ref: 16ea0054046e540a90a8a44fd81c0f7b4ae8024d
dir: /lib/c/strstr.c/
#include <string.h> #undef strstr char * strstr(const char *s1, const char *s2) { const char *p, *q; int c0, c; c0 = *s2; if (c0 == '\0') return (char *) s1; --s1; while ((s1 = strchr(s1 + 1, c0)) != NULL) { p = s1; q = s2; for (;;) { if ((c = *++p) == '\0') return (char *) s1; if (c != *++q) break; } } return NULL; }