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compression_tool - encode/decode files using the Compression library
compression_tool -encode | -decode [-a algorithm] [-A algorithm]
[-i input_file] [-o output_file] [-v] [-h]
compression_tool encodes (compresses), or decodes (uncompresses) files
using the Compression library.
Encode (compress) the input
Decode (uncompress) the input
Set the compression algorithm, valid options are zlib, lzma,
lzfse, lz4, lz4_raw. Default is lzfse.
- zlib raw DEFLATE payload, as defined in IETF RFC 1951,
encoder is zlib level 5,
- lzma LZMA2 payload inside a XZ container, encoder is
LZMA2 preset 6,
- lz4 raw LZ4 payload inside a simple frame format
(described in compression.h),
- lz4_raw raw LZ4 payload,
- lzfse LZFSE payload.
Enable block compression, and set compression algorithm, valid
options are zlib, lzma, lzfse, lz4. Default is lzfse.
Set block size for block compression. The integer value can be
followed by m or k or b.
Set the number of worker threads to use for block compres-
sion/decompression. Default is the number of logical threads on
Input file. If omitted, read from standard input.
Output file. If omitted, write to standard output.
-v Increase verbosity. Default is silent operation.
-h Print usage and exit.
BLOCK COMPRESSION FILE FORMAT
The file starts with a 4-byte header 'p','b','z',<algo>, where <algo>
indicates the algorithm used to compress data. The header is followed
by the 64-bit block size in bytes. Then for each block, we have 64-bit
uncompressed size (will batch the block size, except possibly for the
last block), 64-bit compressed size, and the compressed payload. If
both uncompressed and compressed sizes for a block are equal, the pay-
load is stored uncompressed. All 64-bit values are stored big-endian.
Valid values for <algo> are: 'z' for zlib, 'x' for lzma, '4' for lz4,
and 'e' for lzfse.