<?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;
              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 .= $this->utf162utf8($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(SERVICES_JSON_IN_ARR);
            $arr = array();
          } else {
            if ($this->use & SERVICES_JSON_LOOSE_TYPE) {
              $stk = array(SERVICES_JSON_IN_OBJ);
              $obj = array();
            } else {
              $stk = array(SERVICES_JSON_IN_OBJ);
              $obj = new stdClass();
            }
          }

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

          $chrs = substr($str, 1, -1);
          $chrs = $this->reduce_string($chrs);

          if ($chrs == '') {
            if (reset($stk) == SERVICES_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'] == SERVICES_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' => SERVICES_JSON_SLICE, 'where' => ($c + 1), 'delim' => false));
              //print("Found split at {$c}: ".substr($chrs, $top['where'], (1 + $c - $top['where']))."\n");

              if (reset($stk) == SERVICES_JSON_IN_ARR) {
                // we are in an array, so just push an element onto the stack
                array_push($arr, $this->decode($slice));

              } elseif (reset($stk) == SERVICES_JSON_IN_OBJ) {
                // we are in an object, so figure
                // out the property name and set an
                // element in an associative array,
                // for now
                $parts = array();

                if (preg_match('/^\s*(["\'].*[^\\\]["\'])\s*:\s*(\S.*),?$/Uis', $slice, $parts)) {
                  // "name":value pair
                  $key = $this->decode($parts[1]);
                  $val = $this->decode($parts[2]);

                  if ($this->use & SERVICES_JSON_LOOSE_TYPE) {
                    $obj[$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 = $this->decode($parts[2]);

                  if ($this->use & SERVICES_JSON_LOOSE_TYPE) {
                    $obj[$key] = $val;
                  } else {
                    $obj->$key = $val;
                  }
                }

              }

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

            } elseif (($chrs{$c} == $top['delim']) &&
            ($top['what'] == SERVICES_JSON_IN_STR) &&
            ((strlen(substr($chrs, 0, $c)) - strlen(rtrim(substr($chrs, 0, $c), '\\'))) % 2 != 1)) {
              // found a quote, we're in a string, and it's not escaped
              // we know that it's not escaped becase there is _not_ an
              // odd number of backslashes at the end of the string so far
              array_pop($stk);
              //print("Found end of string at {$c}: ".substr($chrs, $top['where'], (1 + 1 + $c - $top['where']))."\n");

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

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

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

            } elseif (($chrs{$c} == '}') && ($top['what'] == SERVICES_JSON_IN_OBJ)) {
              // found a right-brace, and we're in an object
              array_pop($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(SERVICES_JSON_SLICE, SERVICES_JSON_IN_ARR, SERVICES_JSON_IN_OBJ))) {
              // found a comment start, and we are in an array, object, or slice
              array_push($stk, array('what' => SERVICES_JSON_IN_CMT, 'where' => $c, 'delim' => false));
              $c++;
              //print("Found start of comment at {$c}\n");

            } elseif (($substr_chrs_c_2 == '*/') && ($top['what'] == SERVICES_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) == SERVICES_JSON_IN_ARR) {
            return $arr;

          } elseif (reset($stk) == SERVICES_JSON_IN_OBJ) {
            return $obj;

          }

        }
    }
  }

  /**
   * @todo Ultimately, this should just call PEAR::isError()
   */
  function isError($data, $code = null)
  {
    if (class_exists('pear')) {
      return PEAR::isError($data, $code);
    } elseif (is_object($data) && (get_class($data) == 'services_json_error' ||
    is_subclass_of($data, 'services_json_error'))) {
      return true;
    }

    return false;
  }
}

if (class_exists('PEAR_Error')) {

  class Services_JSON_Error extends PEAR_Error
  {
    function Services_JSON_Error($message = 'unknown error', $code = null,
    $mode = null, $options = null, $userinfo = null)
    {
      parent::PEAR_Error($message, $code, $mode, $options, $userinfo);
    }
  }

} else {

  /**
   * @todo Ultimately, this class shall be descended from PEAR_Error
   */
  class Services_JSON_Error
  {
    function Services_JSON_Error($message = 'unknown error', $code = null,
    $mode = null, $options = null, $userinfo = null)
    {

    }
  }

}

?>
