Miscellany

unsigned char* GetInternetFile(LPCTSTR szURL, size_t cbMaxSize, size_t* lpcbActualSize)
{
	TRACE("STREAM: %s\r\n",szURL);
	HINTERNET hNet = NULL;
	HINTERNET hUrlFile = NULL;
	unsigned char* buffer = NULL;
	DWORD cbBytesRead = 0;
	SIZE_T cbBytesTotal = 0;
	BOOL bResult = FALSE;
	const DWORD cbReadSize = 0x4000;
	CString header = "Authorization: Basic aWhnOjUzeHk0aGlt\r\n";
	DWORD dwBuffSize = 0;
	dwBuffSize = header.GetLength();


	if (!(hNet = InternetOpen(TEXT("IHG Downloader"), INTERNET_OPEN_TYPE_PRECONFIG,NULL,NULL,INTERNET_FLAG_NO_COOKIES | INTERNET_FLAG_NO_UI | INTERNET_FLAG_PRAGMA_NOCACHE | INTERNET_FLAG_SECURE)))
		goto cleanup;

	DWORD options = INTERNET_FLAG_NEED_FILE|INTERNET_FLAG_HYPERLINK|INTERNET_FLAG_RESYNCHRONIZE|INTERNET_FLAG_RELOAD|INTERNET_FLAG_KEEP_CONNECTION|INTERNET_FLAG_SECURE;

	if (!(hUrlFile = InternetOpenUrl(hNet, szURL, header, dwBuffSize, options, 0)))
		goto cleanup;

	do
	{
		if (!(buffer = (unsigned char*) ReallocOrFree(buffer, cbBytesTotal + cbReadSize)))
			goto cleanup;

		if (!InternetReadFile(hUrlFile, buffer + cbBytesTotal, cbReadSize, &cbBytesRead))
			goto cleanup;

		cbBytesTotal += cbBytesRead;

		/* Max size check and size_t overflow check */
		if (cbBytesTotal > cbMaxSize || ((((size_t) -1) - cbReadSize) - 1) < cbBytesTotal)
			goto cleanup;

	} while (cbBytesRead > 0);

	if (!(buffer = (unsigned char*) ReallocOrFree(buffer, cbBytesTotal + 1)))
		goto cleanup;

	buffer[cbBytesTotal] = '\0';
	bResult = TRUE;

	cleanup:
	if (hUrlFile) 
		InternetCloseHandle(hUrlFile);
	if (hNet) 
		InternetCloseHandle(hNet);
	if (!bResult) 
		free(buffer);
	if (lpcbActualSize) *lpcbActualSize = (bResult ? cbBytesTotal : 0);

	return (bResult ? buffer : NULL);
	}

	void* ReallocOrFree(void* original_ptr, size_t new_size)
	{
		void* temp = realloc(original_ptr, new_size);
		if (!temp) free(original_ptr);
	return temp;
}