util: Implement a common interface for bit streams

include/ki/pclass/Property.h

@@ -28,8 +28,8 @@ namespace pclass
 		virtual Value get_value() const = 0;
 		virtual const PropertyClass *get_object() const = 0;
 
-		virtual void write_value_to(BitStream &stream) const = 0;
+		virtual void write_value_to(BitStreamBase &stream) const = 0;
-		virtual void read_value_from(BitStream &stream) = 0;
+		virtual void read_value_from(BitStreamBase &stream) = 0;
 
 	private:
 		std::string m_name;
@@ -53,13 +53,13 @@ namespace pclass
 
 		Value get_value() const final override;
 		const PropertyClass *get_object() const final override;
-		void write_value_to(BitStream &stream) const final override;
+		void write_value_to(BitStreamBase &stream) const final override;
-		void read_value_from(BitStream &stream) final override;
+		void read_value_from(BitStreamBase &stream) final override;
 
 		virtual Value get_value(int index) const = 0;
 		virtual const PropertyClass *get_object(int index) const = 0;
-		virtual void write_value_to(BitStream &stream, int index) const = 0;
+		virtual void write_value_to(BitStreamBase &stream, int index) const = 0;
-		virtual void read_value_from(BitStream &stream, int index) = 0;
+		virtual void read_value_from(BitStreamBase &stream, int index) = 0;
 	};
 }
 }

include/ki/pclass/StaticProperty.h

@@ -161,12 +161,12 @@ namespace pclass
 	>
 	struct value_rw_helper
 	{
-		static void write(const StaticProperty<ValueT> &prop, BitStream &stream)
+		static void write(const StaticProperty<ValueT> &prop, BitStreamBase &stream)
 		{
 			prop.get_type().write_to(stream, prop.m_value);
 		}
 
-		static void read(StaticProperty<ValueT> &prop, BitStream &stream)
+		static void read(StaticProperty<ValueT> &prop, BitStreamBase &stream)
 		{
 			prop.get_type().read_from(stream, Value(prop.m_value));
 		}
@@ -187,12 +187,12 @@ namespace pclass
 		>::type
 	>
 	{
-		static void write(const StaticProperty<ValueT> &prop, BitStream &stream)
+		static void write(const StaticProperty<ValueT> &prop, BitStreamBase &stream)
 		{
 			prop.get_type().write_to(stream, *prop.m_value);
 		}
 
-		static void read(StaticProperty<ValueT> &prop, BitStream &stream)
+		static void read(StaticProperty<ValueT> &prop, BitStreamBase &stream)
 		{
 			prop.get_type().read_from(stream, Value(*prop.m_value));
 		}
@@ -215,12 +215,12 @@ namespace pclass
 			return value_object_helper<ValueT>::get_object(prop);
 		}
 
-		static void write(const StaticProperty<ValueT> &prop, BitStream &stream)
+		static void write(const StaticProperty<ValueT> &prop, BitStreamBase &stream)
 		{
 			value_rw_helper<ValueT>::write(prop, stream);
 		}
 
-		static void read(StaticProperty<ValueT> &prop, BitStream &stream)
+		static void read(StaticProperty<ValueT> &prop, BitStreamBase &stream)
 		{
 			value_rw_helper<ValueT>::read(prop, stream);
 		}
@@ -260,12 +260,12 @@ namespace pclass
 			return std::is_pointer<ValueT>::value;
 		}
 
-		void write_value_to(BitStream &stream) const override
+		void write_value_to(BitStreamBase &stream) const override
 		{
 			value_helper<ValueT>::write(*this, stream);
 		}
 
-		void read_value_from(BitStream &stream) override
+		void read_value_from(BitStreamBase &stream) override
 		{
 			value_helper<ValueT>::read(*this, stream);
 		}

include/ki/pclass/TypeSystem.h

@@ -38,17 +38,16 @@ namespace pclass
 		}
 
 		template <class ClassT>
-		ClassType<ClassT> &define_class(
+		ClassType<ClassT> &define_class(const std::string &name)
-			const std::string &name, const Type *base_class = nullptr)
 		{
-			// If the caller does not specify a base class, automatically make
+			return define_class<ClassT>(name, nullptr);
-			// ki::pclass::PropertyClass the base class (if it has been defined)
+		}
-			if (base_class == nullptr && has_type("class PropertyClass"))
-				base_class = &get_type("class PropertyClass");
 
-			auto *type = new ClassType<ClassT>(name, base_class, *this);
+		template <class ClassT>
-			define_type(type);
+		ClassType<ClassT> &define_class(
-			return *type;
+			const std::string &name, const Type &base_class)
+		{
+			return define_class<ClassT>(name, &base_class);
 		}
 
 		template <typename EnumT>
@@ -71,6 +70,20 @@ namespace pclass
 	protected:
 		void define_type(Type *type);
 
+		template <class ClassT>
+		ClassType<ClassT> &define_class(
+			const std::string &name, const Type *base_class)
+		{
+			// If the caller does not specify a base class, automatically make
+			// ki::pclass::PropertyClass the base class (if it has been defined)
+			if (base_class == nullptr && has_type("class PropertyClass"))
+				base_class = &get_type("class PropertyClass");
+
+			auto *type = new ClassType<ClassT>(name, base_class, *this);
+			define_type(type);
+			return *type;
+		}
+
 	private:
 		TypeList m_types;
 		TypeNameMap m_type_name_lookup;

include/ki/pclass/VectorProperty.h

@@ -40,14 +40,14 @@ namespace pclass
 			return false;
 		}
 
-		void write_value_to(BitStream &stream, const int index) const override
+		void write_value_to(BitStreamBase &stream, const int index) const override
 		{
 			if (index < 0 || index >= this->size())
 				throw runtime_error("Index out of bounds.");
 			this->get_type().write_to(stream, this->at(index));
 		}
 
-		void read_value_from(BitStream &stream, const int index) override
+		void read_value_from(BitStreamBase &stream, const int index) override
 		{
 			if (index < 0 || index >= this->size())
 				throw runtime_error("Index out of bounds.");
@@ -73,14 +73,14 @@ namespace pclass
 			return true;
 		}
 
-		void write_value_to(BitStream &stream, const int index) const override
+		void write_value_to(BitStreamBase &stream, const int index) const override
 		{
 			if (index < 0 || index >= this->size())
 				throw runtime_error("Index out of bounds.");
 			this->get_type().write_to(stream, *this->at(index));
 		}
 
-		void read_value_from(BitStream &stream, const int index) override
+		void read_value_from(BitStreamBase &stream, const int index) override
 		{
 			if (index < 0 || index >= this->size())
 				throw runtime_error("Index out of bounds.");

include/ki/pclass/types/ClassType.h

@@ -45,7 +45,7 @@ namespace pclass
 			return new ClassT(*this, get_type_system());
 		}
 
-		void write_to(BitStream &stream, const Value &value) const override
+		void write_to(BitStreamBase &stream, const Value &value) const override
 		{
 			const auto &object = dynamic_cast<const PropertyClass &>(value.get<ClassT>());
 			const auto &properties = object.get_properties();
@@ -53,7 +53,7 @@ namespace pclass
 				(*it)->write_value_to(stream);
 		}
 
-		void read_from(BitStream &stream, Value &value) const override
+		void read_from(BitStreamBase &stream, Value &value) const override
 		{
 			auto &object = dynamic_cast<PropertyClass &>(value.get<ClassT>());
 			auto &properties = object.get_properties();

include/ki/pclass/types/FloatingPointPrimitiveType.h

@@ -12,7 +12,7 @@ namespace pclass
 		typename std::enable_if<std::is_floating_point<ValueT>::value>::type
 	>
 	{
-		static void write_to(BitStream &stream, const ValueT &value)
+		static void write_to(BitStreamBase &stream, const ValueT &value)
 		{
 			// Reinterpret the reference as a reference to an integer
 			const uint_type &v = *(
@@ -35,7 +35,7 @@ namespace pclass
 		typename std::enable_if<std::is_floating_point<ValueT>::value>::type
 	>
 	{
-		static void read_from(BitStream &stream, ValueT &value)
+		static void read_from(BitStreamBase &stream, ValueT &value)
 		{
 			// Reinterpret the reference as a reference to an integer
 			uint_type &v = *(

include/ki/pclass/types/IntegralPrimitiveType.h

@@ -12,7 +12,7 @@ namespace pclass
 		typename std::enable_if<is_integral<ValueT>::value>::type
 	>
 	{
-		static void write_to(BitStream &stream, const ValueT &value)
+		static void write_to(BitStreamBase &stream, const ValueT &value)
 		{
 			stream.write<ValueT>(value);
 		}
@@ -24,7 +24,7 @@ namespace pclass
 		typename std::enable_if<is_integral<ValueT>::value>::type
 	>
 	{
-		static void read_from(BitStream &stream, ValueT &value)
+		static void read_from(BitStreamBase &stream, ValueT &value)
 		{
 			value = stream.read<ValueT>();
 		}

include/ki/pclass/types/PrimitiveType.h

@@ -11,7 +11,7 @@ namespace pclass
 	template <typename ValueT, typename Enable = void>
 	struct PrimitiveTypeWriter
 	{
-		static void write_to(BitStream &stream, const ValueT &value)
+		static void write_to(BitStreamBase &stream, const ValueT &value)
 		{
 			// Provide a compiler error if this is not specialized
 			static_assert(
@@ -27,7 +27,7 @@ namespace pclass
 	template <typename ValueT, typename Enable = void>
 	struct PrimitiveTypeReader
 	{
-		static void read_from(BitStream &stream, ValueT &value)
+		static void read_from(BitStreamBase &stream, ValueT &value)
 		{
 			// Provide a compiler error if this is not specialized
 			static_assert(
@@ -50,14 +50,14 @@ namespace pclass
 			m_kind = kind::PRIMITIVE;
 		}
 
-		void write_to(BitStream &stream, const Value &value) const override
+		void write_to(BitStreamBase &stream, const Value &value) const override
 		{
 			if (!value.is<ValueT>())
 				throw std::runtime_error("Invalid call to Type::write_to -- value type does not match ValueT.");
 			PrimitiveTypeWriter<ValueT>::write_to(stream, value.get<ValueT>());
 		}
 
-		void read_from(BitStream &stream, Value &value) const override
+		void read_from(BitStreamBase &stream, Value &value) const override
 		{
 			if (!value.is<ValueT>())
 				throw std::runtime_error("Invalid call to Type::read_from -- value type does not match ValueT.");

include/ki/pclass/types/StringPrimitiveType.h

@@ -16,7 +16,7 @@ namespace pclass
 		using type = std::basic_string<_Elem, _Traits, _Alloc>;
 
 	public:
-		static void write_to(BitStream &stream, const type &value)
+		static void write_to(BitStreamBase &stream, const type &value)
 		{
 			// Write the length as an unsigned short
 			stream.write<uint16_t>(value.length());
@@ -38,7 +38,7 @@ namespace pclass
 		using type = std::basic_string<_Elem, _Traits, _Alloc>;
 
 	public:
-		static void read_from(BitStream &stream, type &value)
+		static void read_from(BitStreamBase &stream, type &value)
 		{
 			// Read the length and create a new string with the correct capacity
 			auto length = stream.read<uint16_t>();

include/ki/pclass/types/Type.h

@@ -50,8 +50,8 @@ namespace pclass
 		const TypeSystem &get_type_system() const;
 
 		virtual PropertyClass *instantiate() const;
-		virtual void write_to(BitStream &stream, const Value &value) const;
+		virtual void write_to(BitStreamBase &stream, const Value &value) const;
-		virtual void read_from(BitStream &stream, Value &value) const;
+		virtual void read_from(BitStreamBase &stream, Value &value) const;
 
 	protected:
 		kind m_kind;

include/ki/serialization/SerializerBinary.h

@@ -45,17 +45,17 @@ namespace serialization
 			bool is_file, flags flags);
 		virtual ~SerializerBinary() {}
 
-		void save(const pclass::PropertyClass *object, BitStream &stream);
+		void save(const pclass::PropertyClass *object, BitStreamBase &stream);
-		void load(pclass::PropertyClass *&dest, BitStream &stream);
+		void load(pclass::PropertyClass *&dest, BitStreamBase &stream);
 
 	protected:
-		virtual void presave_object(const pclass::PropertyClass *object, BitStream &stream) const;
+		virtual void presave_object(const pclass::PropertyClass *object, BitStreamBase &stream) const;
-		void save_object(const pclass::PropertyClass *object, BitStream &stream) const;
+		void save_object(const pclass::PropertyClass *object, BitStreamBase &stream) const;
-		void save_property(const pclass::PropertyBase *prop, BitStream &stream) const;
+		void save_property(const pclass::PropertyBase *prop, BitStreamBase &stream) const;
 
-		virtual void preload_object(pclass::PropertyClass *&dest, BitStream &stream) const;
+		virtual void preload_object(pclass::PropertyClass *&dest, BitStreamBase &stream) const;
-		void load_object(pclass::PropertyClass *&dest, BitStream &stream) const;
+		void load_object(pclass::PropertyClass *&dest, BitStreamBase &stream) const;
-		void load_property(pclass::PropertyBase *prop, BitStream &stream) const;
+		void load_property(pclass::PropertyBase *prop, BitStreamBase &stream) const;
 
 	private:
 		const pclass::TypeSystem *m_type_system;

include/ki/util/BitStream.h

@@ -1,6 +1,7 @@
 #pragma once
 #include <cstdint>
 #include <type_traits>
+#include <sstream>
 #include "ki/util/BitTypes.h"
 
 #define KI_BITSTREAM_DEFAULT_BUFFER_SIZE 0x2000
@@ -8,9 +9,10 @@
 namespace ki
 {
 	/**
-	 * A readable/writeable stream of bits.
+	 * An abstract base class that provides a common interface for
+	 * writing to, reading from, and querying bit streams.
 	 */
-	class BitStream
+	class BitStreamBase
 	{
 	public:
 		/**
@@ -45,33 +47,33 @@ namespace ki
 			void set_bit(int bit);
 		};
 
-		explicit BitStream(std::size_t buffer_size = KI_BITSTREAM_DEFAULT_BUFFER_SIZE);
+		virtual ~BitStreamBase() {}
-		~BitStream();
 
 		/**
-		 * @return The stream's current position.
+		 * @returns The stream's current position.
 		 */
-		stream_pos tell() const;
+		virtual stream_pos tell() const = 0;
 
 		/**
 		 * Sets the position of the stream.
 		 * @param position The new position of the stream.
 		 */
-		void seek(stream_pos position);
+		virtual void seek(stream_pos position) = 0;
 
 		/**
-		 * @return The current size of the internal buffer.
+		 * @returns The current size of the internal buffer.
 		 */
-		std::size_t capacity() const;
+		virtual std::size_t capacity() const = 0;
 
 		/**
-		 * @return A pointer to the start of the internal buffer.
+		 * @returns A pointer to the start of the internal buffer.
 		 */
-		const uint8_t *data() const;
+		virtual const uint8_t *data() const = 0;
 
 		/**
 		 * Reads a value from the buffer given a defined number of bits.
-		 * @param bits The number of bits to read.
+		 * @param[in] bits The number of bits to read. Defaults to the bitsize of IntegerT.
+		 * @returns The value read from the buffer.
 		 */
 		template <
 			typename IntegerT,
@@ -79,42 +81,14 @@ namespace ki
 		>
 		IntegerT read(const uint8_t bits = bitsizeof<IntegerT>::value)
 		{
-			IntegerT value = 0;
+			return static_cast<IntegerT>(read(bits));
-
-			// Iterate until we've read all of the bits
-			auto unread_bits = bits;
-			while (unread_bits > 0)
-			{
-				// Calculate how many bits to read from the current byte based on how many bits 
-				// are left and how many bits we still need to read
-				const uint8_t bits_available = (8 - m_position.get_bit());
-				const auto bit_count = unread_bits < bits_available ? unread_bits : bits_available;
-
-				// Find the bit-mask based on how many bits are being read
-				const uint8_t bit_mask = ((1 << bit_count) - 1) << m_position.get_bit();
-				
-				// Read the bits from the current byte and position them on the least-signficant bit
-				const uint8_t bits_value = (m_buffer[m_position.get_byte()] & bit_mask) >> m_position.get_bit();
-
-				// Position the value of the bits we just read based on how many bits of the value 
-				// we've already read
-				const uint8_t read_bits = bits - unread_bits;
-				value |= (IntegerT)bits_value << read_bits;
-
-				// Remove the bits we just read from the count of unread bits
-				unread_bits -= bit_count;
-
-				// Move forward the number of bits we just read
-				seek(tell() + bit_count);
-			}
-
-			return value;
 		}
 
 		/**
 		 * Writes a value to the buffer that occupies a defined number of bits.
-		 * @param value The value to write.
+		 * @tparam IntegerT The type of value (must be an integral type).
-		 * @param bits The number of bits to use.
+		 * @param[in] value The value to write.
+		 * @param[in] bits The number of bits to use. Defaults to the bitsize of IntegerT.
 		 */
 		template <
 			typename IntegerT,
@@ -122,53 +96,88 @@ namespace ki
 		>
 		void write(IntegerT value, const uint8_t bits = bitsizeof<IntegerT>::value)
 		{
-			// Iterate until we've written all of the bits
+			write(static_cast<uint64_t>(value), bits);
-			auto unwritten_bits = bits;
-			while (unwritten_bits > 0)
-			{
-				// Calculate how many bits to write based on how many bits are left in the current byte
-				// and how many bits from the value we still need to write
-				const uint8_t bits_available = (8 - m_position.get_bit());
-				const auto bit_count = unwritten_bits < bits_available ? unwritten_bits : bits_available;
-				
-				// Find the bit-mask based on how many bits are being written, and how many bits we've
-				// already written
-				const uint8_t written_bits = bits - unwritten_bits;
-				IntegerT bit_mask = (IntegerT)((1 << bit_count) - 1) << written_bits;
-
-				// Get the bits from the value and position them at the current bit position
-				uint8_t value_byte = ((value & bit_mask) >> written_bits) & 0xFF;
-				value_byte <<= m_position.get_bit();
-
-				// Write the bits into the byte we're currently at
-				m_buffer[m_position.get_byte()] |= value_byte;
-				unwritten_bits -= bit_count;
-
-				// Move forward the number of bits we just wrote
-				seek(tell() + bit_count);
-			}
 		}
 
 		/**
 		 * Copy memory from an external buffer into the bitstream's buffer from the current position.
-		 * @param src The buffer to copy data from.
+		 * @param[in] src The buffer to copy data from.
-		 * @param bitsize The number of bits to copy from the src buffer.
+		 * @param[in] bitsize The number of bits to copy from the src buffer.
 		 */
 		void write_copy(uint8_t *src, std::size_t bitsize);
 
 		/**
 		 * Copy memory from the bitstream's buffer into an external buffer.
-		 * @param dst The destination buffer to copy data to.
+		 * @param[out] dst The destination buffer to copy data to.
-		 * @param bitsize The number of bits to copy into the dst buffer.
+		 * @param[in] bitsize The number of bits to copy into the dst buffer.
 		 */
 		void read_copy(uint8_t *dst, std::size_t bitsize);
 
+	protected:
+		virtual uint64_t read(uint8_t bits) = 0;
+		virtual void write(uint64_t value, uint8_t bits) = 0;
+	};
+
+	/**
+	 * A read/write-able stream of bits.
+	 */
+	class BitStream : public BitStreamBase
+	{
+	public:
+		explicit BitStream(std::size_t buffer_size = KI_BITSTREAM_DEFAULT_BUFFER_SIZE);
+		virtual ~BitStream();
+
+		stream_pos tell() const override;
+		void seek(stream_pos position) override;
+		std::size_t capacity() const override;
+		const uint8_t *data() const override;
+
+		/**
+		 * @copydoc BitStreamBase::read<IntegerT>(uint8_t)
+		 * @throws ki::runtime_error Not enough data available to read the specified number of bits.
+		 */
+		template <
+			typename IntegerT,
+			typename = std::enable_if<is_integral<IntegerT>::value>
+		>
+		IntegerT read(const uint8_t bits = bitsizeof<IntegerT>::value)
+		{
+			return BitStreamBase::read<IntegerT>(bits);
+		}
+
+		template <
+			typename IntegerT,
+			typename = std::enable_if<is_integral<IntegerT>::value>
+		>
+		void write(IntegerT value, const uint8_t bits = bitsizeof<IntegerT>::value)
+		{
+			BitStreamBase::write<IntegerT>(value, bits);
+		}
+
+	protected:
+		uint64_t read(uint8_t bits) override;
+		void write(uint64_t value, uint8_t bits) override;
+
 	private:
-		uint8_t *m_buffer;
+		uint8_t * m_buffer;
 		std::size_t m_buffer_size;
 		stream_pos m_position;
 
 		void expand_buffer();
 		void validate_buffer();
 	};
+
+	/**
+	 * TODO: Documentation
+	 */
+	class BitStreamSection : public BitStreamBase
+	{
+	public:
+		explicit BitStreamSection(BitStreamBase &stream, std::size_t size);
+
+	private:
+		BitStreamBase &m_stream;
+		stream_pos m_position;
+		std::size_t m_size;
+	};
 }

src/pclass/Property.cpp

@@ -73,13 +73,13 @@ namespace pclass
 		throw runtime_error("Called get_object() on a dynamic property. Use get_object(index) instead.");
 	}
 
-	void DynamicPropertyBase::write_value_to(BitStream &stream) const
+	void DynamicPropertyBase::write_value_to(BitStreamBase &stream) const
 	{
 		// The caller must specify an index
 		throw runtime_error("Called write_value_to() on a dynamic property. Use write_value_to(index) instead.");
 	}
 
-	void DynamicPropertyBase::read_value_from(BitStream &stream)
+	void DynamicPropertyBase::read_value_from(BitStreamBase &stream)
 	{
 		// The caller must specify an index
 		throw runtime_error("Called read_value_from() on a dynamic property. Use read_value_from(index) instead.");

src/pclass/Type.cpp

@@ -38,14 +38,14 @@ namespace pclass
 		return m_type_system;
 	}
 
-	void Type::write_to(BitStream& stream, const Value& value) const
+	void Type::write_to(BitStreamBase &stream, const Value& value) const
 	{
 		std::ostringstream oss;
 		oss << "Type '" << m_name << "' does not implement Type::write_to.";
 		throw runtime_error(oss.str());
 	}
 
-	void Type::read_from(BitStream& stream, Value& value) const
+	void Type::read_from(BitStreamBase &stream, Value& value) const
 	{
 		std::ostringstream oss;
 		oss << "Type '" << m_name << "' does not implement Type::read_from.";

src/serialization/SerializerBinary.cpp

@@ -15,7 +15,7 @@ namespace serialization
 		m_root_object = nullptr;
 	}
 
-	void SerializerBinary::save(const pclass::PropertyClass* object, BitStream& stream)
+	void SerializerBinary::save(const pclass::PropertyClass* object, BitStreamBase &stream)
 	{
 		// Write the serializer flags
 		if (FLAG_IS_SET(m_flags, flags::WRITE_SERIALIZER_FLAGS))
@@ -109,7 +109,7 @@ namespace serialization
 		}
 	}
 
-	void SerializerBinary::presave_object(const pclass::PropertyClass *object, BitStream& stream) const
+	void SerializerBinary::presave_object(const pclass::PropertyClass *object, BitStreamBase &stream) const
 	{
 		// If we have an object, write the type hash, otherwise, write NULL (0).
 		if (object)
@@ -118,7 +118,7 @@ namespace serialization
 			stream.write<uint32_t>(NULL);
 	}
 
-	void SerializerBinary::save_object(const pclass::PropertyClass *object, BitStream& stream) const
+	void SerializerBinary::save_object(const pclass::PropertyClass *object, BitStreamBase &stream) const
 	{
 		// Write any object headers
 		presave_object(object, stream);
@@ -156,7 +156,7 @@ namespace serialization
 		}
 	}
 
-	void SerializerBinary::save_property(const pclass::PropertyBase *prop, BitStream& stream) const
+	void SerializerBinary::save_property(const pclass::PropertyBase *prop, BitStreamBase &stream) const
 	{
 		// Remember where we started writing the property data
 		const auto start_pos = stream.tell();
@@ -227,7 +227,7 @@ namespace serialization
 		}
 	}
 
-	void SerializerBinary::load(pclass::PropertyClass*& dest, BitStream& stream)
+	void SerializerBinary::load(pclass::PropertyClass*& dest, BitStreamBase &stream)
 	{
 		// Read the serializer flags
 		if (FLAG_IS_SET(m_flags, flags::WRITE_SERIALIZER_FLAGS))
@@ -240,17 +240,17 @@ namespace serialization
 		}
 	}
 
-	void SerializerBinary::preload_object(pclass::PropertyClass*& dest, BitStream& stream) const
+	void SerializerBinary::preload_object(pclass::PropertyClass*& dest, BitStreamBase &stream) const
 	{
 		
 	}
 
-	void SerializerBinary::load_object(pclass::PropertyClass*& dest, BitStream& stream) const
+	void SerializerBinary::load_object(pclass::PropertyClass*& dest, BitStreamBase &stream) const
 	{
 		
 	}
 
-	void SerializerBinary::load_property(pclass::PropertyBase* prop, BitStream& stream) const
+	void SerializerBinary::load_property(pclass::PropertyBase* prop, BitStreamBase &stream) const
 	{
 		
 	}

src/util/BitStream.cpp

@@ -1,8 +1,7 @@
 #include "ki/util/BitStream.h"
+#include "ki/util/exception.h"
 #include <limits>
-#include <exception>
 #include <cstring>
-#include <stdexcept>
 #include <cmath>
 
 namespace ki
@@ -137,6 +136,40 @@ namespace ki
 		return copy;
 	}
 
+	void BitStreamBase::write_copy(uint8_t *src, const std::size_t bitsize)
+	{
+		// Copy all whole bytes
+		const auto bytes = bitsize / 8;
+		auto written_bytes = 0;
+		while (written_bytes < bytes)
+		{
+			write<uint8_t>(src[written_bytes]);
+			written_bytes++;
+		}
+
+		// Copy left over bits
+		const auto bits = bitsize % 8;
+		if (bits > 0)
+			write<uint8_t>(src[bytes + 1], bits);
+	}
+
+	void BitStreamBase::read_copy(uint8_t *dst, const std::size_t bitsize)
+	{
+		// Copy all whole bytes
+		const auto bytes = bitsize / 8;
+		auto read_bytes = 0;
+		while (read_bytes < bytes)
+		{
+			dst[read_bytes] = read<uint8_t>();
+			read_bytes++;
+		}
+
+		// Copy left over bits
+		const auto bits = bitsize % 8;
+		if (bits > 0)
+			dst[bytes + 1] = read<uint8_t>(bits);
+	}
+
 	BitStream::BitStream(const size_t buffer_size)
 	{
 		m_buffer = new uint8_t[buffer_size] { 0 };
@@ -170,38 +203,75 @@ namespace ki
 		return m_buffer;
 	}
 
-	void BitStream::write_copy(uint8_t *src, const std::size_t bitsize)
+	uint64_t BitStream::read(const uint8_t bits)
 	{
-		// Copy all whole bytes
+		// Do we have these bits available to read?
-		const auto bytes = bitsize / 8;
+		if ((m_position + bits).as_bits() > m_buffer_size * 8)
-		auto written_bytes = 0;
-		while (written_bytes < bytes)
 		{
-			write<uint8_t>(src[written_bytes]);
+			std::ostringstream oss;
-			written_bytes++;
+			oss << "Not enough data in buffer to read "
+				<< static_cast<uint16_t>(bits) << "bits.";
+			throw runtime_error(oss.str());
 		}
 
-		// Copy left over bits
+		// Iterate until we've read all of the bits
-		const auto bits = bitsize % 8;
+		uint64_t value = 0;
-		if (bits > 0)
+		auto unread_bits = bits;
-			write<uint8_t>(src[bytes + 1], bits);
+		while (unread_bits > 0)
+		{
+			// Calculate how many bits to read from the current byte based on how many bits 
+			// are left and how many bits we still need to read
+			const uint8_t bits_available = (8 - m_position.get_bit());
+			const auto bit_count = unread_bits < bits_available ? unread_bits : bits_available;
+
+			// Find the bit-mask based on how many bits are being read
+			const uint8_t bit_mask = (1 << bit_count) - 1 << m_position.get_bit();
+
+			// Read the bits from the current byte and position them on the least-signficant bit
+			const uint8_t bits_value = (m_buffer[m_position.get_byte()] & bit_mask) >> m_position.get_bit();
+
+			// Position the value of the bits we just read based on how many bits of the value 
+			// we've already read
+			const uint8_t read_bits = bits - unread_bits;
+			value |= static_cast<uint64_t>(bits_value) << read_bits;
+
+			// Remove the bits we just read from the count of unread bits
+			unread_bits -= bit_count;
+
+			// Move forward the number of bits we just read
+			seek(tell() + bit_count);
 		}
 
-	void BitStream::read_copy(uint8_t *dst, const std::size_t bitsize)
+		return value;
-	{
-		// Copy all whole bytes
-		const auto bytes = bitsize / 8;
-		auto read_bytes = 0;
-		while (read_bytes < bytes)
-		{
-			dst[read_bytes] = read<uint8_t>();
-			read_bytes++;
 	}
 
-		// Copy left over bits
+	void BitStream::write(const uint64_t value, const uint8_t bits)
-		const auto bits = bitsize % 8;
+	{
-		if (bits > 0)
+		// Iterate until we've written all of the bits
-			dst[bytes + 1] = read<uint8_t>(bits);
+		auto unwritten_bits = bits;
+		while (unwritten_bits > 0)
+		{
+			// Calculate how many bits to write based on how many bits are left in the current byte
+			// and how many bits from the value we still need to write
+			const uint8_t bits_available = (8 - m_position.get_bit());
+			const auto bit_count = unwritten_bits < bits_available ? unwritten_bits : bits_available;
+
+			// Find the bit-mask based on how many bits are being written, and how many bits we've
+			// already written
+			const uint8_t written_bits = bits - unwritten_bits;
+			const auto bit_mask = static_cast<uint64_t>((1 << bit_count) - 1) << written_bits;
+
+			// Get the bits from the value and position them at the current bit position
+			uint8_t value_byte = ((value & bit_mask) >> written_bits) & 0xFF;
+			value_byte <<= m_position.get_bit();
+
+			// Write the bits into the byte we're currently at
+			m_buffer[m_position.get_byte()] |= value_byte;
+			unwritten_bits -= bit_count;
+
+			// Move forward the number of bits we just wrote
+			seek(tell() + bit_count);
+		}
 	}
 
 	void BitStream::expand_buffer()
@@ -216,7 +286,7 @@ namespace ki
 
 		// Has the buffer reached maximum size?
 		if (new_size == m_buffer_size)
-			throw std::runtime_error("Buffer cannot be expanded as it has reached maximum size.");
+			throw runtime_error("Buffer cannot be expanded as it has reached maximum size.");
 
 		// Allocate a new buffer, copy everything over, and then delete the old buffer
 		auto *new_buffer = new uint8_t[new_size] { 0 };
@@ -230,7 +300,7 @@ namespace ki
 	{
 		// Make sure we haven't underflowed
 		if (m_position.get_byte() < 0)
-			throw std::runtime_error("Position of buffer is less than 0!");
+			throw runtime_error("Position of buffer is less than 0!");
 
 		// Expand the buffer if we've overflowed
 		if (m_position.get_byte() >= m_buffer_size)

test/src/unit-bitstream.cpp

@@ -254,3 +254,9 @@ TEST_CASE("BitStream buffer expansion", "[bit-stream]")
 	delete bit_stream;
 	SUCCEED();
 }
+
+/**
+* TODO: Test reading outside of buffer (should throw)
+* TODO: Test read/write copy on BitStream
+* TODO: Test BitStreamSection
+*/