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28f540f4 RM |
1 | /* Copyright (C) 1991, 1992, 1993, 1994 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. | |
3 | ||
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. | |
8 | ||
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. | |
13 | ||
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 | |
16 | not, write to the Free Software Foundation, Inc., 675 Mass Ave, | |
17 | Cambridge, MA 02139, USA. */ | |
18 | ||
19 | #include <ansidecl.h> | |
20 | #include <stddef.h> | |
21 | #include <string.h> | |
22 | ||
23 | ||
24 | /* Return the first occurrence of NEEDLE in HAYSTACK. */ | |
25 | PTR | |
26 | DEFUN(memmem, (haystack, haystack_len, | |
27 | needle, needle_len), | |
28 | CONST PTRCONST haystack AND CONST size_t haystack_len AND | |
29 | CONST PTRCONST needle AND CONST size_t needle_len) | |
30 | { | |
31 | register CONST char *begin; | |
32 | register CONST char *CONST last_possible | |
33 | = (CONST char *) haystack + haystack_len - needle_len; | |
34 | ||
35 | if (needle_len == 0) | |
36 | return (PTR) &((CONST char *) haystack)[needle_len - 1]; | |
37 | ||
38 | for (begin = (CONST char *) haystack; begin <= last_possible; ++begin) | |
39 | if (begin[0] == ((CONST char *) needle)[0] && | |
40 | !memcmp ((CONST PTR) &begin[1], | |
41 | (CONST PTR) ((CONST char *) needle + 1), | |
42 | needle_len - 1)) | |
43 | return (PTR) begin; | |
44 | ||
45 | return NULL; | |
46 | } |