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42 lines
2.6 KiB
C
42 lines
2.6 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/str/str.h"
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/**
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* Searches for fixed-length substring in memory region.
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*
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* @param haystack is the region of memory to be searched
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* @param haystacklen is its character count
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* @param needle contains the memory for which we're searching
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* @param needlelen is its character count
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* @return pointer to first result or NULL if not found
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*/
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void *memmem(const void *haystack, size_t haystacklen, const void *needle,
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size_t needlelen) {
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size_t i, j;
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if (!needlelen) return haystack;
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for (i = 0; i < haystacklen; ++i) {
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for (j = 0;; ++j) {
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if (j == needlelen) return (/*unconst*/ char *)haystack + i;
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if (i + j == haystacklen) break;
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if (((char *)needle)[j] != ((char *)haystack)[i + j]) break;
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}
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}
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return NULL;
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}
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