ZarrNET.Crc32cCodec Class Reference

The "crc32c" bytes-to-bytes codec (Zarr v3 spec). More...

Inheritance diagram for ZarrNET.Crc32cCodec:

Public Member Functions
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

The "crc32c" bytes-to-bytes codec (Zarr v3 spec).

On encode: computes CRC32C over the input and appends 4 bytes (little-endian). On decode: reads the trailing 4-byte checksum, validates it against the payload, and returns the payload without the checksum bytes.

This codec is commonly used as an index codec in sharding configurations to protect the shard index integrity.

Uses a self-contained CRC32C implementation (Castagnoli polynomial 0x1EDC6F41) with no external NuGet dependencies.

Member Function Documentation

DecodeAsync()

Task< byte[]> ZarrNET.Crc32cCodec.DecodeAsync	(	byte[]	input,
		CancellationToken	ct = default )

Decodes bytes produced by the previous codec step.

Implements ZarrNET.IZarrCodec.

    {
        ct.ThrowIfCancellationRequested();
 
        if (input.Length < 4)
            throw new InvalidOperationException(
                $"crc32c decode: input is {input.Length} bytes, need at least 4 for the checksum.");
 
        var payloadLength = input.Length - 4;
        var storedHash    = (uint)(input[payloadLength]
                          | (input[payloadLength + 1] << 8)
                          | (input[payloadLength + 2] << 16)
                          | (input[payloadLength + 3] << 24));
 
        var computedHash = Crc32CHash.Compute(input, 0, payloadLength);
 
        if (computedHash != storedHash)
            throw new InvalidOperationException(
                $"crc32c checksum mismatch: stored 0x{storedHash:X8}, " +
                $"computed 0x{computedHash:X8}. The data may be corrupted.");
 
        var result = new byte[payloadLength];
        Array.Copy(input, 0, result, 0, payloadLength);
 
        return Task.FromResult(result);
    }

EncodeAsync()

Task< byte[]> ZarrNET.Crc32cCodec.EncodeAsync	(	byte[]	input,
		CancellationToken	ct = default )

Encodes bytes for the next codec step.

Implements ZarrNET.IZarrCodec.

    {
        ct.ThrowIfCancellationRequested();
 
        var hash   = Crc32CHash.Compute(input, 0, input.Length);
        var result = new byte[input.Length + 4];
 
        Array.Copy(input, 0, result, 0, input.Length);
 
        // Append little-endian uint32
        result[input.Length]     = (byte)(hash);
        result[input.Length + 1] = (byte)(hash >> 8);
        result[input.Length + 2] = (byte)(hash >> 16);
        result[input.Length + 3] = (byte)(hash >> 24);
 
        return Task.FromResult(result);
    }

Property Documentation

Name

string ZarrNET.Crc32cCodec.Name

get

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

Implements ZarrNET.IZarrCodec.

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

• ZarrNET/Crc32cCodec.cs