Wondering what files with the .qz1 extension do?
Those are single stream QuickLZ level 1 compressed files.
What is qpress?
qpress, qlzip1 and qlzcat1 do QuickLZ compression/decompression.
qpress works on .qp
archives with multiple files. qlzip1 and
qlzcat1 work on streams of QuickLZ level 1 compressed data. For
those, .qz1
is the preferred extension.
The original source code is here: qpress_1.1.orig.tar.gz
A pre-built Debian/Ubuntu package with patches is here: qpress_1.1-0osso0+anydist_amd64.deb
Usage:
./Dockerfile.buildmany
Builds Debian/Ubuntu packages of qpress
and
qlzcat1/qlunzip1/qlzip1
for a few distributions.
Includes:
- qpress-1.1 as
qpress
; - the updated
quicklz.h
andquicklz.c
, version 1.5.1 BETA 7 (October 2011); qlzip1
,qlunzip1
,qlzcat1
that behave likegzip
,gunzip
andzcat
, but use level 1 QuickLZ compression.
Homepage: http://www.quicklz.com/
qpress is significantly faster than many other compression algorithms. It is however matched in speed/compression by lz4.
As an example take this non-scientific dataset with mostly (base64 encoded) attachments:
1,137,58,9591 mailbox.tar.bz2 <- 15 minutes(!), bzip2 1,534,049,770 mailbox.tar.lz4 <- 5 seconds, lz4 1,624,953,644 mailbox.tar.qp <- 6 seconds, qpress 1,785,057,280 mailbox.tar <- original
General recommendation: using lz4 is better or at least equally good.