Trivial JSON encoder

trivialjson.py

OBJECT_CONSTANTS =  {
    True: '":true,"',
    False: '":false,"',
    None: '":null,"',
}

ARRAY_CONSTANTS = {
    True: 'true,',
    False: 'false,',
    None: 'null,',
}


ESCAPE = re.compile(r'[\x00-\x1f\\"\b\f\n\r\t]')
ESCAPE_DCT = {
    '\\': '\\\\',
    '"': '\\"',
    '\b': '\\b',
    '\f': '\\f',
    '\n': '\\n',
    '\r': '\\r',
    '\t': '\\t',
}
for i in range(0x20):
    ESCAPE_DCT.setdefault(chr(i), '\\u{0:04x}'.format(i))


def replace_escape(match):
    return ESCAPE_DCT[match.group(0)]


def encode_json_object(json_object, res):
    items = sorted(json_object.items())
    if items:
        sep = b'{"'
        for k_str, v_obj in items:
            k_type = type(k_str)
            res.append(sep)
            res.append(ESCAPE.sub(replace_escape, k_str.encode("UTF-8")))
            v_type = type(v_obj)
            if v_type is unicode or v_type is bytes:
                res.append(b'":"')
                res.append(ESCAPE.sub(replace_escape, v_obj.encode("UTF-8")))
                sep = b'","'
            elif v_type is int or v_type is long:
                res.append(b'":')
                res.append(bytes(v_obj))
                sep = b',"'
            elif v_type is dict or v_type is frozendict:
                res.append(b'":')
                encode_json_object(v_obj, res)
                sep = b',"'
            elif v_type is list or v_type is tuple:
                res.append(b'":')
                encode_json_array(v_obj, res)
                sep = b',"'
            else:
                sep = OBJECT_CONSTANTS[v_obj]
        res.append(sep[:-2] + b'}')
    else:
        res.append(b'{}')


def encode_json_array(json_array, res):
    if json_array:
        sep = b'{"'
        for v_obj in json_array:
            res.append(sep)
            v_type = type(v_obj)
            if v_type is unicode or v_type is bytes:
                res.append(b'"')
                res.append(ESCAPE.sub(replace_escape, v_obj.encode("UTF-8")))
                sep = b'",'
            elif v_type is int or v_type is long:
                res.append(bytes(v_obj))
                sep = b','
            elif v_type is dict or v_type is frozendict:
                encode_json_object(v_obj, res)
                sep = b','
            elif v_type is list or v_type is tuple:
                encode_json_array(v_obj, res)
                sep = b','
            else:
                sep = ARRAY_CONSTANTS[v_obj]
        res.append(sep[:-1] + b']')
    else:
        res.append(b'{}')