from struct import Struct
from recordtype import recordtype

def populate(value, mask):
	mask = mask[-1]
	if value:
		return value
	elif mask in 'bBhHiIlLqQfd':
		return 0
	elif mask in 'sp':
		return ''
	elif mask == '?':
		return False

def encode(struct):
	encoder = struct._struct
	params = [populate(x, mask) for x, mask in zip(struct, struct._fieldTypes)]
	return encoder.pack(*params)

def decode(struct, data):
	decoder = struct._struct
	values = decoder.unpack(data)
	for x in zip(struct._fields, values):
		setattr(struct, x[0], x[1])

def sizeof(struct):
	return struct._struct.size

def create(name, description):
	description = description.split(',')
	fields = [field[:field.find(':')] for field in description]
	typeList = [field[field.find(':') + 1:] for field in description]
	types = ''.join(['@'] + typeList)
	newType = recordtype(name, fields, default=None)
	newType._struct = Struct(types)
	newType._fieldTypes = typeList
	newType.encode = encode
	newType.decode = decode
	newType.sizeof = sizeof
	return newType


if __name__ == '__main__':
	Point = create('Point', 'x:f,y:f')
	print Point
	p1 = Point(1, 2)
	p2 = Point(0, 0)
	print p1._asdict().values(), p2
	p2.decode(p1.encode())
	print p2