| |
| XZ Utils To-Do List |
| =================== |
| |
| Known bugs |
| ---------- |
| |
| The test suite is too incomplete. |
| |
| If the memory usage limit is less than about 13 MiB, xz is unable to |
| automatically scale down the compression settings enough even though |
| it would be possible by switching from BT2/BT3/BT4 match finder to |
| HC3/HC4. |
| |
| The code to detect number of CPU cores doesn't count hyperthreading |
| as multiple cores. In context of xz, it probably should. |
| Hyperthreading is good at least with p7zip. |
| |
| XZ Utils compress some files significantly worse than LZMA Utils. |
| This is due to faster compression presets used by XZ Utils, and |
| can often be worked around by using "xz --extreme". With some files |
| --extreme isn't enough though: it's most likely with files that |
| compress extremely well, so going from compression ratio of 0.003 |
| to 0.004 means big relative increase in the compressed file size. |
| |
| xz doesn't quote unprintable characters when it displays file names |
| given on the command line. |
| |
| tuklib_exit() doesn't block signals => EINTR is possible. |
| |
| SIGTSTP is not handled. If xz is stopped, the estimated remaining |
| time and calculated (de)compression speed won't make sense in the |
| progress indicator (xz --verbose). |
| |
| |
| Missing features |
| ---------------- |
| |
| xz doesn't support copying extended attributes, access control |
| lists etc. from source to target file. |
| |
| Multithreaded compression: |
| - Reduce memory usage of the current method. |
| - Implement threaded match finders. |
| - Implement pigz-style threading in LZMA2. |
| |
| Multithreaded decompression |
| |
| Buffer-to-buffer coding could use less RAM (especially when |
| decompressing LZMA1 or LZMA2). |
| |
| I/O library is not implemented (similar to gzopen() in zlib). |
| It will be a separate library that supports uncompressed, .gz, |
| .bz2, .lzma, and .xz files. |
| |
| Check the first 0x00 byte of LZMA data. |
| |
| Support changing lzma_options_lzma.mode with lzma_filters_update(). |
| |
| Support LZMA_FULL_FLUSH for lzma_stream_decoder() to stop at |
| Block and Stream boundaries. |
| |
| lzma_strerror() to convert lzma_ret to human readable form? |
| This is tricky, because the same error codes are used with |
| slightly different meanings, and this cannot be fixed anymore. |
| |
| |
| Documentation |
| ------------- |
| |
| Some tutorial is needed for liblzma. I have planned to write some |
| extremely well commented example programs, which would work as |
| a tutorial. I suppose the Doxygen tags are quite OK as a quick |
| reference once one is familiar with the liblzma API. |
| |
| Document the LZMA1 and LZMA2 algorithms. |
| |
