PyLZHAM

PyLZHAM is a python 3 wrapper for the LZHAM Compression Codec

Installation

In order to install pylzham, you'll simply need to use the following command

python -m pip install pylzham

Note: PyLZHAM use C++ extension which means python need a compiler to build this module

Usage

Compression

You can easily compress data using the following snippet:

>>> import lzham
>>> lzham.compress(b'yourdatahere' * 100)
b'@\x0b\x9f\x85\x07\x96\xf7W&F\x17F\x16\x86P\x07&W\x98(C\xf4\x03\xf7\xf4\x02m\x98\xc0P\xeb\xf9$'

However if you need to compress many files/data, using the LZHAMCompressor class might be a better idea. Here is a quick example:

>>> from lzham import LZHAMCompressor
>>> compressor = LZHAMCompressor()
>>> compressor.compress(b'yourdatahere' * 100)
b'@\x0b\x9f\x85\x07\x96\xf7W&F\x17F\x16\x86P\x07&W\x98(C\xf4\x03\xf7\xf4\x02m\x98\xc0P\xeb\xf9$'
>>> compressor.compress(b'yourotherdata' * 100)
b'@\x07\xcd\xd9\x07\x96\xf7W&\xf7F\x86W&D\xc6\x17F\x17\x98(D\x03\xf7\xf4\x03\xf7\xf4\x01\x98\xc03i*k'

Using compression option

If you wanna set compression options you should use a compression filter. Filters support the following options (specified as additional entries in the dictionary representing the filter):

• dict_size_log2
• level
• table_update_rate
• max_helper_threads
• table_max_update_interval
• table_update_interval_slow_rate

For more information about thoses options you can look there.

Here is an example of using filters with both lzham.compress and LZHAMCompressor:

 >>> filters = {'dict_size_log2': 18}
 >>> lzham.compress(b'yourdata', filters)
 >>> compressor = lzham.LZHAMCompressor(filters)
 >>> compressor.compress(b'yourdata')

Decompression

You can easily decompress data using the following snippet:

>>> import lzham
>>> lzham.decompress(b'D\xad\xc0\x00\x07FW7@\x07i1\x98\xc0f\xb1\x11\x81', 40)
b'testtesttesttesttesttesttesttesttesttest'

Note: Since there is no offical header for LZHAM you have to give the decompressed data size to the lib (40 in our case).

However if you need to decompress many files/data, using the LZHAMDecompressor class might be a better idea. Here is a quick example:

>>> from lzham import LZHAMDecompressor
>>> decompressor = LZHAMDecompressor()
>>> decompressor.decompress(b'D\xad\xc0\x00\x07FW7@\x07i1\x98\xc0f\xb1\x11\x81', 40)
b'testtesttesttesttesttesttesttesttesttest'
>>> decompressor.decompress(b'D\xad\xc0\x00\x07FW7@\x07i1\x98\xc0f\xb1\x11\x81', 40)
b'testtesttesttesttesttesttesttesttesttest'

Using decompression option

If you wanna set decompression options you should use a decompression filter. Filters support the following options (specified as additional entries in the dictionary representing the filter):

• dict_size_log2
• table_update_rate
• table_max_update_interval
• table_update_interval_slow_rate
• compute_adler32_during_decomp
• unbuffered_decompression

For more information about thoses options you can look there.

Here is an example of using filters with both lzham.decompress and LZHAMDecompressor:

 >>> filters = {'dict_size_log2': 18}
 >>> lzham.decompress(b'D\xad\xc0\x00\x07FW7@\x0fi3\x98\xc0f\xb1\x11\x81', 40, filters)
>>> decompressor = lzham.LZHAMDecompressor(filters)
>>> decompressor.decompress(b'D\xad\xc0\x00\x07FW7@\x0fi3\x98\xc0f\xb1\x11\x81', 40)

If you need to modify your LZHAMDecompressor instance filters you can simply call its reinit function like this:

>>> decompressor.reinit(filters)

Note

I'm a C++ newbie so my code might be really trash. If you have any bug to report feel free to contact me at @GaLaXy1036#1601 on Discord.