userspace: Add LibDEFLATE

This can be used to compress and decompress DEFLATE data either in raw
or zlib format

userspace/libraries/LibDEFLATE/include/LibDEFLATE/Compressor.h

@@ -0,0 +1,67 @@
+#pragma once
+
+#include <BAN/ByteSpan.h>
+#include <BAN/HashMap.h>
+#include <BAN/LinkedList.h>
+#include <BAN/NoCopyMove.h>
+#include <BAN/Vector.h>
+
+#include <LibDEFLATE/BitStream.h>
+#include <LibDEFLATE/StreamType.h>
+
+namespace LibDEFLATE
+{
+
+	class Compressor
+	{
+		BAN_NON_COPYABLE(Compressor);
+		BAN_NON_MOVABLE(Compressor);
+
+	public:
+		using HashChain = BAN::LinkedList<BAN::ConstByteSpan>;
+
+		struct LZ77Entry
+		{
+			enum class Type
+			{
+				Literal,
+				DistLength,
+			} type;
+			union
+			{
+				uint8_t literal;
+				struct
+				{
+					uint16_t length;
+					uint16_t distance;
+				} dist_length;
+			} as;
+		};
+
+	public:
+		Compressor(BAN::ConstByteSpan data, StreamType type)
+			: m_type(type)
+			, m_data(data)
+		{ }
+
+		BAN::ErrorOr<BAN::Vector<uint8_t>> compress();
+
+	private:
+		BAN::ErrorOr<void> compress_block(BAN::ConstByteSpan, bool final);
+
+		uint32_t get_hash_key(BAN::ConstByteSpan needle) const;
+		BAN::ErrorOr<void> update_hash_chain(size_t count);
+
+		BAN::ErrorOr<LZ77Entry> find_longest_match(BAN::ConstByteSpan needle) const;
+		BAN::ErrorOr<BAN::Vector<LZ77Entry>> lz77_compress(BAN::ConstByteSpan data);
+
+	private:
+		const StreamType m_type;
+		BAN::ConstByteSpan m_data;
+		BitOutputStream m_stream;
+
+		size_t m_hash_chain_index { 0 };
+		BAN::HashMap<uint32_t, HashChain> m_hash_chain;
+	};
+
+}