[COMPRESS-440] Speed up decoder for deflate64

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 1.16
• Component/s: Compressors
• Assignee: Unassigned
• Reporter: Dawid Weiss
• Created: 11/Jan/18 17:33
• Updated: 28/Jan/18 10:59
• Resolved: 12/Jan/18 16:27

Description

With the buffer applied in COMPRESS-438 the decompression speed is actually quite all right, but there's still room for improvement. I was quite curious what the bounds for pure-java inflater would be and hacked a quick experiment with ZipFile using jzlib's implementation [1] to decompress a large-ish archive (openjdk8 repository).

The results for deflate, deflate64 and java's built-in decompressor are below.

Java (Inflater):
archive.zip 4.38 sec., 444,357,134 archived => 731,621,181 decompressed

jzlib's pure-java inflater:
archive.zip 6.65 sec., 444,357,134 archived => 731,621,181 decompressed

current deflate64 in commons-compress (with my allocation-reducing patch):
archive64.zip 11.35 sec., 443,209,798 archived => 731,630,120 decompressed

[1] http://www.jcraft.com/jzlib/