<?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,v 1.31 2006/06/28 05:54:17 migurski Exp $

* @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

    *

    * @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

                            $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):

                            // 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):

                            // 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

                            $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):

                            // 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;

                        }

                    }

                    return '{' . join(',', $properties) . '}';

                }

                // treat it like a regular array

                $elements = array_map(array($this, 'encode'), $var);

                foreach($elements as $element) {

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

                        return $element;

                    }

                }

                return '[' . join(',', $elements) . ']';

            case 'object':

                $vars = get_object_vars($var);

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

                                        array_keys($vars),

                                        array_values($vars));

                foreach($properties as $property) {

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

                        return $property;

                    }

                }

                return '{' . join(',', $properties) . '}';

            default:

                return ($this->use & SERVICES_JSON_SUPPRESS_ERRORS)

                    ? 'null'

                    : new Services_JSON_Error(gettype($var)." can not be encoded as JSON string");

        }

    }

   /**

    * 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

    */

    function name_value($name, $value)

    {

        $encoded_value = $this->encode($value);

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

            return $encoded_value;

        }

        return $this->encode(strval($name)) . ':' . $encoded_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

    */

    function reduce_string($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

    *

    * @return   mixed   number, boolean, string, array, or object

    *                   corresponding to given JSON input string.

    *                   See argument 1 to Services_JSON() above for object-output behavior.

    *                   Note that decode() always returns strings

    *                   in ASCII or UTF-8 format!

    * @access   public

    */

    function decode($str)

    {

        $str = $this->reduce_string($str);

        switch (strtolower($str)) {

            case 'true':

                return true;

            case 'false':

                return false;

            case 'null':

                return null;

            default:

                $m = array();

                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;