Attempting to use an external library to handle bitstreams. Isn't going the grreatest.

include/bitstream/stream/bit_measure.h

@@ -0,0 +1,235 @@
+#pragma once
+#include "../utility/assert.h"
+#include "../utility/crc.h"
+#include "../utility/endian.h"
+#include "../utility/meta.h"
+
+#include "byte_buffer.h"
+#include "serialize_traits.h"
+
+#include <cstdint>
+#include <cstring>
+#include <limits>
+#include <memory>
+#include <type_traits>
+
+namespace bitstream
+{
+	/**
+	 * @brief A stream for writing objects tightly into a buffer
+	 * @note Does not take ownership of the buffer
+	*/
+	class bit_measure
+	{
+	public:
+		static constexpr bool writing = true;
+		static constexpr bool reading = false;
+
+		/**
+		 * @brief Default construct a writer pointing to a null buffer
+		*/
+		bit_measure() noexcept :
+			m_NumBitsWritten(0),
+			m_TotalBits((std::numeric_limits<uint32_t>::max)()) {}
+
+		/**
+		 * @brief Construct a writer pointing to the given byte array with @p num_bytes size
+		 * @param num_bytes The number of bytes in the array
+		*/
+		bit_measure(uint32_t num_bytes) noexcept :
+			m_NumBitsWritten(0),
+			m_TotalBits(num_bytes * 8) {}
+
+		bit_measure(const bit_measure&) = delete;
+
+		bit_measure(bit_measure&& other) noexcept :
+			m_NumBitsWritten(other.m_NumBitsWritten),
+			m_TotalBits(other.m_TotalBits)
+		{
+			other.m_NumBitsWritten = 0;
+			other.m_TotalBits = 0;
+		}
+
+		bit_measure& operator=(const bit_measure&) = delete;
+
+		bit_measure& operator=(bit_measure&& rhs) noexcept
+		{
+			m_NumBitsWritten = rhs.m_NumBitsWritten;
+			m_TotalBits = rhs.m_TotalBits;
+
+			rhs.m_NumBitsWritten = 0;
+			rhs.m_TotalBits = 0;
+
+			return *this;
+		}
+
+		/**
+		 * @brief Returns the buffer that this writer is currently serializing into
+		 * @return The buffer
+		*/
+		[[nodiscard]] uint8_t* get_buffer() const noexcept { return nullptr; }
+
+		/**
+		 * @brief Returns the number of bits which have been written to the buffer
+		 * @return The number of bits which have been written
+		*/
+		[[nodiscard]] uint32_t get_num_bits_serialized() const noexcept { return m_NumBitsWritten; }
+
+		/**
+		 * @brief Returns the number of bytes which have been written to the buffer
+		 * @return The number of bytes which have been written
+		*/
+		[[nodiscard]] uint32_t get_num_bytes_serialized() const noexcept { return m_NumBitsWritten > 0U ? ((m_NumBitsWritten - 1U) / 8U + 1U) : 0U; }
+
+		/**
+		 * @brief Returns whether the @p num_bits can fit in the buffer
+		 * @param num_bits The number of bits to test
+		 * @return Whether the number of bits can fit in the buffer
+		*/
+		[[nodiscard]] bool can_serialize_bits(uint32_t num_bits) const noexcept { return m_NumBitsWritten + num_bits <= m_TotalBits; }
+
+		/**
+		 * @brief Returns the number of bits which have not been written yet
+		 * @note The same as get_total_bits() - get_num_bits_serialized()
+		 * @return The remaining space in the buffer
+		*/
+		[[nodiscard]] uint32_t get_remaining_bits() const noexcept { return m_TotalBits - m_NumBitsWritten; }
+
+		/**
+		 * @brief Returns the size of the buffer, in bits
+		 * @return The size of the buffer, in bits
+		*/
+		[[nodiscard]] uint32_t get_total_bits() const noexcept { return m_TotalBits; }
+
+		/**
+		 * @brief Instructs the writer that you intend to use `serialize_checksum()` later on, and to reserve the first 32 bits.
+		 * @return Returns false if anything has already been written to the buffer or if there's no space to write the checksum
+		*/
+		[[nodiscard]] bool prepend_checksum() noexcept
+		{
+			BS_ASSERT(m_NumBitsWritten == 0);
+
+			BS_ASSERT(can_serialize_bits(32U));
+
+			m_NumBitsWritten += 32U;
+
+			return true;
+		}
+
+		/**
+		 * @brief Writes a checksum of the @p protocol_version and the rest of the buffer as the first 32 bits
+		 * @param protocol_version A unique version number
+		 * @return The number of bytes written to the buffer
+		*/
+		uint32_t serialize_checksum(uint32_t protocol_version) noexcept
+		{
+			return m_NumBitsWritten;
+		}
+
+		/**
+		 * @brief Pads the buffer up to the given number of bytes with zeros
+		 * @param num_bytes The byte number to pad to
+		 * @return Returns false if the current size of the buffer is bigger than @p num_bytes
+		*/
+		[[nodiscard]] bool pad_to_size(uint32_t num_bytes) noexcept
+		{
+			BS_ASSERT(num_bytes * 8U <= m_TotalBits);
+
+			BS_ASSERT(num_bytes * 8U >= m_NumBitsWritten);
+
+			m_NumBitsWritten = num_bytes * 8U;
+
+			return true;
+		}
+
+		/**
+		 * @brief Pads the buffer up with the given number of bytes
+		 * @param num_bytes The amount of bytes to pad
+		 * @return Returns false if the current size of the buffer is bigger than @p num_bytes or if the padded bits are not zeros.
+		*/
+		[[nodiscard]] bool pad(uint32_t num_bytes) noexcept
+		{
+			return pad_to_size(get_num_bytes_serialized() + num_bytes);
+		}
+
+		/**
+		 * @brief Pads the buffer with up to 8 zeros, so that the next write is byte-aligned
+		 * @return Success
+		*/
+		[[nodiscard]] bool align() noexcept
+		{
+			uint32_t remainder = m_NumBitsWritten % 8U;
+			if (remainder != 0U)
+				m_NumBitsWritten += 8U - remainder;
+			return true;
+		}
+
+		/**
+		 * @brief Writes the first @p num_bits bits of @p value into the buffer
+		 * @param value The value to serialize
+		 * @param num_bits The number of bits of the @p value to serialize
+		 * @return Returns false if @p num_bits is less than 1 or greater than 32 or if writing the given number of bits would overflow the buffer
+		*/
+		[[nodiscard]] bool serialize_bits(uint32_t value, uint32_t num_bits) noexcept
+		{
+			BS_ASSERT(num_bits > 0U && num_bits <= 32U);
+
+			BS_ASSERT(can_serialize_bits(num_bits));
+
+			m_NumBitsWritten += num_bits;
+
+			return true;
+		}
+
+		/**
+		 * @brief Writes the first @p num_bits bits of the given byte array, 32 bits at a time
+		 * @param bytes The bytes to serialize
+		 * @param num_bits The number of bits of the @p bytes to serialize
+		 * @return Returns false if @p num_bits is less than 1 or if writing the given number of bits would overflow the buffer
+		*/
+		[[nodiscard]] bool serialize_bytes(const uint8_t* bytes, uint32_t num_bits) noexcept
+		{
+			BS_ASSERT(num_bits > 0U);
+
+			BS_ASSERT(can_serialize_bits(num_bits));
+
+			m_NumBitsWritten += num_bits;
+
+			return true;
+		}
+
+		/**
+		 * @brief Writes to the buffer, using the given @p Trait.
+		 * @note The Trait type in this function must always be explicitly declared
+		 * @tparam Trait A template specialization of serialize_trait<>
+		 * @tparam ...Args The types of the arguments to pass to the serialize function
+		 * @param ...args The arguments to pass to the serialize function
+		 * @return Whether successful or not
+		*/
+		template<typename Trait, typename... Args, typename = utility::has_serialize_t<Trait, bit_measure, Args...>>
+		[[nodiscard]] bool serialize(Args&&... args) noexcept(utility::is_serialize_noexcept_v<Trait, bit_measure, Args...>)
+		{
+			return serialize_traits<Trait>::serialize(*this, std::forward<Args>(args)...);
+		}
+
+		/**
+		 * @brief Writes to the buffer, by trying to deduce the trait.
+		 * @note The Trait type in this function is always implicit and will be deduced from the first argument if possible.
+		 * If the trait cannot be deduced it will not compile.
+		 * @tparam Trait The type of the first argument, which will be used to deduce the trait specialization
+		 * @tparam ...Args The types of the arguments to pass to the serialize function
+		 * @param arg The first argument to pass to the serialize function
+		 * @param ...args The rest of the arguments to pass to the serialize function
+		 * @return Whether successful or not
+		*/
+		template<typename... Args, typename Trait, typename = utility::has_deduce_serialize_t<Trait, bit_measure, Args...>>
+		[[nodiscard]] bool serialize(Trait&& arg, Args&&... args) noexcept(utility::is_deduce_serialize_noexcept_v<Trait, bit_measure, Args...>)
+		{
+			return serialize_traits<utility::deduce_trait_t<Trait, bit_measure, Args...>>::serialize(*this, std::forward<Trait>(arg), std::forward<Args>(args)...);
+		}
+
+	private:
+		uint32_t m_NumBitsWritten;
+		uint32_t m_TotalBits;
+	};
+}

include/bitstream/stream/bit_reader.h

@@ -0,0 +1,343 @@
+#pragma once
+#include "../utility/assert.h"
+#include "../utility/crc.h"
+#include "../utility/endian.h"
+#include "../utility/meta.h"
+
+#include "byte_buffer.h"
+#include "serialize_traits.h"
+#include "stream_traits.h"
+
+#include <cstdint>
+#include <cstring>
+#include <string>
+#include <type_traits>
+
+namespace bitstream
+{
+	/**
+	 * @brief A stream for reading objects from a tightly packed buffer
+	 * @tparam Policy The underlying representation of the buffer
+	*/
+	template<typename Policy>
+	class bit_reader
+	{
+	public:
+		static constexpr bool writing = false;
+		static constexpr bool reading = true;
+
+		/**
+		 * @brief Construct a reader with the parameters passed to the underlying policy
+		 * @param ...args The arguments to pass to the policy
+		*/
+		template<typename... Ts,
+			typename = std::enable_if_t<std::is_constructible_v<Policy, Ts...>>>
+		bit_reader(Ts&&... args)
+			noexcept(std::is_nothrow_constructible_v<Policy, Ts...>) :
+			m_Policy(std::forward<Ts>(args) ...),
+			m_Scratch(0),
+			m_ScratchBits(0),
+			m_WordIndex(0) {}
+
+		bit_reader(const bit_reader&) = delete;
+        
+		bit_reader(bit_reader&& other) noexcept :
+			m_Policy(std::move(other.m_Policy)),
+            m_Scratch(other.m_Scratch),
+            m_ScratchBits(other.m_ScratchBits),
+            m_WordIndex(other.m_WordIndex)
+        {
+            other.m_Scratch = 0;
+            other.m_ScratchBits = 0;
+            other.m_WordIndex = 0;
+        }
+
+		bit_reader& operator=(const bit_reader&) = delete;
+
+		bit_reader& operator=(bit_reader&& rhs) noexcept
+		{
+			m_Policy = std::move(rhs.m_Policy);
+			m_Scratch = rhs.m_Scratch;
+			m_ScratchBits = rhs.m_ScratchBits;
+			m_WordIndex = rhs.m_WordIndex;
+
+			rhs.m_Scratch = 0;
+			rhs.m_ScratchBits = 0;
+			rhs.m_WordIndex = 0;
+            
+            return *this;
+		}
+
+		/**
+		 * @brief Returns the buffer that this reader is currently serializing from
+		 * @return The buffer
+		*/
+		[[nodiscard]] const uint8_t* get_buffer() const noexcept { return reinterpret_cast<const uint8_t*>(m_Policy.get_buffer()); }
+
+		/**
+		 * @brief Returns the number of bits which have been read from the buffer
+		 * @return The number of bits which have been read
+		*/
+		[[nodiscard]] uint32_t get_num_bits_serialized() const noexcept { return m_Policy.get_num_bits_serialized(); }
+
+		/**
+		 * @brief Returns the number of bytes which have been read from the buffer
+		 * @return The number of bytes which have been read
+		*/
+		[[nodiscard]] uint32_t get_num_bytes_serialized() const noexcept { return get_num_bits_serialized() > 0U ? ((get_num_bits_serialized() - 1U) / 8U + 1U) : 0U; }
+
+		/**
+		 * @brief Returns whether the @p num_bits be read from the buffer
+		 * @param num_bits The number of bits to test
+		 * @return Whether the number of bits can be read from the buffer
+		*/
+		[[nodiscard]] bool can_serialize_bits(uint32_t num_bits) const noexcept { return m_Policy.can_serialize_bits(num_bits); }
+
+		/**
+		 * @brief Returns the number of bits which have not been read yet
+		 * @note The same as get_total_bits() - get_num_bits_serialized()
+		 * @return The remaining space in the buffer
+		*/
+		[[nodiscard]] uint32_t get_remaining_bits() const noexcept { return get_total_bits() - get_num_bits_serialized(); }
+
+		/**
+		 * @brief Returns the size of the buffer, in bits
+		 * @return The size of the buffer, in bits
+		*/
+		[[nodiscard]] uint32_t get_total_bits() const noexcept { return m_Policy.get_total_bits(); }
+
+		/**
+		 * @brief Reads the first 32 bits of the buffer and compares it to a checksum of the @p protocol_version and the rest of the buffer
+		 * @param protocol_version A unique version number
+		 * @return Whether the checksum matches what was written
+		*/
+		[[nodiscard]] bool serialize_checksum(uint32_t protocol_version) noexcept
+		{
+			BS_ASSERT(get_num_bits_serialized() == 0);
+
+			BS_ASSERT(can_serialize_bits(32U));
+
+			uint32_t num_bytes = (get_total_bits() - 1U) / 8U + 1U;
+			const uint32_t* buffer = m_Policy.get_buffer();
+
+			// Generate checksum to compare against
+			uint32_t generated_checksum = utility::crc_uint32(reinterpret_cast<const uint8_t*>(&protocol_version), reinterpret_cast<const uint8_t*>(buffer + 1), num_bytes - 4);
+
+			// Advance the reader by the size of the checksum (32 bits / 1 word)
+			m_WordIndex++;
+
+			BS_ASSERT(m_Policy.extend(32U));
+
+			// Read the checksum
+			uint32_t checksum = *buffer;
+
+			// Compare the checksum
+			return generated_checksum == checksum;
+		}
+
+		/**
+		 * @brief Pads the buffer up to the given number of bytes
+		 * @param num_bytes The byte number to pad to
+		 * @return Returns false if the current size of the buffer is bigger than @p num_bytes or if the padded bits are not zeros.
+		*/
+		[[nodiscard]] bool pad_to_size(uint32_t num_bytes) noexcept
+		{
+			uint32_t num_bits_read = get_num_bits_serialized();
+
+			BS_ASSERT(num_bytes * 8U >= num_bits_read);
+
+			BS_ASSERT(can_serialize_bits(num_bytes * 8U - num_bits_read));
+
+			uint32_t remainder = (num_bytes * 8U - num_bits_read) % 32U;
+			uint32_t zero;
+
+			// Test the last word more carefully, as it may have data
+			if (remainder != 0U)
+			{
+				bool status = serialize_bits(zero, remainder);
+				BS_ASSERT(status && zero == 0);
+			}
+
+			uint32_t offset = get_num_bits_serialized() / 32;
+            uint32_t max = num_bytes / 4;
+
+			// Test for zeros in padding
+			for (uint32_t i = offset; i < max; i++)
+			{
+				bool status = serialize_bits(zero, 32);
+				BS_ASSERT(status && zero == 0);
+			}
+
+			return true;
+		}
+
+		/**
+		 * @brief Pads the buffer up with the given number of bytes
+		 * @param num_bytes The amount of bytes to pad
+		 * @return Returns false if the current size of the buffer is bigger than @p num_bytes or if the padded bits are not zeros.
+		*/
+		[[nodiscard]] bool pad(uint32_t num_bytes) noexcept
+		{
+			return pad_to_size(get_num_bytes_serialized() + num_bytes);
+		}
+
+		/**
+		 * @brief Pads the buffer with up to 8 zeros, so that the next read is byte-aligned
+		 * @notes Return false if the padded bits are not zeros
+		 * @return Returns false if the padded bits are not zeros
+		*/
+		[[nodiscard]] bool align() noexcept
+		{
+			uint32_t remainder = get_num_bits_serialized() % 8U;
+			if (remainder != 0U)
+			{
+				uint32_t zero;
+				bool status = serialize_bits(zero, 8U - remainder);
+
+                BS_ASSERT(status && zero == 0U && get_num_bits_serialized() % 8U == 0U);
+			}
+
+			return true;
+		}
+
+		/**
+		 * @brief Reads the first @p num_bits bits of @p value from the buffer
+		 * @param value The value to serialize
+		 * @param num_bits The number of bits of the @p value to serialize
+		 * @return Returns false if @p num_bits is less than 1 or greater than 32 or if reading the given number of bits would overflow the buffer
+		*/
+		[[nodiscard]] bool serialize_bits(uint32_t& value, uint32_t num_bits) noexcept
+		{
+			BS_ASSERT(num_bits > 0U && num_bits <= 32U);
+
+			BS_ASSERT(m_Policy.extend(num_bits));
+
+			// This is actually slower
+			// Possibly due to unlikely branching
+			/*if (num_bits == 32U && m_ScratchBits == 0U)
+			{
+				const uint32_t* ptr = m_Policy.get_buffer() + m_WordIndex;
+
+				value = utility::to_big_endian32(*ptr);
+
+				m_WordIndex++;
+
+				return true;
+			}*/
+
+			if (m_ScratchBits < num_bits)
+			{
+				const uint32_t* ptr = m_Policy.get_buffer() + m_WordIndex;
+
+				uint64_t ptr_value = static_cast<uint64_t>(utility::to_big_endian32(*ptr)) << (32U - m_ScratchBits);
+				m_Scratch |= ptr_value;
+				m_ScratchBits += 32U;
+				m_WordIndex++;
+			}
+
+			uint32_t offset = 64U - num_bits;
+			value = static_cast<uint32_t>(m_Scratch >> offset);
+
+			m_Scratch <<= num_bits;
+			m_ScratchBits -= num_bits;
+
+			return true;
+		}
+
+		/**
+		 * @brief Reads the first @p num_bits bits of the given byte array, 32 bits at a time
+		 * @param bytes The bytes to serialize
+		 * @param num_bits The number of bits of the @p bytes to serialize
+		 * @return Returns false if @p num_bits is less than 1 or if reading the given number of bits would overflow the buffer
+		*/
+		[[nodiscard]] bool serialize_bytes(uint8_t* bytes, uint32_t num_bits) noexcept
+		{
+			BS_ASSERT(num_bits > 0U);
+            
+			BS_ASSERT(can_serialize_bits(num_bits));
+            
+            // Read the byte array as words
+            uint32_t* word_buffer = reinterpret_cast<uint32_t*>(bytes);
+			uint32_t num_words = num_bits / 32U;
+            
+            if (m_ScratchBits % 32U == 0U && num_words > 0U)
+            {
+				BS_ASSERT(m_Policy.extend(num_words * 32U));
+
+                // If the read buffer is word-aligned, just memcpy it
+                std::memcpy(word_buffer, m_Policy.get_buffer() + m_WordIndex, num_words * 4U);
+                
+                m_WordIndex += num_words;
+            }
+            else
+            {
+                // If the buffer is not word-aligned, serialize a word at a time
+                for (uint32_t i = 0U; i < num_words; i++)
+                {
+                    uint32_t value;
+                    BS_ASSERT(serialize_bits(value, 32U));
+                    
+                    // Casting a byte-array to an int is wrong on little-endian systems
+                    // We have to swap the bytes around
+                    word_buffer[i] = utility::to_big_endian32(value);
+                }
+            }
+            
+            // Early exit if the word-count matches
+            if (num_bits % 32 == 0)
+                return true;
+            
+            uint32_t remaining_bits = num_bits - num_words * 32U;
+            
+            uint32_t num_bytes = (remaining_bits - 1U) / 8U + 1U;
+			for (uint32_t i = 0; i < num_bytes; i++)
+			{
+                uint32_t value;
+				BS_ASSERT(serialize_bits(value, (std::min)(remaining_bits - i * 8U, 8U)));
+                
+				bytes[num_words * 4 + i] = static_cast<uint8_t>(value);
+			}
+
+			return true;
+		}
+
+		/**
+		 * @brief Reads from the buffer, using the given @p Trait.
+		 * @note The Trait type in this function must always be explicitly declared
+		 * @tparam Trait A template specialization of serialize_trait<>
+		 * @tparam ...Args The types of the arguments to pass to the serialize function
+		 * @param ...args The arguments to pass to the serialize function
+		 * @return Whether successful or not
+		*/
+		template<typename Trait, typename... Args, typename = utility::has_serialize_t<Trait, bit_reader, Args...>>
+		[[nodiscard]] bool serialize(Args&&... args) noexcept(utility::is_serialize_noexcept_v<Trait, bit_reader, Args...>)
+		{
+			return serialize_traits<Trait>::serialize(*this, std::forward<Args>(args)...);
+		}
+
+		/**
+		 * @brief Reads from the buffer, by trying to deduce the trait.
+		 * @note The Trait type in this function is always implicit and will be deduced from the first argument if possible.
+		 * If the trait cannot be deduced it will not compile.
+		 * @tparam Trait The type of the first argument, which will be used to deduce the trait specialization
+		 * @tparam ...Args The types of the arguments to pass to the serialize function
+		 * @param arg The first argument to pass to the serialize function
+		 * @param ...args The rest of the arguments to pass to the serialize function
+		 * @return Whether successful or not
+		*/
+		template<typename... Args, typename Trait, typename = utility::has_deduce_serialize_t<Trait, bit_reader, Args...>>
+		[[nodiscard]] bool serialize(Trait&& arg, Args&&... args) noexcept(utility::is_deduce_serialize_noexcept_v<Trait, bit_reader, Args...>)
+		{
+			return serialize_traits<utility::deduce_trait_t<Trait, bit_reader, Args...>>::serialize(*this, std::forward<Trait>(arg), std::forward<Args>(args)...);
+		}
+
+	private:
+		Policy m_Policy;
+
+		uint64_t m_Scratch;
+		uint32_t m_ScratchBits;
+		uint32_t m_WordIndex;
+	};
+
+	using fixed_bit_reader = bit_reader<fixed_policy>;
+}

include/bitstream/stream/bit_writer.h

@@ -0,0 +1,400 @@
+#pragma once
+#include "../utility/assert.h"
+#include "../utility/crc.h"
+#include "../utility/endian.h"
+#include "../utility/meta.h"
+
+#include "byte_buffer.h"
+#include "serialize_traits.h"
+#include "stream_traits.h"
+
+#include <cstdint>
+#include <cstring>
+#include <memory>
+#include <type_traits>
+
+namespace bitstream
+{
+	/**
+	 * @brief A stream for writing objects tightly into a buffer
+	 * @tparam Policy The underlying representation of the buffer
+	*/
+	template<typename Policy>
+	class bit_writer
+	{
+	public:
+		static constexpr bool writing = true;
+		static constexpr bool reading = false;
+
+		/**
+		 * @brief Construct a writer with the parameters passed to the underlying policy
+		 * @param ...args The arguments to pass to the policy
+		*/
+		template<typename... Ts,
+			typename = std::enable_if_t<std::is_constructible_v<Policy, Ts...>>>
+		bit_writer(Ts&&... args)
+			noexcept(std::is_nothrow_constructible_v<Policy, Ts...>) :
+			m_Policy(std::forward<Ts>(args) ...),
+			m_Scratch(0),
+			m_ScratchBits(0),
+			m_WordIndex(0) {}
+
+		bit_writer(const bit_writer&) = delete;
+        
+		bit_writer(bit_writer&& other) noexcept :
+            m_Policy(std::move(other.m_Policy)),
+            m_Scratch(other.m_Scratch),
+            m_ScratchBits(other.m_ScratchBits),
+            m_WordIndex(other.m_WordIndex)
+        {
+            other.m_Scratch = 0;
+            other.m_ScratchBits = 0;
+            other.m_WordIndex = 0;
+        }
+
+		bit_writer& operator=(const bit_writer&) = delete;
+
+		bit_writer& operator=(bit_writer&& rhs) noexcept
+		{
+			m_Policy = std::move(rhs.m_Policy);
+			m_Scratch = rhs.m_Scratch;
+			m_ScratchBits = rhs.m_ScratchBits;
+			m_WordIndex = rhs.m_WordIndex;
+
+			rhs.m_Scratch = 0;
+			rhs.m_ScratchBits = 0;
+			rhs.m_WordIndex = 0;
+            
+            return *this;
+		}
+
+		/**
+		 * @brief Returns the buffer that this writer is currently serializing into
+		 * @return The buffer
+		*/
+		[[nodiscard]] uint8_t* get_buffer() const noexcept { return reinterpret_cast<uint8_t*>(m_Policy.get_buffer()); }
+
+		/**
+		 * @brief Returns the number of bits which have been written to the buffer
+		 * @return The number of bits which have been written
+		*/
+		[[nodiscard]] uint32_t get_num_bits_serialized() const noexcept { return m_Policy.get_num_bits_serialized(); }
+
+		/**
+		 * @brief Returns the number of bytes which have been written to the buffer
+		 * @return The number of bytes which have been written
+		*/
+		[[nodiscard]] uint32_t get_num_bytes_serialized() const noexcept { return get_num_bits_serialized() > 0U ? ((get_num_bits_serialized() - 1U) / 8U + 1U) : 0U; }
+
+		/**
+		 * @brief Returns whether the @p num_bits can fit in the buffer
+		 * @param num_bits The number of bits to test
+		 * @return Whether the number of bits can fit in the buffer
+		*/
+		[[nodiscard]] bool can_serialize_bits(uint32_t num_bits) const noexcept { return m_Policy.can_serialize_bits(num_bits); }
+
+		/**
+		 * @brief Returns the number of bits which have not been written yet
+		 * @note The same as get_total_bits() - get_num_bits_serialized()
+		 * @return The remaining space in the buffer
+		*/
+		[[nodiscard]] uint32_t get_remaining_bits() const noexcept { return get_total_bits() - get_num_bits_serialized(); }
+
+        /**
+         * @brief Returns the size of the buffer, in bits
+         * @return The size of the buffer, in bits
+        */
+		[[nodiscard]] uint32_t get_total_bits() const noexcept { return m_Policy.get_total_bits(); }
+        
+		/**
+		 * @brief Flushes any remaining bits into the buffer. Use this when you no longer intend to write anything to the buffer.
+		 * @return The number of bytes written to the buffer
+		*/
+		uint32_t flush() noexcept
+		{
+			if (m_ScratchBits > 0U)
+			{
+				uint32_t* ptr = m_Policy.get_buffer() + m_WordIndex;
+				uint32_t ptr_value = static_cast<uint32_t>(m_Scratch >> 32U);
+				*ptr = utility::to_big_endian32(ptr_value);
+
+				m_Scratch = 0U;
+				m_ScratchBits = 0U;
+				m_WordIndex++;
+			}
+
+			return get_num_bits_serialized();
+		}
+
+		/**
+		 * @brief Instructs the writer that you intend to use `serialize_checksum()` later on, and to reserve the first 32 bits.
+		 * @return Returns false if anything has already been written to the buffer or if there's no space to write the checksum
+		*/
+		[[nodiscard]] bool prepend_checksum() noexcept
+		{
+			BS_ASSERT(get_num_bits_serialized() == 0);
+
+            BS_ASSERT(m_Policy.extend(32U));
+            
+			// Advance the reader by the size of the checksum (32 bits / 1 word)
+			m_WordIndex++;
+            
+            return true;
+		}
+
+		/**
+		 * @brief Writes a checksum of the @p protocol_version and the rest of the buffer as the first 32 bits
+		 * @param protocol_version A unique version number
+		 * @return The number of bytes written to the buffer
+		*/
+		uint32_t serialize_checksum(uint32_t protocol_version) noexcept
+		{
+			uint32_t num_bits = flush();
+
+			BS_ASSERT(num_bits > 32U);
+
+			// Copy protocol version to buffer
+			uint32_t* buffer = m_Policy.get_buffer();
+			*buffer = protocol_version;
+
+			// Generate checksum of version + data
+			uint32_t checksum = utility::crc_uint32(reinterpret_cast<uint8_t*>(buffer), get_num_bytes_serialized());
+
+			// Put checksum at beginning
+			*buffer = checksum;
+
+			return num_bits;
+		}
+
+		/**
+		 * @brief Pads the buffer up to the given number of bytes with zeros
+		 * @param num_bytes The byte number to pad to
+		 * @return Returns false if the current size of the buffer is bigger than @p num_bytes
+		*/
+		[[nodiscard]] bool pad_to_size(uint32_t num_bytes) noexcept
+		{
+			uint32_t num_bits_written = get_num_bits_serialized();
+
+			BS_ASSERT(num_bytes * 8U >= num_bits_written);
+
+			BS_ASSERT(can_serialize_bits(num_bytes * 8U - num_bits_written));
+
+            if (num_bits_written == 0)
+            {
+				BS_ASSERT(m_Policy.extend(num_bytes * 8U - num_bits_written));
+
+                std::memset(m_Policy.get_buffer(), 0, num_bytes);
+                
+                m_Scratch = 0;
+                m_ScratchBits = 0;
+                m_WordIndex = num_bytes / 4;
+                
+                return true;
+            }
+            
+            uint32_t remainder = (num_bytes * 8U - num_bits_written) % 32U;
+			uint32_t zero = 0;
+
+			// Align to byte
+			if (remainder != 0U)
+				BS_ASSERT(serialize_bits(zero, remainder));
+
+			uint32_t offset = get_num_bits_serialized() / 32;
+            uint32_t max = num_bytes / 4;
+
+			// Serialize words
+			for (uint32_t i = offset; i < max; i++)
+				BS_ASSERT(serialize_bits(zero, 32));
+
+			return true;
+		}
+
+		/**
+		 * @brief Pads the buffer up with the given number of bytes
+		 * @param num_bytes The amount of bytes to pad
+		 * @return Returns false if the current size of the buffer is bigger than @p num_bytes or if the padded bits are not zeros.
+		*/
+		[[nodiscard]] bool pad(uint32_t num_bytes) noexcept
+		{
+			return pad_to_size(get_num_bytes_serialized() + num_bytes);
+		}
+
+		/**
+		 * @brief Pads the buffer with up to 8 zeros, so that the next write is byte-aligned
+		 * @return Success
+		*/
+		[[nodiscard]] bool align() noexcept
+		{
+			uint32_t remainder = m_ScratchBits % 8U;
+			if (remainder != 0U)
+			{
+				uint32_t zero = 0U;
+				bool status = serialize_bits(zero, 8U - remainder);
+
+				BS_ASSERT(status && get_num_bits_serialized() % 8U == 0U);
+			}
+			return true;
+		}
+
+		/**
+		 * @brief Writes the first @p num_bits bits of @p value into the buffer
+		 * @param value The value to serialize
+		 * @param num_bits The number of bits of the @p value to serialize
+		 * @return Returns false if @p num_bits is less than 1 or greater than 32 or if writing the given number of bits would overflow the buffer
+		*/
+		[[nodiscard]] bool serialize_bits(uint32_t value, uint32_t num_bits) noexcept
+		{
+			BS_ASSERT(num_bits > 0U && num_bits <= 32U);
+
+			BS_ASSERT(m_Policy.extend(num_bits));
+
+			// This is actually slower
+			// Possibly due to unlikely branching
+			/*if (num_bits == 32U && m_ScratchBits == 0U)
+			{
+				uint32_t* ptr = m_Policy.get_buffer() + m_WordIndex;
+
+				*ptr = utility::to_big_endian32(value);
+
+				m_WordIndex++;
+
+				return true;
+			}*/
+
+			uint32_t offset = 64U - num_bits - m_ScratchBits;
+			uint64_t ls_value = static_cast<uint64_t>(value) << offset;
+
+			m_Scratch |= ls_value;
+			m_ScratchBits += num_bits;
+
+			if (m_ScratchBits >= 32U)
+			{
+				uint32_t* ptr = m_Policy.get_buffer() + m_WordIndex;
+				uint32_t ptr_value = static_cast<uint32_t>(m_Scratch >> 32U);
+				*ptr = utility::to_big_endian32(ptr_value);
+				m_Scratch <<= 32ULL;
+				m_ScratchBits -= 32U;
+				m_WordIndex++;
+			}
+
+			return true;
+		}
+
+		/**
+		 * @brief Writes the first @p num_bits bits of the given byte array, 32 bits at a time
+		 * @param bytes The bytes to serialize
+		 * @param num_bits The number of bits of the @p bytes to serialize
+		 * @return Returns false if @p num_bits is less than 1 or if writing the given number of bits would overflow the buffer
+		*/
+		[[nodiscard]] bool serialize_bytes(const uint8_t* bytes, uint32_t num_bits) noexcept
+		{
+			BS_ASSERT(num_bits > 0U);
+            
+			BS_ASSERT(can_serialize_bits(num_bits));
+            
+            // Write the byte array as words
+            const uint32_t* word_buffer = reinterpret_cast<const uint32_t*>(bytes);
+			uint32_t num_words = num_bits / 32U;
+            
+            if (m_ScratchBits % 32U == 0U && num_words > 0U)
+            {
+				BS_ASSERT(m_Policy.extend(num_words * 32U));
+
+                // If the written buffer is word-aligned, just memcpy it
+                std::memcpy(m_Policy.get_buffer() + m_WordIndex, word_buffer, num_words * 4U);
+                
+                m_WordIndex += num_words;
+            }
+            else
+            {
+                // If the buffer is not word-aligned, serialize a word at a time
+                for (uint32_t i = 0U; i < num_words; i++)
+                {
+                    // Casting a byte-array to an int is wrong on little-endian systems
+                    // We have to swap the bytes around
+                    uint32_t value = utility::to_big_endian32(word_buffer[i]);
+                    BS_ASSERT(serialize_bits(value, 32U));
+                }
+            }
+            
+            // Early exit if the word-count matches
+            if (num_bits % 32U == 0U)
+                return true;
+            
+            uint32_t remaining_bits = num_bits - num_words * 32U;
+            
+            uint32_t num_bytes = (remaining_bits - 1U) / 8U + 1U;
+			for (uint32_t i = 0U; i < num_bytes; i++)
+			{
+				uint32_t value = static_cast<uint32_t>(bytes[num_words * 4U + i]);
+				BS_ASSERT(serialize_bits(value, (std::min)(remaining_bits - i * 8U, 8U)));
+			}
+
+			return true;
+		}
+
+		/**
+		 * @brief Writes the contents of the buffer into the given @p writer. Essentially copies the entire buffer without modifying it.
+		 * @param writer The writer to copy into
+		 * @return Returns false if writing would overflow the buffer
+		*/
+		[[nodiscard]] bool serialize_into(bit_writer& writer) const noexcept
+		{
+			uint8_t* buffer = reinterpret_cast<uint8_t*>(m_Policy.get_buffer());
+			uint32_t num_bits = get_num_bits_serialized();
+			uint32_t remainder_bits = num_bits % 8U;
+
+			BS_ASSERT(writer.serialize_bytes(buffer, num_bits - remainder_bits));
+
+			if (remainder_bits > 0U)
+			{
+				uint32_t byte_value = buffer[num_bits / 8U] >> (8U - remainder_bits);
+				BS_ASSERT(writer.serialize_bits(byte_value, remainder_bits));
+			}
+
+			return true;
+		}
+
+		/**
+		 * @brief Writes to the buffer, using the given @p Trait.
+		 * @note The Trait type in this function must always be explicitly declared
+		 * @tparam Trait A template specialization of serialize_trait<>
+		 * @tparam ...Args The types of the arguments to pass to the serialize function
+		 * @param ...args The arguments to pass to the serialize function
+		 * @return Whether successful or not
+		*/
+		template<typename Trait, typename... Args, typename = utility::has_serialize_t<Trait, bit_writer, Args...>>
+		[[nodiscard]] bool serialize(Args&&... args) noexcept(utility::is_serialize_noexcept_v<Trait, bit_writer, Args...>)
+		{
+			return serialize_traits<Trait>::serialize(*this, std::forward<Args>(args)...);
+		}
+
+		/**
+		 * @brief Writes to the buffer, by trying to deduce the trait.
+		 * @note The Trait type in this function is always implicit and will be deduced from the first argument if possible.
+		 * If the trait cannot be deduced it will not compile.
+		 * @tparam Trait The type of the first argument, which will be used to deduce the trait specialization
+		 * @tparam ...Args The types of the arguments to pass to the serialize function
+		 * @param arg The first argument to pass to the serialize function
+		 * @param ...args The rest of the arguments to pass to the serialize function
+		 * @return Whether successful or not
+		*/
+		template<typename... Args, typename Trait, typename = utility::has_deduce_serialize_t<Trait, bit_writer, Args...>>
+		[[nodiscard]] bool serialize(Trait&& arg, Args&&... args) noexcept(utility::is_deduce_serialize_noexcept_v<Trait, bit_writer, Args...>)
+		{
+			return serialize_traits<utility::deduce_trait_t<Trait, bit_writer, Args...>>::serialize(*this, std::forward<Trait>(arg), std::forward<Args>(args)...);
+		}
+
+	private:
+		Policy m_Policy;
+
+		uint64_t m_Scratch;
+		int m_ScratchBits;
+		size_t m_WordIndex;
+	};
+
+	using fixed_bit_writer = bit_writer<fixed_policy>;
+
+	template<typename T>
+	using growing_bit_writer = bit_writer<growing_policy<T>>;
+}

include/bitstream/stream/byte_buffer.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+
+namespace bitstream
+{
+	/**
+	 * @brief A byte buffer aligned to 4 bytes.
+	 * Can be used with bit_reader and bit_writer.
+	 * @note Size must be a multiple of 4
+	*/
+	template<size_t Size>
+	struct byte_buffer
+	{
+		static_assert(Size % 4 == 0, "Buffer size must be a multiple of 4");
+
+		alignas(uint32_t) uint8_t Bytes[Size];
+
+		uint8_t& operator[](size_t i) noexcept { return Bytes[i]; }
+	};
+}

include/bitstream/stream/serialize_traits.h

@@ -0,0 +1,12 @@
+#pragma once
+
+namespace bitstream
+{
+	/**
+	 * @brief A class for specializing trait serialization functions
+	 * @tparam Trait Make a specialization on this type
+	 * @tparam Void Use std::enable_if here if you need to, otherwise leave empty
+	*/
+	template<typename Trait, typename Void = void>
+	struct serialize_traits;
+}

include/bitstream/stream/stream_traits.h

@@ -0,0 +1,96 @@
+#pragma once
+
+#include "byte_buffer.h"
+
+#include <cstddef>
+#include <cstdint>
+#include <limits>
+#include <type_traits>
+
+namespace bitstream
+{
+	struct fixed_policy
+	{
+		/**
+		 * @brief Construct a stream pointing to the given byte array with @p num_bytes size
+		 * @param bytes The byte array to serialize to/from. Must be 4-byte aligned and the size must be a multiple of 4
+		 * @param num_bytes The number of bytes in the array
+		*/
+		fixed_policy(void* buffer, uint32_t num_bits) noexcept :
+			m_Buffer(static_cast<uint32_t*>(buffer)),
+			m_NumBitsSerialized(0),
+			m_TotalBits(num_bits) {}
+
+		/**
+		 * @brief Construct a stream pointing to the given @p buffer
+		 * @param buffer The buffer to serialize to/from
+		 * @param num_bits The maximum number of bits that we can read
+		*/
+		template<size_t Size>
+		fixed_policy(byte_buffer<Size>& buffer, uint32_t num_bits) noexcept :
+			m_Buffer(reinterpret_cast<uint32_t*>(buffer.Bytes)),
+			m_NumBitsSerialized(0),
+			m_TotalBits(num_bits) {}
+
+		/**
+		 * @brief Construct a stream pointing to the given @p buffer
+		 * @param buffer The buffer to serialize to/from
+		*/
+		template<size_t Size>
+		fixed_policy(byte_buffer<Size>& buffer) noexcept :
+			m_Buffer(reinterpret_cast<uint32_t*>(buffer.Bytes)),
+			m_NumBitsSerialized(0),
+			m_TotalBits(Size * 8) {}
+
+		uint32_t* get_buffer() const noexcept { return m_Buffer; }
+
+		// TODO: Transition sizes to size_t
+		uint32_t get_num_bits_serialized() const noexcept { return m_NumBitsSerialized; }
+
+		bool can_serialize_bits(uint32_t num_bits) const noexcept { return m_NumBitsSerialized + num_bits <= m_TotalBits; }
+
+		uint32_t get_total_bits() const noexcept { return m_TotalBits; }
+
+		bool extend(uint32_t num_bits) noexcept
+		{
+			if (!can_serialize_bits(num_bits))
+				return false;
+
+			m_NumBitsSerialized += num_bits;
+			return true;
+		}
+
+		uint32_t* m_Buffer;
+		// TODO: Transition sizes to size_t
+		uint32_t m_NumBitsSerialized;
+		uint32_t m_TotalBits;
+	};
+
+	template<typename T>
+	struct growing_policy
+	{
+		growing_policy(T& container) noexcept :
+			m_Buffer(container),
+			m_NumBitsSerialized(0) {}
+
+		uint32_t* get_buffer() const noexcept { return m_Buffer.data(); }
+
+		uint32_t get_num_bits_serialized() const noexcept { return m_NumBitsSerialized; }
+
+		bool can_serialize_bits(uint32_t num_bits) const noexcept { return true; }
+
+		uint32_t get_total_bits() const noexcept { return (std::numeric_limits<uint32_t>::max)(); }
+
+		bool extend(uint32_t num_bits)
+		{
+			m_NumBitsSerialized += num_bits;
+			uint32_t num_bytes = (m_NumBitsSerialized - 1) / 8U + 1;
+			m_Buffer.resize(num_bytes);
+			return true;
+		}
+
+		T& m_Buffer;
+
+		uint32_t m_NumBitsSerialized;
+	};
+}