/*

   +----------------------------------------------------------------------+

   | Copyright © The PHP Group and Contributors.                          |

   +----------------------------------------------------------------------+

   | This source file is subject to the Modified BSD License that is      |

   | bundled with this package in the file LICENSE, and is available      |

   | through the World Wide Web at <https://www.php.net/license/>.        |

   |                                                                      |

   | SPDX-License-Identifier: BSD-3-Clause                                |

   +----------------------------------------------------------------------+

   | Author: Go Kudo <zeriyoshi@php.net>                                  |

   |                                                                      |

   | Based on code from: David Blackman                                   |

   |                     Sebastiano Vigna <vigna@acm.org>                 |

   +----------------------------------------------------------------------+

*/

#ifdef HAVE_CONFIG_H

# include "config.h"

#endif

#include "php.h"

#include "php_random.h"

#include "php_random_csprng.h"

#include "Zend/zend_exceptions.h"

static inline uint64_t splitmix64(uint64_t *seed)

{

  uint64_t r;

  r = (*seed += 0x9e3779b97f4a7c15ULL);

  r = (r ^ (r >> 30)) * 0xbf58476d1ce4e5b9ULL;

  r = (r ^ (r >> 27)) * 0x94d049bb133111ebULL;

  return (r ^ (r >> 31));

}

ZEND_ATTRIBUTE_CONST static inline uint64_t rotl(const uint64_t x, int k)

{

  return (x << k) | (x >> (64 - k));

}

static inline uint64_t generate_state(php_random_status_state_xoshiro256starstar *s)

{

  const uint64_t r = rotl(s->state[1] * 5, 7) * 9;

  const uint64_t t = s->state[1] << 17;

  s->state[2] ^= s->state[0];

  s->state[3] ^= s->state[1];

  s->state[1] ^= s->state[2];

  s->state[0] ^= s->state[3];

  s->state[2] ^= t;

  s->state[3] = rotl(s->state[3], 45);

  return r;

}

static inline void jump(php_random_status_state_xoshiro256starstar *state, const uint64_t *jmp)

{

  uint64_t s0 = 0, s1 = 0, s2 = 0, s3 = 0;

  for (uint32_t i = 0; i < 4; i++) {

    for (uint32_t j = 0; j < 64; j++) {

      if (jmp[i] & 1ULL << j) {

        s0 ^= state->state[0];

        s1 ^= state->state[1];

        s2 ^= state->state[2];

        s3 ^= state->state[3];

      }

      generate_state(state);

    }

  }

  state->state[0] = s0;

  state->state[1] = s1;

  state->state[2] = s2;

  state->state[3] = s3;

}

PHPAPI inline void php_random_xoshiro256starstar_seed256(php_random_status_state_xoshiro256starstar *state, uint64_t s0, uint64_t s1, uint64_t s2, uint64_t s3)

{

  state->state[0] = s0;

  state->state[1] = s1;

  state->state[2] = s2;

  state->state[3] = s3;

}

PHPAPI inline void php_random_xoshiro256starstar_seed64(php_random_status_state_xoshiro256starstar *state, uint64_t seed)

{

  uint64_t s[4];

  s[0] = splitmix64(&seed);

  s[1] = splitmix64(&seed);

  s[2] = splitmix64(&seed);

  s[3] = splitmix64(&seed);

  php_random_xoshiro256starstar_seed256(state, s[0], s[1], s[2], s[3]);

}

static php_random_result generate(void *state)

{

  return (php_random_result){

    .size = sizeof(uint64_t),

    .result = generate_state(state),

  };

}

static zend_long range(void *state, zend_long min, zend_long max)

{

  return php_random_range((php_random_algo_with_state){

    .algo = &php_random_algo_xoshiro256starstar,

    .state = state,

  }, min, max);

}

static bool serialize(void *state, HashTable *data)

{

  php_random_status_state_xoshiro256starstar *s = state;

  zval t;

  for (uint32_t i = 0; i < 4; i++) {

    ZVAL_STR(&t, php_random_bin2hex_le(&s->state[i], sizeof(uint64_t)));

    zend_hash_next_index_insert(data, &t);

  }

  return true;

}

static bool unserialize(void *state, HashTable *data)

{

  php_random_status_state_xoshiro256starstar *s = state;

  zval *t;

  /* Verify the expected number of elements, this implicitly ensures that no additional elements are present. */

  if (zend_hash_num_elements(data) != 4) {

    return false;

  }

  for (uint32_t i = 0; i < 4; i++) {

    t = zend_hash_index_find(data, i);

    if (!t || Z_TYPE_P(t) != IS_STRING || Z_STRLEN_P(t) != (2 * sizeof(uint64_t))) {

      return false;

    }

    if (!php_random_hex2bin_le(Z_STR_P(t), &s->state[i])) {

      return false;

    }

  }

  if (UNEXPECTED(s->state[0] == 0 && s->state[1] == 0 && s->state[2] == 0 && s->state[3] == 0)) {

    return false;

  }

  return true;

}

PHPAPI const php_random_algo php_random_algo_xoshiro256starstar = {

  sizeof(php_random_status_state_xoshiro256starstar),

  generate,

  range,

  serialize,

  unserialize

};

PHPAPI void php_random_xoshiro256starstar_jump(php_random_status_state_xoshiro256starstar *state)

{

  static const uint64_t jmp[] = {0x180ec6d33cfd0aba, 0xd5a61266f0c9392c, 0xa9582618e03fc9aa, 0x39abdc4529b1661c};

  jump(state, jmp);

}

PHPAPI void php_random_xoshiro256starstar_jump_long(php_random_status_state_xoshiro256starstar *state)

{

  static const uint64_t jmp[] = {0x76e15d3efefdcbbf, 0xc5004e441c522fb3, 0x77710069854ee241, 0x39109bb02acbe635};

  jump(state, jmp);

}

/* {{{ Random\Engine\Xoshiro256StarStar::jump() */

PHP_METHOD(Random_Engine_Xoshiro256StarStar, jump)

{

  php_random_algo_with_state engine = Z_RANDOM_ENGINE_P(ZEND_THIS)->engine;

  php_random_status_state_xoshiro256starstar *state = engine.state;

  ZEND_PARSE_PARAMETERS_NONE();

  php_random_xoshiro256starstar_jump(state);

}

/* }}} */

/* {{{ Random\Engine\Xoshiro256StarStar::jumpLong() */

PHP_METHOD(Random_Engine_Xoshiro256StarStar, jumpLong)

{

  php_random_algo_with_state engine = Z_RANDOM_ENGINE_P(ZEND_THIS)->engine;

  php_random_status_state_xoshiro256starstar *state = engine.state;

  ZEND_PARSE_PARAMETERS_NONE();

  php_random_xoshiro256starstar_jump_long(state);

}

/* }}} */

/* {{{ Random\Engine\Xoshiro256StarStar::__construct */

PHP_METHOD(Random_Engine_Xoshiro256StarStar, __construct)

{

  php_random_algo_with_state engine = Z_RANDOM_ENGINE_P(ZEND_THIS)->engine;

  php_random_status_state_xoshiro256starstar *state = engine.state;

  zend_string *str_seed = NULL;

  zend_long int_seed = 0;

  bool seed_is_null = true;

  ZEND_PARSE_PARAMETERS_START(0, 1)

    Z_PARAM_OPTIONAL;

    Z_PARAM_STR_OR_LONG_OR_NULL(str_seed, int_seed, seed_is_null);

  ZEND_PARSE_PARAMETERS_END();

  if (seed_is_null) {

    uint64_t t[4];

    do {

      if (php_random_bytes_throw(&t, sizeof(t)) == FAILURE) {

        zend_throw_exception(random_ce_Random_RandomException, "Failed to generate a random seed", 0);

        RETURN_THROWS();

      }

    } while (UNEXPECTED(t[0] == 0 && t[1] == 0 && t[2] == 0 && t[3] == 0));

    php_random_xoshiro256starstar_seed256(state, t[0], t[1], t[2], t[3]);

  } else {

    if (str_seed) {

      /* char (byte: 8 bit) * 32 = 256 bits */

      if (ZSTR_LEN(str_seed) == 32) {

        uint64_t t[4];

        /* Endianness safe copy */

        for (uint32_t i = 0; i < 4; i++) {

          t[i] = 0;

          for (uint32_t j = 0; j < 8; j++) {

            t[i] += ((uint64_t) (unsigned char) ZSTR_VAL(str_seed)[(i * 8) + j]) << (j * 8);

          }

        }

        if (UNEXPECTED(t[0] == 0 && t[1] == 0 && t[2] == 0 && t[3] == 0)) {

          zend_argument_value_error(1, "must not consist entirely of NUL bytes");

          RETURN_THROWS();

        }

        php_random_xoshiro256starstar_seed256(state, t[0], t[1], t[2], t[3]);

      } else {

        zend_argument_value_error(1, "must be a 32 byte (256 bit) string");

        RETURN_THROWS();

      }

    } else {

      php_random_xoshiro256starstar_seed64(state, (uint64_t) int_seed);

    }

  }

}

/* }}} */