golzmad

Go LZMA Decoder

This is a Go implementation of the LZMA format, this library contains only the decoder, the encoder can be found here.

The library is a port from the Java LZMA SDK.

Usage

Importing the library

To import the library use the following import path:

import "github.com/giovanibageston/golzmad"

Main Library Functions

Create Decoder:

golzmad.NewDecoder() -> Decoder

Returns a new Decoder object.

Decode:

golzmad.Decode(input, output, outSize, decodeHeader) -> bool, error

Decodes the data on the input io.Reader and writes the result to the output io.Writer.

If the parameter decodeHeader is set to true the function will read the LZMA header from the input io.Reader before decoding the data.

Parameter outSize is the size of the output buffer, if the parameter decodeHeader is set to true the parameter outSize will be overwritten with the size contained in the LZMA header.

SetDecoderProperties:

Sets the parameters of the decoder.

golzmad.SetDecoderProperties(lc, lp, pb, dictionarySize) -> bool

These must be the ones used to encode the file.

• lc = number of literal context bits, default=3, range=[0,8]
• lp = number of literal pos bits, default=0, range=[0,4]
• pb = number of pos bits, default=2, range=[0,4]
• dictionarySize = dictionary size in bytes, default= 223, range=[1, 228], must be a power of 2.

Use Explained

First call the function NewDecoder to instantiate the object:

After the decoder was instantiated you have two options:

-You can call the function Decode and let it read the LZMA header from the io.Reader

-You can call the function SetDecoderProperties to set the decoder properties and then call Decode.

Calling Decode WITHOUT setting the decoder properties

In this case, parameter decodeHeader must be true, this will make the Decoder read the LZMA header from the input, in this case the parameter outSize will be overwritten with the size contained in the LZMA header.

Calling Decode AFTER setting the decoder properties

In this case call SetDecoderProperties to set the decoder properties and then call Decode with the parameter decodeHeader set to false.

in this case the parameter outSize will be used as the size of the output buffer.