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zlib ARMlet Port
Introduction zlib is a free, general-purpose, legally
unencumbered, lossless data-compression library that runs on many
different platforms. zlib was written by Jean-loup Gailly
(compression) and Mark Adler (decompression). Jean-loup Gailly
maintains the main zlib
homepage. zlib was ported to a Palm OS shared library by Tom
Zerucha, who has a homepage for his Palm OS port. I have taken Tom's
port and added an ARMlet, which allows it to run significantly faster
on Palm OS devices with ARM processors. Note that this version will
still run on pre-OS 5, non ARM devices.
History
03.07.2003 Added some code so that old apps that still call ZLSetup
will still work, by manually calling zlib_open when necessary.
(114armlet-4)
02.07.2003 Replaced the ZLSetup and ZLTeardown macros with some inline
functions. The old ZLSetup macro failed to call the zlib_open
function. Also took out the #include of zconf.h from SysZLib.h.
(114armlet-3)
01.15.2003 Updated compress2 and uncompress functions, added macros
for compress and uncompress, changed defines for MAX_MEM_LEVEL and
MAX_WBITS. (114armlet-2)
01.09.2003 Initial release. (114armlet-1)
Performance Comparison
The following table shows deflate and inflate speeds on a device with
a 68K processor (m515) and on a device with an ARM processor (Tungsten
T). Results were obtained by running Deflater on the
Asian_24x24.PDB
Anki font database.
| Device Name |
Deflate Speed
(bytes per second) |
Inflate Speed
(bytes per second) |
| Palm m515 |
5,300 |
21,700 |
Palm Tungsten T
68K version |
7,200 |
28,600 |
Palm Tungsten T
ARMlet version |
152,000 |
169,000 |
Download
If you have a Palm OS device with an ARM processor in it, and you run any
applications that use SysZLib, then simply download the following PRC file
and install it onto your device:
SysZLib.prc
If you are a developer and would like to use zlib in your Palm OS
applications, then download the following header file and use zlib as
described in the
zlib manual. Also,
download the DLL and copy it into your Simulator directory, if you would
like to test on the Simulator.
SysZLib.h
zlib_armlet_dll.zip
If you are a developer and wish to modify this port or make any bug fixes,
then download the following patch and apply it to the zlib-1.1.4 distribution:
zlib114armlet-4.dif
Old Versions:
zlib114armlet-3.dif
zlib114armlet-2.dif
zlib114armlet-1.dif
Links
Here are links to a few Palm OS applications that are OS 5.0
compatibile and use zlib for compression:
Contact
If you have any questions or comments about this software, please send me e-mail at
justinc@copera.com
Justin Clark (January 9th, 2003)
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