/*
   +----------------------------------------------------------------------+
   | 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>                                  |
   +----------------------------------------------------------------------+
*/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include "php.h"
#include "php_random.h"

static php_random_result generate(void *state)
{
	php_random_status_state_user *s = state;
	uint64_t result = 0;
	size_t size;
	zval retval;
	zend_string *zstr;

	zend_call_known_instance_method_with_0_params(s->generate_method, s->object, &retval);

	if (EG(exception)) {
		return (php_random_result){
			.size = sizeof(uint64_t),
			.result = 0,
		};
	}

	if (UNEXPECTED(Z_ISREF(retval))) {
		zstr = Z_STR_P(Z_REFVAL(retval));
	} else {
		zstr = Z_STR(retval);
	}

	/* Store generated size in a state */
	size = ZSTR_LEN(zstr);

	/* Guard for over 64-bit results */
	if (size > sizeof(uint64_t)) {
		size = sizeof(uint64_t);
	}

	if (size > 0) {
		/* Endianness safe copy */
		for (size_t i = 0; i < size; i++) {
			result += ((uint64_t) (unsigned char) ZSTR_VAL(zstr)[i]) << (8 * i);
		}
	} else {
		zend_throw_error(random_ce_Random_BrokenRandomEngineError, "A random engine must return a non-empty string");
		zval_ptr_dtor(&retval);
		return (php_random_result){
			.size = sizeof(uint64_t),
			.result = 0,
		};
	}

	zval_ptr_dtor(&retval);

	return (php_random_result){
		.size = size,
		.result = result,
	};
}

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_user,
		.state = state,
	}, min, max);
}

PHPAPI const php_random_algo php_random_algo_user = {
	sizeof(php_random_status_state_user),
	generate,
	range,
	NULL,
	NULL,
};
