42 lines
1.4 KiB
C
42 lines
1.4 KiB
C
/*
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* Copyright (c) 2024 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* 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 WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* string/memmem.c
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* Locate a subsequence.
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*/
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#include <string.h>
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// TODO: Remember the fast algorithm and implemented it here and in strstr.
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void* memmem(const void* haystack, size_t haystack_size,
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const void* needle, size_t needle_size)
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{
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if ( !needle_size )
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return (void*) haystack;
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if ( haystack_size < needle_size )
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return NULL;
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for ( size_t i = 0; i < haystack_size - needle_size; i++ )
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{
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for ( size_t n = 0; n < needle_size; n++ )
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{
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if ( ((char*) haystack)[i + n] != ((char*) needle)[n] )
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break;
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if ( n + 1 == needle_size )
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return (char*) haystack + i;
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}
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}
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return NULL;
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}
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