Blame bibutils/strsearch.c
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/* strsearch.c
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*
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* Copyright (c) Chris Putnam 1995-2018
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*
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* Source code released under the GPL version 2
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*
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* strsearch() locates a case-independent substring
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* e.g. a case-independent version of strstr()
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*
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* returns pointer to first occurrence of substring needle in
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* the string haystack when found, NULL if not found
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*
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* '\0' characters terminating strings are not compared
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*
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* strsearch returns haystack when needle is empty as per strstr()
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* conventions
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*
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*/
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#include <stdio.h>
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#include <ctype.h>
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#include "strsearch.h"
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char *strsearch (const char *haystack, const char *needle)
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{
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char *returnptr=NULL;
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unsigned long pos=0;
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if ( !(*needle) ) returnptr = (char *) haystack;
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while (*(haystack+pos) && returnptr==NULL) {
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if ( toupper((unsigned char)*(haystack+pos)) == toupper((unsigned char)*(needle+pos)) )
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pos++;
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else {
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pos = 0;
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haystack++;
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}
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if ( ! (*(needle+pos)) ) returnptr = (char *) haystack;
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}
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return returnptr;
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}
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