def compress(self, output_file):
"""
Compress data from input file and write compressed data to the output file.
"""
# read input and count chars
freq = defaultdict(int)
length = 0
while True:
# read one char from a file
char = self.file.read(1)
if char:
length += 1
freq[ord(char)] += 1
else:
# EOF
break
# build Huffman trie
root = self._build_trie(freq)
# build symbol table for chars and their binary representation
st = dict()
self._build_code(st, root, '')
bw = BitWriter(output_file)
# write the Huffman trie binary representation to the file
self._write_trie(root, bw)
# write number of bytes in original uncompressed message
bw.writebits(length, 8)
# use Huffman code to encode input
for i in xrange(length):
self.file.seek(i)
code = st[ord(self.file.read(1))]
for c in code:
if c == '0':
bw.writebit(False)
else:
bw.writebit(True)
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()
