def fill_bit_buffer(self):
while self.GetBits < 25: # #define MIN_GET_BITS (32-7)
if self.DataBytesLeft > 0: # Are there some data?
# Attempt to read a byte
if self.unread_marker != 0:
# can't advance past a marker
# There should be enough bits still left in the data segment
# if so, just break out of the outer while loop.
# if (self.GetBits >= nbits)
if (self.GetBits >= 0):
break
uc = byteord(self.Data[self.DataPos])
self.DataPos += 1
self.DataBytesLeft -= 1
# If it's 0xFF, check and discard stuffed zero byte
if uc == 0xFF:
while uc == 0xFF:
uc = byteord(self.Data[self.DataPos])
self.DataPos += 1
self.DataBytesLeft -= 1
if uc == 0:
# Found FF/00, which represents an FF data byte
uc = 0xFF
else:
# Oops, it's actually a marker indicating end of compressed data.
# Better put it back for use later
self.unread_marker = uc
# There should be enough bits still left in the data segment
# if so, just break out of the outer while loop.
# if (self.GetBits >= nbits)
if (self.GetBits >= 0):
break
self.GetBuff = int(self.GetBuff << 8) | uc
self.GetBits += 8
else:
break
def read_word(self):
byte1, byte2 = self.Data[self.DataPos:self.DataPos+2]
self.DataPos += 2
output = (byteord(byte1)<<8) + byteord(byte2)
return output
def read_byte(self):
byte = self.Data[self.DataPos]
self.DataPos += 1
output = byteord(byte)
return output