchmark (format 
> "%d %s %c" 3 "def" ?‘) by 7%, so I installed the attached further patch, which 
> recovered the performance loss for me.

Oops, that introduced an off-by-one error that caused Emacs to access one past 
the end of the 'info' array. To fix this I installed the attached further patch 
into emacs-26 and merged emacs-26 into master.

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From 04e5b28ff1691345e023a944dc6a6a9e9573bd07 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Sat, 2 Dec 2017 21:31:24 -0800
Subject: [PATCH] Fix bug in i18n/l10n optimization

This fixes a off-by-one buffer overrun bug introduced in
2017-06-04T15:39:37Z!eggert@cs.ucla.edu.  Problem uncovered by an
experimental version of Emacs built with -fcheck-pointer-bounds
and running on Intel MPX hardware.
* src/editfns.c (styled_format): Avoid overrunning internal buffers.
---
 src/editfns.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/editfns.c b/src/editfns.c
index f275f33..f7c26b9 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -4919,7 +4919,7 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
 		  else if (discarded[bytepos] == 1)
 		    {
 		      position++;
-		      if (translated == info[fieldn].start)
+		      if (fieldn < nspec && translated == info[fieldn].start)
 			{
 			  translated += info[fieldn].end - info[fieldn].start;
 			  fieldn++;
@@ -4939,7 +4939,7 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
 		  else if (discarded[bytepos] == 1)
 		    {
 		      position++;
-		      if (translated == info[fieldn].start)
+		      if (fieldn < nspec && translated == info[fieldn].start)
 			{
 			  translated += info[fieldn].end - info[fieldn].start;
 			  fieldn++;
-- 
2.7.4