oliver@ Futaura  .co.uk
Version: 1.7 Released: 4 March 2005
-Download: xpkBZP2.lha (94K)
Copyright © 2000-2005 Oliver Roberts, All Rights Reserved.

Block-sorting/huffman xpk compression library based on Julian Seward's bzip2 algorithms
(for 68K, OS4, MorphOS and WarpOS)

Julian Sadler's bzip2 compresses files using the Burrows-Wheeler block sorting text compression algorithm, and Huffman coding. Compression is generally considerably better than that achieved by more conventional LZ77/LZ78-based compressors, and approaches the performance of the PPM family of statistical compressors.

xpkBZP2.library uses the same compression algorithm as bzip2, and allows you to compress files with the same high crunch factor as bzip2, but under the XPK interface.

In summary, xpkBZP2.library offers generally a very high compression ratio, typically around 70-90%. Of course, there's no such thing as a free lunch, and the downside is that the compression routines require lots of memory, although there are modes available which use less memory, at the expense of compression efficiency.

Changes since 1.6:
  • PPC OS4 native version public release - rebuilt with GCC 3.4.3, now 10% faster at packing, and upto 30% faster unpacking
  • MorphOS and WarpOS versions recompiled with VBCC 0.8h, both now 2% faster at packing/unpacking and 6% faster unpacking for MorphOS

Would you like to know when xpkBZP2 is next updated? If so, then subscribe to my announcement list here (or send a blank e-mail to futaura-announce-subscribe@yahoogroups.com), to receive an e-mail as soon as new versions of any of my products are released. Subscribe to


The following benchmarks were generating after booting with no startup-sequence on my 50MHz 68060 and 240MHz 603e. The standard set of benchmark files was used in all cases, with the figures below being generated from the averages.

68k version
ModeRatioPack SpeedUnpack SpeedPack MemUnpack MemDescription
0..1979.5%107K/s330K/s1171K488K100K -1
20..2980.2%111K/s326K/s1953K878K200K -2
30..3980.4%109K/s324K/s2734K1269K300K -3
40..4980.7%106K/s323K/s3515K1660K400K -4
50..5980.8%104K/s320K/s4296K2058K500K -5
60..6980.8%102K/s319K/s5078K2441K600K -6
70..7980.9%103K/s316K/s5957K2832K700K -7
80..8980.9%103K/s313K/s6640K3222K800K -8
90..10080.7%103K/s310K/s7421K3613K900K -9

OS4 version
ModeRatioPack SpeedUnpack SpeedPack MemUnpack MemDescription
0..1979.5%227K/s1231K/s1171K488K100K -1
20..2980.2%239K/s1130K/s1953K878K200K -2
30..3980.4%235K/s1089K/s2734K1269K300K -3
40..4980.7%224K/s1056K/s3515K1660K400K -4
50..5980.8%217K/s1021K/s4296K2058K500K -5
60..6980.8%213K/s996K/s5078K2441K600K -6
70..7980.9%213K/s985K/s5957K2832K700K -7
80..8980.9%213K/s878K/s6640K3222K800K -8
90..10080.7%211K/s964K/s7421K3613K900K -9

WarpOS version
ModeRatioPack SpeedUnpack SpeedPack MemUnpack MemDescription
0..1979.5%201K/s985K/s1171K488K100K -1
20..2980.2%212K/s928K/s1953K878K200K -2
30..3980.4%208K/s900K/s2734K1269K300K -3
40..4980.7%199K/s877K/s3515K1660K400K -4
50..5980.8%195K/s855K/s4296K2058K500K -5
60..6980.8%191K/s850K/s5078K2441K600K -6
70..7980.9%191K/s837K/s5957K2832K700K -7
80..8980.9%191K/s832K/s6640K3222K800K -8
90..10080.7%190K/s822K/s7421K3613K900K -9

MorphOS version
ModeRatioPack SpeedUnpack SpeedPack MemUnpack MemDescription
0..1979.5%198K/s971K/s1171K488K100K -1
20..2980.2%208K/s909K/s1953K878K200K -2
30..3980.4%205K/s885K/s2734K1269K300K -3
40..4980.7%195K/s861K/s3515K1660K400K -4
50..5980.8%191K/s840K/s4296K2058K500K -5
60..6980.8%187K/s834K/s5078K2441K600K -6
70..7980.9%187K/s824K/s5957K2832K700K -7
80..8980.9%187K/s819K/s6640K3222K800K -8
90..10080.7%186K/s810K/s7421K3613K900K -9


  • Kickstart 3.0 or higher
  • XPK compression package
  • At least 8Mb free ram to use maximum compression
68k version
  • 68020 processor or higher (optimized versions included)
OS4 version
  • PPC accelerator card / AmigaOne
  • AmigaOS 4.0 pre-release or newer
WarpOS version
  • PPC accelerator card + 68040/060
  • WarpUp Release 4 (powerpc.library V15) or higher
MorphOS version
  • PPC accelerator card
  • MorphOS beta release 1 or higher

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