add tiny cross-platform TCP socket library from https://github.com/DFHack/clsocket

(todo: hook-up to Bullet cmake/premake build systems, and implement TCP alternative for UDP server)

test/clsocket/RecvAsync.cpp

@@ -0,0 +1,101 @@
+#include <pthread.h>
+#include "PassiveSocket.h"
+
+#ifdef WIN32
+#include <windows.h>
+
+  // usually defined with #include <unistd.h>
+  static void sleep( unsigned int seconds )
+  {
+    Sleep( seconds * 1000 );
+  }
+#endif
+
+#define MAX_PACKET  4096
+#define TEST_PACKET "Test Packet"
+
+struct thread_data
+{
+    const char *pszServerAddr;
+    short int   nPort;
+    int         nNumBytesToReceive;
+    int         nTotalPayloadSize;
+};
+
+
+void *CreateTCPEchoServer(void *param)
+{
+    CPassiveSocket socket;
+    CActiveSocket *pClient = NULL;
+    struct thread_data *pData = (struct thread_data *)param;
+    int            nBytesReceived = 0;
+
+    socket.Initialize();
+    socket.Listen(pData->pszServerAddr, pData->nPort);
+
+    if ((pClient = socket.Accept()) != NULL)
+    {
+        while (nBytesReceived != pData->nTotalPayloadSize)
+        {
+            if (nBytesReceived += pClient->Receive(pData->nNumBytesToReceive))
+            {
+                pClient->Send((const uint8 *)pClient->GetData(), pClient->GetBytesReceived());
+            }
+        }
+
+        sleep(100);
+
+        delete pClient;
+    }
+
+    socket.Close();
+
+    return NULL;
+}
+
+int main(int argc, char **argv)
+{
+    pthread_t          threadId;
+    struct thread_data thData;
+    CActiveSocket      client;
+    char result[1024];
+
+    thData.pszServerAddr = "127.0.0.1";
+    thData.nPort = 6789;
+    thData.nNumBytesToReceive = 1;
+    thData.nTotalPayloadSize = (int)strlen(TEST_PACKET);
+
+    pthread_create(&threadId, 0, CreateTCPEchoServer, &thData);
+    sleep(1); // allow a second for the thread to create and listen
+
+    client.Initialize();
+    client.SetNonblocking();
+
+    if (client.Open("127.0.0.1", 6789))
+    {
+        if (client.Send((uint8 *)TEST_PACKET, strlen(TEST_PACKET)))
+        {
+            int numBytes = -1;
+            int bytesReceived = 0;
+
+            client.Select();
+
+            while (bytesReceived != strlen(TEST_PACKET))
+            {
+                numBytes = client.Receive(MAX_PACKET);
+
+                if (numBytes > 0)
+                {
+                    bytesReceived += numBytes;
+                    memset(result, 0, 1024);
+                    memcpy(result, client.GetData(), numBytes);
+                    printf("received %d bytes: '%s'\n", numBytes, result);
+                }
+                else
+                {
+                    printf("Received %d bytes\n", numBytes);
+                }
+            }
+        }
+    }
+}