moved source directories into `/src` (#264)

* moved source directories into `/src`
* updated bundle.lua for new `src` path
* moved some docs, icon
* removed old test trees

1 files changed, 1353 insertions, 0 deletions

diff --git a/src/zencore/compress.cpp b/src/zencore/compress.cpp
new file mode 100644
index 000000000..632e0e8f3
--- /dev/null
+++ b/src/zencore/compress.cpp
@@ -0,0 +1,1353 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#include <zencore/compress.h>
+
+#include <zencore/blake3.h>
+#include <zencore/compositebuffer.h>
+#include <zencore/crc32.h>
+#include <zencore/endian.h>
+#include <zencore/iohash.h>
+#include <zencore/testing.h>
+
+#include "../../thirdparty/Oodle/include/oodle2.h"
+#if ZEN_PLATFORM_WINDOWS
+#	pragma comment(lib, "oo2core_win64.lib")
+#endif
+
+#include <lz4.h>
+#include <functional>
+#include <limits>
+
+namespace zen::detail {
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+static constexpr uint64_t DefaultBlockSize = 256 * 1024;
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+/** Method used to compress the data in a compressed buffer. */
+enum class CompressionMethod : uint8_t
+{
+	/** Header is followed by one uncompressed block. */
+	None = 0,
+	/** Header is followed by an array of compressed block sizes then the compressed blocks. */
+	Oodle = 3,
+	/** Header is followed by an array of compressed block sizes then the compressed blocks. */
+	LZ4 = 4,
+};
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+/** Header used on every compressed buffer. Always stored in big-endian format. */
+struct BufferHeader
+{
+	static constexpr uint32_t ExpectedMagic = 0xb7756362;  // <dot>ucb
+
+	uint32_t		  Magic = ExpectedMagic;  // A magic number to identify a compressed buffer. Always 0xb7756362.
+	uint32_t		  Crc32 = 0;			  // A CRC-32 used to check integrity of the buffer. Uses the polynomial 0x04c11db7
+	CompressionMethod Method =
+		CompressionMethod::None;	   // The method used to compress the buffer. Affects layout of data following the header
+	uint8_t	 Compressor			 = 0;  // The method-specific compressor used to compress the buffer.
+	uint8_t	 CompressionLevel	 = 0;  // The method-specific compression level used to compress the buffer.
+	uint8_t	 BlockSizeExponent	 = 0;  // The power of two size of every uncompressed block except the last. Size is 1 << BlockSizeExponent
+	uint32_t BlockCount			 = 0;  // The number of blocks that follow the header
+	uint64_t TotalRawSize		 = 0;  // The total size of the uncompressed data
+	uint64_t TotalCompressedSize = 0;  // The total size of the compressed data including the header
+	BLAKE3	 RawHash;				   // The hash of the uncompressed data
+
+	/** Checks validity of the buffer based on the magic number, method, and CRC-32. */
+	static bool IsValid(const CompositeBuffer& CompressedData, IoHash& OutRawHash, uint64_t& OutRawSize);
+	static bool IsValid(const SharedBuffer& CompressedData, IoHash& OutRawHash, uint64_t& OutRawSize)
+	{
+		return IsValid(CompositeBuffer(CompressedData), OutRawHash, OutRawSize);
+	}
+
+	/** Read a header from a buffer that is at least sizeof(BufferHeader) without any validation. */
+	static BufferHeader Read(const CompositeBuffer& CompressedData)
+	{
+		BufferHeader Header;
+		if (sizeof(BufferHeader) <= CompressedData.GetSize())
+		{
+			//			if (CompressedData.GetSegments()[0].AsIoBuffer().IsWholeFile())
+			//			{
+			//				ZEN_ASSERT(true);
+			//			}
+			CompositeBuffer::Iterator It;
+			CompressedData.CopyTo(MakeMutableMemoryView(&Header, &Header + 1), It);
+			Header.ByteSwap();
+		}
+		return Header;
+	}
+
+	/**
+	 * Write a header to a memory view that is at least sizeof(BufferHeader).
+	 *
+	 * @param HeaderView   View of the header to write, including any method-specific header data.
+	 */
+	void Write(MutableMemoryView HeaderView) const
+	{
+		BufferHeader Header = *this;
+		Header.ByteSwap();
+		HeaderView.CopyFrom(MakeMemoryView(&Header, &Header + 1));
+		Header.ByteSwap();
+		Header.Crc32 = CalculateCrc32(HeaderView);
+		Header.ByteSwap();
+		HeaderView.CopyFrom(MakeMemoryView(&Header, &Header + 1));
+	}
+
+	void ByteSwap()
+	{
+		Magic				= zen::ByteSwap(Magic);
+		Crc32				= zen::ByteSwap(Crc32);
+		BlockCount			= zen::ByteSwap(BlockCount);
+		TotalRawSize		= zen::ByteSwap(TotalRawSize);
+		TotalCompressedSize = zen::ByteSwap(TotalCompressedSize);
+	}
+
+	/** Calculate the CRC-32 from a view of a header including any method-specific header data. */
+	static uint32_t CalculateCrc32(MemoryView HeaderView)
+	{
+		uint32_t		   Crc32		= 0;
+		constexpr uint64_t MethodOffset = offsetof(BufferHeader, Method);
+		for (MemoryView View = HeaderView + MethodOffset; const uint64_t ViewSize = View.GetSize();)
+		{
+			const int32_t Size = static_cast<int32_t>(zen::Min<uint64_t>(ViewSize, /* INT_MAX */ 2147483647u));
+			Crc32			   = zen::MemCrc32(View.GetData(), Size, Crc32);
+			View += Size;
+		}
+		return Crc32;
+	}
+};
+
+static_assert(sizeof(BufferHeader) == 64, "BufferHeader is the wrong size.");
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+class BaseEncoder
+{
+public:
+	virtual CompositeBuffer Compress(const CompositeBuffer& RawData, uint64_t BlockSize = DefaultBlockSize) const = 0;
+};
+
+class BaseDecoder
+{
+public:
+	virtual CompositeBuffer Decompress(const BufferHeader& Header, const CompositeBuffer& CompressedData) const = 0;
+	virtual bool			TryDecompressTo(const BufferHeader&	   Header,
+											const CompositeBuffer& CompressedData,
+											MutableMemoryView	   RawView,
+											uint64_t			   RawOffset) const											= 0;
+	virtual uint64_t		GetHeaderSize(const BufferHeader& Header) const										= 0;
+};
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+class NoneEncoder final : public BaseEncoder
+{
+public:
+	[[nodiscard]] CompositeBuffer Compress(const CompositeBuffer& RawData, uint64_t /* BlockSize */) const final
+	{
+		BufferHeader Header;
+		Header.Method			   = CompressionMethod::None;
+		Header.BlockCount		   = 1;
+		Header.TotalRawSize		   = RawData.GetSize();
+		Header.TotalCompressedSize = Header.TotalRawSize + sizeof(BufferHeader);
+		Header.RawHash			   = BLAKE3::HashBuffer(RawData);
+
+		UniqueBuffer HeaderData = UniqueBuffer::Alloc(sizeof(BufferHeader));
+		Header.Write(HeaderData);
+		return CompositeBuffer(HeaderData.MoveToShared(), RawData.MakeOwned());
+	}
+};
+
+class NoneDecoder final : public BaseDecoder
+{
+public:
+	[[nodiscard]] CompositeBuffer Decompress(const BufferHeader& Header, const CompositeBuffer& CompressedData) const final
+	{
+		if (Header.Method == CompressionMethod::None && Header.TotalCompressedSize == CompressedData.GetSize() &&
+			Header.TotalCompressedSize == Header.TotalRawSize + sizeof(BufferHeader))
+		{
+			return CompressedData.Mid(sizeof(BufferHeader), Header.TotalRawSize).MakeOwned();
+		}
+		return CompositeBuffer();
+	}
+
+	[[nodiscard]] bool TryDecompressTo(const BufferHeader&	  Header,
+									   const CompositeBuffer& CompressedData,
+									   MutableMemoryView	  RawView,
+									   uint64_t				  RawOffset) const final
+	{
+		if (Header.Method == CompressionMethod::None && RawOffset + RawView.GetSize() <= Header.TotalRawSize &&
+			Header.TotalCompressedSize == CompressedData.GetSize() &&
+			Header.TotalCompressedSize == Header.TotalRawSize + sizeof(BufferHeader))
+		{
+			CompressedData.CopyTo(RawView, sizeof(BufferHeader) + RawOffset);
+			return true;
+		}
+		return false;
+	}
+
+	[[nodiscard]] uint64_t GetHeaderSize(const BufferHeader&) const final { return sizeof(BufferHeader); }
+};
+
+//////////////////////////////////////////////////////////////////////////
+
+class BlockEncoder : public BaseEncoder
+{
+public:
+	CompositeBuffer Compress(const CompositeBuffer& RawData, uint64_t BlockSize = DefaultBlockSize) const final;
+
+protected:
+	virtual CompressionMethod GetMethod() const															 = 0;
+	virtual uint8_t			  GetCompressor() const														 = 0;
+	virtual uint8_t			  GetCompressionLevel() const												 = 0;
+	virtual uint64_t		  CompressBlockBound(uint64_t RawSize) const								 = 0;
+	virtual bool			  CompressBlock(MutableMemoryView& CompressedData, MemoryView RawData) const = 0;
+
+private:
+	uint64_t GetCompressedBlocksBound(uint64_t BlockCount, uint64_t BlockSize, uint64_t RawSize) const
+	{
+		switch (BlockCount)
+		{
+			case 0:
+				return 0;
+			case 1:
+				return CompressBlockBound(RawSize);
+			default:
+				return CompressBlockBound(BlockSize) - BlockSize + RawSize;
+		}
+	}
+};
+
+CompositeBuffer
+BlockEncoder::Compress(const CompositeBuffer& RawData, const uint64_t BlockSize) const
+{
+	ZEN_ASSERT(IsPow2(BlockSize) && (BlockSize <= (1u << 31)));
+
+	const uint64_t RawSize = RawData.GetSize();
+	BLAKE3Stream   RawHash;
+
+	const uint64_t BlockCount = RoundUp(RawSize, BlockSize) / BlockSize;
+	ZEN_ASSERT(BlockCount <= ~uint32_t(0));
+
+	// Allocate the buffer for the header, metadata, and compressed blocks.
+	const uint64_t MetaSize			  = BlockCount * sizeof(uint32_t);
+	const uint64_t CompressedDataSize = sizeof(BufferHeader) + MetaSize + GetCompressedBlocksBound(BlockCount, BlockSize, RawSize);
+	UniqueBuffer   CompressedData	  = UniqueBuffer::Alloc(CompressedDataSize);
+
+	// Compress the raw data in blocks and store the raw data for incompressible blocks.
+	std::vector<uint32_t> CompressedBlockSizes;
+	CompressedBlockSizes.reserve(BlockCount);
+	uint64_t CompressedSize = 0;
+	{
+		UniqueBuffer	  RawBlockCopy;
+		MutableMemoryView CompressedBlocksView = CompressedData.GetMutableView() + sizeof(BufferHeader) + MetaSize;
+
+		CompositeBuffer::Iterator It = RawData.GetIterator(0);
+
+		for (uint64_t RawOffset = 0; RawOffset < RawSize;)
+		{
+			const uint64_t	 RawBlockSize = zen::Min(RawSize - RawOffset, BlockSize);
+			const MemoryView RawBlock	  = RawData.ViewOrCopyRange(It, RawBlockSize, RawBlockCopy);
+			RawHash.Append(RawBlock);
+
+			MutableMemoryView CompressedBlock = CompressedBlocksView;
+			if (!CompressBlock(CompressedBlock, RawBlock))
+			{
+				return CompositeBuffer();
+			}
+
+			uint64_t CompressedBlockSize = CompressedBlock.GetSize();
+			if (RawBlockSize <= CompressedBlockSize)
+			{
+				CompressedBlockSize	 = RawBlockSize;
+				CompressedBlocksView = CompressedBlocksView.CopyFrom(RawBlock);
+			}
+			else
+			{
+				CompressedBlocksView += CompressedBlockSize;
+			}
+
+			CompressedBlockSizes.push_back(static_cast<uint32_t>(CompressedBlockSize));
+			CompressedSize += CompressedBlockSize;
+			RawOffset += RawBlockSize;
+		}
+	}
+
+	// Return an uncompressed buffer if the compressed data is larger than the raw data.
+	if (RawSize <= MetaSize + CompressedSize)
+	{
+		CompressedData.Reset();
+		return NoneEncoder().Compress(RawData, BlockSize);
+	}
+
+	// Write the header and calculate the CRC-32.
+	for (uint32_t& Size : CompressedBlockSizes)
+	{
+		Size = ByteSwap(Size);
+	}
+	CompressedData.GetMutableView().Mid(sizeof(BufferHeader), MetaSize).CopyFrom(MakeMemoryView(CompressedBlockSizes));
+
+	BufferHeader Header;
+	Header.Method			   = GetMethod();
+	Header.Compressor		   = GetCompressor();
+	Header.CompressionLevel	   = GetCompressionLevel();
+	Header.BlockSizeExponent   = static_cast<uint8_t>(zen::FloorLog2_64(BlockSize));
+	Header.BlockCount		   = static_cast<uint32_t>(BlockCount);
+	Header.TotalRawSize		   = RawSize;
+	Header.TotalCompressedSize = sizeof(BufferHeader) + MetaSize + CompressedSize;
+	Header.RawHash			   = RawHash.GetHash();
+	Header.Write(CompressedData.GetMutableView().Left(sizeof(BufferHeader) + MetaSize));
+
+	const MemoryView CompositeView = CompressedData.GetView().Left(Header.TotalCompressedSize);
+	return CompositeBuffer(SharedBuffer::MakeView(CompositeView, CompressedData.MoveToShared()));
+}
+
+class BlockDecoder : public BaseDecoder
+{
+public:
+	CompositeBuffer		   Decompress(const BufferHeader& Header, const CompositeBuffer& CompressedData) const final;
+	[[nodiscard]] bool	   TryDecompressTo(const BufferHeader&	  Header,
+										   const CompositeBuffer& CompressedData,
+										   MutableMemoryView	  RawView,
+										   uint64_t				  RawOffset) const final;
+	[[nodiscard]] uint64_t GetHeaderSize(const BufferHeader& Header) const final
+	{
+		return sizeof(BufferHeader) + sizeof(uint32_t) * uint64_t(Header.BlockCount);
+	}
+
+protected:
+	virtual bool DecompressBlock(MutableMemoryView RawData, MemoryView CompressedData) const = 0;
+};
+
+CompositeBuffer
+BlockDecoder::Decompress(const BufferHeader& Header, const CompositeBuffer& CompressedData) const
+{
+	if (Header.BlockCount == 0 || Header.TotalCompressedSize != CompressedData.GetSize())
+	{
+		return CompositeBuffer();
+	}
+
+	// The raw data cannot reference the compressed data unless it is owned.
+	// An empty raw buffer requires an empty segment, which this path creates.
+	if (!CompressedData.IsOwned() || Header.TotalRawSize == 0)
+	{
+		UniqueBuffer Buffer = UniqueBuffer::Alloc(Header.TotalRawSize);
+		return TryDecompressTo(Header, CompressedData, Buffer, 0) ? CompositeBuffer(Buffer.MoveToShared()) : CompositeBuffer();
+	}
+
+	std::vector<uint32_t> CompressedBlockSizes;
+	CompressedBlockSizes.resize(Header.BlockCount);
+	CompressedData.CopyTo(MakeMutableMemoryView(CompressedBlockSizes), sizeof(BufferHeader));
+
+	for (uint32_t& Size : CompressedBlockSizes)
+	{
+		Size = ByteSwap(Size);
+	}
+
+	// Allocate the buffer for the raw blocks that were compressed.
+	SharedBuffer	  RawData;
+	MutableMemoryView RawDataView;
+	const uint64_t	  BlockSize = uint64_t(1) << Header.BlockSizeExponent;
+	{
+		uint64_t RawDataSize	  = 0;
+		uint64_t RemainingRawSize = Header.TotalRawSize;
+		for (const uint32_t CompressedBlockSize : CompressedBlockSizes)
+		{
+			const uint64_t RawBlockSize = zen::Min(RemainingRawSize, BlockSize);
+			if (CompressedBlockSize < BlockSize)
+			{
+				RawDataSize += RawBlockSize;
+			}
+			RemainingRawSize -= RawBlockSize;
+		}
+		UniqueBuffer RawDataBuffer = UniqueBuffer::Alloc(RawDataSize);
+		RawDataView				   = RawDataBuffer;
+		RawData					   = RawDataBuffer.MoveToShared();
+	}
+
+	// Decompress the compressed data in blocks and reference the uncompressed blocks.
+	uint64_t				  PendingCompressedSegmentOffset = sizeof(BufferHeader) + uint64_t(Header.BlockCount) * sizeof(uint32_t);
+	uint64_t				  PendingCompressedSegmentSize	 = 0;
+	uint64_t				  PendingRawSegmentOffset		 = 0;
+	uint64_t				  PendingRawSegmentSize			 = 0;
+	std::vector<SharedBuffer> Segments;
+
+	const auto CommitPendingCompressedSegment =
+		[&PendingCompressedSegmentOffset, &PendingCompressedSegmentSize, &CompressedData, &Segments] {
+			if (PendingCompressedSegmentSize)
+			{
+				CompressedData.IterateRange(PendingCompressedSegmentOffset,
+											PendingCompressedSegmentSize,
+											[&Segments](MemoryView View, const SharedBuffer& ViewOuter) {
+												Segments.push_back(SharedBuffer::MakeView(View, ViewOuter));
+											});
+				PendingCompressedSegmentOffset += PendingCompressedSegmentSize;
+				PendingCompressedSegmentSize = 0;
+			}
+		};
+
+	const auto CommitPendingRawSegment = [&PendingRawSegmentOffset, &PendingRawSegmentSize, &RawData, &Segments] {
+		if (PendingRawSegmentSize)
+		{
+			const MemoryView PendingSegment = RawData.GetView().Mid(PendingRawSegmentOffset, PendingRawSegmentSize);
+			Segments.push_back(SharedBuffer::MakeView(PendingSegment, RawData));
+			PendingRawSegmentOffset += PendingRawSegmentSize;
+			PendingRawSegmentSize = 0;
+		}
+	};
+
+	UniqueBuffer CompressedBlockCopy;
+	uint64_t	 RemainingRawSize		 = Header.TotalRawSize;
+	uint64_t	 RemainingCompressedSize = CompressedData.GetSize();
+	for (const uint32_t CompressedBlockSize : CompressedBlockSizes)
+	{
+		if (RemainingCompressedSize < CompressedBlockSize)
+		{
+			return CompositeBuffer();
+		}
+
+		const uint64_t RawBlockSize = zen::Min(RemainingRawSize, BlockSize);
+		if (RawBlockSize == CompressedBlockSize)
+		{
+			CommitPendingRawSegment();
+			PendingCompressedSegmentSize += RawBlockSize;
+		}
+		else
+		{
+			CommitPendingCompressedSegment();
+			const MemoryView CompressedBlock =
+				CompressedData.ViewOrCopyRange(PendingCompressedSegmentOffset, CompressedBlockSize, CompressedBlockCopy);
+			if (!DecompressBlock(RawDataView.Left(RawBlockSize), CompressedBlock))
+			{
+				return CompositeBuffer();
+			}
+			PendingCompressedSegmentOffset += CompressedBlockSize;
+			PendingRawSegmentSize += RawBlockSize;
+			RawDataView += RawBlockSize;
+		}
+
+		RemainingCompressedSize -= CompressedBlockSize;
+		RemainingRawSize -= RawBlockSize;
+	}
+
+	CommitPendingCompressedSegment();
+	CommitPendingRawSegment();
+
+	return CompositeBuffer(std::move(Segments));
+}
+
+bool
+BlockDecoder::TryDecompressTo(const BufferHeader&	 Header,
+							  const CompositeBuffer& CompressedData,
+							  MutableMemoryView		 RawView,
+							  uint64_t				 RawOffset) const
+{
+	if (Header.TotalRawSize < RawOffset + RawView.GetSize() || Header.TotalCompressedSize != CompressedData.GetSize())
+	{
+		return false;
+	}
+
+	const uint64_t BlockSize = uint64_t(1) << Header.BlockSizeExponent;
+
+	UniqueBuffer BlockSizeBuffer;
+	MemoryView BlockSizeView = CompressedData.ViewOrCopyRange(sizeof(BufferHeader), Header.BlockCount * sizeof(uint32_t), BlockSizeBuffer);
+	std::span<uint32_t const> CompressedBlockSizes(reinterpret_cast<const uint32_t*>(BlockSizeView.GetData()), Header.BlockCount);
+
+	UniqueBuffer CompressedBlockCopy;
+	UniqueBuffer UncompressedBlockCopy;
+
+	const size_t   FirstBlockIndex	  = uint64_t(RawOffset / BlockSize);
+	const size_t   LastBlockIndex	  = uint64_t((RawOffset + RawView.GetSize() - 1) / BlockSize);
+	const uint64_t LastBlockSize	  = BlockSize - ((Header.BlockCount * BlockSize) - Header.TotalRawSize);
+	uint64_t	   OffsetInFirstBlock = RawOffset % BlockSize;
+	uint64_t	   CompressedOffset	  = sizeof(BufferHeader) + uint64_t(Header.BlockCount) * sizeof(uint32_t);
+	uint64_t	   RemainingRawSize	  = RawView.GetSize();
+
+	for (size_t BlockIndex = 0; BlockIndex < FirstBlockIndex; BlockIndex++)
+	{
+		const uint32_t CompressedBlockSize = ByteSwap(CompressedBlockSizes[BlockIndex]);
+		CompressedOffset += CompressedBlockSize;
+	}
+
+	for (size_t BlockIndex = FirstBlockIndex; BlockIndex <= LastBlockIndex; BlockIndex++)
+	{
+		const uint64_t UncompressedBlockSize = BlockIndex == Header.BlockCount - 1 ? LastBlockSize : BlockSize;
+		const uint32_t CompressedBlockSize	 = ByteSwap(CompressedBlockSizes[BlockIndex]);
+		const bool	   IsCompressed			 = CompressedBlockSize < UncompressedBlockSize;
+
+		const uint64_t BytesToUncompress = OffsetInFirstBlock > 0 ? zen::Min(RawView.GetSize(), UncompressedBlockSize - OffsetInFirstBlock)
+																  : zen::Min(RemainingRawSize, BlockSize);
+
+		MemoryView CompressedBlock = CompressedData.ViewOrCopyRange(CompressedOffset, CompressedBlockSize, CompressedBlockCopy);
+
+		if (IsCompressed)
+		{
+			MutableMemoryView UncompressedBlock = RawView.Left(BytesToUncompress);
+
+			const bool IsAligned = BytesToUncompress == UncompressedBlockSize;
+			if (!IsAligned)
+			{
+				// Decompress to a temporary buffer when the first or the last block reads are not aligned with the block boundaries.
+				if (UncompressedBlockCopy.IsNull())
+				{
+					UncompressedBlockCopy = UniqueBuffer::Alloc(BlockSize);
+				}
+				UncompressedBlock = UncompressedBlockCopy.GetMutableView().Mid(0, UncompressedBlockSize);
+			}
+
+			if (!DecompressBlock(UncompressedBlock, CompressedBlock))
+			{
+				return false;
+			}
+
+			if (!IsAligned)
+			{
+				RawView.CopyFrom(UncompressedBlock.Mid(OffsetInFirstBlock, BytesToUncompress));
+			}
+		}
+		else
+		{
+			RawView.CopyFrom(CompressedBlock.Mid(OffsetInFirstBlock, BytesToUncompress));
+		}
+
+		OffsetInFirstBlock = 0;
+		RemainingRawSize -= BytesToUncompress;
+		CompressedOffset += CompressedBlockSize;
+		RawView += BytesToUncompress;
+	}
+
+	return RemainingRawSize == 0;
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+struct OodleInit
+{
+	OodleInit()
+	{
+		OodleConfigValues Config;
+		Oodle_GetConfigValues(&Config);
+		// Always read/write Oodle v9 binary data.
+		Config.m_OodleLZ_BackwardsCompatible_MajorVersion = 9;
+		Oodle_SetConfigValues(&Config);
+	}
+};
+
+OodleInit InitOodle;
+
+class OodleEncoder final : public BlockEncoder
+{
+public:
+	OodleEncoder(OodleCompressor InCompressor, OodleCompressionLevel InCompressionLevel)
+	: Compressor(InCompressor)
+	, CompressionLevel(InCompressionLevel)
+	{
+	}
+
+protected:
+	CompressionMethod GetMethod() const final { return CompressionMethod::Oodle; }
+	uint8_t			  GetCompressor() const final { return static_cast<uint8_t>(Compressor); }
+	uint8_t			  GetCompressionLevel() const final { return static_cast<uint8_t>(CompressionLevel); }
+
+	uint64_t CompressBlockBound(uint64_t RawSize) const final
+	{
+		return static_cast<uint64_t>(OodleLZ_GetCompressedBufferSizeNeeded(OodleLZ_Compressor_Kraken, static_cast<OO_SINTa>(RawSize)));
+	}
+
+	bool CompressBlock(MutableMemoryView& CompressedData, MemoryView RawData) const final
+	{
+		const OodleLZ_Compressor	   LZCompressor		  = GetOodleLZCompressor(Compressor);
+		const OodleLZ_CompressionLevel LZCompressionLevel = GetOodleLZCompressionLevel(CompressionLevel);
+		if (LZCompressor == OodleLZ_Compressor_Invalid || LZCompressionLevel == OodleLZ_CompressionLevel_Invalid ||
+			LZCompressionLevel == OodleLZ_CompressionLevel_None)
+		{
+			return false;
+		}
+
+		const OO_SINTa RawSize = static_cast<OO_SINTa>(RawData.GetSize());
+		if (static_cast<OO_SINTa>(CompressedData.GetSize()) < OodleLZ_GetCompressedBufferSizeNeeded(LZCompressor, RawSize))
+		{
+			return false;
+		}
+
+		const OO_SINTa Size = OodleLZ_Compress(LZCompressor, RawData.GetData(), RawSize, CompressedData.GetData(), LZCompressionLevel);
+		CompressedData.LeftInline(static_cast<uint64_t>(Size));
+		return Size > 0;
+	}
+
+	static OodleLZ_Compressor GetOodleLZCompressor(OodleCompressor Compressor)
+	{
+		switch (Compressor)
+		{
+			case OodleCompressor::Selkie:
+				return OodleLZ_Compressor_Selkie;
+			case OodleCompressor::Mermaid:
+				return OodleLZ_Compressor_Mermaid;
+			case OodleCompressor::Kraken:
+				return OodleLZ_Compressor_Kraken;
+			case OodleCompressor::Leviathan:
+				return OodleLZ_Compressor_Leviathan;
+			case OodleCompressor::NotSet:
+			default:
+				return OodleLZ_Compressor_Invalid;
+		}
+	}
+
+	static OodleLZ_CompressionLevel GetOodleLZCompressionLevel(OodleCompressionLevel Level)
+	{
+		const int IntLevel = (int)Level;
+		if (IntLevel < (int)OodleLZ_CompressionLevel_Min || IntLevel > (int)OodleLZ_CompressionLevel_Max)
+		{
+			return OodleLZ_CompressionLevel_Invalid;
+		}
+		return OodleLZ_CompressionLevel(IntLevel);
+	}
+
+private:
+	const OodleCompressor		Compressor;
+	const OodleCompressionLevel CompressionLevel;
+};
+
+class OodleDecoder final : public BlockDecoder
+{
+protected:
+	bool DecompressBlock(MutableMemoryView RawData, MemoryView CompressedData) const final
+	{
+		const OO_SINTa RawSize = static_cast<OO_SINTa>(RawData.GetSize());
+		const OO_SINTa Size	   = OodleLZ_Decompress(CompressedData.GetData(),
+													static_cast<OO_SINTa>(CompressedData.GetSize()),
+													RawData.GetData(),
+													RawSize,
+													OodleLZ_FuzzSafe_Yes,
+													OodleLZ_CheckCRC_Yes,
+													OodleLZ_Verbosity_None);
+		return Size == RawSize;
+	}
+};
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+class LZ4Decoder final : public BlockDecoder
+{
+protected:
+	bool DecompressBlock(MutableMemoryView RawData, MemoryView CompressedData) const final
+	{
+		if (CompressedData.GetSize() <= std::numeric_limits<int>::max())
+		{
+			const int Size = LZ4_decompress_safe(static_cast<const char*>(CompressedData.GetData()),
+												 static_cast<char*>(RawData.GetData()),
+												 static_cast<int>(CompressedData.GetSize()),
+												 static_cast<int>(zen::Min<uint64_t>(RawData.GetSize(), uint64_t(LZ4_MAX_INPUT_SIZE))));
+			return static_cast<uint64_t>(Size) == RawData.GetSize();
+		}
+		return false;
+	}
+};
+
+//////////////////////////////////////////////////////////////////////////
+
+static const BaseDecoder*
+GetDecoder(CompressionMethod Method)
+{
+	static NoneDecoder	None;
+	static OodleDecoder Oodle;
+	static LZ4Decoder	LZ4;
+
+	switch (Method)
+	{
+		default:
+			return nullptr;
+		case CompressionMethod::None:
+			return &None;
+		case CompressionMethod::Oodle:
+			return &Oodle;
+		case CompressionMethod::LZ4:
+			return &LZ4;
+	}
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+bool
+BufferHeader::IsValid(const CompositeBuffer& CompressedData, IoHash& OutRawHash, uint64_t& OutRawSize)
+{
+	uint64_t Size = CompressedData.GetSize();
+	if (Size < sizeof(BufferHeader))
+	{
+		return false;
+	}
+	const size_t  StackBufferSize = 256;
+	uint8_t		  StackBuffer[StackBufferSize];
+	uint64_t	  ReadSize = Min(Size, StackBufferSize);
+	BufferHeader* Header   = reinterpret_cast<BufferHeader*>(StackBuffer);
+	{
+		CompositeBuffer::Iterator It;
+		CompressedData.CopyTo(MutableMemoryView(StackBuffer, StackBuffer + StackBufferSize), It);
+	}
+	Header->ByteSwap();
+	if (Header->Magic != BufferHeader::ExpectedMagic)
+	{
+		return false;
+	}
+	const BaseDecoder* const Decoder = GetDecoder(Header->Method);
+	if (!Decoder)
+	{
+		return false;
+	}
+	uint32_t Crc32		= Header->Crc32;
+	OutRawHash			= IoHash::FromBLAKE3(Header->RawHash);
+	OutRawSize			= Header->TotalRawSize;
+	uint64_t HeaderSize = Decoder->GetHeaderSize(*Header);
+	Header->ByteSwap();
+
+	if (HeaderSize > ReadSize)
+	{
+		// 0.004% of cases on a Fortnite hot cache cook
+		UniqueBuffer			  HeaderCopy = UniqueBuffer::Alloc(HeaderSize);
+		CompositeBuffer::Iterator It;
+		CompressedData.CopyTo(HeaderCopy.GetMutableView(), It);
+		const MemoryView HeaderView = HeaderCopy.GetView();
+		if (Crc32 != BufferHeader::CalculateCrc32(HeaderView))
+		{
+			return false;
+		}
+	}
+	else
+	{
+		MemoryView FullHeaderView(StackBuffer, StackBuffer + HeaderSize);
+		if (Crc32 != BufferHeader::CalculateCrc32(FullHeaderView))
+		{
+			return false;
+		}
+	}
+	return true;
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+template<typename BufferType>
+inline CompositeBuffer
+ValidBufferOrEmpty(BufferType&& CompressedData, IoHash& OutRawHash, uint64_t& OutRawSize)
+{
+	return BufferHeader::IsValid(CompressedData, OutRawHash, OutRawSize) ? CompositeBuffer(std::forward<BufferType>(CompressedData))
+																		 : CompositeBuffer();
+}
+
+CompositeBuffer
+CopyCompressedRange(const BufferHeader& Header, const CompositeBuffer& CompressedData, uint64_t RawOffset, uint64_t RawSize)
+{
+	if (Header.TotalRawSize < RawOffset + RawSize)
+	{
+		return CompositeBuffer();
+	}
+
+	if (Header.Method == CompressionMethod::None)
+	{
+		UniqueBuffer NewCompressedData = UniqueBuffer::Alloc(RawSize);
+		CompressedData.CopyTo(NewCompressedData.GetMutableView(), sizeof(Header) + RawOffset);
+
+		BufferHeader NewHeader		  = Header;
+		NewHeader.Crc32				  = 0;
+		NewHeader.TotalRawSize		  = RawSize;
+		NewHeader.TotalCompressedSize = NewHeader.TotalRawSize + sizeof(BufferHeader);
+		NewHeader.RawHash			  = BLAKE3();
+
+		UniqueBuffer HeaderData = UniqueBuffer::Alloc(sizeof(BufferHeader));
+		NewHeader.Write(HeaderData);
+
+		return CompositeBuffer(HeaderData.MoveToShared(), NewCompressedData.MoveToShared());
+	}
+	else
+	{
+		UniqueBuffer BlockSizeBuffer;
+		MemoryView	 BlockSizeView =
+			CompressedData.ViewOrCopyRange(sizeof(BufferHeader), Header.BlockCount * sizeof(uint32_t), BlockSizeBuffer);
+		std::span<uint32_t const> CompressedBlockSizes(reinterpret_cast<const uint32_t*>(BlockSizeView.GetData()), Header.BlockCount);
+
+		const uint64_t BlockSize		= uint64_t(1) << Header.BlockSizeExponent;
+		const uint64_t LastBlockSize	= BlockSize - ((Header.BlockCount * BlockSize) - Header.TotalRawSize);
+		const size_t   FirstBlock		= uint64_t(RawOffset / BlockSize);
+		const size_t   LastBlock		= uint64_t((RawOffset + RawSize - 1) / BlockSize);
+		uint64_t	   CompressedOffset = sizeof(BufferHeader) + uint64_t(Header.BlockCount) * sizeof(uint32_t);
+
+		const uint64_t		  NewBlockCount		= LastBlock - FirstBlock + 1;
+		const uint64_t		  NewMetaSize		= NewBlockCount * sizeof(uint32_t);
+		uint64_t			  NewCompressedSize = 0;
+		uint64_t			  NewTotalRawSize	= 0;
+		std::vector<uint32_t> NewCompressedBlockSizes;
+
+		NewCompressedBlockSizes.reserve(NewBlockCount);
+		for (size_t BlockIndex = FirstBlock; BlockIndex <= LastBlock; ++BlockIndex)
+		{
+			const uint64_t UncompressedBlockSize = (BlockIndex == Header.BlockCount - 1) ? LastBlockSize : BlockSize;
+			NewTotalRawSize += UncompressedBlockSize;
+
+			const uint32_t CompressedBlockSize = CompressedBlockSizes[BlockIndex];
+			NewCompressedBlockSizes.push_back(CompressedBlockSize);
+			NewCompressedSize += ByteSwap(CompressedBlockSize);
+		}
+
+		const uint64_t	  NewTotalCompressedSize = sizeof(BufferHeader) + NewBlockCount * sizeof(uint32_t) + NewCompressedSize;
+		UniqueBuffer	  NewCompressedData		 = UniqueBuffer::Alloc(NewTotalCompressedSize);
+		MutableMemoryView NewCompressedBlocks	 = NewCompressedData.GetMutableView() + sizeof(BufferHeader) + NewMetaSize;
+
+		// Seek to first compressed block
+		for (size_t BlockIndex = 0; BlockIndex < FirstBlock; ++BlockIndex)
+		{
+			const uint64_t CompressedBlockSize = ByteSwap(CompressedBlockSizes[BlockIndex]);
+			CompressedOffset += CompressedBlockSize;
+		}
+
+		// Copy blocks
+		UniqueBuffer	 CompressedBlockCopy;
+		const MemoryView CompressedRange = CompressedData.ViewOrCopyRange(CompressedOffset, NewCompressedSize, CompressedBlockCopy);
+		NewCompressedBlocks.CopyFrom(CompressedRange);
+
+		// Copy block sizes
+		NewCompressedData.GetMutableView().Mid(sizeof(BufferHeader), NewMetaSize).CopyFrom(MakeMemoryView(NewCompressedBlockSizes));
+
+		BufferHeader NewHeader;
+		NewHeader.Crc32				  = 0;
+		NewHeader.Method			  = Header.Method;
+		NewHeader.Compressor		  = Header.Compressor;
+		NewHeader.CompressionLevel	  = Header.CompressionLevel;
+		NewHeader.BlockSizeExponent	  = Header.BlockSizeExponent;
+		NewHeader.BlockCount		  = static_cast<uint32_t>(NewBlockCount);
+		NewHeader.TotalRawSize		  = NewTotalRawSize;
+		NewHeader.TotalCompressedSize = NewTotalCompressedSize;
+		NewHeader.RawHash			  = BLAKE3();
+		NewHeader.Write(NewCompressedData.GetMutableView().Left(sizeof(BufferHeader) + NewMetaSize));
+
+		return CompositeBuffer(NewCompressedData.MoveToShared());
+	}
+}
+
+}  // namespace zen::detail
+
+namespace zen {
+
+const CompressedBuffer CompressedBuffer::Null;
+
+CompressedBuffer
+CompressedBuffer::Compress(const CompositeBuffer& RawData,
+						   OodleCompressor		  Compressor,
+						   OodleCompressionLevel  CompressionLevel,
+						   uint64_t				  BlockSize)
+{
+	using namespace detail;
+
+	if (BlockSize == 0)
+	{
+		BlockSize = DefaultBlockSize;
+	}
+
+	CompressedBuffer Local;
+	if (CompressionLevel == OodleCompressionLevel::None)
+	{
+		Local.CompressedData = NoneEncoder().Compress(RawData, BlockSize);
+	}
+	else
+	{
+		Local.CompressedData = OodleEncoder(Compressor, CompressionLevel).Compress(RawData, BlockSize);
+	}
+	return Local;
+}
+
+CompressedBuffer
+CompressedBuffer::Compress(const SharedBuffer&	 RawData,
+						   OodleCompressor		 Compressor,
+						   OodleCompressionLevel CompressionLevel,
+						   uint64_t				 BlockSize)
+{
+	return Compress(CompositeBuffer(RawData), Compressor, CompressionLevel, BlockSize);
+}
+
+CompressedBuffer
+CompressedBuffer::FromCompressed(const CompositeBuffer& InCompressedData, IoHash& OutRawHash, uint64_t& OutRawSize)
+{
+	CompressedBuffer Local;
+	Local.CompressedData = detail::ValidBufferOrEmpty(InCompressedData, OutRawHash, OutRawSize);
+	return Local;
+}
+
+CompressedBuffer
+CompressedBuffer::FromCompressed(CompositeBuffer&& InCompressedData, IoHash& OutRawHash, uint64_t& OutRawSize)
+{
+	CompressedBuffer Local;
+	Local.CompressedData = detail::ValidBufferOrEmpty(std::move(InCompressedData), OutRawHash, OutRawSize);
+	return Local;
+}
+
+CompressedBuffer
+CompressedBuffer::FromCompressed(const SharedBuffer& InCompressedData, IoHash& OutRawHash, uint64_t& OutRawSize)
+{
+	CompressedBuffer Local;
+	Local.CompressedData = detail::ValidBufferOrEmpty(InCompressedData, OutRawHash, OutRawSize);
+	return Local;
+}
+
+CompressedBuffer
+CompressedBuffer::FromCompressed(SharedBuffer&& InCompressedData, IoHash& OutRawHash, uint64_t& OutRawSize)
+{
+	CompressedBuffer Local;
+	Local.CompressedData = detail::ValidBufferOrEmpty(std::move(InCompressedData), OutRawHash, OutRawSize);
+	return Local;
+}
+
+CompressedBuffer
+CompressedBuffer::FromCompressedNoValidate(IoBuffer&& InCompressedData)
+{
+	if (InCompressedData.GetSize() <= sizeof(detail::BufferHeader))
+	{
+		return CompressedBuffer();
+	}
+	CompressedBuffer Local;
+	Local.CompressedData = CompositeBuffer(SharedBuffer(std::move(InCompressedData)));
+	return Local;
+}
+
+CompressedBuffer
+CompressedBuffer::FromCompressedNoValidate(CompositeBuffer&& InCompressedData)
+{
+	if (InCompressedData.GetSize() <= sizeof(detail::BufferHeader))
+	{
+		return CompressedBuffer();
+	}
+	CompressedBuffer Local;
+	Local.CompressedData = std::move(InCompressedData);
+	return Local;
+}
+
+bool
+CompressedBuffer::ValidateCompressedHeader(IoBuffer&& CompressedData, IoHash& OutRawHash, uint64_t& OutRawSize)
+{
+	return detail::BufferHeader::IsValid(SharedBuffer(std::move(CompressedData)), OutRawHash, OutRawSize);
+}
+
+bool
+CompressedBuffer::ValidateCompressedHeader(const IoBuffer& CompressedData, IoHash& OutRawHash, uint64_t& OutRawSize)
+{
+	return detail::BufferHeader::IsValid(SharedBuffer(CompressedData), OutRawHash, OutRawSize);
+}
+
+uint64_t
+CompressedBuffer::DecodeRawSize() const
+{
+	return CompressedData ? detail::BufferHeader::Read(CompressedData).TotalRawSize : 0;
+}
+
+IoHash
+CompressedBuffer::DecodeRawHash() const
+{
+	return CompressedData ? IoHash::FromBLAKE3(detail::BufferHeader::Read(CompressedData).RawHash) : IoHash();
+}
+
+CompressedBuffer
+CompressedBuffer::CopyRange(uint64_t RawOffset, uint64_t RawSize) const
+{
+	using namespace detail;
+	const BufferHeader Header		= BufferHeader::Read(CompressedData);
+	const uint64_t	   TotalRawSize = RawSize < ~uint64_t(0) ? RawSize : Header.TotalRawSize - RawOffset;
+
+	CompressedBuffer Range;
+	Range.CompressedData = CopyCompressedRange(Header, CompressedData, RawOffset, TotalRawSize);
+
+	return Range;
+}
+
+bool
+CompressedBuffer::TryDecompressTo(MutableMemoryView RawView, uint64_t RawOffset) const
+{
+	using namespace detail;
+	if (CompressedData)
+	{
+		const BufferHeader Header = BufferHeader::Read(CompressedData);
+		if (Header.Magic == BufferHeader::ExpectedMagic)
+		{
+			if (const BaseDecoder* const Decoder = GetDecoder(Header.Method))
+			{
+				return Decoder->TryDecompressTo(Header, CompressedData, RawView, RawOffset);
+			}
+		}
+	}
+	return false;
+}
+
+SharedBuffer
+CompressedBuffer::Decompress(uint64_t RawOffset, uint64_t RawSize) const
+{
+	using namespace detail;
+	if (CompressedData && RawSize > 0)
+	{
+		const BufferHeader Header = BufferHeader::Read(CompressedData);
+		if (Header.Magic == BufferHeader::ExpectedMagic)
+		{
+			if (const BaseDecoder* const Decoder = GetDecoder(Header.Method))
+			{
+				const uint64_t TotalRawSize = RawSize < ~uint64_t(0) ? RawSize : Header.TotalRawSize - RawOffset;
+				UniqueBuffer   RawData		= UniqueBuffer::Alloc(TotalRawSize);
+				if (Decoder->TryDecompressTo(Header, CompressedData, RawData, RawOffset))
+				{
+					return RawData.MoveToShared();
+				}
+			}
+		}
+	}
+	return SharedBuffer();
+}
+
+CompositeBuffer
+CompressedBuffer::DecompressToComposite() const
+{
+	using namespace detail;
+	if (CompressedData)
+	{
+		const BufferHeader Header = BufferHeader::Read(CompressedData);
+		if (Header.Magic == BufferHeader::ExpectedMagic)
+		{
+			if (const BaseDecoder* const Decoder = GetDecoder(Header.Method))
+			{
+				return Decoder->Decompress(Header, CompressedData);
+			}
+		}
+	}
+	return CompositeBuffer();
+}
+
+bool
+CompressedBuffer::TryGetCompressParameters(OodleCompressor&		  OutCompressor,
+										   OodleCompressionLevel& OutCompressionLevel,
+										   uint64_t&			  OutBlockSize) const
+{
+	using namespace detail;
+	if (CompressedData)
+	{
+		switch (const BufferHeader Header = BufferHeader::Read(CompressedData); Header.Method)
+		{
+			case CompressionMethod::None:
+				OutCompressor		= OodleCompressor::NotSet;
+				OutCompressionLevel = OodleCompressionLevel::None;
+				OutBlockSize		= 0;
+				return true;
+			case CompressionMethod::Oodle:
+				OutCompressor		= OodleCompressor(Header.Compressor);
+				OutCompressionLevel = OodleCompressionLevel(Header.CompressionLevel);
+				OutBlockSize		= uint64_t(1) << Header.BlockSizeExponent;
+				return true;
+			default:
+				break;
+		}
+	}
+	return false;
+}
+
+/**
+	______________________ _____________________________
+	\__    ___/\_   _____//   _____/\__    ___/   _____/
+	  |    |    |    __)_ \_____  \   |    |  \_____  \
+	  |    |    |        \/        \  |    |  /        \
+	  |____|   /_______  /_______  /  |____| /_______  /
+					   \/        \/                  \/
+ */
+
+#if ZEN_WITH_TESTS
+
+TEST_CASE("CompressedBuffer")
+{
+	uint8_t Zeroes[1024]{};
+	uint8_t Ones[1024];
+	memset(Ones, 1, sizeof Ones);
+
+	{
+		CompressedBuffer Buffer = CompressedBuffer::Compress(CompositeBuffer(SharedBuffer::MakeView(MakeMemoryView(Zeroes))),
+															 OodleCompressor::NotSet,
+															 OodleCompressionLevel::None);
+
+		CHECK(Buffer.DecodeRawSize() == sizeof(Zeroes));
+		CHECK(Buffer.GetCompressedSize() == (sizeof(Zeroes) + sizeof(detail::BufferHeader)));
+
+		CompositeBuffer	 Compressed = Buffer.GetCompressed();
+		IoHash			 DecodedHash;
+		uint64_t		 DecodedRawSize;
+		CompressedBuffer BufferD = CompressedBuffer::FromCompressed(Compressed, DecodedHash, DecodedRawSize);
+
+		CHECK(BufferD.IsNull() == false);
+
+		CompositeBuffer Decomp = BufferD.DecompressToComposite();
+
+		CHECK(Decomp.GetSize() == DecodedRawSize);
+		CHECK(IoHash::HashBuffer(Decomp) == DecodedHash);
+	}
+
+	{
+		CompressedBuffer Buffer = CompressedBuffer::Compress(
+			CompositeBuffer(SharedBuffer::MakeView(MakeMemoryView(Zeroes)), SharedBuffer::MakeView(MakeMemoryView(Ones))),
+			OodleCompressor::NotSet,
+			OodleCompressionLevel::None);
+
+		CHECK(Buffer.DecodeRawSize() == (sizeof(Zeroes) + sizeof(Ones)));
+		CHECK(Buffer.GetCompressedSize() == (sizeof(Zeroes) + sizeof(Ones) + sizeof(detail::BufferHeader)));
+
+		CompositeBuffer	 Compressed = Buffer.GetCompressed();
+		IoHash			 DecodedHash;
+		uint64_t		 DecodedRawSize;
+		CompressedBuffer BufferD = CompressedBuffer::FromCompressed(Compressed, DecodedHash, DecodedRawSize);
+
+		CHECK(BufferD.IsNull() == false);
+
+		CompositeBuffer Decomp = BufferD.DecompressToComposite();
+
+		CHECK(Decomp.GetSize() == DecodedRawSize);
+		CHECK(IoHash::HashBuffer(Decomp) == DecodedHash);
+	}
+
+	{
+		CompressedBuffer Buffer = CompressedBuffer::Compress(CompositeBuffer(SharedBuffer::MakeView(MakeMemoryView(Zeroes))));
+
+		CHECK(Buffer.DecodeRawSize() == sizeof(Zeroes));
+		CHECK(Buffer.GetCompressedSize() < sizeof(Zeroes));
+
+		CompositeBuffer	 Compressed = Buffer.GetCompressed();
+		IoHash			 DecodedHash;
+		uint64_t		 DecodedRawSize;
+		CompressedBuffer BufferD = CompressedBuffer::FromCompressed(Compressed, DecodedHash, DecodedRawSize);
+
+		CHECK(BufferD.IsNull() == false);
+
+		CompositeBuffer Decomp = BufferD.DecompressToComposite();
+
+		CHECK(Decomp.GetSize() == DecodedRawSize);
+		CHECK(IoHash::HashBuffer(Decomp) == DecodedHash);
+	}
+
+	{
+		CompressedBuffer Buffer = CompressedBuffer::Compress(
+			CompositeBuffer(SharedBuffer::MakeView(MakeMemoryView(Zeroes)), SharedBuffer::MakeView(MakeMemoryView(Ones))));
+
+		CHECK(Buffer.DecodeRawSize() == (sizeof(Zeroes) + sizeof(Ones)));
+		CHECK(Buffer.GetCompressedSize() < (sizeof(Zeroes) + sizeof(Ones)));
+
+		CompositeBuffer	 Compressed = Buffer.GetCompressed();
+		IoHash			 DecodedHash;
+		uint64_t		 DecodedRawSize;
+		CompressedBuffer BufferD = CompressedBuffer::FromCompressed(Compressed, DecodedHash, DecodedRawSize);
+
+		CHECK(BufferD.IsNull() == false);
+
+		CompositeBuffer Decomp = BufferD.DecompressToComposite();
+
+		CHECK(Decomp.GetSize() == DecodedRawSize);
+		CHECK(IoHash::HashBuffer(Decomp) == DecodedHash);
+	}
+
+	auto GenerateData = [](uint64_t N) -> std::vector<uint64_t> {
+		std::vector<uint64_t> Data;
+		Data.resize(N);
+		for (size_t Idx = 0; Idx < Data.size(); ++Idx)
+		{
+			Data[Idx] = Idx;
+		}
+		return Data;
+	};
+
+	auto ValidateData = [](std::span<uint64_t const> Values, std::span<uint64_t const> ExpectedValues, uint64_t Offset) {
+		for (size_t Idx = Offset; uint64_t Value : Values)
+		{
+			const uint64_t ExpectedValue = ExpectedValues[Idx++];
+			CHECK(Value == ExpectedValue);
+		}
+	};
+
+	SUBCASE("decompress with offset and size")
+	{
+		auto UncompressAndValidate = [&ValidateData](CompressedBuffer			  Compressed,
+													 uint64_t					  OffsetCount,
+													 uint64_t					  Count,
+													 const std::vector<uint64_t>& ExpectedValues) {
+			SharedBuffer Uncompressed = Compressed.Decompress(OffsetCount * sizeof(uint64_t), Count * sizeof(uint64_t));
+			CHECK(Uncompressed.GetSize() == Count * sizeof(uint64_t));
+			std::span<uint64_t const> Values((const uint64_t*)Uncompressed.GetData(), Uncompressed.GetSize() / sizeof(uint64_t));
+			ValidateData(Values, ExpectedValues, OffsetCount);
+		};
+
+		const uint64_t		  BlockSize		 = 64 * sizeof(uint64_t);
+		const uint64_t		  N				 = 5000;
+		std::vector<uint64_t> ExpectedValues = GenerateData(N);
+		CompressedBuffer	  Compressed	 = CompressedBuffer::Compress(SharedBuffer::MakeView(MakeMemoryView(ExpectedValues)),
+																  OodleCompressor::Mermaid,
+																  OodleCompressionLevel::Optimal4,
+																  BlockSize);
+		UncompressAndValidate(Compressed, 0, N, ExpectedValues);
+		UncompressAndValidate(Compressed, 1, N - 1, ExpectedValues);
+		UncompressAndValidate(Compressed, N - 1, 1, ExpectedValues);
+		UncompressAndValidate(Compressed, 0, 1, ExpectedValues);
+		UncompressAndValidate(Compressed, 2, 4, ExpectedValues);
+		UncompressAndValidate(Compressed, 0, 512, ExpectedValues);
+		UncompressAndValidate(Compressed, 3, 514, ExpectedValues);
+		UncompressAndValidate(Compressed, 256, 512, ExpectedValues);
+		UncompressAndValidate(Compressed, 512, 512, ExpectedValues);
+	}
+
+	SUBCASE("decompress with offset only")
+	{
+		const uint64_t			  BlockSize		 = 64 * sizeof(uint64_t);
+		const uint64_t			  N				 = 1000;
+		std::vector<uint64_t>	  ExpectedValues = GenerateData(N);
+		CompressedBuffer		  Compressed	 = CompressedBuffer::Compress(SharedBuffer::MakeView(MakeMemoryView(ExpectedValues)),
+																  OodleCompressor::Mermaid,
+																  OodleCompressionLevel::Optimal4,
+																  BlockSize);
+		const uint64_t			  OffsetCount	 = 150;
+		SharedBuffer			  Uncompressed	 = Compressed.Decompress(OffsetCount * sizeof(uint64_t));
+		std::span<uint64_t const> Values((const uint64_t*)Uncompressed.GetData(), Uncompressed.GetSize() / sizeof(uint64_t));
+		ValidateData(Values, ExpectedValues, OffsetCount);
+	}
+
+	SUBCASE("decompress buffer with one block")
+	{
+		const uint64_t			  BlockSize		 = 256 * sizeof(uint64_t);
+		const uint64_t			  N				 = 100;
+		std::vector<uint64_t>	  ExpectedValues = GenerateData(N);
+		CompressedBuffer		  Compressed	 = CompressedBuffer::Compress(SharedBuffer::MakeView(MakeMemoryView(ExpectedValues)),
+																  OodleCompressor::Mermaid,
+																  OodleCompressionLevel::Optimal4,
+																  BlockSize);
+		const uint64_t			  OffsetCount	 = 2;
+		const uint64_t			  Count			 = 50;
+		SharedBuffer			  Uncompressed	 = Compressed.Decompress(OffsetCount * sizeof(uint64_t), Count * sizeof(uint64_t));
+		std::span<uint64_t const> Values((const uint64_t*)Uncompressed.GetData(), Uncompressed.GetSize() / sizeof(uint64_t));
+		ValidateData(Values, ExpectedValues, OffsetCount);
+	}
+
+	SUBCASE("decompress uncompressed buffer")
+	{
+		const uint64_t		  N				 = 4242;
+		std::vector<uint64_t> ExpectedValues = GenerateData(N);
+		CompressedBuffer	  Compressed	 = CompressedBuffer::Compress(SharedBuffer::MakeView(MakeMemoryView(ExpectedValues)),
+																  OodleCompressor::NotSet,
+																  OodleCompressionLevel::None);
+		{
+			const uint64_t			  OffsetCount  = 0;
+			const uint64_t			  Count		   = N;
+			SharedBuffer			  Uncompressed = Compressed.Decompress(OffsetCount * sizeof(uint64_t), Count * sizeof(uint64_t));
+			std::span<uint64_t const> Values((const uint64_t*)Uncompressed.GetData(), Uncompressed.GetSize() / sizeof(uint64_t));
+			ValidateData(Values, ExpectedValues, OffsetCount);
+		}
+
+		{
+			const uint64_t			  OffsetCount  = 21;
+			const uint64_t			  Count		   = 999;
+			SharedBuffer			  Uncompressed = Compressed.Decompress(OffsetCount * sizeof(uint64_t), Count * sizeof(uint64_t));
+			std::span<uint64_t const> Values((const uint64_t*)Uncompressed.GetData(), Uncompressed.GetSize() / sizeof(uint64_t));
+			ValidateData(Values, ExpectedValues, OffsetCount);
+		}
+	}
+
+	SUBCASE("copy range")
+	{
+		const uint64_t		  BlockSize		 = 64 * sizeof(uint64_t);
+		const uint64_t		  N				 = 1000;
+		std::vector<uint64_t> ExpectedValues = GenerateData(N);
+
+		CompressedBuffer Compressed = CompressedBuffer::Compress(SharedBuffer::MakeView(MakeMemoryView(ExpectedValues)),
+																 OodleCompressor::Mermaid,
+																 OodleCompressionLevel::Optimal4,
+																 BlockSize);
+
+		{
+			const uint64_t OffsetCount	= 0;
+			const uint64_t Count		= N;
+			SharedBuffer   Uncompressed = Compressed.CopyRange(OffsetCount * sizeof(uint64_t), Count * sizeof(uint64_t)).Decompress();
+			std::span<uint64_t const> Values((const uint64_t*)Uncompressed.GetData(), Uncompressed.GetSize() / sizeof(uint64_t));
+			CHECK(Values.size() == Count);
+			ValidateData(Values, ExpectedValues, OffsetCount);
+		}
+
+		{
+			const uint64_t OffsetCount	= 64;
+			const uint64_t Count		= N - 64;
+			SharedBuffer   Uncompressed = Compressed.CopyRange(OffsetCount * sizeof(uint64_t), Count * sizeof(uint64_t)).Decompress();
+			std::span<uint64_t const> Values((const uint64_t*)Uncompressed.GetData(), Uncompressed.GetSize() / sizeof(uint64_t));
+			CHECK(Values.size() == Count);
+			ValidateData(Values, ExpectedValues, OffsetCount);
+		}
+
+		{
+			const uint64_t OffsetCount		= 64 * 2 + 32;
+			const uint64_t Count			= N - OffsetCount;
+			const uint64_t RawOffset		= OffsetCount * sizeof(uint64_t);
+			const uint64_t RawSize			= Count * sizeof(uint64_t);
+			uint64_t	   FirstBlockOffset = RawOffset % BlockSize;
+
+			SharedBuffer			  Uncompressed = Compressed.CopyRange(RawOffset, RawSize).Decompress();
+			std::span<uint64_t const> AllValues((const uint64_t*)Uncompressed.GetData(), RawSize / sizeof(uint64_t));
+			std::span<uint64_t const> Values((const uint64_t*)(((const uint8_t*)(Uncompressed.GetData()) + FirstBlockOffset)),
+											 RawSize / sizeof(uint64_t));
+			CHECK(Values.size() == Count);
+			ValidateData(Values, ExpectedValues, OffsetCount);
+		}
+
+		{
+			const uint64_t OffsetCount		= 64 * 2 + 63;
+			const uint64_t Count			= N - OffsetCount - 5;
+			const uint64_t RawOffset		= OffsetCount * sizeof(uint64_t);
+			const uint64_t RawSize			= Count * sizeof(uint64_t);
+			uint64_t	   FirstBlockOffset = RawOffset % BlockSize;
+
+			SharedBuffer			  Uncompressed = Compressed.CopyRange(RawOffset, RawSize).Decompress();
+			std::span<uint64_t const> AllValues((const uint64_t*)Uncompressed.GetData(), RawSize / sizeof(uint64_t));
+			std::span<uint64_t const> Values((const uint64_t*)(((const uint8_t*)(Uncompressed.GetData()) + FirstBlockOffset)),
+											 RawSize / sizeof(uint64_t));
+			CHECK(Values.size() == Count);
+			ValidateData(Values, ExpectedValues, OffsetCount);
+		}
+	}
+
+	SUBCASE("copy uncompressed range")
+	{
+		const uint64_t		  N				 = 1000;
+		std::vector<uint64_t> ExpectedValues = GenerateData(N);
+
+		CompressedBuffer Compressed = CompressedBuffer::Compress(SharedBuffer::MakeView(MakeMemoryView(ExpectedValues)),
+																 OodleCompressor::NotSet,
+																 OodleCompressionLevel::None);
+
+		{
+			const uint64_t OffsetCount	= 0;
+			const uint64_t Count		= N;
+			SharedBuffer   Uncompressed = Compressed.CopyRange(OffsetCount * sizeof(uint64_t), Count * sizeof(uint64_t)).Decompress();
+			std::span<uint64_t const> Values((const uint64_t*)Uncompressed.GetData(), Uncompressed.GetSize() / sizeof(uint64_t));
+			CHECK(Values.size() == Count);
+			ValidateData(Values, ExpectedValues, OffsetCount);
+		}
+
+		{
+			const uint64_t OffsetCount	= 1;
+			const uint64_t Count		= N - OffsetCount;
+			SharedBuffer   Uncompressed = Compressed.CopyRange(OffsetCount * sizeof(uint64_t), Count * sizeof(uint64_t)).Decompress();
+			std::span<uint64_t const> Values((const uint64_t*)Uncompressed.GetData(), Uncompressed.GetSize() / sizeof(uint64_t));
+			CHECK(Values.size() == Count);
+			ValidateData(Values, ExpectedValues, OffsetCount);
+		}
+
+		{
+			const uint64_t OffsetCount	= 42;
+			const uint64_t Count		= 100;
+			SharedBuffer   Uncompressed = Compressed.CopyRange(OffsetCount * sizeof(uint64_t), Count * sizeof(uint64_t)).Decompress();
+			std::span<uint64_t const> Values((const uint64_t*)Uncompressed.GetData(), Uncompressed.GetSize() / sizeof(uint64_t));
+			CHECK(Values.size() == Count);
+			ValidateData(Values, ExpectedValues, OffsetCount);
+		}
+	}
+}
+
+void
+compress_forcelink()
+{
+}
+#endif
+
+}  // namespace zen