ZarrNET.BloscCodec Class Reference

Blosc bytes-to-bytes codec. More...

Inheritance diagram for ZarrNET.BloscCodec:

Public Member Functions
	BloscCodec (string cname="lz4", int clevel=5, BloscShuffle shuffle=BloscShuffle.ByteShuffle, int typesize=1, int blocksize=0)
Task< byte[]>	DecodeAsync (byte[] input, CancellationToken ct=default)
	Decodes bytes produced by the previous codec step.
Task< byte[]>	EncodeAsync (byte[] input, CancellationToken ct=default)
	Encodes bytes for the next codec step.
Public Member Functions inherited from ZarrNET.IZarrCodec

Properties
string	Name [get]
	Codec name as it appears in zarr.json (e.g. "gzip", "zstd", "bytes").
Properties inherited from ZarrNET.IZarrCodec

Detailed Description

Blosc bytes-to-bytes codec.

Blosc is a meta-compressor: it applies an optional shuffle filter to improve compressibility, then compresses each block with an inner codec (lz4, zstd, zlib, blosclz, snappy). The 16-byte Blosc1 frame header stores the parameters needed to decode, so decoding is self-describing from the frame alone.

Blosc1 frame layout: [16-byte header] [bstarts table: nblocks x int32] – byte offsets of each block from the start of block data [block data – nblocks contiguous compressed/raw blocks]

Shuffle is applied per-block before compression, so unshuffle must also be per-block.

Supported inner codecs: lz4, lz4hc, zstd, zlib Unsupported (throws NotSupportedException): blosclz, snappy, bit-shuffle, split blocks

NuGet dependencies: K4os.Compression.LZ4 (lz4 / lz4hc inner codec) ZstdSharp.Port (zstd inner codec – already a project dependency)

Constructor & Destructor Documentation

BloscCodec()

ZarrNET.BloscCodec.BloscCodec	(	string	cname = "lz4",
		int	clevel = 5,
		BloscShuffle	shuffle = BloscShuffle::ByteShuffle,
		int	typesize = 1,
		int	blocksize = 0 )

Parameters

cname	Inner compressor name: "lz4", "lz4hc", "zstd", "zlib".
clevel	Compression level. Meaning is inner-codec-specific.
shuffle	Shuffle filter applied before compression.
typesize	Element size in bytes, used by the shuffle filter.
blocksize	Uncompressed block size in bytes. 0 = auto (256 KiB).

    {
        _cname     = ParseInternalCodecName(cname);
        _clevel    = clevel;
        _shuffle   = shuffle;
        _typesize  = Math.Max(1, typesize);
        _blocksize = blocksize;
    }

Member Function Documentation

DecodeAsync()

Task< byte[]> ZarrNET.BloscCodec.DecodeAsync	(	byte[]	input,
		CancellationToken	ct = default )

Decodes bytes produced by the previous codec step.

Implements ZarrNET.IZarrCodec.

    {
        ct.ThrowIfCancellationRequested();
 
        var header = ParseFrameHeader(input);
        var output = new byte[header.UncompressedBytes];
 
        DecompressBlocks(input, header, output);
 
        return Task.FromResult(output);
    }

EncodeAsync()

Task< byte[]> ZarrNET.BloscCodec.EncodeAsync	(	byte[]	input,
		CancellationToken	ct = default )

Encodes bytes for the next codec step.

Implements ZarrNET.IZarrCodec.

    {
        ct.ThrowIfCancellationRequested();
 
        var blockSize  = ResolveBlockSize(_blocksize, input.Length);
        var blockCount = (input.Length + blockSize - 1) / blockSize;
        var frame      = CompressAndWriteFrame(input, blockSize, blockCount);
 
        return Task.FromResult(frame);
    }

Property Documentation

Name

string ZarrNET.BloscCodec.Name

get

Codec name as it appears in zarr.json (e.g. "gzip", "zstd", "bytes").

Implements ZarrNET.IZarrCodec.

---

The documentation for this class was generated from the following file:

• ZarrNET/BloscCodec.cs