| /* Return the offset of one string within another. |
| Copyright (C) 1994-2014 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/>. */ |
| |
| /* This particular implementation was written by Eric Blake, 2008. */ |
| |
| #ifndef _LIBC |
| # include <config.h> |
| #endif |
| |
| /* Specification of strstr. */ |
| #include <string.h> |
| |
| #include <stdbool.h> |
| |
| #ifndef _LIBC |
| # define __builtin_expect(expr, val) (expr) |
| #endif |
| |
| #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 |
| #include "str-two-way.h" |
| |
| #undef strstr |
| |
| #ifndef STRSTR |
| #define STRSTR strstr |
| #endif |
| |
| /* Return the first occurrence of NEEDLE in HAYSTACK. Return HAYSTACK |
| if NEEDLE is empty, otherwise NULL if NEEDLE is not found in |
| HAYSTACK. */ |
| char * |
| STRSTR (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 &= *haystack++ == *needle++; |
| if (*needle) |
| return NULL; |
| if (ok) |
| return (char *) haystack_start; |
| |
| /* Reduce the size of haystack using strchr, since it has a smaller |
| linear coefficient than the Two-Way algorithm. */ |
| needle_len = needle - needle_start; |
| haystack = strchr (haystack_start + 1, *needle_start); |
| if (!haystack || __builtin_expect (needle_len == 1, 0)) |
| return (char *) haystack; |
| needle -= needle_len; |
| haystack_len = (haystack > haystack_start + needle_len ? 1 |
| : needle_len + haystack_start - haystack); |
| |
| /* 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, needle_len); |
| return two_way_long_needle ((const unsigned char *) haystack, haystack_len, |
| (const unsigned char *) needle, needle_len); |
| } |
| libc_hidden_builtin_def (strstr) |
| |
| #undef LONG_NEEDLE_THRESHOLD |