json_class.php

<?php
/**
* 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!
*
* 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.
*
* @author	  Michal Migurski <mike-json@teczno.com>
* @author	  Matt Knapp <mdknapp[at]gmail[dot]com>
* @author	  Brett Stimmerman <brettstimmerman[at]gmail[dot]com>
* @copyright   2005 Michal Migurski
* @license	 http://www.opensource.org/licenses/bsd-license.php
* @link		http://pear.php.net/pepr/pepr-proposal-show.php?id=198
*/

/**
 * CJSON converts PHP data to and from JSON format.
 *
 * @author	 Michal Migurski <mike-json@teczno.com>
 * @author	 Matt Knapp <mdknapp[at]gmail[dot]com>
 * @author	 Brett Stimmerman <brettstimmerman[at]gmail[dot]com>
 * @version $Id: CJSON.php 2163 2010-06-04 14:49:37Z alexander.makarow $
 * @package	system.web.helpers
 * @since 1.0
 */
class JSON
{
	/**
	 * Marker constant for JSON::decode(), used to flag stack state
	 */
	const JSON_SLICE = 1;

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

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

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

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

   /**
	* Encodes an arbitrary variable into JSON format
	*
	* @param	mixed   $var	any number, boolean, string, array, or object to be encoded.
	*						   see argument 1 to JSON() above for array-parsing behavior.
	*						   if var is a strng, note that encode() always expects it
	*						   to be in ASCII or UTF-8 format!
	*
	* @return   string  JSON string representation of input var
	*/
	public static function encode($var)
	{
		switch (gettype($var)) {
			case 'boolean':
				return $var ? 'true' : 'false';

			case 'NULL':
				return 'null';

			case 'integer':
				return (int) $var;

			case 'double':
			case 'float':
				return (float) $var;

			case 'string':
				if(function_exists('json_encode'))
					return json_encode($var);

				if (($enc=strtoupper(Tiny::app()->charset))!=='UTF-8')
					$var=iconv($enc, 'UTF-8', $var);

				// 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 (true) {
						case $ord_var_c == 0x08:
							$ascii .= '\b';
							break;
						case $ord_var_c == 0x09:
							$ascii .= '\t';
							break;
						case $ord_var_c == 0x0A:
							$ascii .= '\n';
							break;
						case $ord_var_c == 0x0C:
							$ascii .= '\f';
							break;
						case $ord_var_c == 0x0D:
							$ascii .= '\r';
							break;

						case $ord_var_c == 0x22:
						case $ord_var_c == 0x2F:
						case $ord_var_c == 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;
							$utf16 =  self::utf8ToUTF16BE($char);
							$ascii .= sprintf('\u%04s', bin2hex($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;
							$utf16 = self::utf8ToUTF16BE($char);
							$ascii .= sprintf('\u%04s', bin2hex($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;
							$utf16 = self::utf8ToUTF16BE($char);
							$ascii .= sprintf('\u%04s', bin2hex($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;
							$utf16 = self::utf8ToUTF16BE($char);
							$ascii .= sprintf('\u%04s', bin2hex($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;
							$utf16 = self::utf8ToUTF16BE($char);
							$ascii .= sprintf('\u%04s', bin2hex($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 '{' .
						   join(',', array_map(array('JSON', 'nameValue'),
											   array_keys($var),
											   array_values($var)))
						   . '}';
				}

				// treat it like a regular array
				return '[' . join(',', array_map(array('JSON', 'encode'), $var)) . ']';

			case 'object':
				if ($var instanceof Traversable)
				{
					$vars = array();
					foreach ($var as $k=>$v)
						$vars[$k] = $v;
				}
				else
					$vars = get_object_vars($var);
				return '{' .
					   join(',', array_map(array('JSON', 'nameValue'),
										   array_keys($vars),
										   array_values($vars)))
					   . '}';

			default:
				return '';
		}
	}

   /**
	* array-walking function for use in generating JSON-formatted name-value pairs
	*
	* @param	string  $name   name of key to use
	* @param	mixed   $value  reference to an array element to be encoded
	*
	* @return   string  JSON-formatted name-value pair, like '"name":value'
	* @access   private
	*/
	protected static function nameValue($name, $value)
	{
		return self::encode(strval($name)) . ':' . self::encode($value);
	}

   /**
	* reduce a string by removing leading and trailing comments and whitespace
	*
	* @param	$str	string	  string value to strip of comments and whitespace
	*
	* @return   string  string value stripped of comments and whitespace
	* @access   private
	*/
	protected static function reduceString($str)
	{
		$str = preg_replace(array(

				// eliminate single line comments in '// ...' form
				'#^\s*//(.+)$#m',

				// eliminate multi-line comments in '/* ... */' form, at start of string
				'#^\s*/\*(.+)\*/#Us',

				// eliminate multi-line comments in '/* ... */' form, at end of string
				'#/\*(.+)\*/\s*$#Us'

			), '', $str);

		// eliminate extraneous space
		return trim($str);
	}

   /**
	* decodes a JSON string into appropriate variable
	*
	* @param	string  $str	JSON-formatted string
	* @param    boolean  whether to use associative array to represent object data
	*
	* @return   mixed   number, boolean, string, array, or object
	*				   corresponding to given JSON input string.
	*				   See argument 1 to JSON() above for object-output behavior.
	*				   Note that decode() always returns strings
	*				   in ASCII or UTF-8 format!
	* @access   public
	*/
	public static function decode($str, $useArray=true)
	{
		if(function_exists('json_decode'))
			return json_decode($str,$useArray);

		$str = self::reduceString($str);

		switch (strtolower($str)) {
			case 'true':
				return true;

			case 'false':
				return false;

			case 'null':
				return null;

			default:
				if (is_numeric($str)) {
					// Lookie-loo, it's a number

					// This would work on its own, but I'm trying to be
					// good about returning integers where appropriate:
					// return (float)$str;

					// Return float or int, as appropriate
					return ((float)$str == (integer)$str)
						? (integer)$str
						: (float)$str;

				} elseif (preg_match('/^("|\').+(\1)$/s', $str, $m) && $m[1] == $m[2]) {
					// STRINGS RETURNED IN UTF-8 FORMAT
					$delim = substr($str, 0, 1);
					$chrs = substr($str, 1, -1);
					$utf8 = '';
					$strlen_chrs = strlen($chrs);

					for ($c = 0; $c < $strlen_chrs; ++$c) {

						$substr_chrs_c_2 = substr($chrs, $c, 2);
						$ord_chrs_c = ord($chrs{$c});

						switch (true) {
							case $substr_chrs_c_2 == '\b':
								$utf8 .= chr(0x08);
								++$c;
								break;
							case $substr_chrs_c_2 == '\t':
								$utf8 .= chr(0x09);
								++$c;
								break;
							case $substr_chrs_c_2 == '\n':
								$utf8 .= chr(0x0A);
								++$c;
								break;
							case $substr_chrs_c_2 == '\f':
								$utf8 .= chr(0x0C);
								++$c;
								break;
							case $substr_chrs_c_2 == '\r':
								$utf8 .= chr(0x0D);
								++$c;
								break;

							case $substr_chrs_c_2 == '\\"':
							case $substr_chrs_c_2 == '\\\'':
							case $substr_chrs_c_2 == '\\\\':
							case $substr_chrs_c_2 == '\\/':
								if (($delim == '"' && $substr_chrs_c_2 != '\\\'') ||
								   ($delim == "'" && $substr_chrs_c_2 != '\\"')) {
									$utf8 .= $chrs{++$c};
								}
								break;

							case preg_match('/\\\u[0-9A-F]{4}/i', substr($chrs, $c, 6)):
								// single, escaped unicode character
								$utf16 = chr(hexdec(substr($chrs, ($c+2), 2)))
									   . chr(hexdec(substr($chrs, ($c+4), 2)));
								$utf8 .= self::utf16beToUTF8($utf16);
								$c+=5;
								break;

							case ($ord_chrs_c >= 0x20) && ($ord_chrs_c <= 0x7F):
								$utf8 .= $chrs{$c};
								break;

							case ($ord_chrs_c & 0xE0) == 0xC0:
								// characters U-00000080 - U-000007FF, mask 110XXXXX
								//see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
								$utf8 .= substr($chrs, $c, 2);
								++$c;
								break;

							case ($ord_chrs_c & 0xF0) == 0xE0:
								// characters U-00000800 - U-0000FFFF, mask 1110XXXX
								// see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
								$utf8 .= substr($chrs, $c, 3);
								$c += 2;
								break;

							case ($ord_chrs_c & 0xF8) == 0xF0:
								// characters U-00010000 - U-001FFFFF, mask 11110XXX
								// see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
								$utf8 .= substr($chrs, $c, 4);
								$c += 3;
								break;

							case ($ord_chrs_c & 0xFC) == 0xF8:
								// characters U-00200000 - U-03FFFFFF, mask 111110XX
								// see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
								$utf8 .= substr($chrs, $c, 5);
								$c += 4;
								break;

							case ($ord_chrs_c & 0xFE) == 0xFC:
								// characters U-04000000 - U-7FFFFFFF, mask 1111110X
								// see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
								$utf8 .= substr($chrs, $c, 6);
								$c += 5;
								break;

						}

					}

					return $utf8;

				} elseif (preg_match('/^\[.*\]$/s', $str) || preg_match('/^\{.*\}$/s', $str)) {
					// array, or object notation

					if ($str{0} == '[') {
						$stk = array(self::JSON_IN_ARR);
						$arr = array();
					} else {
						if ($useArray) {
							$stk = array(self::JSON_IN_OBJ);
							$obj = array();
						} else {
							$stk = array(self::JSON_IN_OBJ);
							$obj = new stdClass();
						}
					}

					array_push($stk, array('what'  => self::JSON_SLICE,
										   'where' => 0,
										   'delim' => false));

					$chrs = substr($str, 1, -1);
					$chrs = self::reduceString($chrs);

					if ($chrs == '') {
						if (reset($stk) == self::JSON_IN_ARR) {
							return $arr;

						} else {
							return $obj;

						}
					}

					//print("\nparsing {$chrs}\n");

					$strlen_chrs = strlen($chrs);

					for ($c = 0; $c <= $strlen_chrs; ++$c) {

						$top = end($stk);
						$substr_chrs_c_2 = substr($chrs, $c, 2);

						if (($c == $strlen_chrs) || (($chrs{$c} == ',') && ($top['what'] == self::JSON_SLICE))) {
							// found a comma that is not inside a string, array, etc.,
							// OR we've reached the end of the character list
							$slice = substr($chrs, $top['where'], ($c - $top['where']));
							array_push($stk, array('what' => self::JSON_SLICE, 'where' => ($c + 1), 'delim' => false));
							//print("Found split at {$c}: ".substr($chrs, $top['where'], (1 + $c - $top['where']))."\n");

							if (reset($stk) == self::JSON_IN_ARR) {
								// we are in an array, so just push an element onto the stack
								array_push($arr, self::decode($slice,$useArray));

							} elseif (reset($stk) == self::JSON_IN_OBJ) {
								// we are in an object, so figure
								// out the property name and set an
								// element in an associative array,
								// for now
								if (preg_match('/^\s*(["\'].*[^\\\]["\'])\s*:\s*(\S.*),?$/Uis', $slice, $parts)) {
									// "name":value pair
									$key = self::decode($parts[1],$useArray);
									$val = self::decode($parts[2],$useArray);

									if ($useArray) {
										$obj[$key] = $val;
									} else {
										$obj->$key = $val;
									}
								} elseif (preg_match('/^\s*(\w+)\s*:\s*(\S.*),?$/Uis', $slice, $parts)) {
									// name:value pair, where name is unquoted
									$key = $parts[1];
									$val = self::decode($parts[2],$useArray);

									if ($useArray) {
										$obj[$key] = $val;
									} else {
										$obj->$key = $val;
									}
								}

							}

						} elseif ((($chrs{$c} == '"') || ($chrs{$c} == "'")) && ($top['what'] != self::JSON_IN_STR)) {
							// found a quote, and we are not inside a string
							array_push($stk, array('what' => self::JSON_IN_STR, 'where' => $c, 'delim' => $chrs{$c}));
							//print("Found start of string at {$c}\n");

						} elseif (($chrs{$c} == $top['delim']) &&
								 ($top['what'] == self::JSON_IN_STR) &&
								 (($chrs{$c - 1} != "\\") ||
								 ($chrs{$c - 1} == "\\" && $chrs{$c - 2} == "\\"))) {
							// found a quote, we're in a string, and it's not escaped
							array_pop($stk);
							//print("Found end of string at {$c}: ".substr($chrs, $top['where'], (1 + 1 + $c - $top['where']))."\n");

						} elseif (($chrs{$c} == '[') &&
								 in_array($top['what'], array(self::JSON_SLICE, self::JSON_IN_ARR, self::JSON_IN_OBJ))) {
							// found a left-bracket, and we are in an array, object, or slice
							array_push($stk, array('what' => self::JSON_IN_ARR, 'where' => $c, 'delim' => false));
							//print("Found start of array at {$c}\n");

						} elseif (($chrs{$c} == ']') && ($top['what'] == self::JSON_IN_ARR)) {
							// found a right-bracket, and we're in an array
							array_pop($stk);
							//print("Found end of array at {$c}: ".substr($chrs, $top['where'], (1 + $c - $top['where']))."\n");

						} elseif (($chrs{$c} == '{') &&
								 in_array($top['what'], array(self::JSON_SLICE, self::JSON_IN_ARR, self::JSON_IN_OBJ))) {
							// found a left-brace, and we are in an array, object, or slice
							array_push($stk, array('what' => self::JSON_IN_OBJ, 'where' => $c, 'delim' => false));
							//print("Found start of object at {$c}\n");

						} elseif (($chrs{$c} == '}') && ($top['what'] == self::JSON_IN_OBJ)) {
							// found a right-brace, and we're in an object
							array_pop($stk);
							//print("Found end of object at {$c}: ".substr($chrs, $top['where'], (1 + $c - $top['where']))."\n");

						} elseif (($substr_chrs_c_2 == '/*') &&
								 in_array($top['what'], array(self::JSON_SLICE, self::JSON_IN_ARR, self::JSON_IN_OBJ))) {
							// found a comment start, and we are in an array, object, or slice
							array_push($stk, array('what' => self::JSON_IN_CMT, 'where' => $c, 'delim' => false));
							$c++;
							//print("Found start of comment at {$c}\n");

						} elseif (($substr_chrs_c_2 == '*/') && ($top['what'] == self::JSON_IN_CMT)) {
							// found a comment end, and we're in one now
							array_pop($stk);
							$c++;

							for ($i = $top['where']; $i <= $c; ++$i)
								$chrs = substr_replace($chrs, ' ', $i, 1);

							//print("Found end of comment at {$c}: ".substr($chrs, $top['where'], (1 + $c - $top['where']))."\n");

						}

					}

					if (reset($stk) == self::JSON_IN_ARR) {
						return $arr;

					} elseif (reset($stk) == self::JSON_IN_OBJ) {
						return $obj;

					}

				}
		}
	}

	/**
	* This function returns any UTF-8 encoded text as a list of
	* Unicode values:
	*
	* @author Scott Michael Reynen <scott@randomchaos.com>
	* @link   http://www.randomchaos.com/document.php?source=php_and_unicode
	* @see	unicodeToUTF8()
	*/
	protected static function utf8ToUnicode( &$str )
	{
		$unicode = array();
		$values = array();
		$lookingFor = 1;

		for ($i = 0; $i < strlen( $str ); $i++ )
		{
			$thisValue = ord( $str[ $i ] );
			if ( $thisValue < 128 )
				$unicode[] = $thisValue;
			else
			{
				if ( count( $values ) == 0 )
					$lookingFor = ( $thisValue < 224 ) ? 2 : 3;
				$values[] = $thisValue;
				if ( count( $values ) == $lookingFor )
				{
					$number = ( $lookingFor == 3 ) ?
						( ( $values[0] % 16 ) * 4096 ) + ( ( $values[1] % 64 ) * 64 ) + ( $values[2] % 64 ):
						( ( $values[0] % 32 ) * 64 ) + ( $values[1] % 64 );
					$unicode[] = $number;
					$values = array();
					$lookingFor = 1;
				}
			}
		}
		return $unicode;
	}

	/**
	* This function converts a Unicode array back to its UTF-8 representation
	*
	* @author Scott Michael Reynen <scott@randomchaos.com>
	* @link   http://www.randomchaos.com/document.php?source=php_and_unicode
	* @see	utf8ToUnicode()
	*/
	protected static function unicodeToUTF8( &$str )
	{
		$utf8 = '';
		foreach( $str as $unicode )
		{
			if ( $unicode < 128 )
			{
				$utf8.= chr( $unicode );
			}
			elseif ( $unicode < 2048 )
			{
				$utf8.= chr( 192 +  ( ( $unicode - ( $unicode % 64 ) ) / 64 ) );
				$utf8.= chr( 128 + ( $unicode % 64 ) );
			}
			else
			{
				$utf8.= chr( 224 + ( ( $unicode - ( $unicode % 4096 ) ) / 4096 ) );
				$utf8.= chr( 128 + ( ( ( $unicode % 4096 ) - ( $unicode % 64 ) ) / 64 ) );
				$utf8.= chr( 128 + ( $unicode % 64 ) );
			}
		}
		return $utf8;
	}

	/**
	* UTF-8 to UTF-16BE conversion.
	*
	* Maybe really UCS-2 without mb_string due to utf8ToUnicode limits
	*/
	protected static function utf8ToUTF16BE(&$str, $bom = false)
	{
		$out = $bom ? "\xFE\xFF" : '';
		if(function_exists('mb_convert_encoding'))
			return $out.mb_convert_encoding($str,'UTF-16BE','UTF-8');

		$uni = self::utf8ToUnicode($str);
		foreach($uni as $cp)
			$out .= pack('n',$cp);
		return $out;
	}

	/**
	 * UTF-8 to UTF-16BE conversion.
	 *
	 * Maybe really UCS-2 without mb_string due to utf8ToUnicode limits
	 */
	protected static function utf16beToUTF8(&$str)
	{
		$uni = unpack('n*',$str);
		return self::unicodeToUTF8($uni);
	}
}