NetBitStreamWriter.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreTypes.h"
 
namespace UE::Net
{
 
class FNetBitStreamWriter
{
public:
    IRISCORE_API FNetBitStreamWriter();
    IRISCORE_API ~FNetBitStreamWriter();
 
    IRISCORE_API void InitBytes(void* Buffer, uint32 ByteCount);
 
    IRISCORE_API void WriteBits(uint32 Value, uint32 BitCount);
 
    inline bool WriteBool(bool Value);
 
    IRISCORE_API void WriteBitStream(const uint32* Src, uint32 SrcBitOffset, uint32 BitCount);
 
    IRISCORE_API void CommitWrites();
 
    IRISCORE_API void Seek(uint32 BitPosition);
 
    inline uint32 GetPosBytes() const { return (BufferBitPosition - BufferBitStartOffset + 7) >> 3U; }
 
    inline uint32 GetPosBits() const { return BufferBitPosition - BufferBitStartOffset; }
 
    inline uint32 GetAbsolutePosBits() const { return BufferBitPosition; }
 
    inline uint32 GetBitsLeft() const { return (OverflowBitCount ? 0U : (BufferBitCapacity - BufferBitPosition)); }
 
    IRISCORE_API void DoOverflow();
 
    inline bool IsOverflown() const { return OverflowBitCount != 0; }
 
    IRISCORE_API FNetBitStreamWriter CreateSubstream(uint32 MaxBitCount = ~0U);
 
    IRISCORE_API void CommitSubstream(FNetBitStreamWriter& Substream);
 
    IRISCORE_API void DiscardSubstream(FNetBitStreamWriter& Substream);
 
private:
    uint32* Buffer;
    uint32 BufferBitCapacity;
    // For substreams this indicate the bit position in the buffer where it may start writing
    uint32 BufferBitStartOffset;
    uint32 BufferBitPosition;
    uint32 PendingWord;
    uint32 OverflowBitCount;
 
    uint32 bHasSubstream : 1;
    uint32 bIsSubstream : 1;
    uint32 bIsInvalid : 1;
};
 
bool FNetBitStreamWriter::WriteBool(bool Value)
{
    // This is to support a Value other than 0 or 1.
    volatile int8 ValueAsInt8 = Value;
    WriteBits(ValueAsInt8 ? 1U : 0U, 1U);
    return ValueAsInt8 ? true : false;
}
 
}
 
inline uint32 GetBitStreamPositionForNetTrace(const UE::Net::FNetBitStreamWriter& Stream)
{
    return (uint32(Stream.IsOverflown()) - 1U) & Stream.GetAbsolutePosBits();
}