Lots of content was updated on the xz man page.
Technical improvements:
- Start a new sentence on a new line.
- Use fairly short lines.
- Use constant-width font for examples (where supported).
- Some minor cleanups.
Thanks to Jonathan Nieder for some language fixes.
The code assumed that printing numbers with thousand separators
and decimal points would always produce only US-ASCII characters.
This was used for buffer sizes (with snprintf(), no overflows)
and aligning columns of the progress indicator and --list. That
assumption was wrong (e.g. LC_ALL=fi_FI.UTF-8 with glibc), so
multibyte character support was added in this commit. The old
way is used if the operating system doesn't have enough multibyte
support (e.g. lacks wcwidth()).
The sizes of buffers were increased to accomodate multibyte
characters. I don't know how big they should be exactly, but
they aren't used for anything critical, so it's not too bad.
If they still aren't big enough, I hopefully get a bug report.
snprintf() takes care of avoiding buffer overflows.
Some static buffers were replaced with buffers allocated on
stack. double_to_str() was removed. uint64_to_str() and
uint64_to_nicestr() now share the static buffer and test
for thousand separator support.
Integrity check names "None" and "Unknown-N" (2 <= N <= 15)
were marked to be translated. I had forgot these, plus they
wouldn't have worked correctly anyway before this commit,
because printing tables with multibyte strings didn't work.
Thanks to Marek Černocký for reporting the bug about
misaligned table columns in --list output.
This should reduce the cases where --extreme makes
compression worse. On the other hand, some other
files may now benefit slightly less from --extreme.
Testing compression at level -4 now requires 48 MiB of free store at
compression time and 5 MiB at decompression time.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
It was 8 + nice_len / 4, now it is 4 + nice_len / 4.
This allows faster settings at lower nice_len values,
even though it seems that I won't use automatic depth
calcuation with HC3 and HC4 in the presets.
For several people, the limiter causes bigger problems that
it solves, so it is better to have it disabled by default.
Those who want to have a limiter by default need to enable
it via the environment variable XZ_DEFAULTS.
Support for environment variable XZ_DEFAULTS was added. It is
parsed before XZ_OPT and technically identical with it. The
intended uses differ quite a bit though; see the man page.
The memory usage limit can now be set separately for
compression and decompression using --memlimit-compress and
--memlimit-decompress. To set both at once, -M or --memlimit
can be used. --memory was retained as a legacy alias for
--memlimit for backwards compatibility.
The semantics of --info-memory were changed in backwards
incompatible way. Compatibility wasn't meaningful due to
changes in the memory usage limiter functionality.
The memory usage limiter info is no longer shown at the
bottom of xz --long -help.
The memory usage limiter support for removed completely from xzdec.
xz's man page was updated to match the above changes. Various
unrelated fixes were also made to the man page.
Hopefully these help a bit when learning the basics
of liblzma API. I plan to write detailed examples about
both basic and advanced features with lots of comments,
but these two examples are good have right now.
The examples were written by Daniel Mealha Cabrita. Thanks.
When using -O2 with GCC, it liked to swap two comparisons
in one "if" statement. It's otherwise fine except that
the latter part, which is seemingly never executed, got
executed (nothing wrong with that) and then triggered
warning in Valgrind about conditional jump depending on
uninitialized variable. A few people find this annoying
so do things a bit differently to avoid the warning.
Lasse Collin
Jonathan Nieder