json.php

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<?php
/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */

/** 
 * Converts to and from JSON format.
 * 
 * JSON (JavaScript Object Notation) is a lightweight data-interchange
 * format. It is easy for humans to read and write. It is easy for machines
 * to parse and generate. It is based on a subset of the JavaScript
 * Programming Language, Standard ECMA-262 3rd Edition - December 1999.
 * This feature can also be found in  Python. JSON is a text format that is
 * completely language independent but uses conventions that are familiar
 * to programmers of the C-family of languages, including C, C++, C#, Java,
 * JavaScript, Perl, TCL, and many others. These properties make JSON an
 * ideal data-interchange language.
 * 
 * This package provides a simple encoder and decoder for JSON notation. It
 * is intended for use with client-side Javascript applications that make
 * use of HTTPRequest to perform server communication functions - data can
 * be encoded into JSON notation for use in a client-side javascript, or
 * decoded from incoming Javascript requests. JSON format is native to
 * Javascript, and can be directly eval()'ed with no further parsing
 * overhead
 *
 * All strings should be in ASCII or UTF-8 format!
 *
 * PHP versions 4 and 5
 *
 * LICENSE: Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * conditions are met: Redistributions of source code must retain the
 * above copyright notice, this list of conditions and the following
 * disclaimer. Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 * 
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
 * NO EVENT SHALL CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
 * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 * 
 * @category   
 * @package    
 * @author      Michal Migurski <[e-mail]>
 * @author      Matt Knapp <mdknapp[at]gmail[dot]com>
 * @author      Brett Stimmerman <brettstimmerman[at]gmail[dot]com>
 * @copyright   2005 Michal Migurski
 * @license     http://www.freebsd.org/copyright/freebsd-license.html
 * @link        http://pear.php.net/pepr/pepr-proposal-show.php?id=198
 */

/**
 * Marker constant for JSON::decode(), used to flag stack state
 */
define('JSON_SLICE',   1);

/**
 * Marker constant for JSON::decode(), used to flag stack state
 */
define('JSON_IN_STR',  2);

/**
 * Marker constant for JSON::decode(), used to flag stack state
 */
define('JSON_IN_ARR',  4);

/**
 * Marker constant for JSON::decode(), used to flag stack state
 */
define('JSON_IN_OBJ',  8);

/**
 * Marker constant for JSON::decode(), used to flag stack state
 */
define('JSON_IN_CMT', 16);

/**
 * Behavior switch for JSON::decode()
 */
define('JSON_LOOSE_TYPE', 10);

/**
 * Behavior switch for JSON::decode()
 */
define('JSON_STRICT_TYPE', 11);

/** 
 * Converts to and from JSON format.
 *
 * @category   
 * @package    
 * @author     Michal Migurski <[e-mail]>
 * @author     Matt Knapp <mdknapp[at]gmail[dot]com>
 * @author     Brett Stimmerman <brettstimmerman[at]gmail[dot]com>
 * @copyright  2005 Michal Migurski
 * @license    http://www.php.net/license/3_0.txt  PHP License 3.0
 * @version    
 * @link       
 * @see        
 * @since      
 * @deprecated 
 */
class JSON
{
   /**
    * constructs a new JSON instance
    *
    * @param    int     $use    object behavior: when encoding or decoding,
    *                           be loose or strict about object/array usage
    *
    *                           possible values:
    *                              JSON_STRICT_TYPE - strict typing, default
    *                                                 "{...}" syntax creates objects in decode.
    *                               JSON_LOOSE_TYPE - loose typing
    *                                                 "{...}" syntax creates associative arrays in decode.
    */
    function JSON($use=JSON_STRICT_TYPE)
    {
        $this->use = $use;
    }

   /**
    * encodes an arbitrary variable into JSON format
    *
    * @param    mixed   $var    any number, boolean, string, array, or object to be encoded.
    *                           see argument 1 to JSON() above for array-parsing behavior.
    *                           if var is a strng, note that encode() always expects it
    *                           to be in ASCII or UTF-8 format!
    *
    * @return   string  JSON string representation of input var
    * @access   public
    */
    function encode($var)
    {
        switch (gettype($var)) {
            case 'boolean':
                return $var ? 'true' : 'false';
            
            case 'NULL':
                return 'null';
            
            case 'integer':
                return sprintf('%d', $var);
                
            case 'double':
            case 'float':
                return sprintf('%f', $var);
                
            case 'string':
                // STRINGS ARE EXPECTED TO BE IN ASCII OR UTF-8 FORMAT
                $ascii = '';
                $strlen_var = strlen($var);

               /*
                * Iterate over every character in the string,
                * escaping with a slash or encoding to UTF-8 where necessary
                */
                for ($c = 0; $c < $strlen_var; ++$c) {
                    
                    $ord_var_c = ord($var{$c});
                    
                    switch ($ord_var_c) {
                        case 0x08:  $ascii .= '\b';  break;
                        case 0x09:  $ascii .= '\t';  break;
                        case 0x0A:  $ascii .= '\n';  break;
                        case 0x0C:  $ascii .= '\f';  break;
                        case 0x0D:  $ascii .= '\r';  break;

                        case 0x22:
                        case 0x2F:
                        case 0x5C:
                            // double quote, slash, slosh
                            $ascii .= '\\'.$var{$c};
                            break;
                            
                        case (($ord_var_c >= 0x20) && ($ord_var_c <= 0x7F)):
                            // characters U-00000000 - U-0000007F (same as ASCII)
                            $ascii .= $var{$c};
                            break;
                        
                        case (($ord_var_c & 0xE0) == 0xC0):
                            // characters U-00000080 - U-000007FF, mask 110XXXXX
                            // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
                            $char = pack('C*', $ord_var_c, ord($var{$c+1}));
                            $c+=1;
                            $utf16 = mb_convert_encoding($char, 'UTF-16', 'UTF-8');
                            $ascii .= sprintf('\u%04s', bin2hex($utf16));
                            break;
    
                        case (($ord_var_c & 0xF0) == 0xE0):
                            // characters U-00000800 - U-0000FFFF, mask 1110XXXX
                            // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
                            $char = pack('C*', $ord_var_c,
                                         ord($var{$c+1}),
                                         ord($var{$c+2}));
                            $c+=2;
                            $utf16 = mb_convert_encoding($char, 'UTF-16', 'UTF-8');
                            $ascii .= sprintf('\u%04s', bin2hex($utf16));
                            break;
    
                        case (($ord_var_c & 0xF8) == 0xF0):
                            // characters U-00010000 - U-001FFFFF, mask 11110XXX
                            // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
                            $char = pack('C*', $ord_var_c,
                                         ord($var{$c+1}),
                                         ord($var{$c+2}),
                                         ord($var{$c+3}));
                            $c+=3;
                            $utf16 = mb_convert_encoding($char, 'UTF-16', 'UTF-8');
                            $ascii .= sprintf('\u%04s', bin2hex($utf16));
                            break;
    
                        case (($ord_var_c & 0xFC) == 0xF8):
                            // characters U-00200000 - U-03FFFFFF, mask 111110XX
                            // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
                            $char = pack('C*', $ord_var_c,
                                         ord($var{$c+1}),
                                         ord($var{$c+2}),
                                         ord($var{$c+3}),
                                         ord($var{$c+4}));
                            $c+=4;
                            $utf16 = mb_convert_encoding($char, 'UTF-16', 'UTF-8');
                            $ascii .= sprintf('\u%04s', bin2hex($utf16));
                            break;
    
                        case (($ord_var_c & 0xFE) == 0xFC):
                            // characters U-04000000 - U-7FFFFFFF, mask 1111110X
                            // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
                            $char = pack('C*', $ord_var_c,
                                         ord($var{$c+1}),
                                         ord($var{$c+2}),
                                         ord($var{$c+3}),
                                         ord($var{$c+4}),
                                         ord($var{$c+5}));
                            $c+=5;
                            $utf16 = mb_convert_encoding($char, 'UTF-16', 'UTF-8');
                            $ascii .= sprintf('\u%04s', bin2hex($utf16));
                            break;
                    }
                }
                
                return '"'.$ascii.'"';
                
            case 'array':
               /*
                * As per JSON spec if any array key is not an integer
                * we must treat the the whole array as an object. We
                * also try to catch a sparsely populated associative
                * array with numeric keys here because some JS engines
                * will create an array with empty indexes up to
                * max_index which can cause memory issues and because
                * the keys, which may be relevant, will be remapped
                * otherwise.
                * 
                * As per the ECMA and JSON specification an object may
                * have any string as a property. Unfortunately due to
                * a hole in the ECMA specification if the key is a
                * ECMA reserved word or starts with a digit the
                * parameter is only accessible using ECMAScript's
                * bracket notation.
                */
                
                // treat as a JSON object  
                if (is_array($var) && count($var) && (array_keys($var) !== range(0, sizeof($var) - 1))) {
                    return sprintf('{%s}', join(',', array_map(array($this, 'name_value'),
                                                               array_keys($var),
                                                               array_values($var))));
                }

                // treat it like a regular array
                return sprintf('[%s]', join(',', array_map(array($this, 'encode'), $var)));
                
            case 'object':
                $vars = get_object_vars($var);
                return sprintf('{%s}', join(',', array_map(array($this, 'name_value'),
                                                           array_keys($vars),
                                                           array_values($vars))));                    

            default:
                return '';
        }
    }
    
   /**
    * encodes an arbitrary variable into JSON format, alias for encode()
    */
    function enc($var)
    {
        return $this->encode($var);
    }
    
   /** function name_value
    * array-walking function for use in generating JSON-formatted name-value pairs
    *
    * @param    string  $name   name of key to use
    * @param    mixed   $value  reference to an array element to be encoded
    *
    * @return   string  JSON-formatted name-value pair, like '"name":value'
    * @access   private
    */