// Copyright 2026 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.

#include <stddef.h>

#include <stdint.h>

#include <string.h>

#include <sodium.h>

extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {

  if (sodium_init() == -1) {

    return 0;

  }

  // We need some data for outlen, keylen, and the message itself

  if (size < 2) {

    return 0;

  }

  size_t outlen = (data[0] % (crypto_generichash_BYTES_MAX - crypto_generichash_BYTES_MIN + 1)) + crypto_generichash_BYTES_MIN;

  size_t keylen = (data[1] % (crypto_generichash_KEYBYTES_MAX - crypto_generichash_KEYBYTES_MIN + 1));

  if (keylen > 0 && size < 2 + keylen) {

      keylen = 0;

  }

  const uint8_t *key = keylen > 0 ? data + 2 : NULL;

  const uint8_t *msg = data + 2 + keylen;

  size_t msglen = size - (2 + keylen);

  unsigned char out[crypto_generichash_BYTES_MAX];

  // Single-part API

  crypto_generichash(out, outlen, msg, msglen, key, keylen);

  // Multi-part API

  crypto_generichash_state state;

  if (crypto_generichash_init(&state, key, keylen, outlen) == 0) {

      // Split msg into two parts if possible

      if (msglen > 0) {

          size_t part1 = msglen / 2;

          crypto_generichash_update(&state, msg, part1);

          crypto_generichash_update(&state, msg + part1, msglen - part1);

      } else {

          crypto_generichash_update(&state, msg, 0);

      }

      crypto_generichash_final(&state, out, outlen);

  }

  return 0;

}