strstr.c
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/* public domain rewrite of strstr(3) */
#include "ruby/missing.h"
size_t strlen(const char*);
char *
strstr(const char *haystack, const char *needle)
{
const char *hend;
const char *a, *b;
if (*needle == 0) return (char *)haystack;
hend = haystack + strlen(haystack) - strlen(needle) + 1;
while (haystack < hend) {
if (*haystack == *needle) {
a = haystack;
b = needle;
for (;;) {
if (*b == 0) return (char *)haystack;
if (*a++ != *b++) {
break;
}
}
}
haystack++;
}
return 0;
}