From 9a5c6c856892fde5df07666d4bb6641a05f33712 Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Wed, 19 Feb 2014 19:22:24 -0800
Subject: [PATCH 1/2] maint: give dfa.c's using_utf8 function external scope

* src/dfa.c (using_utf8): Remove "static inline".
* src/dfa.h (using_utf8): Declare it.
* src/searchutils.c (is_mb_middle): Use using_utf8 rather than
rolling our own.
---
 src/dfa.c         | 2 +-
 src/dfa.h         | 2 ++
 src/searchutils.c | 9 ++-------
 3 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/src/dfa.c b/src/dfa.c
index a133e03..ba9e7a2 100644
--- a/src/dfa.c
+++ b/src/dfa.c
@@ -753,7 +753,7 @@ setbit_case_fold_c (int b, charclass c)

 /* UTF-8 encoding allows some optimizations that we can't otherwise
    assume in a multibyte encoding.  */
-static inline int
+int
 using_utf8 (void)
 {
   static int utf8 = -1;
diff --git a/src/dfa.h b/src/dfa.h
index bacd489..7e0674f 100644
--- a/src/dfa.h
+++ b/src/dfa.h
@@ -99,3 +99,5 @@ extern void dfawarn (const char *);
    takes a single argument, a NUL-terminated string describing the error.
    The user must supply a dfaerror.  */
 extern _Noreturn void dfaerror (const char *);
+
+extern int using_utf8 (void);
diff --git a/src/searchutils.c b/src/searchutils.c
index 3478417..7363701 100644
--- a/src/searchutils.c
+++ b/src/searchutils.c
@@ -19,6 +19,7 @@
 #include <config.h>
 #include <assert.h>
 #include "search.h"
+#include "dfa.h"
 #if HAVE_LANGINFO_CODESET
 # include <langinfo.h>
 #endif
@@ -234,13 +235,8 @@ is_mb_middle (const char **good, const char *buf, const char *end,
   const char *p = *good;
   const char *prev = p;
   mbstate_t cur_state;
-#if HAVE_LANGINFO_CODESET
-  static int is_utf8 = -1;
-
-  if (is_utf8 == -1)
-    is_utf8 = STREQ (nl_langinfo (CODESET), "UTF-8");

-  if (is_utf8 && buf - p > MB_CUR_MAX)
+  if (using_utf8 () && buf - p > MB_CUR_MAX)
     {
       for (p = buf; buf - p > MB_CUR_MAX; p--)
         if (mbclen_cache[to_uchar (*p)] != (size_t) -1)
@@ -249,7 +245,6 @@ is_mb_middle (const char **good, const char *buf, const char *end,
       if (buf - p == MB_CUR_MAX)
         p = buf;
     }
-#endif

   memset (&cur_state, 0, sizeof cur_state);

-- 
1.9.0


From 5295d1d528afabba15ed0710211ba24854c0c7ab Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Wed, 19 Feb 2014 19:31:43 -0800
Subject: [PATCH 2/2] grep -i: avoid 200x perf. regression in multibyte
 non-UTF8 locales

* src/main.c: Include dfa.h.
(trivial_case_ignore): Perform this optimization only for UTF8 locales.
This rectifies a 200x performance regression in multi-byte non-UTF8
locales like ja_JP.eucJP.  The regression was introduced by the 10x
UTF8/grep-i speedup, commit v2.16-4-g97318f5.
* NEWS (Bug fixes): Mention it.
Reported by Norihiro Tanaka in http://debbugs.gnu.org/16232#50
---
 NEWS       | 5 +++++
 src/main.c | 6 ++++++
 2 files changed, 11 insertions(+)

diff --git a/NEWS b/NEWS
index 6785a96..49a17b0 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,11 @@ GNU grep NEWS                                    -*- outline -*-

 * Noteworthy changes in release ?.? (????-??-??) [?]

+** Bug fixes
+
+  grep -i in a multibyte, non-UTF8 locale could be up to 200 times slower
+  than in 2.16.  [bug introduced in grep-2.17]
+

 * Noteworthy changes in release 2.17 (2014-02-17) [stable]

diff --git a/src/main.c b/src/main.c
index bd20297..56ec6b3 100644
--- a/src/main.c
+++ b/src/main.c
@@ -34,6 +34,7 @@
 #include "c-ctype.h"
 #include "closeout.h"
 #include "colorize.h"
+#include "dfa.h"
 #include "error.h"
 #include "exclude.h"
 #include "exitfail.h"
@@ -1883,6 +1884,11 @@ static bool
 trivial_case_ignore (size_t len, char const *keys,
                      size_t *new_len, char **new_keys)
 {
+  /* Perform this translation only for UTF-8.  Otherwise, this would induce
+     a 100-200x performance penalty for non-UTF8 multibyte locales.  */
+  if ( ! using_utf8 ())
+    return false;
+
   /* FIXME: consider removing the following restriction:
      Reject if KEYS contain ASCII '\\' or '['.  */
   if (memchr (keys, '\\', len) || memchr (keys, '[', len))
-- 
1.9.0