class Twig_TokenStream

class Twig_TokenStream {
  protected $tokens;
  protected $current;
  protected $filename;

  /**
   * Constructor.
   *
   * @param array  $tokens   An array of tokens
   * @param string $filename The name of the filename which tokens are associated with
   */
  public function __construct(array $tokens, $filename = null) {
    $this->tokens = $tokens;
    $this->current = 0;
    $this->filename = $filename;
  }

  /**
   * Returns a string representation of the token stream.
   *
   * @return string
   */
  public function __toString() {
    return implode("\n", $this->tokens);
  }
  public function injectTokens(array $tokens) {
    $this->tokens = array_merge(array_slice($this->tokens, 0, $this->current), $tokens, array_slice($this->tokens, $this->current));
  }

  /**
   * Sets the pointer to the next token and returns the old one.
   *
   * @return Twig_Token
   */
  public function next() {
    if (!isset($this->tokens[++$this->current])) {
      throw new Twig_Error_Syntax('Unexpected end of template', -1, $this->filename);
    }
    return $this->tokens[$this->current - 1];
  }

  /**
   * Tests a token and returns it or throws a syntax error.
   *
   * @return Twig_Token
   */
  public function expect($type, $value = null, $message = null) {
    $token = $this->tokens[$this->current];
    if (!$token
      ->test($type, $value)) {
      $line = $token
        ->getLine();
      throw new Twig_Error_Syntax(sprintf('%sUnexpected token "%s" of value "%s" ("%s" expected%s)', $message ? $message . '. ' : '', Twig_Token::typeToEnglish($token
        ->getType(), $line), $token
        ->getValue(), Twig_Token::typeToEnglish($type, $line), $value ? sprintf(' with value "%s"', $value) : ''), $line, $this->filename);
    }
    $this
      ->next();
    return $token;
  }

  /**
   * Looks at the next token.
   *
   * @param integer $number
   *
   * @return Twig_Token
   */
  public function look($number = 1) {
    if (!isset($this->tokens[$this->current + $number])) {
      throw new Twig_Error_Syntax('Unexpected end of template', -1, $this->filename);
    }
    return $this->tokens[$this->current + $number];
  }

  /**
   * Tests the current token
   *
   * @return bool
   */
  public function test($primary, $secondary = null) {
    return $this->tokens[$this->current]
      ->test($primary, $secondary);
  }

  /**
   * Checks if end of stream was reached
   *
   * @return bool
   */
  public function isEOF() {
    return $this->tokens[$this->current]
      ->getType() === Twig_Token::EOF_TYPE;
  }

  /**
   * Gets the current token
   *
   * @return Twig_Token
   */
  public function getCurrent() {
    return $this->tokens[$this->current];
  }

  /**
   * Gets the filename associated with this stream
   *
   * @return string
   */
  public function getFilename() {
    return $this->filename;
  }

}