diff options
Diffstat (limited to 'REORG.TODO/string/strcasestr.c')
| -rw-r--r-- | REORG.TODO/string/strcasestr.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/REORG.TODO/string/strcasestr.c b/REORG.TODO/string/strcasestr.c new file mode 100644 index 0000000000..2acf003155 --- /dev/null +++ b/REORG.TODO/string/strcasestr.c @@ -0,0 +1,104 @@ +/* Return the offset of one string within another. + Copyright (C) 1994-2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library 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. + + The GNU C Library 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 the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +/* + * My personal strstr() implementation that beats most other algorithms. + * Until someone tells me otherwise, I assume that this is the + * fastest implementation of strstr() in C. + * I deliberately chose not to comment it. You should have at least + * as much fun trying to understand it, as I had to write it :-). + * + * Stephen R. van den Berg, berg@pool.informatik.rwth-aachen.de */ + +/* Specification. */ +#include <string.h> + +#include <ctype.h> +#include <stdbool.h> +#include <strings.h> + +#define TOLOWER(Ch) tolower (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 CHECK_EOL (1) +#define RET0_IF_0(a) if (!a) goto ret0 +#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" + +#undef strcasestr +#undef __strcasestr + +#ifndef STRCASESTR +#define STRCASESTR __strcasestr +#endif + + +/* 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 + +#ifndef NO_ALIAS +weak_alias (__strcasestr, strcasestr) +#endif |