refactor bitfield io

This commit is contained in:
2025-07-29 14:52:22 +02:00
parent 366a40afee
commit 01e406cd89
8 changed files with 182 additions and 141 deletions

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@@ -4,34 +4,13 @@
namespace sp {
/**
* \brief Serialize value to (network byte order) big endian
*/
bool IsLittleEndian();
void SwapBytes(std::uint8_t* begin, std::uint8_t* end);
template<typename T>
void ToNetwork(T& value) {}
template <>
void ToNetwork<std::uint16_t>(std::uint16_t& value);
template <>
void ToNetwork<std::uint32_t>(std::uint32_t& value);
template <>
void ToNetwork<std::uint64_t>(std::uint64_t& value);
/**
* \brief Deserialize value from (network byte order) big endian
*/
template <typename T>
void FromNetwork(T& value) {}
template <>
void FromNetwork<std::uint16_t>(std::uint16_t& value);
template <>
void FromNetwork<std::uint32_t>(std::uint32_t& value);
template <>
void FromNetwork<std::uint64_t>(std::uint64_t& value);
void SwapBytes(T& a_Data) {
SwapBytes(reinterpret_cast<std::uint8_t*>(&a_Data), reinterpret_cast<std::uint8_t*>(&a_Data) + sizeof(T));
}
} // namespace sp

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@@ -10,10 +10,11 @@
#include <cassert>
#include <cstdint>
#include <cstring>
#include <string>
#include <sp/common/VarInt.h>
#include <vector>
#include <map>
#include <sp/common/VarInt.h>
#include <sp/common/ByteSwapping.h>
#include <string>
#include <vector>
namespace sp {
@@ -23,16 +24,18 @@ namespace sp {
*/
class DataBuffer {
private:
typedef std::vector<std::uint8_t> Data;
using Data = std::vector<std::uint8_t>;
private:
Data m_Buffer;
std::size_t m_ReadOffset;
public:
typedef Data::iterator iterator;
typedef Data::const_iterator const_iterator;
typedef Data::reference reference;
typedef Data::const_reference const_reference;
typedef Data::difference_type difference_type;
using iterator = Data::iterator;
using const_iterator = Data::const_iterator;
using reference = Data::reference;
using const_reference = Data::const_reference;
using difference_type = Data::difference_type;
DataBuffer();
DataBuffer(std::size_t a_InitialSize);
@@ -46,21 +49,23 @@ class DataBuffer {
/**
* \brief Append data to the buffer
* \warning No endian checks
*/
template <typename T>
void Append(const T& data) {
std::size_t size = sizeof(data);
void Append(const T& a_Data) {
std::size_t size = sizeof(a_Data);
std::size_t end_pos = m_Buffer.size();
m_Buffer.resize(m_Buffer.size() + size);
std::memcpy(&m_Buffer[end_pos], &data, size);
std::memcpy(&m_Buffer[end_pos], &a_Data, size);
}
/**
* \brief Append data to the buffer
* \brief Append data to the buffer (converted to big endian)
*/
template <typename T>
DataBuffer& operator<<(const T& data) {
Append(data);
DataBuffer& operator<<(T a_Data) {
SwapBytes(a_Data);
Append(a_Data);
return *this;
}
@@ -115,14 +120,24 @@ class DataBuffer {
return *this;
}
/**
* \brief Read data into a_Data
* \warning No endian checks
*/
template <typename T>
void Read(T& a_Data) {
assert(m_ReadOffset + sizeof(T) <= GetSize());
std::memcpy(&a_Data, m_Buffer.data() + m_ReadOffset, sizeof(T));
m_ReadOffset += sizeof(T);
}
/**
* \brief Read some data from the buffer and assign to desired variable
*/
template <typename T>
DataBuffer& operator>>(T& data) {
assert(m_ReadOffset + sizeof(T) <= GetSize());
data = *(reinterpret_cast<T*>(&m_Buffer[m_ReadOffset]));
m_ReadOffset += sizeof(T);
DataBuffer& operator>>(T& a_Data) {
Read(a_Data);
SwapBytes(a_Data);
return *this;
}

90
include/sp/io/BitBuffer.h Normal file
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@@ -0,0 +1,90 @@
#pragma once
#include <sp/common/DataBuffer.h>
#include <sp/protocol/BitField.h>
namespace sp {
// TODO: flush if offset exceeds 64
class BitBuffer {
private:
using Data = std::uint64_t;
private:
DataBuffer& m_Buffer;
Data m_Data;
std::size_t m_Offset;
bool m_WasBitField;
public:
BitBuffer(DataBuffer& a_Buffer) : m_Buffer(a_Buffer), m_Data(0), m_Offset(0), m_WasBitField(false) {}
void UpdateWrite(bool a_IsBitField) {
if (m_Offset == 0)
return;
if ((m_Offset % 8 == 0) || (!a_IsBitField && m_WasBitField)) {
Flush();
}
m_WasBitField = a_IsBitField;
}
void UpdateRead(bool a_IsBitField) {
if (m_Offset == 0)
return;
if ((m_Offset % 8 == 0) || (!a_IsBitField && m_WasBitField)) {
MoveReadOffset();
}
m_WasBitField = a_IsBitField;
}
template <typename T, std::size_t BitSize>
void Append(T a_Data) {
Data bin = static_cast<Data>(a_Data);
bin &= ((1 << BitSize) - 1); // prevents overflow
std::size_t pushCount = sizeof(Data) * 8 - m_Offset - BitSize;
m_Data |= bin << pushCount;
m_Offset += BitSize;
}
template <typename T, std::size_t BitSize>
void Read(T& a_Data) {
std::size_t byteCount = GetByteCount(m_Offset + BitSize);
constexpr Data dataMask = (1 << BitSize) - 1;
m_Buffer.ReadSome(reinterpret_cast<std::uint8_t*>(&m_Data), byteCount);
SwapBytes(reinterpret_cast<std::uint8_t*>(&m_Data), reinterpret_cast<std::uint8_t*>(&m_Data) + byteCount);
m_Data >>= byteCount * 8 - m_Offset - BitSize;
m_Data &= dataMask;
a_Data = T(m_Data);
m_Buffer.SetReadOffset(m_Buffer.GetReadOffset() - byteCount);
m_Offset += BitSize;
}
private:
void Flush() {
std::size_t byteCount = GetByteCount();
m_Data >>= (sizeof(Data) - byteCount) * 8;
SwapBytes(reinterpret_cast<std::uint8_t*>(&m_Data), reinterpret_cast<std::uint8_t*>(&m_Data) + byteCount);
m_Buffer.WriteSome(reinterpret_cast<std::uint8_t*>(&m_Data), byteCount);
m_Offset = 0;
m_WasBitField = false;
m_Data = 0;
}
void MoveReadOffset() {
std::size_t byteCount = GetByteCount();
m_Buffer.SetReadOffset(m_Buffer.GetReadOffset() + byteCount);
m_Offset = 0;
m_WasBitField = false;
m_Data = 0;
}
std::size_t GetByteCount(std::size_t a_Offset = -1) const {
if (a_Offset == static_cast<std::size_t>(-1))
a_Offset = m_Offset;
if (a_Offset <= 8)
return 1;
return (a_Offset - 1) / 8 + 1;
}
};
} // namespace sp

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@@ -1,78 +1,53 @@
#pragma once
#include <boost/pfr.hpp>
#include <sp/common/ByteSwapping.h>
#include <sp/common/DataBuffer.h>
#include <sp/protocol/BitField.h>
#include <sp/io/BitBuffer.h>
namespace sp {
namespace details {
template <typename T, std::size_t BitSize>
void WriteField(DataBuffer& a_Buffer, const BitField<T, BitSize>& a_Data, BitBuffer& a_BitBuffer) {
a_BitBuffer.Append<T, BitSize>(*a_Data);
a_BitBuffer.UpdateWrite(true);
}
template <typename T>
void WriteBitField(DataBuffer& a_Buffer, std::uint64_t& a_DataRaw, std::size_t& a_Offset) {
T filled = static_cast<T>(a_DataRaw);
ToNetwork(filled);
a_Buffer << filled;
a_Offset = 0;
a_DataRaw = 0;
void WriteField(DataBuffer& a_Buffer, const T& a_Data, BitBuffer& a_BitBuffer) {
a_Buffer << a_Data;
a_BitBuffer.UpdateWrite(false);
}
template <typename T, std::size_t BitSize>
void WriteField(DataBuffer& a_Buffer, const BitField<T, BitSize>& a_Data, std::uint64_t& a_DataRaw, std::size_t& a_Offset) {
T cut = *a_Data & ((1 << a_Data.GetBitSize()) - 1);
std::size_t pushCount = sizeof(T) * 8 - a_Offset - a_Data.GetBitSize();
a_DataRaw |= cut << pushCount;
a_Offset += a_Data.GetBitSize();
if (a_Offset == sizeof(T) * 8) {
WriteBitField<T>(a_Buffer, a_DataRaw, a_Offset);
}
void ReadField(DataBuffer& a_Buffer, BitField<T, BitSize>& a_Data, BitBuffer& a_BitBuffer) {
a_BitBuffer.Read<T, BitSize>(*a_Data);
a_BitBuffer.UpdateRead(true);
}
template <typename T>
void WriteField(DataBuffer& a_Buffer, const T& a_Data, std::uint64_t& a_DataRaw, std::size_t& a_Offset) {
T swapped = a_Data;
ToNetwork(swapped);
a_Buffer << swapped;
}
template <typename T, std::size_t BitSize>
void ReadField(DataBuffer& a_Buffer, BitField<T, BitSize>& a_Data, std::size_t& a_Offset) {
a_Buffer >> *a_Data;
FromNetwork(*a_Data);
*a_Data >>= sizeof(T) * 8 - a_Offset - a_Data.GetBitSize();
*a_Data &= (1 << a_Data.GetBitSize()) - 1;
if (a_Offset != sizeof(T) * 8) {
a_Buffer.SetReadOffset(a_Buffer.GetReadOffset() - sizeof(T));
a_Offset += a_Data.GetBitSize();
} else {
a_Offset = 0;
}
}
template <typename T>
void ReadField(DataBuffer& a_Buffer, T& a_Data, std::size_t& a_Offset) {
void ReadField(DataBuffer& a_Buffer, T& a_Data, BitBuffer& a_BitBuffer) {
a_Buffer >> a_Data;
FromNetwork(a_Data);
a_BitBuffer.UpdateRead(false);
}
} // namespace details
template <typename TData>
DataBuffer WriteMessage(const TData& a_MessageData) {
DataBuffer buffer;
std::size_t currentOffset = 0;
std::uint64_t dataRaw = 0;
boost::pfr::for_each_field(a_MessageData,
[&buffer, &dataRaw, &currentOffset](const auto& a_Field) { WriteField(buffer, a_Field, dataRaw, currentOffset); });
BitBuffer bitBuffer(buffer);
boost::pfr::for_each_field(
a_MessageData, [&buffer, &bitBuffer](const auto& a_Field) { details::WriteField(buffer, a_Field, bitBuffer); });
bitBuffer.UpdateWrite(false);
return buffer;
}
template <typename TData>
void ReadMessage(DataBuffer& a_Buffer, TData& a_MessageData) {
std::size_t currentOffset = 0;
BitBuffer bitBuffer(a_Buffer);
boost::pfr::for_each_field(
a_MessageData, [&a_Buffer, &currentOffset](auto& a_Field) { ReadField(a_Buffer, a_Field, currentOffset); });
a_MessageData, [&a_Buffer, &bitBuffer](auto& a_Field) { details::ReadField(a_Buffer, a_Field, bitBuffer); });
bitBuffer.UpdateRead(false);
}
} // namespace details
} // namespace sp

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@@ -27,11 +27,11 @@ class ConcreteMessage : public MessageBase {
}
virtual void Read(DataBuffer& a_Buffer) override {
details::ReadMessage(a_Buffer, m_Data);
ReadMessage(a_Buffer, m_Data);
}
virtual DataBuffer Write() const override {
return details::WriteMessage(m_Data);
return WriteMessage(m_Data);
}
DataType& operator*() {

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@@ -1,49 +1,21 @@
#include <sp/common/ByteSwapping.h>
#ifdef _WIN32
#include <winsock2.h>
#else
#include <arpa/inet.h>
#include <endian.h>
#define htonll htobe64
#define ntohll be64toh
#endif
#include <algorithm>
namespace sp {
template <>
void ToNetwork<std::uint16_t>(std::uint16_t& value) {
value = htons(value);
bool IsLittleEndian() {
#ifdef SP_BIG_ENDIAN
return false;
#else
return true;
#endif
}
template <>
void ToNetwork<std::uint32_t>(std::uint32_t& value) {
value = htonl(value);
void SwapBytes(std::uint8_t* begin, std::uint8_t* end) {
if (IsLittleEndian()) {
std::reverse(begin, end);
}
template <>
void ToNetwork<std::uint64_t>(std::uint64_t& value) {
value = htonll(value);
}
template <>
void FromNetwork<std::uint16_t>(std::uint16_t& value) {
value = ntohs(value);
}
template <>
void FromNetwork<std::uint32_t>(std::uint32_t& value) {
value = ntohl(value);
}
template <>
void FromNetwork<std::uint64_t>(std::uint64_t& value) {
value = ntohll(value);
}
} // namespace sp

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@@ -12,7 +12,7 @@
#include <fstream>
#include <iostream>
enum class PacketID { KeepAlive = 0, MDC = 1 };
enum class PacketID : std::uint8_t { KeepAlive = 0, MDC = 1 };
class PacketHandler;
@@ -26,8 +26,13 @@ struct KeepAlivePacket {
sp::BitField<std::uint16_t, 4> two;
};
struct MDCPacket {
sp::BitField<std::uint16_t, 12> one;
sp::BitField<PacketID, 4> two;
};
using KeepAliveMessage = Message<KeepAlivePacket, PacketID::KeepAlive>;
using MDCMessage = Message<KeepAlivePacket, PacketID::MDC>;
using MDCMessage = Message<MDCPacket, PacketID::MDC>;
using AllMessages = std::tuple<KeepAliveMessage, MDCMessage>;
@@ -39,7 +44,7 @@ class MyHandler : public PacketHandler {
std::cout << "I recieved a keep alive : " << *msg->one << " : " << *msg->two << "\n";
}
virtual void Handle(const MDCMessage& msg) override {
std::cout << "I recieved a keep alive : " << *msg->one << " : " << *msg->two << "\n";
std::cout << "I recieved a mdc : " << *msg->one << " : " << static_cast<unsigned>(*msg->two) << "\n";
}
};
@@ -57,6 +62,7 @@ int main() {
MyHandler h;
PacketDispatcher d;
d.RegisterHandler(PacketID::KeepAlive, &h);
d.RegisterHandler(PacketID::MDC, &h);
d.Dispatch(m);
PacketFactory f;
auto message = f.CreateMessage(PacketID::KeepAlive);
@@ -73,6 +79,7 @@ int main() {
PacketStream p(std::make_shared<sp::StdOuput>(file));
p.WriteMessage(m);
p.WriteMessage(MDCMessage{42, PacketID::MDC});
file.flush();
@@ -81,10 +88,10 @@ int main() {
PacketStream p2(std::make_shared<sp::StdInput>(file2));
auto message2 = p2.ReadMessage();
auto message3 = p2.ReadMessage();
d.Dispatch(*message2);
// Todo : verify bitfields
d.Dispatch(*message3);
// message->Write(file);
// file << std::endl;

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@@ -1,5 +1,7 @@
add_rules("mode.debug", "mode.release")
includes("@builtin/check")
add_requires("boost_pfr")
set_warnings("all")
@@ -76,6 +78,7 @@ target("SimpleProtocol")
set_group("Library")
set_kind("$(kind)")
add_packages("boost_pfr", {public = true})
check_bigendian("SP_BIG_ENDIAN")
add_headerfiles("include/(sp/**.h)", "include/(sp/**.inl)")