/* Copyright (C) 1991,92,93,94,96,97,98,2000 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/>. */ #include <string.h> #include <stddef.h> #ifdef __USE_GNU /* Return the first occurrence of NEEDLE in HAYSTACK. */ void *memmem (const void *haystack, size_t haystack_len, const void *needle, size_t needle_len) { const char *begin; const char *const last_possible = (const char *) haystack + haystack_len - needle_len; if (needle_len == 0) /* The first occurrence of the empty string is deemed to occur at the beginning of the string. */ return (void *) haystack; /* Sanity check, otherwise the loop might search through the whole memory. */ if (__builtin_expect (haystack_len < needle_len, 0)) return NULL; for (begin = (const char *) haystack; begin <= last_possible; ++begin) if (begin[0] == ((const char *) needle)[0] && !memcmp ((const void *) &begin[1], (const void *) ((const char *) needle + 1), needle_len - 1)) return (void *) begin; return NULL; } #endif