make dec8.bit.Bitfield reversible

dec8/bit.py

@@ -12,7 +12,21 @@ class Bitfield:
 		self.value <<= length
 		self.value |= value
 		self.length += length
+	
+	def shift_out(self, length):
+		mask = 2**length - 1
+		tmp = self.value & mask
+		self.value >>= length
 		
+		return tmp
+	
+	def load(self, raw):
+		self.value = 0
+		self.length = 0
+		
+		for b in raw:
+			self.shift_in(b, 8)
+	
 	def dump(self, align=True):
 		value = self.value
 		length = self.length