hush/libbb/strrstr.c

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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) 2008 Bernhard Reutner-Fischer
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*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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#include "libbb.h"
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/*
* The strrstr() function finds the last occurrence of the substring needle
* in the string haystack. The terminating nul characters are not compared.
*/
char* FAST_FUNC strrstr(const char *haystack, const char *needle)
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{
char *r = NULL;
if (!needle[0])
return (char*)haystack + strlen(haystack);
while (1) {
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char *p = strstr(haystack, needle);
if (!p)
return r;
r = p;
haystack = p + 1;
}
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}
#if ENABLE_UNIT_TEST
BBUNIT_DEFINE_TEST(strrstr)
{
static const struct {
const char *h, *n;
int pos;
} test_array[] = {
/* 0123456789 */
{ "baaabaaab", "aaa", 5 },
{ "baaabaaaab", "aaa", 6 },
{ "baaabaab", "aaa", 1 },
{ "aaa", "aaa", 0 },
{ "aaa", "a", 2 },
{ "aaa", "bbb", -1 },
{ "a", "aaa", -1 },
{ "aaa", "", 3 },
{ "", "aaa", -1 },
{ "", "", 0 },
};
int i;
i = 0;
while (i < sizeof(test_array) / sizeof(test_array[0])) {
const char *r = strrstr(test_array[i].h, test_array[i].n);
if (r == NULL)
r = test_array[i].h - 1;
BBUNIT_ASSERT_EQ(r, test_array[i].h + test_array[i].pos);
i++;
}
BBUNIT_ENDTEST;
}
#endif /* ENABLE_UNIT_TEST */