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   1  <?php
   2  /**
   3   * Random_* Compatibility Library
   4   * for using the new PHP 7 random_* API in PHP 5 projects
   5   *
   6   * The MIT License (MIT)
   7   *
   8   * Copyright (c) 2015 - 2018 Paragon Initiative Enterprises
   9   *
  10   * Permission is hereby granted, free of charge, to any person obtaining a copy
  11   * of this software and associated documentation files (the "Software"), to deal
  12   * in the Software without restriction, including without limitation the rights
  13   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  14   * copies of the Software, and to permit persons to whom the Software is
  15   * furnished to do so, subject to the following conditions:
  16   *
  17   * The above copyright notice and this permission notice shall be included in
  18   * all copies or substantial portions of the Software.
  19   *
  20   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  21   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  23   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  25   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  26   * SOFTWARE.
  27   */
  28  
  29  if (!is_callable('random_bytes')) {
  30      /**
  31       * If the libsodium PHP extension is loaded, we'll use it above any other
  32       * solution.
  33       *
  34       * libsodium-php project:
  35       * @ref https://github.com/jedisct1/libsodium-php
  36       *
  37       * @param int $bytes
  38       *
  39       * @throws Exception
  40       *
  41       * @return string
  42       */
  43      function random_bytes($bytes)
  44      {
  45          try {
  46              /** @var int $bytes */
  47              $bytes = RandomCompat_intval($bytes);
  48          } catch (TypeError $ex) {
  49              throw new TypeError(
  50                  'random_bytes(): $bytes must be an integer'
  51              );
  52          }
  53  
  54          if ($bytes < 1) {
  55              throw new Error(
  56                  'Length must be greater than 0'
  57              );
  58          }
  59  
  60          /**
  61           * @var string
  62           */
  63          $buf = '';
  64  
  65          /**
  66           * \Sodium\randombytes_buf() doesn't allow more than 2147483647 bytes to be
  67           * generated in one invocation.
  68           */
  69          if ($bytes > 2147483647) {
  70              for ($i = 0; $i < $bytes; $i += 1073741824) {
  71                  $n = ($bytes - $i) > 1073741824
  72                      ? 1073741824
  73                      : $bytes - $i;
  74                  $buf .= Sodium::randombytes_buf((int) $n);
  75              }
  76          } else {
  77              $buf .= Sodium::randombytes_buf((int) $bytes);
  78          }
  79  
  80          if (is_string($buf)) {
  81              if (RandomCompat_strlen($buf) === $bytes) {
  82                  return $buf;
  83              }
  84          }
  85  
  86          /**
  87           * If we reach here, PHP has failed us.
  88           */
  89          throw new Exception(
  90              'Could not gather sufficient random data'
  91          );
  92      }
  93  }