My compression algorithm

compress.php

<?
class Compressor {
  function compress($input, $output) {
    $input = fopen($input, 'r');
    $output = fopen($output, 'w');

    while($line = fread($input, 8)) {
      $lineLength = strlen($line);
      for($i = 0; $i < $lineLength; $i += 8) {
        $n = 0;
        for($j = $i; $j < $i + 8; $j++) {
          $n += $this->encode($line{$j});
          if ($j != $i + 7) {
            $n = $n << 5;
          }
        }
        for($j = 0; $j < 5; $j++) {
          fwrite($output, pack('C', $n % 256));
          $n = (int)($n / 256);
        }
      }
    }

    fclose($input);
    fclose($output);
  }

  function decompress($input, $output) {
    $input = fopen($input, 'r');
    $output = fopen($output, 'w');

    $letters = array();

    while($line = fread($input, 1000)) {
      $lineLength = strlen($line);
      for($i = 0; $i < $lineLength; $i += 5) {
        $n = 0;
        for($j = $i + 4; $j >= $i; $j--) {
          $n += ord($line{$j});
          if ($j != $i) {
            $n = $n << 8;
          }
        }
        for($j = 0; $j < 8; $j++) {
          $letters[$j] = $this->decode($n % 32);
          $n = (int)($n / 32);
        }
        for($x = 7; $x >= 0; $x--) {
          fwrite($output, $letters[$x]);
        }
      }
    }

    fclose($input);
    fclose($output);
  }

  private function encode($char) {
    $char = ord($char);
    switch($char) {
    case 32: // space
      return 26;
    case 10: // enter
      return 27;
    case 44: // ,
      return 28;
    case 46: // .
      return 29;
    default:
      if (97 <= $char && $char <= 122) {
        return $char - 97;
      } else {
        return $char - 65;
      }
    }
  }

  private function decode($num) {
    switch($num) {
    case 26:
      return ' ';
    case 27:
      return "\n";
    case 28:
      return ',';
    case 29:
      return '.';
    default:
      return chr($num + 97);
    }
  }
}

$compressor = new Compressor();
$compressor->compress('../php_nextive_data/compression_dummy_data.txt', '../php_nextive_data/output.txt');
$compressor->decompress('../php_nextive_data/output.txt', '../php_nextive_data/output2.txt');
?>