mbs_endswith.c

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Hash : 26fd3545
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Date : 2025-09-16T23:08:01

stringeq: prefer streq to strcmp in other modules

* lib/acl-internal.c, lib/argmatch.c, lib/argp-help.c:
* lib/argp-parse.c, lib/bcp47.c, lib/c32_get_mapping.c:
* lib/c32_get_type_test.c, lib/concat-filename.c:
* lib/cpu-supports.h, lib/dfa.c, lib/duplocale.c, lib/exclude.c:
* lib/findprog-in.c, lib/findprog.c, lib/fopen.c, lib/freopen.c:
* lib/fts.c, lib/gen-uni-tables.c, lib/getfilecon.c:
* lib/getlogin.c, lib/getugroups.c, lib/hard-locale.c:
* lib/hashcode-named-file.c, lib/hashkey-string.c:
* lib/iconv_open.c, lib/idcache.c, lib/lc-charset-unicode.c:
* lib/localcharset.c, lib/localename-environ.c:
* lib/localename-unsafe.c, lib/mbs_endswith.c, lib/mountlist.c:
* lib/newlocale.c, lib/nl_langinfo.c, lib/nproc.c, lib/open.c:
* lib/os2-spawn.c, lib/parse-datetime.y, lib/popen.c:
* lib/progreloc.c, lib/propername.c, lib/pt_chown.c, lib/putenv.c:
* lib/qcopy-acl.c, lib/readutmp.c, lib/rpmatch.c:
* lib/setlocale-fixes.c, lib/setlocale.c, lib/sig2str.c:
* lib/spawni.c, lib/stat.c, lib/str_endswith.c, lib/streq.h:
* lib/striconveha.c, lib/struniq.h, lib/supersede.c:
* lib/time_rz.c, lib/unicodeio.c, lib/vasnprintf.c:
* lib/vc-mtime.c, lib/wctrans-impl.h, lib/wctype-impl.h:
Prefer streq to strcmp when either will do.
Do not make this change to files shared with glibc.
Do not make the change to test files, at least not for now.
* lib/gen-uni-tables.c (streq): New static function, in same style.
* modules/acl-permissions, modules/argp, modules/c32_get_mapping:
* modules/c32_get_type_test, modules/concat-filename:
* modules/cpu-supports, modules/dfa, modules/duplocale:
* modules/exclude, modules/findprog, modules/findprog-in:
* modules/fopen, modules/fopen-gnu, modules/freopen, modules/fts:
* modules/getlocalename_l-simple, modules/getlocalename_l-unsafe:
* modules/getlogin, modules/getugroups, modules/hard-locale:
* modules/hashcode-named-file, modules/hashkey-string:
* modules/iconv_open, modules/idcache, modules/localcharset:
* modules/localename, modules/localename-unsafe:
* modules/mbs_endswith, modules/mountlist, modules/newlocale:
* modules/nl_langinfo, modules/nproc, modules/open:
* modules/parse-datetime, modules/popen:
* modules/posix_spawn-internal, modules/propername:
* modules/pt_chown, modules/putenv-gnu, modules/qcopy-acl:
* modules/rpmatch, modules/selinux-h, modules/setenv:
* modules/setlocale, modules/setlocale-fixes, modules/sig2str:
* modules/spawn-pipe, modules/stat, modules/str_endswith:
* modules/streq, modules/striconveha, modules/supersede:
* modules/time_rz, modules/uchar-h, modules/unicodeio:
* modules/uniconv/base, modules/wctrans, modules/wctype:
(Depends-on): Add stringeq.

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lib/mbs_endswith.c

/* mbs_endswith function.
   Copyright (C) 2025 Free Software Foundation, Inc.

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

   This file 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 Lesser General Public License for more details.

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

/* Written by Bruno Haible <bruno@clisp.org>, 2025.  */

#include <config.h>

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

#include "mbiter.h"

bool
mbs_endswith (const char *string, const char *suffix)
{
  if ((unsigned char) suffix[0] < 0x30)
    /* Some knowledge about the possible multibyte encodings:

       Encoding    First byte of character    Which of these can occur
                                              as second or later byte?

        EUC-JP     0x00..0x7F, 0x8E..0xFE     0xA1..0xFE
        EUC-KR     0x00..0x7F, 0xA1..0xFD     0xA1..0xFD
        GB2312     0x00..0x7F, 0xA1..0xF7     0xA1..0xF7
        EUC-TW     0x00..0x7F, 0x8E..0xFD     0xA1..0xFD
        BIG5       0x00..0x7F, 0xA1..0xF9     0x40..0x7E, 0xA1..0xF9
        GB18030    0x00..0x7F, 0x81..0xFE     0x30..0x39, 0x40..0x7E, 0x81..0xFE
        SJIS       0x00..0x7F, 0x81..0xF9     0x40..0x7E, 0x81..0xF9
        UTF-8      0x00..0x7F, 0xC2..0xF7     none

       Therefore, if the first byte of SUFFIX is < 0x30, it cannot occur as
       second or later byte, and therefore it is OK to do a bytewise search.  */
    return str_endswith (string, suffix);

  /* Here, suffix is not empty.  */

  size_t nbytes = strlen (string);
  if (nbytes >= strlen (suffix))
    {
      size_t len = mbslen (string);
      size_t n = mbslen (suffix);
      if (len >= n)
        {
          mbi_iterator_t iter;
          mbi_init (iter, string, nbytes);
          /* Advance past (len - n) multibyte characters.  */
          for (; len > n; len--)
            {
              if (!mbi_avail (iter))
                /* We can get here due to incomplete multibyte characters.  */
                return false;
              mbi_advance (iter);
            }
          if (!mbi_avail (iter))
            /* We can get here due to incomplete multibyte characters.  */
            return false;
          return streq (mbi_cur_ptr (iter), suffix);
        }
    }
  return false;
}

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kc3-lang/gnulib/lib/mbs_endswith.c

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lib/mbs_endswith.c