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// StringCompression.h

// Interfaces to the wrapping functions for compression and decompression

#pragma once





struct libdeflate_compressor;
struct libdeflate_decompressor;





namespace Compression
{
/** Contains the result of a compression or extraction operation. */
struct Result
{
	using Static = std::array<std::byte, 128 KiB>;
	using Dynamic = std::unique_ptr<std::byte[]>;

	static constexpr size_t StaticCapacity =
		sizeof(Compression::Result::Static) / sizeof(Compression::Result::Static::value_type);

	/** Returns a view (of type char) of the internal store. */
	std::string_view GetStringView() const;

	/** Returns a view (of type std::byte) of the internal store. */
	ContiguousByteBufferView GetView() const;

	/** A store allocated on either the stack or heap. */
	std::variant<Static, Dynamic> Storage;

	/** The length of valid data in the store. */
	size_t Size;
};

/** Contains routines for data compression. */
class Compressor
{
  public:
	/** Creates a new compressor instance with a compression factor [0-12]. */
	Compressor(int CompressionFactor = 6);
	~Compressor();

	Result CompressGZip(ContiguousByteBufferView Input);
	Result CompressZLib(ContiguousByteBufferView Input);
	Result CompressZLib(const void * Input, size_t Size);

  private:
	template <auto Algorithm> Result Compress(const void * Input, size_t Size);

	libdeflate_compressor * m_Handle;
};

/** Contains routines for data extraction. */
class Extractor
{
  public:
	/** Creates a new extractor instance. */
	Extractor();
	~Extractor();

	Result ExtractGZip(ContiguousByteBufferView Input);
	Result ExtractZLib(ContiguousByteBufferView Input);
	Result ExtractZLib(ContiguousByteBufferView Input, size_t UncompressedSize);

  private:
	template <auto Algorithm> Result Extract(ContiguousByteBufferView Input);
	template <auto Algorithm> Result Extract(ContiguousByteBufferView Input, size_t UncompressedSize);

	libdeflate_decompressor * m_Handle;
};
}  // namespace Compression