Port of Python's `subprocess.list2cmdline` to C.

list2cmdline.c

#define MAX_CMDLINE 8191

	wchar_t result[MAX_CMDLINE];
	memset(result, 0, sizeof(result));
	BOOL needquote = FALSE;

	for (int i = 2; i < argc; i++) {
		wchar_t *arg = argv[i];

		wprintf(L"arg %d = %ls\n", i, arg);

		size_t len = wcslen(arg);

		wchar_t bs_buf[MAX_CMDLINE];
		memset(bs_buf, 0, sizeof(bs_buf));
		BOOL bs_buf_empty = TRUE;

		if (wcslen(result))
			wcscat(result, L" ");

		needquote = len ? FALSE : TRUE;
		for (int j = 0; j < len; j++) {
			if (arg[j] == L' ' || arg[j] == L'\t') {
				needquote = TRUE;
				break;
			}
		}

		if (needquote) {
			result[wcslen(result)] = L'"';
		}

		for (int j = 0; j < len; j++) {
			wchar_t c = arg[j];
			switch (c) {
			case L'\\':
				bs_buf[wcslen(bs_buf)] = c;
				break;
			case L'"':
				for (int k = 0; k < wcslen(bs_buf) * 2; k++) {
					wcscat(result, L"\\");
				}

				memset(bs_buf, 0, sizeof(bs_buf));
				wcscat(result, L"\\\"");
				break;
			default:
				if (wcslen(bs_buf)) {
					wcscat(result, bs_buf);
					memset(bs_buf, 0, sizeof(bs_buf));
				}

				result[wcslen(result)] = c;
			}
		}

		if (wcslen(bs_buf)) {
			wcscat(result, bs_buf);
		}

		if (needquote) {
			wcscat(result, bs_buf);
			wcscat(result, L"\"");
		}
	}