<?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!

 *

 * 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		Services_JSON

 * @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

 * @version     CVS: $Id: JSON.php 288200 2009-09-09 15:41:29Z alan_k $

 * @license		http://www.opensource.org/licenses/bsd-license.php

 * @link		http://pear.php.net/pepr/pepr-proposal-show.php?id=198

 */

/**

 * Marker constant for Services_JSON::decode(), used to flag stack state

 */

define('SERVICES_JSON_SLICE', 1);

/**

 * Marker constant for Services_JSON::decode(), used to flag stack state

 */

define('SERVICES_JSON_IN_STR',  2);

/**

 * Marker constant for Services_JSON::decode(), used to flag stack state

 */

define('SERVICES_JSON_IN_ARR',  3);

/**

 * Marker constant for Services_JSON::decode(), used to flag stack state

 */

define('SERVICES_JSON_IN_OBJ',  4);

/**

 * Marker constant for Services_JSON::decode(), used to flag stack state

 */

define('SERVICES_JSON_IN_CMT', 5);

/**

 * Behavior switch for Services_JSON::decode()

 */

define('SERVICES_JSON_LOOSE_TYPE', 16);

/**

 * Behavior switch for Services_JSON::decode()

 */

define('SERVICES_JSON_SUPPRESS_ERRORS', 32);

/**

 * Converts to and from JSON format.

 *

 * Brief example of use:

 *

 * <code>

 * // create a new instance of Services_JSON

 * $json = new Services_JSON();

 *

 * // convert a complexe value to JSON notation, and send it to the browser

 * $value = array('foo', 'bar', array(1, 2, 'baz'), array(3, array(4)));

 * $output = $json->encode($value);

 *

 * print($output);

 * // prints: ["foo","bar",[1,2,"baz"],[3,[4]]]

 *

 * // accept incoming POST data, assumed to be in JSON notation

 * $input = file_get_contents('php://input', 1000000);

 * $value = $json->decode($input);

 * </code>

 */

class Services_JSON

{

 /**

	* constructs a new JSON instance

	*

	* @param int $use object behavior flags; combine with boolean-OR

	*

	*						possible values:

	*						- SERVICES_JSON_LOOSE_TYPE:  loose typing.

	*								"{...}" syntax creates associative arrays

	*								instead of objects in decode().

	*						- SERVICES_JSON_SUPPRESS_ERRORS:  error suppression.

	*								Values which can't be encoded (e.g. resources)

	*								appear as NULL instead of throwing errors.

	*								By default, a deeply-nested resource will

	*								bubble up with an error, so all return values

	*								from encode() should be checked with isError()

	*/

	function Services_JSON($use = 0)

	{

		$this->use = $use;

	}

 /**

	* convert a string from one UTF-16 char to one UTF-8 char

	*

	* Normally should be handled by mb_convert_encoding, but

	* provides a slower PHP-only method for installations

	* that lack the multibye string extension.

	*

	* @param	string  $utf16  UTF-16 character

	* @return string  UTF-8 character

	* @access private

	*/

	function utf162utf8($utf16)

	{

		// oh please oh please oh please oh please oh please

		if(function_exists('mb_convert_encoding')) {

			return mb_convert_encoding($utf16, 'UTF-8', 'UTF-16');

		}

		$bytes = (ord($utf16{0}) << 8) | ord($utf16{1});

		switch(true) {

			case ((0x7F & $bytes) == $bytes):

				// this case should never be reached, because we are in ASCII range

				// see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8

				return chr(0x7F & $bytes);

			case (0x07FF & $bytes) == $bytes:

				// return a 2-byte UTF-8 character

				// see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8

				return chr(0xC0 | (($bytes >> 6) & 0x1F))

					. chr(0x80 | ($bytes & 0x3F));

			case (0xFFFF & $bytes) == $bytes:

				// return a 3-byte UTF-8 character

				// see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8

				return chr(0xE0 | (($bytes >> 12) & 0x0F))

					. chr(0x80 | (($bytes >> 6) & 0x3F))

					. chr(0x80 | ($bytes & 0x3F));

		}

		// ignoring UTF-32 for now, sorry

		return '';

	}

 /**

	* convert a string from one UTF-8 char to one UTF-16 char

	*

	* Normally should be handled by mb_convert_encoding, but

	* provides a slower PHP-only method for installations

	* that lack the multibye string extension.

	*

	* @param	string  $utf8 UTF-8 character

	* @return string  UTF-16 character

	* @access private

	*/

	function utf82utf16($utf8)

	{

		// oh please oh please oh please oh please oh please

		if(function_exists('mb_convert_encoding')) {

			return mb_convert_encoding($utf8, 'UTF-16', 'UTF-8');

		}

		switch(strlen($utf8)) {

			case 1:

				// this case should never be reached, because we are in ASCII range

				// see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8

				return $utf8;

			case 2:

				// return a UTF-16 character from a 2-byte UTF-8 char

				// see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8

				return chr(0x07 & (ord($utf8{0}) >> 2))

					. chr((0xC0 & (ord($utf8{0}) << 6))

						| (0x3F & ord($utf8{1})));

			case 3:

				// return a UTF-16 character from a 3-byte UTF-8 char

				// see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8

				return chr((0xF0 & (ord($utf8{0}) << 4))

						| (0x0F & (ord($utf8{1}) >> 2)))

					. chr((0xC0 & (ord($utf8{1}) << 6))

						| (0x7F & ord($utf8{2})));

		}

		// ignoring UTF-32 for now, sorry

		return '';

	}

 /**

	* encodes an arbitrary variable into JSON format (and sends JSON Header)

	*

	* @param	mixed $var	any number, boolean, string, array, or object to be encoded.

	*						see argument 1 to Services_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 mixed JSON string representation of input var or an error if a problem occurs

	* @access public

	*/

	function encode($var)

	{

		header('Content-type: application/json');

		return $this->_encode($var);

	}

	/**

	* encodes an arbitrary variable into JSON format without JSON Header - warning - may allow CSS!!!!)

	*

	* @param	mixed $var	any number, boolean, string, array, or object to be encoded.

	*						see argument 1 to Services_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 mixed JSON string representation of input var or an error if a problem occurs

	* @access public

	*/

	function encodeUnsafe($var)

	{

		return $this->_encode($var);

	}

	/**

	* PRIVATE CODE that does the work of encodes an arbitrary variable into JSON format

	*

	* @param	mixed $var	any number, boolean, string, array, or object to be encoded.

	*						see argument 1 to Services_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 mixed JSON string representation of input var or an error if a problem occurs

	* @access public

	*/

	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':

				// 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

							if ($c+1 >= $strlen_var) {

								$c += 1;

								$ascii .= '?';

								break;

							}

							$char = pack('C*', $ord_var_c, ord($var{$c + 1}));

							$c += 1;

							$utf16 = $this->utf82utf16($char);

							$ascii .= sprintf('\u%04s', bin2hex($utf16));

							break;

						case (($ord_var_c & 0xF0) == 0xE0):

							if ($c+2 >= $strlen_var) {

								$c += 2;

								$ascii .= '?';

								break;

							}

							// 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 = $this->utf82utf16($char);

							$ascii .= sprintf('\u%04s', bin2hex($utf16));

							break;

						case (($ord_var_c & 0xF8) == 0xF0):

							if ($c+3 >= $strlen_var) {

								$c += 3;

								$ascii .= '?';

								break;

							}

							// 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 = $this->utf82utf16($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

							if ($c+4 >= $strlen_var) {

								$c += 4;

								$ascii .= '?';

								break;

							}

							$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 = $this->utf82utf16($char);

							$ascii .= sprintf('\u%04s', bin2hex($utf16));

							break;

						case (($ord_var_c & 0xFE) == 0xFC):

						if ($c+5 >= $strlen_var) {

								$c += 5;

								$ascii .= '?';

								break;

							}

							// 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 = $this->utf82utf16($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))) {

					$properties = array_map(array($this, 'name_value'),

											array_keys($var),

											array_values($var));

					foreach($properties as $property) {

						if(Services_JSON::isError($property)) {

							return $property;

						}