def decode(nxt, quiet=False):
'''Decompress a stream of bytes compressed by "lz.encode".
Consume bytes. Produce decompressed bytes.
When finished:
Treat remaining bytes as a lone prefix. (If any leftover)
Print a message to stderr. (Set quiet to True to disable)
'''
table = {} # map blockids to known chunks
try:
for blockid in itertools.count():
blockm = bytearray()
# accumulate the next block
for _ in range(ints.bytewidth(blockid) + 1):
blockm.append((yield))
block = bytes(blockm)
# decompress the block to a chunk
pointerb, newbyte = block[:-1], block[-1:]
pointer = ints.frombytes(pointerb)
prefix = b'' if pointer == blockid else table[pointer]
# remember the chunk
table[blockid] = prefix + newbyte
# send the chunk
nxt.send(table[blockid])
finally:
if blockm:
pointerb = bytes(blockm)
pointer = ints.frombytes(pointerb)
nxt.send(table[pointer])
if not quiet:
ct = blockid + (0.5 if blockm else 0)
print('lz.decoder: {} blocks done'.format(ct), file=sys.stderr)
def decode(nxt, quiet=False):
'''Decompress a stream of bytes compressed by "lz.encode".
Consume bytes. Produce decompressed bytes.
When finished:
Treat remaining bytes as a lone prefix. (If any leftover)
Print a message to stderr. (Set quiet to True to disable)
'''
table = {} # map blockids to known chunks
try:
for blockid in itertools.count():
blockm = bytearray()
# accumulate the next block
for _ in range(ints.bytewidth(blockid) + 1):
blockm.append((yield))
block = bytes(blockm)
# decompress the block to a chunk
pointerb, newbyte = block[:-1], block[-1:]
pointer = ints.frombytes(pointerb)
prefix = b'' if pointer == blockid else table[pointer]
# remember the chunk
table[blockid] = prefix + newbyte
# send the chunk
nxt.send(table[blockid])
finally:
if blockm:
pointerb = bytes(blockm)
pointer = ints.frombytes(pointerb)
nxt.send(table[pointer])
if not quiet:
ct = blockid + (0.5 if blockm else 0)
print('lz.decoder: {} blocks done'.format(ct), file=sys.stderr)
def encode(nxt, quiet=False):
'''Compress a stream of bytes according to LempelZiv.
Consume bytes. Produce pointer-newbyte bytes.
When finished:
Send buffer as a lone prefix. (If any leftover)
Print a message to stderr. (Set quiet to True to disable)
'''
table = {} # map known chunks to blockids
try:
for blockid in itertools.count():
chunkm = bytearray()
chunk = None
# accumulate an unfamiliar chunk
while chunk in table or chunk is None:
chunkm.append((yield))
chunk = bytes(chunkm)
# remember the chunk
table[chunk] = blockid
# compress the chunk to a block
prefix, newbyte = chunk[:-1], chunk[-1:]
pointer = table[prefix] if prefix else blockid
pointerb = ints.tobytes(pointer, length=ints.bytewidth(blockid))
# send the block
nxt.send(pointerb + newbyte)
finally:
if chunkm:
pointer = table[chunk]
pointerb = ints.tobytes(pointer, length=ints.bytewidth(blockid))
# send partial block
nxt.send(pointerb)
if not quiet:
ct = blockid + (0.5 if chunkm else 0)
print('lz.encoder: {} blocks done'.format(ct), file=sys.stderr)
def encode(nxt, quiet=False):
'''Compress a stream of bytes according to LempelZiv.
Consume bytes. Produce pointer-newbyte bytes.
When finished:
Send buffer as a lone prefix. (If any leftover)
Print a message to stderr. (Set quiet to True to disable)
'''
table = {} # map known chunks to blockids
try:
for blockid in itertools.count():
chunkm = bytearray()
chunk = None
# accumulate an unfamiliar chunk
while chunk in table or chunk is None:
chunkm.append((yield))
chunk = bytes(chunkm)
# remember the chunk
table[chunk] = blockid
# compress the chunk to a block
prefix, newbyte = chunk[:-1], chunk[-1:]
pointer = table[prefix] if prefix else blockid
pointerb = ints.tobytes(pointer, length=ints.bytewidth(blockid))
# send the block
nxt.send(pointerb + newbyte)
finally:
if chunkm:
pointer = table[chunk]
pointerb = ints.tobytes(pointer, length=ints.bytewidth(blockid))
# send partial block
nxt.send(pointerb)
if not quiet:
ct = blockid + (0.5 if chunkm else 0)
print('lz.encoder: {} blocks done'.format(ct), file=sys.stderr)
