TCPSocket.cpp

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// ****************************************************************************
// This file is part of the Integrating Vision Toolkit (IVT).
//
// The IVT is maintained by the Karlsruhe Institute of Technology (KIT)
// (www.kit.edu) in cooperation with the company Keyetech (www.keyetech.de).
//
// Copyright (C) 2014 Karlsruhe Institute of Technology (KIT).
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
//
// 3. Neither the name of the KIT nor the names of its contributors may be
//    used to endorse or promote products derived from this software
//    without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE KIT AND CONTRIBUTORS “AS IS” AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE KIT OR CONTRIBUTORS BE LIABLE FOR ANY
// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
// THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// ****************************************************************************
// ****************************************************************************
// Filename:  TCPSocket.cpp
// Author:    Florian Hecht
// Date:      08.01.2009
// ****************************************************************************

#include <new> // for explicitly using correct new/delete operators on VC DSPs

#include "TCPSocket.h"

#include <stdio.h>
#ifndef __TI_COMPILER_VERSION__
#include <memory.h>
#endif

#include <stdlib.h>
#include <errno.h>


#if defined(WIN32)
#define _WINSOCKAPI_
#include <windows.h>
#include <winsock2.h>

static int socket_ref_count = 0;

void InitWinSock()
{
        socket_ref_count++;

        if (socket_ref_count > 1)
                return;

        WORD wVersionRequested;
        WSADATA wsaData;
        int wsaerr;

        wVersionRequested = MAKEWORD(2, 0);
        wsaerr = WSAStartup(wVersionRequested, &wsaData);
        if (wsaerr != 0)
        {
                // Tell the user that we couldn't find the WinSock DLL
                printf("Error: couldn't initialize WinSock!\n");
        }

        return;
}

void ShutdownWinSock()
{
        socket_ref_count--;
        if (socket_ref_count > 0)
                return;

        WSACleanup();
}

#elif defined(__TI_COMPILER_VERSION__)
#include <string.h>
#include "Networking/VCNet.h"
#else
#include <unistd.h>
#include <signal.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netdb.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#endif



CTCPSocket::CTCPSocket() : m_socket(-1), m_bListening(false)
{
#ifdef WIN32
        InitWinSock();
#endif
}

CTCPSocket::~CTCPSocket()
{
        Close();

#ifdef WIN32
        ShutdownWinSock();
#endif
}

bool CTCPSocket::Listen(const unsigned char *ip, int port)
{
        Close();
        
#ifdef WIN32
        SOCKET sock = socket(AF_INET, SOCK_STREAM, 0);
        if (sock == INVALID_SOCKET)
        {
                m_socket = -1;
                return false;
        }

        m_socket = (int)sock;

        // set linger on - helps in closing socket immidiately
        linger li;
        li.l_onoff = true;
        li.l_linger = 0;
        
        if(setsockopt(sock, SOL_SOCKET, SO_LINGER, (const char*)&li, sizeof(li)) == -1)
        {
                printf("setting linger option failed\n");
                Close();
                return false;
        }

        // set non blocking
        u_long v = 1;
        if (ioctlsocket(sock, FIONBIO, &v) == SOCKET_ERROR)
        {
                printf("setting non-blocking option failed\n");
                Close();
                return false;
        }

        struct sockaddr_in serv_addr;
        memset((char *)&serv_addr, 0, sizeof(serv_addr));
        
        serv_addr.sin_family = AF_INET;
        if (ip != NULL)
        {
                memcpy((char *)&serv_addr.sin_addr.s_addr, ip, 4);
        }
        else
        {
                serv_addr.sin_addr.s_addr = INADDR_ANY;
        }
        serv_addr.sin_port = htons(port);
        
        if (bind(sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0)
        {
                Close();
                return false;
        }
        
        listen(sock, 5);
        m_bListening = true;

#elif defined(__TI_COMPILER_VERSION__)
        uint_32 error;
        
        m_socket = socket_stream();
        if (m_socket == VCRT_SOCKET_ERROR) 
        {
                m_socket = -1;
                return false;
        }
        
        //set linger on - helps in closing socket immidiately

        // SO_LINGER socket option is not available on VCRT.
        // But in Close() the shutdown flag FLAG_ABORT_CONNECTION enforces hard closing of the socket
        // as would SO_LINGER with zero timeout on other platforms.
        
        //set non blocking

        // there is no socket-global (non-)blocking flag on VCRT
        // - accept() is always blocking and therefore guarded by VCRT_selectset().
        // - recv() behavior is set during Recv() depending on bWait flag
        // - send(): don't wait for data to be transmitted, return after buffering. this resembles behavior of Send() on other platforms
        uint_32 opt_value = TRUE;
        error = setsockopt(m_socket, SOL_TCP, OPT_SEND_NOWAIT, &opt_value, sizeof(opt_value));
        if (error != VCRT_OK)
        {
                printf("Error, setsockopt(OPT_SEND_NOWAIT) failed with error code 0x%x\n", error);
                Close();
                return false;
        }
        
        sockaddr_in serv_addr;
        memset( &serv_addr, 0, sizeof(serv_addr));
        serv_addr.sin_family      = AF_INET;
        if (ip != NULL)
        {
                //never cast ip to an int pointer! this would imply 4byte alignment.
                memcpy((char *)&serv_addr.sin_addr.s_addr, ip, 4);
                // vcrt expects inverse order of ip chars
                // than provided by RemoteApplicationHandler.cpp
                serv_addr.sin_addr.s_addr = revert_byte_order(serv_addr.sin_addr.s_addr);
        }
        else
        {
                serv_addr.sin_addr.s_addr = INADDR_ANY;
        }
        serv_addr.sin_port = port; //htons(port); VCRT does not want the port in network byte order
        
        error = bind(m_socket, &serv_addr, sizeof(serv_addr));
        if (error!=VCRT_OK)
        {
                printf("\nsocket bind failed, error code: 0x%x\n", error);
                Close();
                return false;
        }
        
        error = listen(m_socket, 5);
        if (error!=VCRT_OK)
        {
                printf("\nsocket listen failed, error code: 0x%x\n", error);
                Close();
                return false;
        }
        m_bListening = true;

#else
        m_socket = socket(AF_INET, SOCK_STREAM, 0);
        if (m_socket < 0) 
        {
                m_socket = -1;
                return false;
        }
        
        // set linger on - helps in closing socket immidiately
        linger li;
        li.l_onoff = true;
        li.l_linger = 0;
        
        if(setsockopt(m_socket, SOL_SOCKET, SO_LINGER, &li, sizeof(li)) == -1)
        {
                printf("setting linger option failed\n");
                Close();
                return false;
        }
        
        // set non blocking
        if (fcntl(m_socket, F_SETFL, O_NONBLOCK) == -1)
        {
                printf("setting non-blocking option failed\n");
                Close();
                return false;
        }
        
        struct sockaddr_in serv_addr;
        bzero((char *)&serv_addr, sizeof(serv_addr));
        
        serv_addr.sin_family = AF_INET;
        if (ip != NULL)
        {
                bcopy(ip, (char *)&serv_addr.sin_addr.s_addr, 4);
        }
        else
        {
                serv_addr.sin_addr.s_addr = INADDR_ANY;
        }
        serv_addr.sin_port = htons(port);
        
        if (bind(m_socket, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0)
        {
                Close();
                return false;
        }
        
        listen(m_socket, 5);
        m_bListening = true;
#endif
        
        return true;
}

CTCPSocket* CTCPSocket::Accept(unsigned char *ip)
{
        if (m_socket == -1 || !m_bListening)
                return NULL;
                
#ifdef WIN32
        SOCKET sock = (SOCKET)m_socket;
        struct sockaddr_in cli_addr;
        int clilen = sizeof(cli_addr);

        SOCKET new_socket = accept(sock, (struct sockaddr *) &cli_addr, &clilen);
        if (new_socket == INVALID_SOCKET)
        {
                return NULL;
        }

        // set non blocking
        u_long v = 1;
        if (ioctlsocket(new_socket, FIONBIO, &v) == SOCKET_ERROR)
        {
                printf("setting non-blocking option failed\n");
                Close();
                return false;
        }
        
        // set no delay for sending
        int v2 = 1;
        if (setsockopt(new_socket, IPPROTO_TCP, TCP_NODELAY, (const char*)&v2, sizeof(v2)) == -1)
        {
                printf("newly accepted socket couldn't be set to no delay mode\n");
        }

        if (ip != NULL)
        {
                memcpy(ip, (char *) &cli_addr.sin_addr.s_addr, 4);
        }
        
        CTCPSocket *s = new CTCPSocket();
        s->m_socket = (int) new_socket;

        return s;

#elif defined(__TI_COMPILER_VERSION__)
        uint_32 error;
        
        // acccept is always blocking on vcrt, so we need to test for activity first
        // which is not blocking
        error = VCRT_selectset(&m_socket, 1, (uint_32)-1);
        
        if (error==0) //no new connections, nothing to do
        {
                return NULL;
        }
        if (error==VCRT_SOCKET_ERROR) //an error occured
        {
                printf("Error in accept(): VCRT_selectset failed, error code 0x%x\n", VCRT_geterror(m_socket));
                return NULL;    
        }
        if (error!=m_socket) //should never happen as we check only this socket.
        {
                printf("Error in accept(): VCRT_selectset returned invalid socket");
                return NULL;    
        }
        

        sockaddr_in cli_addr;
        uint_16 clilen = sizeof(cli_addr);
        
        int new_socket = accept(m_socket, &cli_addr, &clilen);
        if (new_socket == VCRT_SOCKET_ERROR)
        {
                error = VCRT_geterror(m_socket);
                if (error == VCRT_OK)
                {
                        printf("\nAccept: Connection reset by peer");
                }
                else
                {
                        printf("Error, accept() failed with error code 0x%x\n", error);
                }
                return NULL;
        }
        
        
        
        // set non blocking

        // there is no socket-global (non-)blocking flag on VCRT
        // - accept() is always blocking and therefore guarded by VCRT_selectset().
        // - recv() behavior is set during Recv() depending on bWait flag
        // - send(): don't wait for data to be transmitted, return after buffering. this resembles behavior of Send() on other platforms
        uint_32 opt_value;
        
        opt_value = TRUE;
        error = setsockopt(m_socket, SOL_TCP, OPT_SEND_NOWAIT, &opt_value, sizeof(opt_value));
        if (error != VCRT_OK)
        {
                printf("Error, setsockopt(OPT_SEND_NOWAIT) failed with error code 0x%x\n", error);
        }
        
        
        
        // set no delay for sending
        // OPT_NO_NAGLE_ALGORITHM is the VCRT equivalent to TCP_NODELAY
        opt_value = TRUE;
        error = setsockopt(m_socket, SOL_TCP, OPT_NO_NAGLE_ALGORITHM, &opt_value, sizeof(opt_value));
        if (error != VCRT_OK)
        {
                printf("Error, setsockopt(OPT_NO_NAGLE_ALGORITHM) failed with error code 0x%x\n", error);
        }
        
        
        
        if (ip != NULL)
        {
                // vcrt expects inverse order of ip chars
                // than provided by RemoteApplicationHandler.cpp
                cli_addr.sin_addr.s_addr = revert_byte_order(cli_addr.sin_addr.s_addr);
                //never cast ip to an int pointer! this would imply 4byte alignment.
                memcpy( ip, &cli_addr.sin_addr.s_addr, 4);
        }
        
        CTCPSocket *sock = new CTCPSocket();
        sock->m_socket = new_socket;
        
        return sock;

#else
        struct sockaddr_in cli_addr;
        socklen_t clilen = sizeof(cli_addr);
        
        int new_socket = accept(m_socket, (struct sockaddr *) &cli_addr, &clilen);
        if (new_socket < 0)
        {
                return NULL;
        }
        
        // set non blocking
        if (fcntl(new_socket, F_SETFL, O_NONBLOCK) == -1)
        {
                printf("newly accepted socket couldn't be set to non blocking mode\n");
        }
        
        // set no delay for sending
        int v = 1;
        if (setsockopt(new_socket, IPPROTO_TCP, TCP_NODELAY, &v, sizeof(v)) == -1)
        {
                printf("newly accepted socket couldn't be set to no delay mode\n");
        } 
        
        if (ip != NULL)
        {
                bcopy((char *)&cli_addr.sin_addr.s_addr, ip, 4);
        }
        
        CTCPSocket *sock = new CTCPSocket();
        sock->m_socket = new_socket;
        
        return sock;
#endif
}

bool CTCPSocket::Open(const unsigned char *ip, int port)
{
        Close();
        
#ifdef WIN32
        SOCKET sock = socket(AF_INET, SOCK_STREAM, 0);
        if (sock == INVALID_SOCKET)
        {
                m_socket = -1;
                return false;
        }

        m_socket = (int)sock;

        struct sockaddr_in serv_addr;
        memset((char *)&serv_addr, 0, sizeof(serv_addr));
        
        serv_addr.sin_family = AF_INET;
        memcpy((char *)&serv_addr.sin_addr.s_addr, ip, 4);
        serv_addr.sin_port = htons(port);
        
        if (connect(sock, (const sockaddr*)&serv_addr, sizeof(serv_addr)) < 0)
        {
                Close();
                return false;
        }
        
        // set non blocking (after connect)
        u_long v = 1;
        if (ioctlsocket(sock, FIONBIO, &v) == SOCKET_ERROR)
        {
                printf("setting non-blocking option failed\n");
                Close();
                return false;
        }
        
        // set no delay for sending
        int v2 = 1;
        if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, (const char*)&v2, sizeof(v2)) == -1)
        {
                printf("socket couldn't be set to no delay mode\n");
        }

        m_bListening = false; 

#elif defined(__TI_COMPILER_VERSION__)
        uint_32 error;

        m_socket = socket_stream();
        if (m_socket == VCRT_SOCKET_ERROR) 
        {
                printf("Error in Open(): socket_stream() failed\n");
                m_socket = -1;
                return false;
        }
        
        sockaddr_in serv_addr;
        memset( &serv_addr, 0, sizeof(serv_addr));
        serv_addr.sin_family      = AF_INET;
        
        //never cast ip to an int pointer! this would imply 4byte alignment.
        memcpy(&(serv_addr.sin_addr.s_addr), ip, 4);
        // vcrt expects inverse order of ip chars
        // than provided by RemoteApplicationHandler.cpp
        serv_addr.sin_addr.s_addr = revert_byte_order(serv_addr.sin_addr.s_addr);
        
        serv_addr.sin_port = port; //htons(port); VCRT does not want the port in network byte order

        //printf("DEBUG: chars %d,%d,%d,%d,  serv_addr.sin_addr.s_addr: 0x%x\n", ip[0], ip[1], ip[2], ip[3], serv_addr.sin_addr.s_addr);
        
        error = connect(m_socket, &serv_addr, sizeof(serv_addr));
        if (error != VCRT_OK)
        {
                printf("Error in Open(): connect failed, error code 0x%x\n", error);
                Close();
                return false;
        }

        // set non blocking (after connect)

        // there is no socket-global (non-)blocking flag on VCRT
        // - accept() is always blocking and therefore guarded by VCRT_selectset().
        // - recv() behavior is set during Recv() depending on bWait flag
        // - send(): don't wait for data to be transmitted, return after buffering. this resembles behavior of Send() on other platforms
        uint_32 opt_value;
        
        opt_value = TRUE;
        error = setsockopt(m_socket, SOL_TCP, OPT_SEND_NOWAIT, &opt_value, sizeof(opt_value));
        if (error != VCRT_OK)
        {
                printf("Error, setsockopt(OPT_SEND_NOWAIT) failed with error code 0x%x\n", error);
                Close();
                return false;
        }

        
        // set no delay for sending
        // OPT_NO_NAGLE_ALGORITHM is the VCRT equivalent to TCP_NODELAY
        opt_value = TRUE;
        error = setsockopt(m_socket, SOL_TCP, OPT_NO_NAGLE_ALGORITHM, &opt_value, sizeof(opt_value));
        if (error != VCRT_OK)
        {
                printf("Error, setsockopt(OPT_NO_NAGLE_ALGORITHM) failed with error code 0x%x\n", error);
                Close();
                return false;
        }
        
        m_bListening = false;

#else
        m_socket = socket(AF_INET, SOCK_STREAM, 0);
        if (m_socket < 0) 
        {
                m_socket = -1;
                return false;
        }
        
        struct sockaddr_in serv_addr;
        bzero((char *)&serv_addr, sizeof(serv_addr));
        
        serv_addr.sin_family = AF_INET;
        bcopy(ip, (char *)&serv_addr.sin_addr.s_addr, 4);
        serv_addr.sin_port = htons(port);
        
        if (connect(m_socket, (const sockaddr*)&serv_addr, sizeof(serv_addr)) < 0)
        {
                Close();
                return false;
        }
        
        // set non blocking (after connect)
        if (fcntl(m_socket, F_SETFL, O_NONBLOCK) == -1)
        {
                Close();
                return false;
        }
        
        // set no delay for sending
        int v = 1;
        if (setsockopt(m_socket, IPPROTO_TCP, TCP_NODELAY, &v, sizeof(v)) == -1)
        {
                Close();
                return false;
        } 
        
        m_bListening = false;
#endif
        
        return true;
}

void CTCPSocket::Close()
{
        if (m_socket == -1)
                return;
                
#ifdef WIN32
        SOCKET sock = (SOCKET)m_socket;
        closesocket(sock);

#elif defined(__TI_COMPILER_VERSION__)
        // FLAG_ABORT_CONNECTION enforces hard closing of the socket as specified
        // by the SO_LINGER socket option with zero timeout on other platforms.
        // SO_LINGER is not available on VCRT.
        uint_32 error = shutdown(m_socket, FLAG_ABORT_CONNECTION);
        if(error!= VCRT_OK)
        {
                printf("\nsocket shutdown failed, error code: 0x%x\n", error);
        }
#else
        close(m_socket);
#endif

        m_socket = -1;
}

bool CTCPSocket::Send(const void *pData, int nBytes)
{
        if (m_socket == -1 || m_bListening)
                return false;
        
#ifdef WIN32
        SOCKET sock = (SOCKET)m_socket;
        int size = 0;
        unsigned char *ptr = (unsigned char*) pData;
        while (true)
        {
                int s = send(sock, (const char *) ptr, nBytes, 0);
                if (s == SOCKET_ERROR)
                {
                        int errnum = WSAGetLastError();
                        if (errnum == WSAEWOULDBLOCK)
                                continue;
                        
                        return false;
                }
                
                size += s;
                ptr += s;
                nBytes -= s;
                if (nBytes == 0)
                        break;
                
        }

#elif defined(__TI_COMPILER_VERSION__)
        
        char *ptr = (char *) pData;
        while (nBytes>0)
        {
                // as OPT_SEND_NOWAIT is set above, this blocks until data is buffered
                // but does not wait for data to be send and acknowledged.
                // Send() therefore blocks until all data is passed on to the OS.
                int_32 count = send(m_socket, ptr, nBytes, 0);

                if (count==VCRT_ERROR)
                {
                        printf("Error in Send(): send failed, error code 0x%x\n", VCRT_geterror(m_socket));
                        return false;
                }
                
                ptr += count;
                nBytes -= count;
        }

#else
        int size = 0;
        unsigned char *ptr = (unsigned char *) pData;
        while (true)
        {
                int s = write(m_socket, ptr, nBytes);
                if (s == -1)
                {
                        int errnum = errno;
                        if (errnum == EAGAIN)
                                continue;
                        
                        return false;
                }
                
                size += s;
                ptr += s;
                nBytes -= s;
                if (nBytes == 0)
                        break;
                
        }
#endif
        
        return true;
}

int CTCPSocket::Recv(void *pData, int nMaxBytes, bool bWait)
{
        if (m_socket == -1 || m_bListening)
                return -1;
        
#ifdef WIN32
        SOCKET sock = (SOCKET) m_socket;

        if (bWait)
        {
                int size = 0;
                unsigned char *ptr = (unsigned char*) pData;
                while (true)
                {
                        int s = recv(sock, (char *) ptr, nMaxBytes, 0);
                        if (s == SOCKET_ERROR)
                        {
                                int errnum = WSAGetLastError();
                                if (errnum == WSAEWOULDBLOCK)
                                        continue;
                        
                                // this is really bad, the connection is probably dead
                                return -1;
                        }
                        
                        ptr += s;
                        size += s;
                        nMaxBytes -= s; 
                        
                        if (nMaxBytes == 0)
                                return size;
                                
                }
        }
        else
        {
                int size = recv(sock, (char *) pData, nMaxBytes, 0);
                if (size == SOCKET_ERROR)
                {
                        int errnum = WSAGetLastError();
                        if (errnum == WSAEWOULDBLOCK)
                                return 0;
                        
                        // this is really bad, the connection is probably dead
                
                        return -1;
                }
                else if (size == 0)
                {
                        return -1;
                }
                
                return size;
        }

#elif defined(__TI_COMPILER_VERSION__)
        //set OPT_RECV_NOWAIT depending on bWait
        // if bWait==false: behaves like a non-blocking socket on other platforms
        // else: recv() blocks, avoiding polling with busy waiting.
        //       recv() may non the less return early in case of a PUSH flag.
        uint_32 opt_value = bWait? FALSE : TRUE;
        uint_32 error = setsockopt(m_socket, SOL_TCP, OPT_RECEIVE_NOWAIT, &opt_value, sizeof(opt_value));
        if (error != VCRT_OK)
        {
                printf("Error in Recv(), setsockopt(OPT_RECEIVE_NOWAIT) failed with error code 0x%x\n", error);
                return -1;
        }

        if (bWait)
        {
                int size = 0;
                char *ptr = (char *) pData;
                while (nMaxBytes>0)
                {
                        int_32 count = recv(m_socket, ptr, nMaxBytes, 0); //is set to blocking above
                        
                        if (count == VCRT_ERROR)
                        {
                                printf("Error in Recv(): recv failed, error code 0x%x\n", VCRT_geterror(m_socket));
                                // this is really bad, the connection is probably dead
                                return -1;
                        }
                        
                        ptr += count;
                        size += count;
                        nMaxBytes -= count; 
                }
                return size;
        }
        else
        {
                //receive whatever data is available and return immediately
                int_32 count = recv(m_socket, (char*)pData, nMaxBytes, 0); //is set to non-blocking above

                if (count == VCRT_ERROR)
                {
                        printf("Error in Recv(): recv failed, error code 0x%x\n", VCRT_geterror(m_socket));
                        // this is really bad, the connection is probably dead
                        return -1;
                }
                // on vcrt, count==0 means zero bytes received and not connection closed by peer.
                // so in this case 0 is returned and not -1.
                
                return count;
        }

#else
        if (bWait)
        {
                int size = 0;
                unsigned char *ptr = (unsigned char *) pData;
                while (true)
                {
                        int s = (int) recv(m_socket, ptr, nMaxBytes, 0);
                        if (s == -1)
                        {
                                int errnum = errno;
                                if (errnum == EAGAIN)
                                        continue;
                        
                                // this is really bad, the connection is probably dead
                
                                return -1;
                        }
                        
                        ptr += s;
                        size += s;
                        nMaxBytes -= s; 
                        
                        if (nMaxBytes == 0)
                                return size;
                                
                }
        }
        else
        {
                int size = (int) recv(m_socket, pData, nMaxBytes, 0);
                if (size == -1)
                {
                        int errnum = errno;
                        if (errnum == EAGAIN)
                                return 0;
                        
                        // this is really bad, the connection is probably dead
                
                        return -1;
                }
                else if (size == 0)
                {
                        return -1;
                }
                
                return size;
        }
#endif
        
        return -1;
}