<?php
/**
* The content of this file is (c) 2003-2005 digital media center GmbH
* All rights reserved
*
* a JSON parser / generator.
* implemented as 100% compatible port of the original JSON parser
* by Douglas Crockford on http://www.JSON.org.
*
* @package      JSON
* @access       public
* @copyright    Copyright (c) 2005-2006 Dominique Stender - http://sf.net/projects/cpaint
* @license      http://www.crockford.com/JSON/license.html
* @author       Dominique Stender <dstender@st-webdevelopment.de>
* @version      $id: json.php 315 2006-09-30 08:29:39Z saloon12yrd $
*/


  /**
  * a JSON parser / generator
  *
  * @access public
  * @author Dominique Stender <dst@dmc.de>
  * @version 1.0.1
  */
  class JSON {
    /**
    * line counter
    *
    * @access   private
    * @var      integer    $at
    */
    public $at = 0;

    /**
    *
    * @access   private
    * @var      string    $ch
    */
    public $ch = ' ';

    /**
    * JSON representation
    *
    * @access   private
    * @var      string    $text
    */
    public $text = '';

    /**
    * takes an arbitrary PHP data structure and generates a valid JSON representation from it
    *
    * @param    mixed    $arg    an arbitrary PHP data structure
    * @access   public
    * @return   string
    * @version  1.0.1   fixed tests whether $s has content by using strlen(). this enables the user to use 0 as very first character
    */
    public function stringify($arg) {
      $returnValue  = '';
      $c            = '';
      $i            = '';
      $l            = '';
      $s            = '';
      $v            = '';
      $numeric      = true;

      switch (gettype($arg)) {

        case 'array':
          // do a test whether all array keys are numeric
          foreach ($arg as $i => $v) {
            if (!is_numeric($i)) {
              $numeric = false;
              break;
            }
          }

          if ($numeric) {

            foreach ($arg as $i => $v) {
              if (strlen($s) > 0) {
                $s .= ',';
              }

              $s .= $this->stringify($arg[$i]);
            } // end: foreach

            $returnValue = '[' . $s . ']';

          } else {
            // associative array
            foreach ($arg as $i => $v) {
              if (strlen($s) > 0) {
                $s .= ',';
              }
              $s .= $this->stringify($i) . ':' . $this->stringify($arg[$i]);
            }
            // return as object
            $returnValue = '{' . $s . '}';
          }
          break;

        case 'object':

          foreach (get_object_vars($arg) as $i => $v) {
            $v = $this->stringify($v);

            if (strlen($s) > 0) {
              $s .= ',';
            }

            $s .= $this->stringify($i) . ':' . $v;
          }

          $returnValue = '{' . $s . '}';
          break;

        case 'integer':
        case 'double':
          $returnValue = is_numeric($arg) ? (string) $arg : 'null';
          break;

        case 'string':
          $aString = preg_split('//', $arg, -1, PREG_SPLIT_NO_EMPTY);
          $s = '"';

          foreach ($aString as $char) {
            $c = $char;

            if (ord($c) >= ord(' ')) {

              if ($c == '\\'
                || $c == '"') {

                $s .= '\\';
              }
              $s .= $c;

            } else {

              switch ($c) {

                case '\b':
                  $s .= '\\b';
                  break;

                case '\f':
                  $s .= '\\f';
                  break;

                case '\n':
                  $s .= '\\n';
                  break;

                case '\r':
                  $s .= '\\r';
                  break;

                case '\t':
                  $s .= '\\t';
                  break;

                default:
                  $s .= '\u00' . sprintf('%02x', ord($c));
              }
            }
          }
          $returnValue = $s . '"';
          break;

        case 'boolean':
          $returnValue = (string) $arg;
          break;

        default:
          $returnValue = 'null';
      }

      return $returnValue;
    }


    /**
    * parses the given string into a PHP data structure
    *
    * @param    string    $text    JSON data representation
    * @access   public
    * @return   mixed
    */
    public function parse($text) {
      $this->at  = 0;
      $this->ch  = ' ';
      $this->text  = $text;

      return $this->val();
    }

    /**
    * triggers a PHP_ERROR
    *
    * @access   private
    * @param    string    $m    error message
    * @return   void
    */
    public function error($m) {
      trigger_error($m . ' at offset ' . $this->at . ': ' . $this->text, E_USER_ERROR);
    }

    /**
    * returns the next character of a JSON string
    *
    * @access  private
    * @return  string
    */
    public function next() {
      $this->ch = $this->text[$this->at];
      $this->at++;
      return $this->ch;
    }

    /**
    * handles whitespace and comments
    *
    * @access  private
    * @return  void
    */
    public function white() {

      while ($this->ch != ''
        && ord($this->ch) <= ord(' ')) {

        $this->next();
      }
    }

    /**
    * handles strings
    *
    * @access  private
    * @return  void
    */
    public function str() {
      $i = '';
      $s = '';
      $t = '';
      $u = '';

      if ($this->ch == '"') {

        while ($this->next() !== null) {

          if ($this->ch == '"') {
            $this->next();
            return $s;

          } elseif ($this->ch == '\\') {

            switch ($this->next()) {
              case 'b':
                $s .= '\b';
                break;

              case 'f':
                $s .= '\f';
                break;

              case 'n':
                $s .= '\n';
                break;

              case 'r':
                $s .= '\r';
                break;

              case 't':
                $s .= '\t';
                break;

              case 'u':
                $u = 0;

                for ($i = 0; $i < 4; $i += 1) {
                  $t = (integer) sprintf('%01c', hexdec($this->next()));

                  if (!is_numeric($t)) {
                    break 2;
                  }
                  $u = $u * 16 + $t;
                }

                $s .= chr($u);
                break;

              default:
                $s .= $this->ch;
            }
          } else {
            $s .= $this->ch;
          }
        }
      }

      $this->error('Bad string');
    }

    /**
    * handless arrays
    *
    * @access  private
    * @return  void
    */
    public function arr() {
      $a = array();

      if ($this->ch == '[') {
        $this->next();
        $this->white();

        if ($this->ch == ']') {
          $this->next();
          return $a;
        }

        while ($this->ch) {
          array_push($a, $this->val());
          $this->white();

          if ($this->ch == ']') {
            $this->next();
            return $a;

          } elseif ($this->ch != ',') {
            break;
          }

          $this->next();
          $this->white();
        }

        $this->error('Bad array');
      }
    }

    /**
    * handles objects
    *
    * @access  public
    * @return  void
    */
    public function obj() {
      $k = '';
      $o = new stdClass();

      if ($this->ch == '{') {
        $this->next();
        $this->white();

        if ($this->ch == '}') {
          $this->next();
          return $o;
        }

        while ($this->ch) {
          $k = $this->str();
          $this->white();

          if ($this->ch != ':') {
            break;
          }

          $this->next();
          $o->$k = $this->val();
          $this->white();

          if ($this->ch == '}') {
            $this->next();
            return $o;

          } elseif ($this->ch != ',') {
            break;
          }

          $this->next();
          $this->white();
        }
      }

      $this->error('Bad object');
    }

    /**
    * handles objects
    *
    * @access  public
    * @return  void
    */
    public function assoc() {
      $k = '';
      $a = array();

      if ($this->ch == '<') {
        $this->next();
        $this->white();

        if ($this->ch == '>') {
          $this->next();
          return $a;
        }

        while ($this->ch) {
          $k = $this->str();
          $this->white();

          if ($this->ch != ':') {
            break;
          }

          $this->next();
          $a[$k] = $this->val();
          $this->white();

          if ($this->ch == '>') {
            $this->next();
            return $a;

          } elseif ($this->ch != ',') {
            break;
          }

          $this->next();
          $this->white();
        }
      }

      $this->error('Bad associative array');
    }

    /**
    * handles numbers
    *
    * @access  private
    * @return  void
    */
    public function num() {
      $n = '';
      $v = '';

      if ($this->ch == '-') {
        $n = '-';
        $this->next();
      }

      while ($this->ch >= '0'
        && $this->ch <= '9') {

        $n .= $this->ch;
        $this->next();
      }

      if ($this->ch == '.') {
        $n .= '.';

        while ($this->next()
          && $this->ch >= '0'
          && $this->ch <= '9') {

            $n .= $this->ch;
          }
        }

      if ($this->ch == 'e'
        || $this->ch == 'E') {

        $n .= 'e';
        $this->next();

        if ($this->ch == '-'
          || $this->ch == '+') {

          $n .= $this->ch;
          $this->next();
        }

        while ($this->ch >= '0'
          && $this->ch <= '9') {

          $n .= $this->ch;
          $this->next();
        }
      }

      $v += $n;

      if (!is_numeric($v)) {
        $this->error('Bad number');

      } else {
        return $v;
      } // end: if
    }

    /**
    * handles words
    *
    * @access  private
    * @return  mixed
    */
    public function word() {
      switch ($this->ch) {

        case 't':

          if ($this->next() == 'r'
            && $this->next() == 'u'
            && $this->next() == 'e') {

            $this->next();
            return true;
          }
          break;

        case 'f':
          if ($this->next() == 'a'
            && $this->next() == 'l'
            && $this->next() == 's'
            && $this->next() == 'e') {

            $this->next();
            return false;
          }
          break;

        case 'n':
          if ($this->next() == 'u'
            && $this->next() == 'l'
            && $this->next() == 'l') {

            $this->next();
            return null;
          }
          break;
      }

      $this->error('Syntax error');
    }

    /**
    * generic value handler
    *
    * @access  private
    * @return  mixed
    */
    public function val() {
      $this->white();

      switch ($this->ch) {

        case '{':
          return $this->obj();

        case '[':
          return $this->arr();

        case '<':
          return $this->assoc();

        case '"':
          return $this->str();

        case '-':
          return $this->num();

        default:
          return ($this->ch >= '0' && $this->ch <= '9') ? $this->num() : $this->word();
      }
    }
  }

?>