Function ExtractFile

tools/CascExtractor/CascExtractor/CascExtractor.cpp:214–344

}

static bool ExtractFile(HANDLE hStorage, const CASC_FIND_DATA& findData, const char* targetDirPath, const char* targetFilePath) {
	namespace fs = std::filesystem;

	PCASC_FILE_SPAN_INFO pSpans = nullptr;
	HANDLE hFile = nullptr;
	CASC_FILE_FULL_INFO fileInfo{};
	LPCSTR szOpenName = findData.szFileName;
	DWORD dwErrCode = ERROR_SUCCESS;

	if (CascOpenFile(hStorage, szOpenName, NULL /*dwLocaleFlags*/, CASC_STRICT_DATA_CHECK, &hFile))
	{
		// Retrieve the information about file spans.
		if ((pSpans = GetFileInfo(hFile, fileInfo)) != nullptr && fileInfo.ContentSize > 0)
		{
			DWORD dwBytesRead = 0;
			ULONGLONG totalWritten = 0;
			FILE* pOutFile = nullptr;

			// Load the entire file, one read request per span.
			// Using span-aligned reads will cause CascReadFile not to do any caching,
			// and the amount of memcpys will be almost zero
			for (DWORD i = 0; i < fileInfo.SpanCount && dwErrCode == ERROR_SUCCESS; ++i)
			{
				const CASC_FILE_SPAN_INFO* const pFileSpan = pSpans + i;
				LPBYTE pbFileSpan = nullptr;
				const auto cbFileSpan = (DWORD) (pFileSpan->EndOffset - pFileSpan->StartOffset);
				bool bReadOk = true;

				// Do not read empty spans.
				if (cbFileSpan == 0)
				{
					continue;
				}

				// Allocate span buffer
				pbFileSpan = CASC_ALLOC<BYTE>(cbFileSpan);
				if (pbFileSpan == nullptr)
				{
					std::cerr << "   ERROR: Not enough memory to allocate " << cbFileSpan << " bytes" << std::endl;
					dwErrCode = ERROR_NOT_ENOUGH_MEMORY;
					break;
				}

				// CascReadFile will read as much as possible. If there is a frame error
				// (e.g. MD5 mismatch, missing encryption key or disc error),
				// CascReadFile only returns frames that are loaded entirely.
				bReadOk = CascReadFile(hFile, pbFileSpan, cbFileSpan, &dwBytesRead);
				if (bReadOk) {
					// prepare file stream
					if (!pOutFile) {

						if (fs::exists(targetDirPath) || fs::create_directories(targetDirPath)) {

							// create filestream and empty file
							if ((pOutFile = OpenExtractedFile(targetFilePath)) == nullptr) {
								std::cerr << "   ERROR: Could not create file: " << targetFilePath << std::endl;
							}
						}