wininet 으로 파일 업로드/다운로드 콜백 처리

#include<windows.h>
#include<wininet.h>
#include<iostream.h>

void main(int argc, char *argv[])
{
    if (argc != 3)
    {
        cout << "Usage: progress <host> <object>" << endl;
        return;
    }

    HINTERNET hSession = InternetOpen("WinInet Progress Sample",
                                      INTERNET_OPEN_TYPE_PRECONFIG,
                                      NULL,
                                      NULL,
                                      0);
    HINTERNET hConnection = InternetConnect(hSession,
                                            argv[1],  // Server
                                            INTERNET_DEFAULT_HTTP_PORT,
                                            NULL,     // Username
                                            NULL,     // Password
                                            INTERNET_SERVICE_HTTP,
                                            0,        // Synchronous
                                            NULL);    // No Context

    HINTERNET hRequest = HttpOpenRequest(hConnection,
                                         "GET",
                                         argv[2],
                                         NULL,    // Default HTTP Version
                                         NULL,    // No Referer
                                         (const char**)"*/*\0", // Accept
                                                                // anything
                                         0,       // Flags
                                         NULL);   // No Context
    HttpSendRequest(hRequest,
                    NULL,    // No extra headers
                    0,       // Header length
                    NULL,    // No Body
                    0);      // Body length

    DWORD dwContentLen;
    DWORD dwBufLen = sizeof(dwContentLen);
    if (HttpQueryInfo(hRequest,
                      HTTP_QUERY_CONTENT_LENGTH | HTTP_QUERY_FLAG_NUMBER,
                      (LPVOID)&dwContentLen,
                      &dwBufLen,
                      0))
    {
        // You have a content length so you can calculate percent complete
        char *pData = (char*)GlobalAlloc(GMEM_FIXED, dwContentLen + 1);
        DWORD dwReadSize = dwContentLen / 10;   // We will read 10% of data
                                                // with each read.

        cout << "Download Progress:" << endl;
        cout << "    0----------100%" << endl;
        cout << "     ";
        cout.flush();

        DWORD cReadCount;
        DWORD dwBytesRead;
        char *pCopyPtr = pData;
        for (cReadCount = 0; cReadCount < 10; cReadCount++)
        {
            InternetReadFile(hRequest, pCopyPtr, dwReadSize, &dwBytesRead);
            cout << "*";
            cout.flush();
            pCopyPtr = pCopyPtr + dwBytesRead;
        }
        // extra read to account for integer division round off
        InternetReadFile(hRequest,
                         pCopyPtr,
                         dwContentLen - (pCopyPtr - pData),
                         &dwBytesRead);
        // Null terminate data
        pData[dwContentLen] = 0;

        // Display
        cout << endl << "Download Complete" << endl;
        cout << pData;
    }
    else
    {
        DWORD err = GetLastError();
        // No content length...impossible to calculate % complete
        // Just read until we are done.
        char pData[100];
        DWORD dwBytesRead = 1;
        while (dwBytesRead)
        {
            InternetReadFile(hRequest, pData, 99, &dwBytesRead);
            pData[dwBytesRead] = 0;
            cout << pData;
        }
    }
}