Editor/Embedded/Compression/Lz4Chain.cs
An editor-only helper that maintains a rolling 64K LZ4 dictionary and decodes LZ4 blocks into a provided output buffer. It calls a static Lz4.Decode method, updates an internal history buffer capped at 65536 bytes, and exposes DecodeAndDrain and Dispose.
File Access
// Bounded LZ4 block decoding, including the chained 64K dictionary used by binary KV3 blobs.
#nullable enable
using System;
using System.IO;
namespace HumanoidRetargeter.EditorTools.Embedded.Compression;
internal sealed class Lz4Chain : IDisposable
{
byte[] history = Array.Empty<byte>();
public Lz4Chain(int frameSize, int unused) { }
public bool DecodeAndDrain(ReadOnlySpan<byte> input, Span<byte> output, out int decoded)
{
decoded = Lz4.Decode(input, output, history);
var length = Math.Min(65536, history.Length + decoded);
var next = new byte[length];
var copied = Math.Min(decoded, length);
history.AsSpan(history.Length - (length - copied)).CopyTo(next);
output.Slice(decoded - copied, copied).CopyTo(next.AsSpan(length - copied));
history = next;
return true;
}
public void Dispose() { }
}