<?php
  
  namespace Masterminds\HTML5\Parser;
  
  use Masterminds\HTML5\Entities;
  
  /**
   * Manage entity references.
   *
   * This is a simple resolver for HTML5 character reference entitites. See Entities for the list of supported entities.
   */
  class CharacterReference
  {
      protected static $numeric_mask = array(
          0x0,
          0x2FFFF,
          0,
          0xFFFF,
      );
  
      /**
       * Given a name (e.g. 'amp'), lookup the UTF-8 character ('&').
       *
       * @param string $name The name to look up.
       *
       * @return string The character sequence. In UTF-8 this may be more than one byte.
       */
      public static function lookupName($name)
      {
          // Do we really want to return NULL here? or FFFD
          return isset(Entities::$byName[$name]) ? Entities::$byName[$name] : null;
      }
  
      /**
       * Given a decimal number, return the UTF-8 character.
       *
       * @param $int
       *
       * @return false|string|string[]|null
       */
      public static function lookupDecimal($int)
      {
          $entity = '&#' . $int . ';';
  
          // UNTESTED: This may fail on some planes. Couldn't find full documentation
          // on the value of the mask array.
          return mb_decode_numericentity($entity, static::$numeric_mask, 'utf-8');
      }
  
      /**
       * Given a hexidecimal number, return the UTF-8 character.
       *
       * @param $hexdec
       *
       * @return false|string|string[]|null
       */
      public static function lookupHex($hexdec)
      {
          return static::lookupDecimal(hexdec($hexdec));
      }
  }