/* See LICENSE file for copyright and license details. */
#include "libsimple.h"
void *
libsimple_memrmem(const void *hay_, size_t hayn, const void *sub_, size_t subn)
{
char *hay = (void *)hay_, *start;
const char *sub = sub_;
if (!subn)
return hay;
if (hayn < subn)
return NULL;
if (subn == 1)
return libsimple_memrchr(hay, *sub, hayn);
start = hay;
hay = &hay[hayn - subn];
do {
if (*hay == *sub && !memcmp(hay, sub, subn))
return hay;
} while (hay-- != start);
return NULL;
}
#ifdef TEST
#include <assert.h>
int
main(void)
{
assert(!strcmp(libsimple_memrmem("test", 4, "test", 4), "test"));
assert(!strcmp(libsimple_memrmem("", 0, "", 0), ""));
assert(!strcmp(libsimple_memrmem("test", 4, "", 0), ""));
assert(!libsimple_memrmem("", 0, "test", 4));
assert(!libsimple_memrmem("t", 1, "test", 4));
assert(!strcmp(libsimple_memrmem("test", 4, "t", 1), "t"));
assert(!strcmp(libsimple_memrmem("test", 4, "e", 1), "est"));
assert(!strcmp(libsimple_memrmem("test", 4, "s", 1), "st"));
assert(!libsimple_memrmem("test", 4, "x", 1));
assert(!strcmp(libsimple_memrmem("test", 4, "te", 2), "test"));
assert(!strcmp(libsimple_memrmem("test", 4, "es", 2), "est"));
assert(!strcmp(libsimple_memrmem("test", 4, "st", 2), "st"));
assert(!strcmp(libsimple_memrmem("test", 5, "t", 2), "t"));
assert(!libsimple_memrmem("test", 4, "xx", 2));
assert(!strcmp(libsimple_memrmem("abc", 3, "c", 1), "c"));
assert(!strcmp(libsimple_memrmem("abc", 3, "bc", 2), "bc"));
assert(!strcmp(libsimple_memrmem("abc", 3, "abc", 3), "abc"));
assert(!libsimple_memrmem("abc", 3, "abc", 4));
assert(!strcmp(libsimple_memrmem("abcabc", 6, "bc", 2), "bc"));
return 0;
}
#endif
