root
/
xz
mirror of https://git.tukaani.org/xz.git
1
0
Fork 0
Code Issues Releases Wiki Activity

Fix a few typos and add some missing articles in some documents. 

Also hyphenate several compound adjectives.

Signed-off-by: Benno Schulenberg <bensberg@justemail.net>
This commit is contained in:
Benno Schulenberg 2012-03-13 22:04:04 +01:00 committed by Lasse Collin
parent afb6ce8c82
commit 532b3e4c56
4 changed files with 65 additions and 65 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
AUTHORS
View File

@ -16,11 +16,11 @@ Authors of XZ Utils
Some scripts have been adapted from gzip. The original versions
were written by Jean-loup Gailly, Charles Levert, and Paul Eggert.
Andrew Dudman helped adapting the script and their man pages for
Andrew Dudman helped adapting the scripts and their man pages for
XZ Utils.
The GNU Autotools based build system contains files from many authors,
which I'm not trying list here.
The GNU Autotools-based build system contains files from many authors,
which I'm not trying to list here.
Several people have contributed fixes or reported bugs. Most of them
are mentioned in the file THANKS.

42
README
View File

@ -5,7 +5,7 @@ XZ Utils
0. Overview
1. Documentation
1.1. Overall documentation
1.2. Documentation for command line tools
1.2. Documentation for command-line tools
1.3. Documentation for liblzma
2. Version numbering
3. Reporting bugs
@ -17,21 +17,21 @@ XZ Utils
0. Overview
-----------
XZ Utils provide a general-purpose data compression library and
command line tools. The native file format is the .xz format, but
XZ Utils provide a general-purpose data-compression library plus
command-line tools. The native file format is the .xz format, but
also the legacy .lzma format is supported. The .xz format supports
multiple compression algorithms, which are called "filters" in
multiple compression algorithms, which are called "filters" in the
context of XZ Utils. The primary filter is currently LZMA2. With
typical files, XZ Utils create about 30 % smaller files than gzip.
To ease adapting support for the .xz format into existing applications
and scripts, the API of liblzma is somewhat similar to the API of the
popular zlib library. For the same reason, the command line tool xz
has similar command line syntax than that of gzip.
popular zlib library. For the same reason, the command-line tool xz
has a command-line syntax similar to that of gzip.
When aiming for the highest compression ratio, LZMA2 encoder uses
When aiming for the highest compression ratio, the LZMA2 encoder uses
a lot of CPU time and may use, depending on the settings, even
hundreds of megabytes of RAM. However, in fast modes, LZMA2 encoder
hundreds of megabytes of RAM. However, in fast modes, the LZMA2 encoder
competes with bzip2 in compression speed, RAM usage, and compression
ratio.
@ -44,8 +44,8 @@ XZ Utils
since that needs to be done only once to benefit many people.
With some file types, combining (or "chaining") LZMA2 with an
additional filter can improve compression ratio. A filter chain may
contain up to four filters, although usually only one two is used.
additional filter can improve the compression ratio. A filter chain may
contain up to four filters, although usually only one or two are used.
For example, putting a BCJ (Branch/Call/Jump) filter before LZMA2
in the filter chain can improve compression ratio of executable files.
@ -88,9 +88,9 @@ XZ Utils
packages.
1.2. Documentation for command line tools
1.2. Documentation for command-line tools
The command line tools are documented as man pages. In source code
The command-line tools are documented as man pages. In source code
releases (and possibly also in some binary packages), the man pages
are also provided in plain text (ASCII only) and PDF formats in the
directory "doc/man" to make the man pages more accessible to those
@ -109,7 +109,7 @@ XZ Utils
written yet.
For now, if you have never used liblzma, libbzip2, or zlib, I
recommend learning *basics* of zlib API. Once you know that, it
recommend learning the *basics* of the zlib API. Once you know that, it
should be easier to learn liblzma.
http://zlib.net/manual.html
@ -125,11 +125,11 @@ XZ Utils
API and ABI break.
- Y is the minor version. It is incremented when new features are
added without breaking existing API or ABI. Even Y indicates
stable release and odd Y indicates unstable (alpha or beta
added without breaking the existing API or ABI. An even Y indicates
a stable release and an odd Y indicates unstable (alpha or beta
version).
- Z is the revision. This has different meaning for stable and
- Z is the revision. This has a different meaning for stable and
unstable releases:
* Stable: Z is incremented when bugs get fixed without adding
@ -141,10 +141,10 @@ XZ Utils
in earlier unstable releases having the same X.Y may break.
- S indicates stability of the release. It is missing from the
stable releases where Y is an even number. When Y is odd, S
stable releases, where Y is an even number. When Y is odd, S
is either "alpha" or "beta" to make it very clear that such
versions are not stable releases. The same X.Y.Z combination is
not used for more than one stability level i.e. after X.Y.Zalpha,
not used for more than one stability level, i.e. after X.Y.Zalpha,
the next version can be X.Y.(Z+1)beta but not X.Y.Zbeta.
@ -180,7 +180,7 @@ XZ Utils
Don't send core dump files or any executables. If you have a small
example file(s) (total size less than 256 KiB), please include
it/them as an attachment. If you have bigger test files, put them
online somewhere and include an URL to the file(s) in the bug report.
online somewhere and include a URL to the file(s) in the bug report.
Always include the exact version number of XZ Utils in the bug report.
If you are using a snapshot from the git repository, use "git describe"
@ -197,7 +197,7 @@ XZ Utils
The messages from the xz tool have been translated into a few
languages. Before starting to translate into a new language, ask
the author that someone else hasn't already started working on it.
the author whether someone else hasn't already started working on it.
Test your translation. Testing includes comparing the translated
output to the original English version by running the same commands
@ -218,7 +218,7 @@ XZ Utils
Note especially the following:
- The output of --help and --long-help must look nice on
a 80-column terminal. It's OK to add extra lines if needed.
an 80-column terminal. It's OK to add extra lines if needed.
- In contrast, don't add extra lines to error messages and such.
They are often preceded with e.g. a filename on the same line,

24
doc/faq.txt
View File

@ -26,7 +26,7 @@ Q: There are many LZMA related projects. How does XZ Utils relate to them?
A: 7-Zip and LZMA SDK are the original projects. LZMA SDK is roughly
a subset of the 7-Zip source tree.
p7zip is 7-Zip's command line tools ported to POSIX-like systems.
p7zip is 7-Zip's command-line tools ported to POSIX-like systems.
LZMA Utils provide a gzip-like lzma tool for POSIX-like systems.
LZMA Utils are based on LZMA SDK. XZ Utils are the successor to
@ -42,7 +42,7 @@ Q: Why is liblzma named liblzma if its primary file format is .xz?
A: When the designing of the .xz format began, the idea was to replace
the .lzma format and use the same .lzma suffix. It would have been
quite OK to reuse the suffix when there were very few .lzma files
around. However, the old .lzma format become popular before the
around. However, the old .lzma format became popular before the
new format was finished. The new format was renamed to .xz but the
name of liblzma wasn't changed.
@ -73,7 +73,7 @@ A: For now, no. Since XZ Utils supports the .lzma format, it's usually
Technically, there is a way to make the conversion relatively fast
(roughly twice the time that normal decompression takes). Writing
such a tool would take quite a bit time though, and would probably
such a tool would take quite a bit of time though, and would probably
be useful to only a few people. If you really want such a conversion
tool, contact Lasse Collin and offer some money.
@ -84,7 +84,7 @@ Q: I have installed xz, but my tar doesn't recognize .tar.xz files.
A: xz -dc foo.tar.xz | tar xf -
Q: Can I recover parts of a broken .xz file (e.g. corrupted CD-R)?
Q: Can I recover parts of a broken .xz file (e.g. a corrupted CD-R)?
A: It may be possible if the file consists of multiple blocks, which
typically is not the case if the file was created in single-threaded
@ -94,7 +94,7 @@ A: It may be possible if the file consists of multiple blocks, which
Q: Is (some part of) XZ Utils patented?
A: Lasse Collin is not aware of any patents that could affect XZ Utils.
However, due to nature of software patents, it's not possible to
However, due to the nature of software patents, it's not possible to
guarantee that XZ Utils isn't affected by any third party patent(s).
@ -105,8 +105,8 @@ A: The .xz format is documented in xz-file-format.txt. It is a container
filters.
Documenting LZMA and LZMA2 is planned, but for now, there is no other
documentation that the source code. Before you begin, you should know
the basics of LZ77 and range coding algorithms. LZMA is based on LZ77,
documentation than the source code. Before you begin, you should know
the basics of LZ77 and range-coding algorithms. LZMA is based on LZ77,
but LZMA is a lot more complex. Range coding is used to compress
the final bitstream like Huffman coding is used in Deflate.
@ -148,7 +148,7 @@ A: See the documentation in XZ Embedded. In short, something like
xz --check=crc32 --powerpc --lzma2=preset=6e,dict=64KiB
Adjust dictionary size to get a good compromise between
Adjust the dictionary size to get a good compromise between
compression ratio and decompressor memory usage. Note that
in single-call decompression mode of XZ Embedded, a big
dictionary doesn't increase memory usage.
@ -184,10 +184,10 @@ A: It is planned and has been taken into account when designing
The third method is pigz-style threading (I use that name, because
pigz <http://www.zlib.net/pigz/> uses that method). It doesn't
affect compression ratio significantly and scales to many cores.
The memory usage scales linearly when threads are added. It isn't
significant with pigz, because Deflate uses only 32 KiB dictionary,
The memory usage scales linearly when threads are added. This isn't
significant with pigz, because Deflate uses only a 32 KiB dictionary,
but with LZMA2 the memory usage will increase dramatically just like
with the independent blocks method. There is also a constant
with the independent-blocks method. There is also a constant
computational overhead, which may make pigz-method a bit dull on
dual-core compared to the parallel match finder method, but with more
cores the overhead is not a big deal anymore.
@ -197,7 +197,7 @@ A: It is planned and has been taken into account when designing
can cut the memory usage by 50 %.
It is possible that the single-threaded method will be modified to
create files indentical to the pigz-style method. We'll see once
create files identical to the pigz-style method. We'll see once
pigz-style threading has been implemented in liblzma.

58
doc/history.txt
View File

@ -4,11 +4,11 @@ History of LZMA Utils and XZ Utils
Tukaani distribution
In 2005, there was a small group working on Tukaani distribution, which
was a Slackware fork. One of the project goals was to fit the distro on
In 2005, there was a small group working on the Tukaani distribution, which
was a Slackware fork. One of the project's goals was to fit the distro on
a single 700 MiB ISO-9660 image. Using LZMA instead of gzip helped a
lot. Roughly speaking, one could fit data that took 1000 MiB in gzipped
form into 700 MiB with LZMA. Naturally compression ratio varied across
form into 700 MiB with LZMA. Naturally, the compression ratio varied across
packages, but this was what we got on average.
Slackware packages have traditionally had .tgz as the filename suffix,
@ -30,13 +30,13 @@ Tukaani distribution
First steps of LZMA Utils
The first version of LZMA Utils (4.22.0) included a shell script called
lzmash. It was wrapper that had gzip-like command line interface. It
lzmash. It was a wrapper that had a gzip-like command-line interface. It
used the LZMA_Alone tool from LZMA SDK to do all the real work. zgrep,
zdiff, and related scripts from gzip were adapted work with LZMA and
zdiff, and related scripts from gzip were adapted to work with LZMA and
were part of the first LZMA Utils release too.
LZMA Utils 4.22.0 included also lzmadec, which was a small (less than
10 KiB) decoder-only command line tool. It was written on top of the
10 KiB) decoder-only command-line tool. It was written on top of the
decoder-only C code found from the LZMA SDK. lzmadec was convenient in
situations where LZMA_Alone (a few hundred KiB) would be too big.
@ -48,31 +48,31 @@ Second generation
The lzmash script was an ugly and not very secure hack. The last
version of LZMA Utils to use lzmash was 4.27.1.
LZMA Utils 4.32.0beta1 introduced a new lzma command line tool written
LZMA Utils 4.32.0beta1 introduced a new lzma command-line tool written
by Ville Koskinen. It was written in C++, and used the encoder and
decoder from C++ LZMA SDK with little modifications. This tool replaced
both the lzmash script and the LZMA_Alone command line tool in LZMA
decoder from C++ LZMA SDK with some little modifications. This tool replaced
both the lzmash script and the LZMA_Alone command-line tool in LZMA
Utils.
Introducing this new tool caused some temporary incompatibilities,
because LZMA_Alone executable was simply named lzma like the new
command line tool, but they had completely different command line
because the LZMA_Alone executable was simply named lzma like the new
command-line tool, but they had a completely different command-line
interface. The file format was still the same.
Lasse wrote liblzmadec, which was a small decoder-only library based
on the C code found from LZMA SDK. liblzmadec had API similar to zlib,
on the C code found from LZMA SDK. liblzmadec had an API similar to zlib,
although there were some significant differences, which made it
non-trivial to use it in some applications designed for zlib and
libbzip2.
The lzmadec command line tool was converted to use liblzmadec.
The lzmadec command-line tool was converted to use liblzmadec.
Alexandre Sauvé helped converting build system to use GNU Autotools.
This made is easier to test for certain less portable features needed
by the new command line tool.
Alexandre Sauvé helped converting the build system to use GNU Autotools.
This made it easier to test for certain less portable features needed
by the new command-line tool.
Since the new command line tool never got completely finished (for
example, it didn't support LZMA_OPT environment variable), the intent
Since the new command-line tool never got completely finished (for
example, it didn't support the LZMA_OPT environment variable), the intent
was to not call 4.32.x stable. Similarly, liblzmadec wasn't polished,
but appeared to work well enough, so some people started using it too.
@ -85,16 +85,16 @@ Second generation
File format problems
The file format used by LZMA_Alone was primitive. It was designed for
embedded systems in mind, and thus provided only minimal set of
features. The two biggest problems for non-embedded use were lack of
magic bytes and integrity check.
The file format used by LZMA_Alone was primitive. It was designed with
embedded systems in mind, and thus provided only a minimal set of
features. The two biggest problems for non-embedded use were the lack of
magic bytes and an integrity check.
Igor and Lasse started developing a new file format with some help
from Ville Koskinen. Also Mark Adler, Mikko Pouru, H. Peter Anvin,
and Lars Wirzenius helped with some minor things at some point of the
development. Designing the new format took quite a long time (actually,
too long time would be more appropriate expression). It was mostly
too long a time would be a more appropriate expression). It was mostly
because Lasse was quite slow at getting things done due to personal
reasons.
@ -102,7 +102,7 @@ File format problems
that was already used by the old file format. Switching to the new
format wouldn't have caused much trouble when the old format wasn't
used by many people. But since the development of the new format took
so long time, the old format got quite popular, and it was decided
such a long time, the old format got quite popular, and it was decided
that the new file format must use a different suffix.
It was decided to use .xz as the suffix of the new file format. The
@ -125,13 +125,13 @@ Transition to XZ Utils
The early versions of XZ Utils were called LZMA Utils. The first
releases were 4.42.0alphas. They dropped the rest of the C++ LZMA SDK.
The code was still directly based on LZMA SDK but ported to C and
converted from callback API to stateful API. Later, Igor Pavlov made
C version of the LZMA encoder too; these ports from C++ to C were
converted from a callback API to a stateful API. Later, Igor Pavlov made
a C version of the LZMA encoder too; these ports from C++ to C were
independent in LZMA SDK and LZMA Utils.
The core of the new LZMA Utils was liblzma, a compression library with
zlib-like API. liblzma supported both the old and new file format. The
gzip-like lzma command line tool was rewritten to use liblzma.
a zlib-like API. liblzma supported both the old and new file format. The
gzip-like lzma command-line tool was rewritten to use liblzma.
The new LZMA Utils code base was renamed to XZ Utils when the name
of the new file format had been decided. The liblzma compression
@ -139,7 +139,7 @@ Transition to XZ Utils
caused unnecessary breakage in applications already using the early
liblzma snapshots.
The xz command line tool can emulate the gzip-like lzma tool by
The xz command-line tool can emulate the gzip-like lzma tool by
creating appropriate symlinks (e.g. lzma -> xz). Thus, practically
all scripts using the lzma tool from LZMA Utils will work as is with
XZ Utils (and will keep using the old .lzma format). Still, the .lzma