userspace: Add LibDEFLATE

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

userspace/libraries/LibDEFLATE/include/LibDEFLATE/HuffmanTree.h

@@ -0,0 +1,61 @@
+#pragma once
+
+#include <BAN/Array.h>
+#include <BAN/NoCopyMove.h>
+#include <BAN/Optional.h>
+#include <BAN/Vector.h>
+
+namespace LibDEFLATE
+{
+
+	class HuffmanTree
+	{
+		BAN_NON_COPYABLE(HuffmanTree);
+
+	public:
+		static constexpr uint8_t MAX_BITS = 15;
+
+		struct Leaf
+		{
+			uint16_t code;
+			uint8_t len;
+		};
+
+		struct Instant
+		{
+			uint16_t symbol;
+			uint8_t len;
+		};
+
+		HuffmanTree() {}
+		HuffmanTree(HuffmanTree&& other) { *this = BAN::move(other); }
+		HuffmanTree& operator=(HuffmanTree&& other);
+
+		static BAN::ErrorOr<HuffmanTree> create(BAN::Span<const uint8_t> bit_lengths);
+
+		static BAN::ErrorOr<HuffmanTree> fixed_tree();
+		BAN::Optional<Instant> get_symbol_instant(uint16_t code) const;
+
+		BAN::Optional<uint16_t> get_symbol(uint16_t code, uint8_t len) const;
+
+		uint8_t instant_bits() const { return m_instant_bits; }
+		uint8_t min_bits() const { return m_min_bits; }
+		uint8_t max_bits() const { return m_max_bits; }
+		bool empty() const { return m_min_bits == 0; }
+
+	private:
+		BAN::ErrorOr<void> initialize(BAN::Span<const uint8_t> bit_lengths);
+		BAN::ErrorOr<void> build_instant_table(BAN::Span<const Leaf> tree);
+		BAN::ErrorOr<void> build_slow_table(BAN::Span<const Leaf> tree);
+
+	private:
+		uint8_t m_instant_bits { 0 };
+		uint8_t m_min_bits { 0 };
+		uint8_t m_max_bits { 0 };
+
+		BAN::Vector<Instant> m_instant;
+		BAN::Array<uint16_t, MAX_BITS + 1> m_min_code;
+		BAN::Vector<BAN::Vector<uint16_t>> m_slow_table;
+	};
+
+}