73 lines
2.6 KiB
C
73 lines
2.6 KiB
C
/*
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* Copyright (c) 1995, 1996, 1997 Kungliga Tekniska Högskolan
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* (Royal Institute of Technology, Stockholm, Sweden).
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <config.h>
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#include <stdlib.h>
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#include <string.h>
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#ifndef HAVE_MEMMEM
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#include "roken.h"
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ROKEN_LIB_FUNCTION void * ROKEN_LIB_CALL
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memmem(const void *haystack,
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size_t haystacklen,
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const void *needle,
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size_t needlelen)
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{
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const unsigned char *hs = haystack;
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const unsigned char *n = needle;
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size_t hsi, ni;
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if (haystacklen < needlelen || haystacklen == 0)
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return NULL;
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/*
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* Imagine a haystack of length 5 and needle of length 2, then the largest
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* index in the haystack at which we can bother looking for the needle is:
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*
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* 0 1 2 3 4
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* +---------+
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* |?|?|?|?|?|
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* +---------+
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* ^
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* \
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* here, at index 3, which is 5 - 2, and less than (5 - 2 + 1).
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*/
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for (hsi = 0, ni = 0; hsi < (haystacklen - needlelen + 1); hsi++, ni = 0) {
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while (ni < needlelen && n[ni] == hs[hsi + ni])
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ni++;
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if (ni == needlelen)
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return rk_UNCONST(&hs[hsi]);
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}
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return NULL;
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}
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#endif
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