AyCode.Core/AyCode.Core/Compression/README.md

Compression

Three compression algorithms with a unified static API. All implementations use ArrayPool<byte> and stackalloc for minimal GC pressure.

Key Files

• BrotliHelper.cs — Brotli compress/decompress. Stack-allocates for small inputs, pools for large. IsBrotliCompressed() detection.
• GzipHelper.cs — GZip compress/decompress. Same API shape as BrotliHelper. IsGzipCompressed() checks magic bytes (0x1F, 0x8B).
• Lz4.cs — High-level LZ4 facade. Dispatches to Block or BlockArray mode via Lz4CompressionMode.
• Lz4Compressor.cs — Pure managed LZ4 block compressor. Hash table pattern matching (4K entries, 12-bit hash), MinMatch=4. WASM-compatible (no native dependencies).
• Lz4Decompressor.cs — LZ4 block/BlockArray decompressor. Handles overlapping copies for match references.
• Lz4CompressionMode.cs — Enum: None, Block (single), BlockArray (64KB chunked).

LZ4 Modes

Mode	Use Case
Block	Single contiguous block with 4-byte size header
BlockArray	Chunked (64KB default) for streaming/large data

Dependencies

• System.IO.Compression (Brotli, GZip)
• System.Buffers (ArrayPool)