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Options understood by ``zip''are:
| -mode |
Allowed arguments are ``compress'', ``decompress'' and all
unique abbreviations of these.
For immediate usage it specifies the
operation to use.
For attached transformations it specifies the
operation to use for writing. Reading
will automatically use the reverse operation.
|
| -level |
Possible arguments are ``default'' and integer numbers in the
range 1 ... 9. It specifies the used compression level.
|
| -nowrap |
Possible arguments are ``default'' and everything accepted
by Tcl_GetBoolean(FromObj).
Normally the compressed stream is "wrapped" between
2 header-bytes (id) and 4 footer-bytes (crc). When using
-nowrap, those bytes are stripped off the stream.
They are only used for error-checking and not for the actual
compression/decompression. Because the ZIP file format
has its own error-checking already, there is no need
to duplicate it in the stream.
Thus using '-nowrap 1' allows a much simpler processing of
ZIP files.
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This transformation uses the freely available zlib compression
library to accomplish its task. It uses the unpatented
``deflate''-algorithm employed by gzip, pkzip and others.
The current version is 1.1.3, but trf will work with any version
from 1.0.4 and upward.
The official homepage can be found at http://www.info-zip.org/pub/infozip/zlib/. A downloading page
is available there too. Additional sources of information are
rfc1950.txt, rfc1951.txt and rfc1952.txt.
trf requires a shared library version of zlib. People without
such don't loose however.
-
The unix-specific makefile contains the target ``zlib''. This
will generate a shared library for zlib. It assumes that the
zlib source distribution is available as subdirectory
zlib (a sibling to unix !).
-
A binary distribution for Windows® is available too, just take a
look at http://www.winimage.com/zLibDll.
A note of caution: The provided library kept crashing on my
Windows NT® system. At least often enough to render it unusable in
my eyes. YMMV however.
Because of this the subdirectory zlib.vc contains
everything to compile zlib as shared library (with MSVC++
4.2). Just copy its contents into a zlib source distribution,
copy makefile.vc to makefile, adapt the paths
to your directory structure, then type nmake in a dos box.
At last copy the newly generated zlib.dll into the
system directory of your machine.
- I have no information about its availability on MacIntoshes.
Remark: The current version of zlib (1.1.3) uses
configure from GNU autoconf to configure itself for a variety of
unix systems. This includes generation of a shared library too and
makes compilation of this library much easier.
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