new module 'mbsrchr'

[Bruno Haible]

mbsrchr() is the analogon of strrchr() that works with characters strings
(in other words, with strings also in multibyte locales).

2007-02-04  Bruno Haible  <address@hidden>

        New module mbsrchr.
        * modules/mbsrchr: New file.
        * lib/mbsrchr.c: New file.
        * lib/string_.h (strrchr): Add a conditional link warning.
        (mbsrchr): New declaration.
        * m4/mbsrchr.m4: New file.
        * m4/string_h.m4 (gl_STRING_MODULE_INDICATOR_DEFAULTS): Initialize
        GNULIB_MBSRCHR.
        * modules/string (string.h): Also substitute GNULIB_MBSRCHR.
        * MODULES.html.sh (Internationalization functions): Add mbsrchr.

========================= modules/mbsrchr =====================================
Description:
mbsrchr() function: search a string for a character, from the end.

Files:
lib/mbsrchr.c
m4/mbsrchr.m4
m4/mbrtowc.m4

Depends-on:
mbuiter
string

configure.ac:
gl_FUNC_MBSRCHR
gl_STRING_MODULE_INDICATOR([mbsrchr])

Makefile.am:
lib_SOURCES += mbsrchr.c

Include:
<string.h>

License:
LGPL

Maintainer:
Bruno Haible

========================== lib/mbsrchr.c ======================================
/* Searching a string for the last occurrence of a character.
   Copyright (C) 2007 Free Software Foundation, Inc.
   Written by Bruno Haible <address@hidden>, 2007.

   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 2, 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */

#include <config.h>

/* Specification.  */
#include <string.h>

#if HAVE_MBRTOWC
# include "mbuiter.h"
#endif

/* Locate the last single-byte character C in the character string STRING,
   and return a pointer to it.  Return NULL if C is not found in STRING.  */
char *
mbsrchr (const char *string, int c)
{
#if HAVE_MBRTOWC
  if (MB_CUR_MAX > 1
      /* Optimization: We know that ASCII characters < 0x30 don't occur as
         part of multibyte characters longer than 1 byte.  Hence, if c < 0x30,
         the faster unibyte loop can be used.  */
      && (unsigned char) c >= 0x30)
    {
      const char *result = NULL;
      mbui_iterator_t iter;

      for (mbui_init (iter, string);; mbui_advance (iter))
        {
          if (mb_len (mbui_cur (iter)) == 1
              && (unsigned char) * mbui_cur_ptr (iter) == (unsigned char) c)
            result = mbui_cur_ptr (iter);
          if (!mbui_avail (iter))
            break;
        }
      return (char *) result;
    }
  else
#endif
    return strrchr (string, c);
}
=========================== m4/mbsrchr.m4 =====================================
# mbsrchr.m4 serial 1
dnl Copyright (C) 2007 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.

AC_DEFUN([gl_FUNC_MBSRCHR],
[
  gl_PREREQ_MBSRCHR
])

# Prerequisites of lib/mbsrchr.c.
AC_DEFUN([gl_PREREQ_MBSRCHR], [
  AC_REQUIRE([gl_FUNC_MBRTOWC])
  :
])
===============================================================================
--- MODULES.html.sh     5 Feb 2007 01:01:37 -0000       1.181
+++ MODULES.html.sh     5 Feb 2007 01:12:07 -0000
@@ -2162,6 +2162,7 @@
   func_module localcharset
   func_module hard-locale
   func_module mbschr
+  func_module mbsrchr
   func_module mbswidth
   func_module memcasecmp
   func_module memcoll
--- lib/string_.h       5 Feb 2007 01:01:37 -0000       1.8
+++ lib/string_.h       5 Feb 2007 01:12:07 -0000
@@ -213,6 +213,15 @@
 # define strpbrk 
strpbrk_is_unportable__use_gnulib_module_strpbrk_for_portability
 #endif
 
+#if defined GNULIB_POSIXCHECK
+/* strrchr() does not work with multibyte strings if the locale encoding is
+   GB18030 and the character to be searched is a digit.  */
+# undef strrchr
+# define strrchr(s,c) \
+    (GL_LINK_WARNING ("strrchr cannot work correctly on character strings in 
some multibyte locales - use mbsrchr if you care about internationalization"), \
+     strrchr (s, c))
+#endif
+
 /* Search the next delimiter (char listed in DELIM) starting at *STRINGP.
    If one is found, overwrite it with a NUL, and advance *STRINGP
    to point to the next char after it.  Otherwise, set *STRINGP to NULL.
@@ -317,6 +326,15 @@
 extern char * mbschr (const char *string, int c);
 #endif
 
+#if @GNULIB_MBSRCHR@
+/* Locate the last single-byte character C in the character string STRING,
+   and return a pointer to it.  Return NULL if C is not found in STRING.
+   Unlike strrchr(), this function works correctly in multibyte locales with
+   encodings such as GB18030.  */
+# define mbsrchr rpl_mbsrchr /* avoid collision with HP-UX function */
+extern char * mbsrchr (const char *string, int c);
+#endif
+
 
 #ifdef __cplusplus
 }
--- m4/string_h.m4      5 Feb 2007 01:01:37 -0000       1.6
+++ m4/string_h.m4      5 Feb 2007 01:12:07 -0000
@@ -71,4 +71,5 @@
   GNULIB_STRCASESTR=0;  AC_SUBST([GNULIB_STRCASESTR])
   GNULIB_STRTOK_R=0;    AC_SUBST([GNULIB_STRTOK_R])
   GNULIB_MBSCHR=0;      AC_SUBST([GNULIB_MBSCHR])
+  GNULIB_MBSRCHR=0;     AC_SUBST([GNULIB_MBSRCHR])
 ])
--- modules/string      5 Feb 2007 01:01:37 -0000       1.5
+++ modules/string      5 Feb 2007 01:12:07 -0000
@@ -22,6 +22,7 @@
        { echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */' && \
          sed -e 's|@''ABSOLUTE_STRING_H''@|$(ABSOLUTE_STRING_H)|g' \
              -e 's|@''GNULIB_MBSCHR''@|$(GNULIB_MBSCHR)|g' \
+             -e 's|@''GNULIB_MBSRCHR''@|$(GNULIB_MBSRCHR)|g' \
              -e 's|@''GNULIB_MEMMEM''@|$(GNULIB_MEMMEM)|g' \
              -e 's|@''GNULIB_MEMPCPY''@|$(GNULIB_MEMPCPY)|g' \
              -e 's|@''GNULIB_MEMRCHR''@|$(GNULIB_MEMRCHR)|g' \