| /* Case-insensitive searching in a string. |
| Copyright (C) 2005-2020 Free Software Foundation, Inc. |
| Written by Bruno Haible <bruno@clisp.org>, 2005. |
| |
| 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, see <https://www.gnu.org/licenses/>. */ |
| |
| #include <config.h> |
| |
| /* Specification. */ |
| #include <string.h> |
| |
| #include <ctype.h> |
| #include <stdbool.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 |