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Diffstat (limited to 'sysdeps/generic/memmem.c')
-rw-r--r-- | sysdeps/generic/memmem.c | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/sysdeps/generic/memmem.c b/sysdeps/generic/memmem.c new file mode 100644 index 0000000000..79b4544db5 --- /dev/null +++ b/sysdeps/generic/memmem.c @@ -0,0 +1,46 @@ +/* Copyright (C) 1991, 1992, 1993, 1994 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 Library General Public License as +published by the Free Software Foundation; either version 2 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 +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + +#include <ansidecl.h> +#include <stddef.h> +#include <string.h> + + +/* Return the first occurrence of NEEDLE in HAYSTACK. */ +PTR +DEFUN(memmem, (haystack, haystack_len, + needle, needle_len), + CONST PTRCONST haystack AND CONST size_t haystack_len AND + CONST PTRCONST needle AND CONST size_t needle_len) +{ + register CONST char *begin; + register CONST char *CONST last_possible + = (CONST char *) haystack + haystack_len - needle_len; + + if (needle_len == 0) + return (PTR) &((CONST char *) haystack)[needle_len - 1]; + + for (begin = (CONST char *) haystack; begin <= last_possible; ++begin) + if (begin[0] == ((CONST char *) needle)[0] && + !memcmp ((CONST PTR) &begin[1], + (CONST PTR) ((CONST char *) needle + 1), + needle_len - 1)) + return (PTR) begin; + + return NULL; +} |