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