在C++中通過UDP發送緩衝圖像

Question

我已經從回調後的here這段代碼調整了這段代碼，它將圖像保存到緩衝區中。現在我想通過UDP數據包發送這個緩衝區。我很困惑如何使用sendmail函數（ ）插座。我明白你可以提供任何幫助。

{ 
    IStream *pStream = NULL; 
    LARGE_INTEGER liZero = {}; 
    ULARGE_INTEGER pos = {}; 
    STATSTG stg = {}; 
    ULONG bytesRead=0; 
    HRESULT hrRet=S_OK; 

    BYTE* buffer = NULL; // this is your buffer that will hold the jpeg bytes 
    DWORD dwBufferSize = 0; // this is the size of that buffer; 


    hrRet = CreateStreamOnHGlobal(NULL, TRUE, &pStream); 
    //hrRet = pScreenShot->Save(pStream, &imageCLSID, &encoderParams) == 0 ? S_OK : E_FAIL; 
    bitmap.Save(pStream, &clsid, &encoderParameters); 
    hrRet = pStream->Seek(liZero, STREAM_SEEK_SET, &pos); 
    hrRet = pStream->Stat(&stg, STATFLAG_NONAME); 

    // allocate a byte buffer big enough to hold the jpeg stream in memory 
    buffer = new BYTE[stg.cbSize.LowPart]; 
    hrRet = (buffer == NULL) ? E_OUTOFMEMORY : S_OK; 
    dwBufferSize = stg.cbSize.LowPart; 

    // copy the stream into memory 
    hrRet = pStream->Read(buffer, stg.cbSize.LowPart, &bytesRead); 

    // now go save "buffer" and "dwBufferSize" off somewhere. This is the jpeg buffer 
    // don't forget to free it when you are done 

    // After success or if any of the above calls fail, don't forget to release the stream 
    if (pStream) 
    { 
     pStream->Release(); 
    } 
} 

Answer 1

請找到下面的代碼使用sendto()你只需要添加代碼 讀取圖像並將其存儲在緩衝區通過UDP發送數據（我已經提到在下面的代碼裏添加你的代碼）。而請不是我在c中寫這段代碼，所以在你身邊你需要一些從c到c++的對話。

#include <sys/types.h> 
#include <sys/socket.h> 
#include <netinet/in.h> 
#include <arpa/inet.h> 
#include <netdb.h> 
#include <stdio.h> 
#include <unistd.h> 
#include <string.h> 
#include <sys/time.h> 

#define REMOTE_SERVER_PORT 1501 
#define MAX_MSG 100 


int main(int argc, char *argv[]) { 

    int sd, rc, i; 
    struct sockaddr_in cliAddr, remoteServAddr; 
    struct hostent *h; 
    FILE* filein; 
long lSize; 
char *buffer; 

    /* get server IP address (no check if input is IP address or DNS name */ 
    h = gethostbyname(argv[1]); 
    if(h==NULL) { 
    printf("%s: unknown host '%s' \n", argv[0], argv[1]); 
    exit(1); 
    } 

    printf("%s: sending data to '%s' (IP : %s) \n", argv[0], h->h_name, 
    inet_ntoa(*(struct in_addr *)h->h_addr_list[0])); 

    remoteServAddr.sin_family = h->h_addrtype; 
    memcpy((char *) &remoteServAddr.sin_addr.s_addr, 
    h->h_addr_list[0], h->h_length); 
    remoteServAddr.sin_port = htons(REMOTE_SERVER_PORT); 

    /* socket creation */ 
    sd = socket(AF_INET,SOCK_DGRAM,0); 
    if(sd<0) { 
    printf("%s: cannot open socket \n",argv[0]); 
    exit(1); 
    } 

    /* bind any port */ 
    cliAddr.sin_family = AF_INET; 
    cliAddr.sin_addr.s_addr = htonl(INADDR_ANY); 
    cliAddr.sin_port = htons(0); 

    rc = bind(sd, (struct sockaddr *) &cliAddr, sizeof(cliAddr)); 
    if(rc<0) { 
    printf("%s: cannot bind port\n", argv[0]); 
    exit(1); 
    } 

//please put Here your code to read image and store it in buffer  


    // send data 

    rc = sendto(sd, buffer, sizeof(buffer)+1, 0, 
     (struct sockaddr *) &remoteServAddr, 
     sizeof(remoteServAddr)); 

    if(rc<0) { 
     printf("%s: cannot send data %d \n",argv[0],i-1); 
     close(sd); 
     exit(1); 
    } 

    return 1; 

}