<?php

/**

 * Random_* Compatibility Library

 * for using the new PHP 7 random_* API in PHP 5 projects

 *

 * The MIT License (MIT)

 *

 * Copyright (c) 2015 - 2017 Paragon Initiative Enterprises

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

 * SOFTWARE.

 */

if (!is_callable('RandomCompat_strlen')) {

    if (

        defined('MB_OVERLOAD_STRING') &&

        ini_get('mbstring.func_overload') & MB_OVERLOAD_STRING

    ) {

        /**

         * strlen() implementation that isn't brittle to mbstring.func_overload

         *

         * This version uses mb_strlen() in '8bit' mode to treat strings as raw

         * binary rather than UTF-8, ISO-8859-1, etc

         *

         * @param string $binary_string

         *

         * @throws TypeError

         *

         * @return int

         */

        function RandomCompat_strlen($binary_string)

        {

            if (!is_string($binary_string)) {

                throw new TypeError(

                    'RandomCompat_strlen() expects a string'

                );

            }

            return (int) mb_strlen($binary_string, '8bit');

        }

    } else {

        /**

         * strlen() implementation that isn't brittle to mbstring.func_overload

         *

         * This version just used the default strlen()

         *

         * @param string $binary_string

         *

         * @throws TypeError

         *

         * @return int

         */

        function RandomCompat_strlen($binary_string)

        {

            if (!is_string($binary_string)) {

                throw new TypeError(

                    'RandomCompat_strlen() expects a string'

                );

            }

            return (int) strlen($binary_string);

        }

    }

}

if (!is_callable('RandomCompat_substr')) {

    if (

        defined('MB_OVERLOAD_STRING')

        &&

        ini_get('mbstring.func_overload') & MB_OVERLOAD_STRING

    ) {

        /**

         * substr() implementation that isn't brittle to mbstring.func_overload

         *

         * This version uses mb_substr() in '8bit' mode to treat strings as raw

         * binary rather than UTF-8, ISO-8859-1, etc

         *

         * @param string $binary_string

         * @param int $start

         * @param int $length (optional)

         *

         * @throws TypeError

         *

         * @return string

         */

        function RandomCompat_substr($binary_string, $start, $length = null)

        {

            if (!is_string($binary_string)) {

                throw new TypeError(

                    'RandomCompat_substr(): First argument should be a string'

                );

            }

            if (!is_int($start)) {

                throw new TypeError(

                    'RandomCompat_substr(): Second argument should be an integer'

                );

            }

            if ($length === null) {

                /**

                 * mb_substr($str, 0, NULL, '8bit') returns an empty string on

                 * PHP 5.3, so we have to find the length ourselves.

                 */

                $length = RandomCompat_strlen($binary_string) - $start;

            } elseif (!is_int($length)) {

                throw new TypeError(

                    'RandomCompat_substr(): Third argument should be an integer, or omitted'

                );

            }

            // Consistency with PHP's behavior

            if ($start === RandomCompat_strlen($binary_string) && $length === 0) {

                return '';

            }

            if ($start > RandomCompat_strlen($binary_string)) {

                return '';

            }

            return (string) mb_substr($binary_string, $start, $length, '8bit');

        }

    } else {

        /**

         * substr() implementation that isn't brittle to mbstring.func_overload

         *

         * This version just uses the default substr()

         *

         * @param string $binary_string

         * @param int $start

         * @param int $length (optional)

         *

         * @throws TypeError

         *

         * @return string

         */

        function RandomCompat_substr($binary_string, $start, $length = null)

        {

            if (!is_string($binary_string)) {

                throw new TypeError(

                    'RandomCompat_substr(): First argument should be a string'

                );

            }

            if (!is_int($start)) {

                throw new TypeError(

                    'RandomCompat_substr(): Second argument should be an integer'

                );

            }

            if ($length !== null) {

                if (!is_int($length)) {

                    throw new TypeError(

                        'RandomCompat_substr(): Third argument should be an integer, or omitted'

                    );

                }

                return (string) substr($binary_string, $start, $length);

            }

            return (string) substr($binary_string, $start);

        }

    }

}