84 lines
1.9 KiB
C
84 lines
1.9 KiB
C
/*
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MIT License
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Copyright (c) 2024 Roy Merkel
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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*/
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#include "memmem.h"
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void *memmem_impl(void *haystack, size_t haystacklen, const void *needle, size_t needlelen)
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{
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const unsigned char *cmpp;
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const unsigned char *p;
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const unsigned char *endp;
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const unsigned char *q;
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const unsigned char *endq;
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unsigned char found;
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if(haystack == NULL)
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{
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return NULL;
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}
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if(needle == NULL)
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{
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return haystack;
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}
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if(haystacklen == 0)
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{
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return NULL;
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}
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if(needlelen == 0)
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{
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return haystack;
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}
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if(needlelen > haystacklen)
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{
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return NULL;
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}
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endp = haystack + haystacklen - needlelen;
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endq = needle + needlelen;
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for(p = haystack; p <= endp; p++)
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{
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found = 1;
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cmpp = p;
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for(q = needle; q < endq; q++)
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{
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if(*cmpp != *q)
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{
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found = 0;
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break;
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}
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else
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{
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cmpp++;
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}
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}
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if(found)
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{
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return (void*)p;
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}
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}
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return NULL;
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}
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