[TCP] recv Helper 함수(버퍼 크기만큼 받을때까지..)

// TCP/IP recv를 버퍼 크기만큼 받을때까지 계속 받는 함수
int Receiven(SOCKET s, BYTE *lpBuff, int nBuffLength, int flags)
{
  ASSERT( IsBadWritePtr(lpBuff, nBuffLength) == FALSE );
 
  BYTE* pBuff = lpBuff;
  int nLeft = nBuffLength;
  int nError;
 
  while( nLeft > 0 )
  {
    int nRead = recv( s, pBuff, nLeft, int flags );
   
    // 파일 전송 에러 처리
    switch( nRead )
    {
    case 0:
      /* the connection has been closed */
      break;
     
    case SOCKET_ERROR:
      nError = WSAGetLastError();
     
      if( nError == WSAEWOULDBLOCK )
      {
      /* The socket is marked as nonblocking and
        the Receive operation would block. */
        TRACE0("Receiven - WSABLOCK\n");
        break;
      }
      else
      {
        TRACE1("Receiven() - Error Code = %d\n", nError);
        return SOCKET_ERROR;
      }
     
      break;
     
    default:
      if( nRead >= nBuffLength )
      {
        nLeft -= nRead;
        pBuff += nRead;
      }
      else
      {
        return nRead;
      }
     
      break;
    }
  }
 
  return ( nBuffLength - nLeft );
}