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/* See LICENSE file for copyright and license details. */
#include "common.h"
#ifndef TEST
void *
libsimple_memmem(const void *hay_, size_t hayn, const void *sub_, size_t subn)
{
const unsigned char *hay = hay_;
const unsigned char *sub = sub_;
size_t *next, i, j;
if (!subn)
return REMOVE_CONST(hay, unsigned char *);
if (hayn < subn)
return NULL;
if (subn == 1)
return memchr(hay, *sub, hayn);
next = alloca((subn + 1U) * sizeof(*next));
i = 0, j = SIZE_MAX;
goto beginning;
for (; i < subn; i++, j++) {
if (sub[i] == sub[j]) {
next[i] = next[j];
} else {
beginning:
next[i] = j;
while (j != SIZE_MAX && sub[i] != sub[j])
j = next[j];
}
}
for (i = j = 0; i < hayn;) {
while (j != SIZE_MAX && sub[j] != hay[i])
j = next[j];
i++;
if (++j == subn) {
hay = &hay[i - j];
return REMOVE_CONST(hay, unsigned char *);
}
}
return NULL;
}
#else
#include "test.h"
int
main(void)
{
assert(!strcmpnul(libsimple_memmem("test", 4, "test", 4), "test"));
assert(!strcmpnul(libsimple_memmem("", 0, "", 0), ""));
assert(!strcmpnul(libsimple_memmem("test", 4, "", 0), "test"));
assert(!libsimple_memmem("", 0, "test", 4));
assert(!libsimple_memmem("t", 1, "test", 4));
assert(!strcmpnul(libsimple_memmem("test", 4, "t", 1), "test"));
assert(!strcmpnul(libsimple_memmem("test", 4, "e", 1), "est"));
assert(!strcmpnul(libsimple_memmem("test", 4, "s", 1), "st"));
assert(!libsimple_memmem("test", 4, "x", 1));
assert(!strcmpnul(libsimple_memmem("test", 4, "te", 2), "test"));
assert(!strcmpnul(libsimple_memmem("test", 4, "es", 2), "est"));
assert(!strcmpnul(libsimple_memmem("test", 4, "st", 2), "st"));
assert(!strcmpnul(libsimple_memmem("test", 5, "t", 2), "t"));
assert(!libsimple_memmem("test", 4, "xx", 2));
assert(!strcmpnul(libsimple_memmem("abc", 3, "c", 1), "c"));
assert(!strcmpnul(libsimple_memmem("abc", 3, "bc", 2), "bc"));
assert(!strcmpnul(libsimple_memmem("abc", 3, "abc", 3), "abc"));
assert(!libsimple_memmem("abc", 3, "abc", 4));
assert(!strcmpnul(libsimple_memmem("abcabc", 6, "bc", 2), "bcabc"));
assert(!strcmpnul(libsimple_memmem("ABCABC", 6, "BC", 2), "BCABC"));
assert(!libsimple_memmem("ABCDEF", 6, "bc", 2));
assert(!libsimple_memmem("abcdef", 6, "BC", 2));
return 0;
}
#endif
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