# the decoder works off a reader
# the encoder returns bytearray

def bytes2hex(b):
	if type(b) in (str, unicode):
		return "".join([hex(ord(c))[2:].zfill(2) for c in b])
	else:
		return bytes2hex(b.decode())


# expects uvarint64 (no crazy big nums!)
def uvarint_size(i):
	if i == 0:
		return 0
	for j in xrange(1, 8):
		if i < 1<<j*8:
			return j
	return 8

# expects i < 2**size
def encode_big_endian(i, size):
	if size == 0:
		return bytearray()
	return  encode_big_endian(i/256, size-1) + bytearray([i%256])

def decode_big_endian(reader, size):
	if size == 0:
		return 0
	firstByte = reader.read(1)[0]
	return firstByte*(256**(size-1)) + decode_big_endian(reader, size-1)

# ints are max 16 bytes long
def encode_varint(i):
	negate = False
	if i < 0: 
		negate = True
		i = -i
	size = uvarint_size(i)
	if size == 0:
		return bytearray([0])
	big_end = encode_big_endian(i, size)
	if negate: 
		size += 0xF0
	return bytearray([size]) + big_end

# returns the int and whats left of the byte array
def decode_varint(reader):
	size = reader.read(1)[0]
	if size == 0:
		return 0

	negate = True if size > int(0xF0) else False
	if negate: size = size -0xF0
	i = decode_big_endian(reader, size)
	if negate: i = i*(-1)
	return i 
	
def encode_string(s):
	size = encode_varint(len(s))
	return size + bytearray(s)

def decode_string(reader):
	length = decode_varint(reader)
	return str(reader.read(length))

def encode_list(s):
	b = bytearray()
	map(b.extend, map(encode, s))
	return encode_varint(len(s)) + b

def encode(s):
	if s == None:
		return bytearray()
	if isinstance(s, int):
		return encode_varint(s)
	elif isinstance(s, str):
		return encode_string(s)
	elif isinstance(s, list):
		return encode_list(s)
	else:
		print "UNSUPPORTED TYPE!", type(s), s


import binascii
	
if __name__ == '__main__':
	ns = [100,100,1000,256]
	ss = [2,5,5,2]
	bs = map(encode_big_endian, ns,ss)
	ds = map(decode_big_endian, bs,ss)
	print ns
	print [i[0] for i in ds]

	ss = ["abc", "hi there jim", "ok now what"]
	e = map(encode_string, ss)
	d = map(decode_string, e)
	print ss
	print [i[0] for i in d]