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52 lines
1.1 KiB
C
52 lines
1.1 KiB
C
/*
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FUNCTION
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<<strnstr>>---find string segment
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INDEX
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strnstr
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SYNOPSIS
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#include <string.h>
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size_t strnstr(const char *<[s1]>, const char *<[s2]>, size_t <[n]>);
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DESCRIPTION
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Locates the first occurrence in the string pointed to by <[s1]> of
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the sequence of limited to the <[n]> characters in the string
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pointed to by <[s2]>
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RETURNS
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Returns a pointer to the located string segment, or a null
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pointer if the string <[s2]> is not found. If <[s2]> points to
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a string with zero length, <[s1]> is returned.
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PORTABILITY
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<<strnstr>> is a BSD extension.
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<<strnstr>> requires no supporting OS subroutines.
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QUICKREF
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strnstr pure
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*/
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#define _GNU_SOURCE
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#include <string.h>
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/*
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* Find the first occurrence of find in s, where the search is limited to the
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* first slen characters of s.
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*/
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char *
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strnstr(const char *haystack, const char *needle, size_t haystack_len)
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{
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size_t needle_len = strnlen(needle, haystack_len);
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if (needle_len < haystack_len || !needle[needle_len]) {
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char *x = memmem(haystack, haystack_len, needle, needle_len);
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if (x && !memchr(haystack, 0, x - haystack))
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return x;
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}
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return NULL;
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}
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