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   1  <?php
   2  
   3  declare(strict_types=1);
   4  
   5  namespace MaxMind\Db\Reader;
   6  
   7  class Util
   8  {
   9      /**
  10       * @param resource $stream
  11       */
  12      public static function read($stream, int $offset, int $numberOfBytes): string
  13      {
  14          if ($numberOfBytes === 0) {
  15              return '';
  16          }
  17          if (fseek($stream, $offset) === 0) {
  18              $value = fread($stream, $numberOfBytes);
  19  
  20              // We check that the number of bytes read is equal to the number
  21              // asked for. We use ftell as getting the length of $value is
  22              // much slower.
  23              if ($value !== false && ftell($stream) - $offset === $numberOfBytes) {
  24                  return $value;
  25              }
  26          }
  27  
  28          throw new InvalidDatabaseException(
  29              'The MaxMind DB file contains bad data'
  30          );
  31      }
  32  }