Snzip, a compression/decompression tool based on snappy.
What is snzip.
Note that this tool's status is experimental. The file format may be changed to support the standardized format discussed in Issue 34: Command line tool and I cannot say that the tool keeps backward compatibilities with obsolete formats.
Download snzip-0.0.2.tar.gz from https://github.com/kubo/snzip, uncompress and untar it, and run configure.
tar xvfz snzip-0.0.2.tar.gz cd snzip-0.0.2 ./configure
If you didn't install snappy under /usr or /usr/local, you need to specify the location by '--with-snappy' as follows.
# insall snappy tar xvfz snappy-1.0.4.tar.gz cd snappy-1.0.4 ./configure --prefix=/usr/local/snappy make make install cd .. # install snzip tar xvfz snzip-0.0.2.tar.gz cd snzip-0.0.2 ./configure --with-snappy=/usr/local/snappy
To use source code in the github repository.
git clone git://github.com/kubo/snzip.git cd snzip ./autogen.sh ./configure
To compress file.tar:
Compressed file name is 'file.tar.snz' and the original file is deleted. Timestamp, mode and permissions are not changed as possible as it can.
The file format is SNZ. You need to add an option '-t snappy-java' or '-t snappy-in-java' to use other formats.
snzip -t snappy-java file.tar
snzip -t snappy-in-java file.tar
To compress file.tar and output to standard out.
snzip -c file.tar > file.tar.snz
cat file.tar | snzip > file.tar.snz
You need to add an option '-t [format-name]' to use formats except SNZ.
To uncompress file.tar.snz:
snzip -d file.tar.snz
Uncompressed file name is 'file.tar' and the original file is deleted. Timestamp, mode and permissions are not changed as possible as it can.
If the program name includes 'un' such as snunzip, it acts as '-d' is set.
The file format is automatically determined from the first byte of the file.
To uncompress file.tar.snz and output to standard out.
snzip -dc file.tar.snz > file.tar snunzip -c file.tar.snz > file.tar snzcat file.tar.snz > file.tar cat file.tar.snz | snzcat > file.tar
If the program name includes 'cat' such as snzcat, it acts as '-dc' is set.
SNZ File format
The first three bytes are magic characters 'SNZ'.
The fourth byte is the file format version. It is 0x01.
The fifth byte is the order of the block size. The input data is divided into fixed-length blocks and each block is compressed by snappy. When it is 16 (default value), the block size is 16th power of 2; 64 kilobytes.
The rest is pairs of a compressed data length and a compressed data block The compressed data length is encoded as snappy::Varint::Encode32() does. If the length is zero, it is the end of data.
Though the rest after the end of data is ignored for now, they may be continuously read as a next compressed file as gzip does.
Note that the uncompressed length of each compressed data block must be less than or equal to the block size specified by the fifth byte.
2-clause BSD-style license.