json_encode.php

<?php

/**
 * json_encode() only takes an $option argument in PHP 5.3.0+
 * We need the FORCE_JSON_OBJECT option, so we'll roll our
 * own json_encode() on PHP < 5.3.0
 * @author Matt McCollow <mmccollow@gmail.com>
 */
 
if(!defined('JSON_FORCE_OBJECT')) {
  define('JSON_FORCE_OBJECT', 0x05); // just guessing at this value
}

define('ITEM_SEPARATOR', ', ');
define('KEY_SEPARATOR', ': ');

function get_json_encoder() {
  if(version_compare(PHP_VERSION, '5.3.0') >= 0) {
    $json_encode_func = 'json_encode';
  } else {
    $json_encode_func = 'my_json_encode';
  }
  return $json_encode_func;
}
 
function my_json_encode($value, $options = 0) {
  if(empty($value)) { return ""; }
  if(is_scalar($value)) {
    return _json_encode_base_string($value);
  }
  if(is_object($value) || $options == JSON_FORCE_OBJECT) {
    return "[" . _json_encode_object($value) . "]";
  }
  if(is_array($value)) {
    return "[" . _json_encode_array($value) . "]";
  }
}

function _json_encode_base_string($value) {
  $to_escape = array(
    '\\' => '\\\\',
    '/' => '\\/',
    '"' => '\\"',
    '\b' => '\\b',
    '\f' => '\\f',
    '\n' => '\\n',
    '\r' => '\\r',
    '\t' => '\\t'
  );
  $chr_array = str_split($value);
  foreach($chr_array as $chr) {
    if(array_key_exists($chr, $to_escape)) {
      $ret_str .= $to_escape[$chr];
    } else {
      $ret_str .= $chr;
    }
  }
  return "\"" . $ret_str . "\"";
}

function _json_encode_array($values) {
  // TODO: this does not support single-element arrays
  foreach($values as $value) {
    if(is_scalar($value)) {
      $output .= _json_encode_base_string($value) . ITEM_SEPARATOR;
    } else if(is_array($value)) {
      $output .= "[" . _json_encode_array($value) . "]" . ITEM_SEPARATOR;
    }
  }
  return rtrim($output, ", ");
}

function _json_encode_object($values) {
  // TODO: this does not support single-element arrays
  foreach($values as $key => $value) {
    if(is_scalar($value)) {
      $output .= _json_encode_base_string($key) . KEY_SEPARATOR . _json_encode_base_string($value) . ITEM_SEPARATOR;
    } else if(is_array($value)) {
      $output .= "{" . _json_encode_object($value) . "}" . ITEM_SEPARATOR;
    }
  }
  return rtrim($output, ", ");
}

?>