77.txt

Winsock2的发布使得Socket I/O有了和文件I/O统一的接口。我们可以通过使用Win32文件操纵函数ReadFile和WriteFile来进行Socket I/O。伴随而来的

#include <winsock2.h>
#include <stdio.h>

#define PORT    5150
#define MSGSIZE 1024

#pragma comment(lib, "ws2_32.lib")

typedef struct
{
  WSAOVERLAPPED overlap;
  WSABUF        Buffer;
  char          szMessage[MSGSIZE];
  DWORD         NumberOfBytesRecvd;
  DWORD         Flags;
}PER_IO_OPERATION_DATA, *LPPER_IO_OPERATION_DATA;

int                     g_iTotalConn = 0;
SOCKET                  g_CliSocketArr[MAXIMUM_WAIT_OBJECTS];
WSAEVENT                g_CliEventArr[MAXIMUM_WAIT_OBJECTS];
LPPER_IO_OPERATION_DATA g_pPerIODataArr[MAXIMUM_WAIT_OBJECTS];

DWORD WINAPI WorkerThread(LPVOID);
void Cleanup(int);

int main()
{
  WSADATA     wsaData;
  SOCKET      sListen, sClient;
  SOCKADDR_IN local, client;
  DWORD       dwThreadId;
  int         iaddrSize = sizeof(SOCKADDR_IN);

  // Initialize Windows Socket library
  WSAStartup(0x0202, &wsaData);

  // Create listening socket
  sListen = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

  // Bind
  local.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
 local.sin_family = AF_INET;
 local.sin_port = htons(PORT);
  bind(sListen, (struct sockaddr *)&local, sizeof(SOCKADDR_IN));

  // Listen
  listen(sListen, 3);

  // Create worker thread
  CreateThread(NULL, 0, WorkerThread, NULL, 0, &dwThreadId);

  while (TRUE)
  {
    // Accept a connection
    sClient = accept(sListen, (struct sockaddr *)&client, &iaddrSize);
    printf("Accepted client:%s:%d\n", inet_ntoa(client.sin_addr), ntohs(client.sin_port));

    g_CliSocketArr[g_iTotalConn] = sClient;
    
    // Allocate a PER_IO_OPERATION_DATA structure
    g_pPerIODataArr[g_iTotalConn] = (LPPER_IO_OPERATION_DATA)HeapAlloc(
      GetProcessHeap(),
      HEAP_ZERO_MEMORY,
      sizeof(PER_IO_OPERATION_DATA));
    g_pPerIODataArr[g_iTotalConn]->Buffer.len = MSGSIZE;
    g_pPerIODataArr[g_iTotalConn]->Buffer.buf = g_pPerIODataArr[g_iTotalConn]->szMessage;
    g_CliEventArr[g_iTotalConn] = g_pPerIODataArr[g_iTotalConn]->overlap.hEvent = WSACreateEvent();

    // Launch an asynchronous operation
    WSARecv(
      g_CliSocketArr[g_iTotalConn],
      &g_pPerIODataArr[g_iTotalConn]->Buffer,
      1,
      &g_pPerIODataArr[g_iTotalConn]->NumberOfBytesRecvd,
      &g_pPerIODataArr[g_iTotalConn]->Flags,
      &g_pPerIODataArr[g_iTotalConn]->overlap,
      NULL);
    
    g_iTotalConn++;
  }
  
  closesocket(sListen);
  WSACleanup();
  return 0;
}

DWORD WINAPI WorkerThread(LPVOID lpParam)
{
  int   ret, index;
  DWORD cbTransferred;

  while (TRUE)
  {
    ret = WSAWaitForMultipleEvents(g_iTotalConn, g_CliEventArr, FALSE, 1000, FALSE);
    if (ret == WSA_WAIT_FAILED || ret == WSA_WAIT_TIMEOUT)
    {
      continue;
    }

    index = ret - WSA_WAIT_EVENT_0;
    WSAResetEvent(g_CliEventArr[index]);

    WSAGetOverlappedResult(
      g_CliSocketArr[index],
      &g_pPerIODataArr[index]->overlap,
      &cbTransferred,
      TRUE,
      &g_pPerIODataArr[g_iTotalConn]->Flags);

    if (cbTransferred == 0)
    {
      // The connection was closed by client
      Cleanup(index);
    }
    else
    {
      // g_pPerIODataArr[index]->szMessage contains the received data
      g_pPerIODataArr[index]->szMessage[cbTransferred] = '\0';
      send(g_CliSocketArr[index], g_pPerIODataArr[index]->szMessage,\
        cbTransferred, 0);

      // Launch another asynchronous operation
      WSARecv(
        g_CliSocketArr[index],
        &g_pPerIODataArr[index]->Buffer,
        1,
        &g_pPerIODataArr[index]->NumberOfBytesRecvd,
        &g_pPerIODataArr[index]->Flags,
        &g_pPerIODataArr[index]->overlap,
        NULL);
    }
  }

  return 0;
}

void Cleanup(int index)
{
  closesocket(g_CliSocketArr[index]);
  WSACloseEvent(g_CliEventArr[index]);
  HeapFree(GetProcessHeap(), 0, g_pPerIODataArr[index]);

  if (index < g_iTotalConn - 1)
  {
    g_CliSocketArr[index] = g_CliSocketArr[g_iTotalConn - 1];
    g_CliEventArr[index] = g_CliEventArr[g_iTotalConn - 1];
    g_pPerIODataArr[index] = g_pPerIODataArr[g_iTotalConn - 1];
  }

  g_pPerIODataArr[--g_iTotalConn] = NULL;
}