<?php

/*

 * This file is part of SwiftMailer.

 * (c) 2004-2009 Chris Corbyn

 *

 * For the full copyright and license information, please view the LICENSE

 * file that was distributed with this source code.

 */

/**

 * Provides fixed-width byte sizes for reading fixed-width character sets.

 * @package Swift

 * @subpackage Encoder

 * @author Chris Corbyn

 * @author Xavier De Cock <xdecock@gmail.com>

 */

class Swift_CharacterReader_GenericFixedWidthReader

  implements Swift_CharacterReader

{

  /**

   * The number of bytes in a single character.

   * @var int

   * @access private

   */

  private $_width;

  /**

   * Creates a new GenericFixedWidthReader using $width bytes per character.

   * @param int $width

   */

  public function __construct($width)

  {

    $this->_width = $width;

  }

  /**

   * Returns the complete charactermap

   *

   * @param string $string

   * @param int $startOffset

   * @param array $currentMap

   * @param mixed $ignoredChars

   * @return $int

   */

  public function getCharPositions($string, $startOffset, &$currentMap, &$ignoredChars)

  {

  	$strlen = strlen($string);

  	// % and / are CPU intensive, so, maybe find a better way

  	$ignored = $strlen%$this->_width;

  	$ignoredChars = substr($string, - $ignored);

  	$currentMap = $this->_width;

  	return ($strlen - $ignored)/$this->_width;

  }

  /**

   * Returns mapType

   * @int mapType

   */

  public function getMapType()

  {

  	return self::MAP_TYPE_FIXED_LEN;

  }

  /**

   * Returns an integer which specifies how many more bytes to read.

   * A positive integer indicates the number of more bytes to fetch before invoking

   * this method again.

   * A value of zero means this is already a valid character.

   * A value of -1 means this cannot possibly be a valid character.

   * @param string $bytes

   * @return int

   */

  public function validateByteSequence($bytes, $size)

  {

    $needed = $this->_width - $size;

    return ($needed > -1)

      ? $needed

      : -1

      ;

  }

  /**

   * Returns the number of bytes which should be read to start each character.

   * @return int

   */

  public function getInitialByteSize()

  {

    return $this->_width;

  }

}