ddn.compressor.lzma

LZMA/XZ compression/decompression provider built on ddn-lib-lzma.

This module implements the streaming Compressor and Decompressor interfaces from ddn.api.compressor and registers itself under:

Enum registry: CompressionFormat.XZ
String registry: formatId "xz" with provider name "lib-xz"

The implementation uses liblzma's streaming API (lzma_easy_encoder / lzma_stream_decoder / lzma_code) for true incremental compression and decompression. The produced .xz streams are fully interoperable with the system xz command-line tool.

Provider name convention: vendor "lib", toString() returns "lib-xz".

Copyright

BSD-3-Clause

class LzmaCompressor LzmaDecompressor

fn classifyLzmaError makeLzmaCompressor makeLzmaDecompressor throwLzmaError toLzmaCheck toLzmaLevel

Module Initializers 1

shared static this()

Types 2

classLzmaCompressor : Compressor

LZMA/XZ compressor that implements ddn.api.compressor.Compressor using liblzma's streaming API (lzma_easy_encoder + lzma_code).

Fields

private CompressionOptions _opts

private OutputSink _sink

private bool _finished

private lzma_stream _strm

private ubyte[] _outBuf

private ulong _bytesIn

private ulong _bytesOut

private lzma_ret _lastCode

Methods

CompressionOptions options() @property constReturn the options used to create this compressor.

void setOutputSink(OutputSink sink)Set the output sink delegate.

void setProgressCallback(ProgressCallback callback)Set the progress callback.

ulong bytesInTotal() @property constTotal uncompressed bytes consumed.

ulong bytesOutTotal() @property constTotal compressed bytes produced.

void write(const(ubyte)[] data)Feed uncompressed data into the stream.

void flush(FlushMode mode = FlushMode.SYNC)Flush pending output.

void finish()Finalize the stream.

void reset()Reset the compression context for reuse.

private void applyEncoder()Apply all stored compression parameters by (re-)initialising the encoder.

private size_t drainEncoder(lzma_action action)Run `lzma_code` with the given action and copy produced bytes to `outBuf`.

bool setDictionary(const(ubyte)[] dict)Set a compression dictionary.

bool isFinished() @property constReturns true if finish() has been called.

Constructors

this(CompressionOptions opts)Create a compressor with provided options.

Destructors

~this

classLzmaDecompressor : Decompressor

LZMA/XZ decompressor that implements ddn.api.compressor.Decompressor using liblzma's streaming API (lzma_stream_decoder + lzma_code).

Supports concatenated .xz streams: when input contains multiple streams concatenated together, all streams are decompressed in sequence. Trailing bytes that do not form a valid .xz stream are rejected with a CompressionError.

Fields

private DecompressionOptions _opts

private OutputSink _sink

private bool _finished

private lzma_stream _strm

private ubyte[] _outBuf

private ulong _bytesIn

private ulong _bytesOut

private bool _streamEndSeen

Methods

DecompressionOptions options() @property constReturn the options used to create this decompressor.

void setOutputSink(OutputSink sink)Set the output sink delegate.

void setProgressCallback(ProgressCallback callback)Set the progress callback.

ulong bytesInTotal() @property constTotal compressed bytes consumed.

ulong bytesOutTotal() @property constTotal decompressed bytes produced.

void write(const(ubyte)[] data)Feed compressed data into the stream.

void finish()Finalize the stream.

void reset()Reset the decompression context for reuse.

private void applyDecoder()Apply all stored decompression parameters by (re-)initialising the decoder.

bool setDictionary(const(ubyte)[] dict)Provide a dictionary if required.

bool isFinished() @property constReturns true if finish() has been called.

Constructors

this(DecompressionOptions opts)Create a decompressor with provided options.

Destructors

~this

Functions 6

private fnint toLzmaLevel(CompressionOptions opts)Map `CompressionLevel` / `numericLevel` to an LZMA preset (0..9).

private fnlzma_check toLzmaCheck(ChecksumType cs)Map `ChecksumType` to an `lzma_check` value.

private fnErrorCode classifyLzmaError(lzma_ret rc)Map an `lzma_ret` to the most appropriate `ErrorCode`.

private fnvoid throwLzmaError(lzma_ret rc, string context)Throw a `CompressionError` classified from an `lzma_ret` return code.

fnCompressor makeLzmaCompressor(CompressionOptions opts)Factory function that constructs a `LzmaCompressor`.

fnDecompressor makeLzmaDecompressor(DecompressionOptions opts)Factory function that constructs a `LzmaDecompressor`.