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lzostream

Lzostream is a windows command line tool that uses Oberhumer LZO to compress and decompress files and streams.

It was written with Visual Studio in C++ for Windows and can easy be customized for other platforms.

Usage

Run lzostream.exe in a command line without any arguments for a short help

LZOStream v1.0

Usage: LZOStream <command> [<option>...] [> output] [< input]

<Commands>
    c|compress              Compress    (-i -o -f -h -l)
    d|decompress            Decompress  (-i -o -f -h -b)
    i|info                  Info        (-i -o)

<Options>
    -i|--input <file>       Input file
    -o|--output <file>      Output file
    -f|--format <method>    Compression method (compress/ decompress headerless)
    -h|--headerless         Headerless output (compress)
    -l|--limitless          No limitation (compress: data maybe larger)
    -b|--block <size>       Block size (decompress: headerless)

<Methods>
    Lzo1,  Lzo1_99
    Lzo1a, Lzo1a_99
    Lzo1b, Lzo1b_1 ... Lzo1b_9, Lzo1b_99, Lzo1b_999
    Lzo1c, Lzo1c_1 ... Lzo1c_9, Lzo1c_99, Lzo1c_999
    Lzo1f, Lzo1f_1, Lzo1f_999
    Lzo1x, Lzo1x_1, Lzo1x_1_11, Lzo1x_1_12, Lzo1x_1_15, Lzo1x_999
    Lzo1y, Lzo1y_1, Lzo1y_999
    Lzo1z, Lzo1z_999
    Lzo2a, Lzo2a_999

Command c|compress

Compresses files or streams ('input.txt' is compressed to 'output.lzo')

lzostream c -i input.txt -o output.lzo

You can also stream data ('dir' output is compressed to 'dir.lzo')

dir | lzostream c -o dir.lzo

Command d|decompress

Decompresses files or streams

lzostream d -i input.lzo -o output.txt

Streaming is also possible ('dir.lzo' is decompressed to 'dir.txt')

lzostream d > dir.txt < dir.lzo

Command i|info

Displays header information. An lzostream header is written before the compressed data.

[0x00] HeaderId        : 0x1c4f5a4c (ok)
[0x04] FormatId        : 0xf7a9daf2 Lzo1x_999
[0x08] SourceSize      : 0x0000021b 539 (ok)
[0x0c] DestinationSize : 0x00000446 1094
[0x10] SourceHash      : 0x77908678 (ok)
[0x14] DestinationHash : 0x26c3f2a9
[0x18] HeaderHash      : 0x926eb563 (ok)
[0x1c] ...               0x00000237 567
  • HeaderId is the magic number for the 'Lzostream header'
  • FormatId is the magic number for the compression method
  • SourceSize is the number of bytes for compressed data
  • DestinationSize the number of bytes for uncompressed data
  • SourceHash is the adler32 hash for the compressed data
  • DestinationHash is the adler32 hash for the uncompressed data
  • HeaderHash is the crc32 hash for this header (HeaderHash itself excluded)

Option -i|--input <file>

Specifies the input file. File names with space should be enclosed in quotation marks.

Option -o|--output <file>

Specifies the output file. File names with space should be enclosed in quotation marks.

Option -f|--format <method>

Specifies the compression method. Default compression method is Lzo1x_999. As the used method is part of the lzostream header the correct method is used for decompression. In headerless mode you have to specify the used method.

Option -h|--headerless

In headerless mode, no lzostream header is written during compression. You must specify the compression method and the block size (target size) when decompressing.

Option -l|--limitless

In limitless mode, compression does not check whether the compressed data has become larger. Even ineffective compression method is then used.

Option -b|--block <size>

In headerless decompression you have to specify the size of the decompressed data.

Methods

More information on the possible compression methods can be found at Oberhumer LZO.

License

The source code in this repository is distributed under the terms of GNU General Public License v2. A copy of the GPL license text is part of the repository.

Acknowledgements

We would like to thank Markus Oberhumer Oberhumer LZO who made this work possible. Lzo was integrated with the Nuget package lzo-msvc-x86.