Comment # 1
on bug 8563
from Guy Harris
For bzip2, there's libbzip2:
http://www.bzip.org
The page at
http://www.bzip.org/1.0.5/bzip2-manual-1.0.5.html#limits
says
Further ahead, it would be nice to be able to do random access into files.
This will require some careful design of compressed file formats.
although
http://www.bzip.org/1.0.5/bzip2-manual-1.0.5.html#recovering
says
bzip2 compresses files in blocks, usually 900kbytes long. Each block is
handled independently.
which already puts it ahead of gzip format in its ability to conveniently
support random access (there aren't convenient block boundaries of that sort in
gzip files, so we have to checkpoint the decompression dictionary).
http://tukaani.org/xz/format.html
says
Random-access reading: The data can be split into independently compressed
blocks. Every .xz file contains an index of the blocks, which makes limited
random-access reading possible when the block size is small enough.
which is very very very very very very very very very very very very very very
very good news for xz support, as we really want random access to files to do
something less gross than "sequentially read to seek forward, rewind and
sequentially read forward to seek backward" (Jakub Zawadzki already got Wiretap
to handle that in gzipped files by adapting some sample code from the zlib
source).
You are receiving this mail because:
- You are watching all bug changes.