/*
 * Copyright 2024 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

///////////////////////////////////////
// Implements:
//   char *strstr(const char *s1, const char *s2);
///////////////////////////////////////
// Notes:
//   Tuned for code size.

#include <stddef.h>
#include <string.h>

char *strstr(const char *s1, const char *s2) {
  size_t len = strlen(s2);
  while (*s1) {
    if (strncmp(s1, s2, len) == 0) {
      return (char*)s1;
    }
    s1++;
  }
  return NULL;
}