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acefile - read/test/extract ACE 1.0 and 2.0 archives in pure python

Copyright (C) 2017-2019, Daniel Roethlisberger.


pip install acefile

# python library
import acefile
with'example.ace') as f:

# unace utility
acefile-unace -x example.ace


This single-file, pure python 3, no-dependencies implementation is intended to be used as a library, but also provides a stand-alone unace utility. As mostly pure-python implementation, it is significantly slower than native implementations, but more robust against vulnerabilities.

This implementation supports up to version 2.0 of the ACE archive format, including the EXE, DELTA, PIC and SOUND modes of ACE 2.0, password protected archives and multi-volume archives. It does not support writing to archives. It is an implementation from scratch, based on the 1998 document titled "Technical information of the archiver ACE v1.2" by Marcel Lemke, using unace 2.5 and WinAce 2.69 by Marcel Lemke as reference implementations.

For more information, API documentation, source code, packages and release notifications, refer to:


Python 3. No other dependencies.


pip install acefile

The acefile package includes an optional acebitstream module that implements the bit stream class in c, resulting in a 50% speedup. It is automatically used wherever it builds cleanly, but is not required.

Library usage examples

Extract all files in the archive, with directories, to current working dir:

import acefile
with'example.ace') as f:

Walk all files in the archive and test each one of them:

import acefile
with'example.ace') as f:
    for member in f:
        if member.is_dir():
        if f.test(member):
            print("CRC OK:     %s" % member.filename)
            print("CRC FAIL:   %s" % member.filename)

In-memory decompression of a specific archive member:

import acefile
import io

filelike = io.BytesIO(b'\x73\x83\x31\x00\x00\x00\x90**ACE**\x14\x14' ...)
with as f:
    data ='example.txt')

Handle archives potentially containing large members in chunks to avoid fully reading them into memory:

import acefile

with'large.ace') as fi:
    with open('large.iso', 'wb') as fo:
        for block in fi.readblocks('large.iso'):

Check the API documentation for a complete description of the API.

Utility usage examples

Extract all files in the archive, with directories, to current working dir:

acefile-unace -x example.ace

Test all files in the archive, verbosely:

acefile-unace -tv example.ace

List archive contents, verbosely:

acefile-unace -lv example.ace

Check usage for more functionality:

acefile-unace -h


Marcel Lemke for designing the ACE archive format and ACE compression and decompression algorithms.