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4775243a | 1 | /* Copyright (C) 1991, 92, 93, 94, 96, 97, 98 Free Software Foundation, Inc. |
63551311 | 2 | This file is part of the GNU C Library. |
28f540f4 | 3 | |
63551311 UD |
4 | The GNU C Library is free software; you can redistribute it and/or |
5 | modify it under the terms of the GNU Library General Public License as | |
6 | published by the Free Software Foundation; either version 2 of the | |
7 | License, or (at your option) any later version. | |
28f540f4 | 8 | |
63551311 UD |
9 | The GNU C Library is distributed in the hope that it will be useful, |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | Library General Public License for more details. | |
28f540f4 | 13 | |
63551311 UD |
14 | You should have received a copy of the GNU Library General Public |
15 | License along with the GNU C Library; see the file COPYING.LIB. If not, | |
478b92f0 UD |
16 | write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
17 | Boston, MA 02111-1307, USA. */ | |
28f540f4 | 18 | |
28f540f4 RM |
19 | #include <stddef.h> |
20 | #include <string.h> | |
21 | ||
9a0a462c | 22 | #undef memmem |
28f540f4 RM |
23 | |
24 | /* Return the first occurrence of NEEDLE in HAYSTACK. */ | |
63551311 UD |
25 | void * |
26 | memmem (haystack, haystack_len, needle, needle_len) | |
27 | const void *haystack; | |
28 | size_t haystack_len; | |
29 | const void *needle; | |
30 | size_t needle_len; | |
28f540f4 | 31 | { |
63551311 UD |
32 | const char *begin; |
33 | const char *const last_possible | |
34 | = (const char *) haystack + haystack_len - needle_len; | |
28f540f4 RM |
35 | |
36 | if (needle_len == 0) | |
dc825f85 | 37 | /* The first occurrence of the empty string is deemed to occur at |
4775243a | 38 | the beginning of the string. */ |
9aae565a | 39 | return (void *) haystack; |
28f540f4 | 40 | |
63551311 UD |
41 | for (begin = (const char *) haystack; begin <= last_possible; ++begin) |
42 | if (begin[0] == ((const char *) needle)[0] && | |
43 | !memcmp ((const void *) &begin[1], | |
44 | (const void *) ((const char *) needle + 1), | |
28f540f4 | 45 | needle_len - 1)) |
63551311 | 46 | return (void *) begin; |
28f540f4 RM |
47 | |
48 | return NULL; | |
49 | } |