MyJSONHelper.php

<?php

// http://www.php.net/manual/ja/function.json-encode.php#80339
// by PHP Documentation Group
function json_format($json)
{    
    $tab          = "  ";
    $new_json     = "";
    $indent_level = 0;
    $in_string    = false;

    $json_obj = json_decode($json);

    if(!$json_obj)
        return false;

    $json = json_encode($json_obj);
    $len = strlen($json);

    for($c = 0; $c < $len; $c++)
    {
        $char = $json[$c];
        switch($char)
        {
            case '{':
            case '[':
                if(!$in_string)
                {
                    $new_json .= $char . "\n" . str_repeat($tab, $indent_level+1);
                    $indent_level++;
                }
                else
                {
                    $new_json .= $char;
                }
                break;
            case '}':
            case ']':
                if(!$in_string)
                {
                    $indent_level--;
                    $new_json .= "\n" . str_repeat($tab, $indent_level) . $char;
                }
                else
                {
                    $new_json .= $char;
                }
                break;
            case ',':
                if(!$in_string)
                {
                    $new_json .= ",\n" . str_repeat($tab, $indent_level);
                }
                else
                {
                    $new_json .= $char;
                }
                break;
            case ':':
                if(!$in_string)
                {
                    $new_json .= ": ";
                }
                else
                {
                    $new_json .= $char;
                }
                break;
            case '"':
                $in_string = !$in_string;
            default:
                $new_json .= $char;
                break;
        }
    }

    return $new_json;
}

// Unicodeエスケープされた文字列をUTF-8文字列に戻す
function unicode_encode($str)
{
    return preg_replace_callback("/\\\\u([0-9a-zA-Z]{4})/", "encode_callback", $str);
}

function encode_callback($matches)
{
    $char = mb_convert_encoding(pack("H*", $matches[1]), "UTF-8", "UTF-16");
    return $char;
}