58 lines
1.2 KiB
C++
58 lines
1.2 KiB
C++
#include <sp/common/VarInt.h>
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#include <sp/common/DataBuffer.h>
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#include <stdexcept>
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namespace sp {
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static constexpr int SEGMENT_BITS = (1 << 7) - 1;
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static constexpr int CONTINUE_BIT = 1 << 7;
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std::size_t VarInt::GetSerializedLength() const {
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DataBuffer buffer;
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buffer << *this;
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return buffer.GetSize();
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}
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DataBuffer& operator<<(DataBuffer& out, const VarInt& var) {
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std::uint64_t value = var.m_Value;
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while (true) {
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if ((value & ~static_cast<std::uint64_t>(SEGMENT_BITS)) == 0) {
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out << static_cast<std::uint8_t>(value);
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return out;
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}
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out << static_cast<std::uint8_t>((value & SEGMENT_BITS) | CONTINUE_BIT);
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value >>= 7;
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}
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}
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DataBuffer& operator>>(DataBuffer& in, VarInt& var) {
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var.Read([&in](std::uint8_t& data){
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in.ReadSome(&data, 1);
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});
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return in;
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}
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void VarInt::Read(const ReadFunc& read) {
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m_Value = 0;
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unsigned int position = 0;
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std::uint8_t currentByte;
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while (true) {
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read(currentByte);
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m_Value |= static_cast<std::uint64_t>(currentByte & SEGMENT_BITS) << position;
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if ((currentByte & CONTINUE_BIT) == 0)
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break;
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position += 7;
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if (position >= 8 * sizeof(m_Value))
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throw std::runtime_error("VarInt is too big");
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}
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}
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} // namespace sp
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