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/* -*-comment-start: "//";comment-end:""-*-
* GNU Mes --- Maxwell Equations of Software
* Copyright © 1997--2015,2017,2018 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
* Copyright (C) 1997--2015,2018 Han-Wen Nienhuys <hanwen@xs4all.nl>
*
* This file is part of GNU Mes.
*
* GNU Mes is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or (at
* your option) any later version.
*
* GNU Mes 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU Mes. If not, see <http://www.gnu.org/licenses/>.
*/
#include <string.h>
/** locate a substring. #memmem# finds the first occurrence of
#needle# in #haystack#. This is not ANSI-C.
The prototype is not in accordance with the Linux Programmer's
Manual v1.15, but it is with /usr/include/string.h */
unsigned char *
_memmem (unsigned char const *haystack, int haystack_len, unsigned char const *needle, int needle_len)
{
unsigned char const *end_haystack = haystack + haystack_len - needle_len + 1;
unsigned char const *end_needle = needle + needle_len;
/* Ahhh ... Some minimal lowlevel stuff. This *is* nice; Varation
is the spice of life */
while (haystack < end_haystack)
{
unsigned char const *subneedle = needle;
unsigned char const *subhaystack = haystack;
while (subneedle < end_needle)
if (*subneedle++ != *subhaystack++)
goto next;
/* Completed the needle. Gotcha. */
return (unsigned char *) haystack;
next:
haystack++;
}
return 0;
}
void *
memmem (void const *haystack, int haystack_len, void const *needle, int needle_len)
{
unsigned char const *haystack_byte_c = (unsigned char const *) haystack;
unsigned char const *needle_byte_c = (unsigned char const *) needle;
return _memmem (haystack_byte_c, haystack_len, needle_byte_c, needle_len);
}
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