kc3-lang/gnulib/lib/strcasestr.c

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• Hash : 32a72f45
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  Date : 2023-01-01T01:14:21
  

  maint: run 'make update-copyright'
  

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• lib/strcasestr.c

• /* Case-insensitive searching in a string.
     Copyright (C) 2005-2023 Free Software Foundation, Inc.
     Written by Bruno Haible <bruno@clisp.org>, 2005.
  
     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 2.1 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/>.  */
  
  #include <config.h>
  
  /* Specification.  */
  #include <string.h>
  
  #include <ctype.h>
  #include <strings.h>
  
  #define TOLOWER(Ch) (isupper (Ch) ? tolower (Ch) : (Ch))
  
  /* Two-Way algorithm.  */
  #define RETURN_TYPE char *
  #define AVAILABLE(h, h_l, j, n_l)                       \
    (!memchr ((h) + (h_l), '\0', (j) + (n_l) - (h_l))     \
     && ((h_l) = (j) + (n_l)))
  #define CANON_ELEMENT(c) TOLOWER (c)
  #define CMP_FUNC(p1, p2, l)                             \
    strncasecmp ((const char *) (p1), (const char *) (p2), l)
  #include "str-two-way.h"
  
  /* Find the first occurrence of NEEDLE in HAYSTACK, using
     case-insensitive comparison.  This function gives unspecified
     results in multibyte locales.  */
  char *
  strcasestr (const char *haystack_start, const char *needle_start)
  {
    const char *haystack = haystack_start;
    const char *needle = needle_start;
    size_t needle_len; /* Length of NEEDLE.  */
    size_t haystack_len; /* Known minimum length of HAYSTACK.  */
    bool ok = true; /* True if NEEDLE is prefix of HAYSTACK.  */
  
    /* Determine length of NEEDLE, and in the process, make sure
       HAYSTACK is at least as long (no point processing all of a long
       NEEDLE if HAYSTACK is too short).  */
    while (*haystack && *needle)
      {
        ok &= (TOLOWER ((unsigned char) *haystack)
               == TOLOWER ((unsigned char) *needle));
        haystack++;
        needle++;
      }
    if (*needle)
      return NULL;
    if (ok)
      return (char *) haystack_start;
    needle_len = needle - needle_start;
    haystack = haystack_start + 1;
    haystack_len = needle_len - 1;
  
    /* Perform the search.  Abstract memory is considered to be an array
       of 'unsigned char' values, not an array of 'char' values.  See
       ISO C 99 section 6.2.6.1.  */
    if (needle_len < LONG_NEEDLE_THRESHOLD)
      return two_way_short_needle ((const unsigned char *) haystack,
                                   haystack_len,
                                   (const unsigned char *) needle_start,
                                   needle_len);
    return two_way_long_needle ((const unsigned char *) haystack, haystack_len,
                                (const unsigned char *) needle_start,
                                needle_len);
  }
  
  #undef LONG_NEEDLE_THRESHOLD
  

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