Add separate blockstore.h/.cpp

1 files changed, 103 insertions, 0 deletions

diff --git a/zenstore/include/zenstore/blockstore.h b/zenstore/include/zenstore/blockstore.h
new file mode 100644
index 000000000..29f520722
--- /dev/null
+++ b/zenstore/include/zenstore/blockstore.h
@@ -0,0 +1,103 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#pragma once
+
+#include <zencore/zencore.h>
+
+namespace zen {
+
+//////////////////////////////////////////////////////////////////////////
+
+struct BlockStoreLocation
+{
+	uint32_t BlockIndex;
+	uint64_t Offset;
+	uint64_t Size;
+};
+
+#pragma pack(push)
+#pragma pack(1)
+
+struct BlockStoreDiskLocation
+{
+	constexpr static uint32_t MaxBlockIndexBits = 20;
+	constexpr static uint32_t MaxOffsetBits		= 28;
+	constexpr static uint32_t MaxBlockIndex		= (1ul << BlockStoreDiskLocation::MaxBlockIndexBits) - 1ul;
+	constexpr static uint32_t MaxOffset			= (1ul << BlockStoreDiskLocation::MaxOffsetBits) - 1ul;
+
+	BlockStoreDiskLocation(const BlockStoreLocation& Location, uint64_t OffsetAlignement)
+	{
+		Init(Location.BlockIndex, Location.Offset / OffsetAlignement, Location.Size);
+	}
+
+	BlockStoreDiskLocation() = default;
+
+	inline BlockStoreLocation Get(uint64_t OffsetAlignement) const
+	{
+		uint64_t PackedOffset = 0;
+		memcpy(&PackedOffset, &m_Offset, sizeof m_Offset);
+		return {.BlockIndex = static_cast<std::uint32_t>(PackedOffset >> MaxOffsetBits),
+				.Offset		= (PackedOffset & MaxOffset) * OffsetAlignement,
+				.Size		= GetSize()};
+	}
+
+	inline uint32_t GetBlockIndex() const
+	{
+		uint64_t PackedOffset = 0;
+		memcpy(&PackedOffset, &m_Offset, sizeof m_Offset);
+		return static_cast<std::uint32_t>(PackedOffset >> MaxOffsetBits);
+	}
+
+	inline uint64_t GetOffset() const
+	{
+		uint64_t PackedOffset = 0;
+		memcpy(&PackedOffset, &m_Offset, sizeof m_Offset);
+		return PackedOffset & MaxOffset;
+	}
+
+	inline uint64_t GetSize() const { return m_Size; }
+
+private:
+	inline void Init(uint32_t BlockIndex, uint64_t Offset, uint64_t Size)
+	{
+		ZEN_ASSERT(BlockIndex <= MaxBlockIndex);
+		ZEN_ASSERT(Offset <= MaxOffset);
+		ZEN_ASSERT(Size <= std::numeric_limits<std::uint32_t>::max());
+
+		m_Size				  = static_cast<uint32_t>(Size);
+		uint64_t PackedOffset = (static_cast<uint64_t>(BlockIndex) << MaxOffsetBits) + Offset;
+		memcpy(&m_Offset[0], &PackedOffset, sizeof m_Offset);
+	}
+
+	uint32_t m_Size;
+	uint8_t	 m_Offset[6];
+};
+
+#pragma pack(pop)
+
+struct BlockStoreFile
+{
+	explicit BlockStoreFile(const std::filesystem::path& BlockPath);
+	~BlockStoreFile();
+	const std::filesystem::path& GetPath() const;
+	void						 Open();
+	void						 Create(uint64_t InitialSize);
+	void						 MarkAsDeleteOnClose(std::error_code& Ec);
+	uint64_t					 FileSize();
+	IoBuffer					 GetChunk(uint64_t Offset, uint64_t Size);
+	void						 Read(void* Data, uint64_t Size, uint64_t FileOffset);
+	void						 Write(const void* Data, uint64_t Size, uint64_t FileOffset);
+	void						 Flush();
+	void StreamByteRange(uint64_t FileOffset, uint64_t Size, std::function<void(const void* Data, uint64_t Size)>&& ChunkFun);
+
+private:
+	void						InternalOpen();
+	const std::filesystem::path m_Path;
+	RwLock						m_OpenLock;
+	BasicFile					m_File;
+	IoBuffer					m_IoBuffer;
+};
+
+void blockstore_forcelink();
+
+}  // namespace zen