def extract(self, output_file):
"""
Restore the compressed data
"""
# create a dictionary with key => string matches
st = dict()
for i in xrange(self.radix):
st[i] = chr(i)
i += 1 # i = 256 - reserved as an EOF signal
br = BitReader(self.file)
codeword = int(br.readbits(self.codeword_width))
val = st[codeword]
while True:
# write unpacked value
output_file.write(val)
codeword = int(br.readbits(self.codeword_width))
if codeword == self.radix:
# EOF
break
if i == codeword:
# special case hack (when we don't have the needed key in st, but we have just met in input)
new_value = val + val[0]
else:
new_value = st[codeword]
if i < self.codeword_limit:
i += 1
st[i] = val + new_value[0]
val = new_value
def extract(self, output_file):
"""
Restore the compressed data
"""
# create a dictionary with key => string matches
st = dict()
for i in xrange(self.radix):
st[i] = chr(i)
i += 1 # i = 256 - reserved as an EOF signal
br = BitReader(self.file)
codeword = int(br.readbits(self.codeword_width))
val = st[codeword]
while True:
# write unpacked value
output_file.write(val)
codeword = int(br.readbits(self.codeword_width))
if codeword == self.radix:
# EOF
break
if i == codeword:
# special case hack (when we don't have the needed key in st, but we have just met in input)
new_value = val + val[0]
else:
new_value = st[codeword]
if i < self.codeword_limit:
i += 1
st[i] = val + new_value[0]
val = new_value
def compress(tree, uncompressed, compressed):
'''First write the given tree to the stream 'compressed' using the
write_tree function. Then use the same tree to encode the data
from the input stream 'uncompressed' and write it to 'compressed'.
If there are any partially-written bytes remaining at the end,
write 0 bits to form a complete byte.
Args:
tree: A Huffman tree.
uncompressed: A file stream from which you can read the input.
compressed: A file stream that will receive the tree description
and the coded input data.
'''
table = huffman.make_encoding_table(tree)
uncomp = BitReader(uncompressed)
comp = BitWriter(compressed)
write_tree(tree, comp)
while True:
try:
uncomp_btye = uncomp.readbits(8)
print(uncomp_btye)
comp_path = table[uncomp_btye]
for bit in comp_path:
if bit == False:
comp.writebit(0)
elif bit == True:
comp.writebit(1)
print(comp_path)
except EOFError:
comp_path = table[None]
print("EOF")
for bit in comp_path:
comp.writebit(bit)
print(comp_path)
break
comp.flush()
def extract(self, output_file):
"""
Restore the compressed data
"""
br = BitReader(self.file)
root = self._read_trie(br)
# number of bytes to write
length = int(br.readbits(8))
bw = BitWriter(output_file)
# decode using the Huffman trie
for i in xrange(length):
node = root
while not node.is_leaf:
bit = br.readbit()
if bit:
node = node.right
else:
node = node.left
# write the character to output
bw.writebits(node.char, 8)
