(C++ : IOCP-40) Recv Buffer

#pragma once

/*--------------
	RecvBuffer
----------------*/

class RecvBuffer
{
	enum { BUFFER_COUNT = 10 };

public:
	RecvBuffer(int32 bufferSize);
	~RecvBuffer();

	void			Clean();
	bool			OnRead(int32 numOfBytes);
	bool			OnWrite(int32 numOfBytes);

	BYTE*			ReadPos() { return &_buffer[_readPos]; }
	BYTE*			WritePos() { return &_buffer[_writePos]; }
	int32			DataSize() { return _writePos - _readPos; }
	int32			FreeSize() { return _capacity - _writePos; }

private:
	int32			_capacity = 0;
	int32			_bufferSize = 0;
	int32			_readPos = 0;
	int32			_writePos = 0;
	Vector<BYTE>	_buffer;
};

#include "pch.h"
#include "RecvBuffer.h"

/*--------------
	RecvBuffer
----------------*/

RecvBuffer::RecvBuffer(int32 bufferSize) : _bufferSize(bufferSize)
{
	_capacity = bufferSize * BUFFER_COUNT;
	_buffer.resize(_capacity);
}

RecvBuffer::~RecvBuffer()
{
}

void RecvBuffer::Clean()
{
	int32 dataSize = DataSize();
	if (dataSize == 0)
	{
		// 딱 마침 읽기+쓰기 커서가 동일한 위치라면, 둘 다 리셋.
		_readPos = _writePos = 0;
	}
	else
	{
		// 여유 공간이 버퍼 1개 크기 미만이면, 데이터를 앞으로 땅긴다.
		if (FreeSize() < _bufferSize)
		{
			::memcpy(&_buffer[0], &_buffer[_readPos], dataSize);
			_readPos = 0;
			_writePos = dataSize;
		}
	}
}

bool RecvBuffer::OnRead(int32 numOfBytes)
{
	if (numOfBytes > DataSize())
		return false;

	_readPos += numOfBytes;
	return true;
}

bool RecvBuffer::OnWrite(int32 numOfBytes)
{
	if (numOfBytes > FreeSize())
		return false;

	_writePos += numOfBytes;
	return true;
}

void Session::RegisterRecv()
{
	if (IsConnected() == false)
		return;

	_recvEvent.Init();
	_recvEvent.owner = shared_from_this(); // ADD_REF

	WSABUF wsaBuf;
	wsaBuf.buf = reinterpret_cast<char*>(_recvBuffer.WritePos());
	wsaBuf.len = _recvBuffer.FreeSize();

	DWORD numOfBytes = 0;
	DWORD flags = 0;
	if (SOCKET_ERROR == ::WSARecv(_socket, &wsaBuf, 1, OUT &numOfBytes, OUT &flags, &_recvEvent, nullptr))
	{
		int32 errorCode = ::WSAGetLastError();
		if (errorCode != WSA_IO_PENDING)
		{
			HandleError(errorCode);
			_recvEvent.owner = nullptr; // RELEASE_REF
		}
	}
}

void Session::ProcessRecv(int32 numOfBytes)
{
	_recvEvent.owner = nullptr; // RELEASE_REF

	if (numOfBytes == 0)
	{
		Disconnect(L"Recv 0");
		return;
	}

	if (_recvBuffer.OnWrite(numOfBytes) == false)
	{
		Disconnect(L"OnWrite Overflow");
		return;
	}

	int32 dataSize = _recvBuffer.DataSize();
	int32 processLen = OnRecv(_recvBuffer.ReadPos(), dataSize); // 컨텐츠 코드에서 재정의
	if (processLen < 0 || dataSize < processLen || _recvBuffer.OnRead(processLen) == false)
	{
		Disconnect(L"OnRead Overflow");
		return;
	}
	
	// 커서 정리
	_recvBuffer.Clean();

	// 수신 등록
	RegisterRecv();
}