<?php
/**
 * Using json_encode() with some character sets can result in false being returned.
 * These functions allow creation of JSON strings from any value/object that may need
 * UTF-8 encoding.
 */


/**
 * Given the output from serialize(), this will encode or decode UTF-8 characters
 * and adjust length markers as necessary.
 *
 * @param string $input The input string
 * @param boolean $encode Are we encoding (or decoding) the string
 * @return string
 */
function utf8Adjust($input, $encode=TRUE) {
   if (preg_match('//u', $input) === 1) {
      // Already using UTF-8, no encoding to do

      if ($encode) return $input;
   } else {
      // Not UTF-8, no decoding to do

      if (!$encode) return $input;
   }

   $output = '';

   // Copy input string characters until we get to 's' - a string, or 'O' - a class name
   for ($i=0; $i<strlen($input); ++$i) {
      $output .= $input{$i};

      if ($input{$i} === 's' || $input{$i} === 'O') {
         ++$i; // ':'

         // After 's:' or 'O:' is the length
         $length = '';

         while ($input{++$i} !== ':') {
            $length .= $input{$i};
         }

         $length = (int) $length;

         $i += 2; // ':"'

         // Now we can get the string itself
         $string = substr($input, $i, $length);

         // We can use this function to encode and decode
         $string = ($encode) ? utf8_encode($string) : utf8_decode($string);

         // Join everything back together
         $output .= ':' . strlen($string) . ':"' . $string . '"';

         $i += $length;
      }
   }

   return $output;
}

/**
 * UTF-8 encode an input value
 *
 * @param mixed $input
 * @return mixed
 */
function utf8Encode($input) {
   return unserialize(utf8Adjust(serialize($input), TRUE));
}

/**
 * UTF-8 decode an input value
 *
 * @param mixed $input
 * @return mixed
 */
function utf8Decode($input) {
   return unserialize(utf8Adjust(serialize($input), FALSE));
}

/**
 * JSON encode - handling UTF-8 encoding
 *
 * @param mixed $input
 * @return string
 */
function jsonEncode($input) {
   return json_encode(utf8Encode($input));
}

/**
 * JSON decode - handling UTF-8 encoding
 *
 * @param string $input
 * @param boolean $assoc [optional] When TRUE, returned objects will be
 * converted into associative arrays.
 * @param integer $depth [optional] User specified recursion depth.
 * @param integer $options [optional] Bitmask of JSON decode options.
 * Currently only JSON_BIGINT_AS_STRING is supported (default is to cast
 * large integers as floats)
 * @return mixed
 */
function jsonDecode($input, $assoc=FALSE, $depth=512, $options=0) {
   return utf8Decode(json_decode($input, $assoc, $depth, $options));
}