<?php
  /**
   * @package php-font-lib
   * @link    http://php-font-lib.googlecode.com/
   * @author  Fabien Ménager <fabien.menager@gmail.com>
   * @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
   * @version $Id: font_table_loca.cls.php 43 2012-02-05 22:26:53Z fabien.menager $
   */
  
  /**
   * `loca` font table.
   * 
   * @package php-font-lib
   */
  class Font_Table_loca extends Font_Table {
    protected function _parse(){
      $font = $this->getFont();
      $offset = $font->pos();
      
      $indexToLocFormat = $font->getData("head", "indexToLocFormat");
      $numGlyphs = $font->getData("maxp", "numGlyphs");
      
      $font->seek($offset);
      
      $data = array();
      
      // 2 bytes
      if ($indexToLocFormat == 0) {
        $d = $font->read(($numGlyphs + 1) * 2);
        $loc = unpack("n*", $d);
        
        for ($i = 0; $i <= $numGlyphs; $i++) {
          $data[] = $loc[$i+1] * 2;
        }
      }
      
      // 4 bytes
      else if ($indexToLocFormat == 1) {
        $d = $font->read(($numGlyphs + 1) * 4);
        $loc = unpack("N*", $d);
        
        for ($i = 0; $i <= $numGlyphs; $i++) {
          $data[] = $loc[$i+1];
        }
      }
      
      $this->data = $data;
    }
    
    function _encode(){
      $font = $this->getFont();
      $data = $this->data;
      
      $indexToLocFormat = $font->getData("head", "indexToLocFormat");
      $numGlyphs = $font->getData("maxp", "numGlyphs");
      $length = 0;
      
      // 2 bytes
      if ($indexToLocFormat == 0) {
        for ($i = 0; $i <= $numGlyphs; $i++) {
          $length += $font->writeUInt16($data[$i] / 2);
        }
      }
      
      // 4 bytes
      else if ($indexToLocFormat == 1) {
        for ($i = 0; $i <= $numGlyphs; $i++) {
          $length += $font->writeUInt32($data[$i]);
        }
      }
      
      return $length;
    }
  }