FindFirstFile/FindNextFile

find_first_file.c

#include <stdlib.h>
#include <stdio.h>
#include <locale.h>

#define WIN32_LEAN_AND_MEAN
#define _UNICODE
#include <windows.h>

int print_sys_error(DWORD last_error)
{
	DWORD rc;
	LPWSTR msg;

	rc = FormatMessageW(
			FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM,
			NULL,
			last_error,
			0,
			(LPWSTR)&msg,
			0,
			NULL);
	if (rc == 0) {
		fputws(L"FormatMessage failed\n", stderr);
		abort();
	}

	fputws(msg, stderr);

	LocalFree(msg);

	return 0;
}

DWORD print_matching(const wchar_t *pattern)
{
	HANDLE hFile;
	WIN32_FIND_DATAW ffd;

	SetLastError(0);

	hFile = FindFirstFileW(pattern, &ffd);
	if (hFile == INVALID_HANDLE_VALUE) {
		return GetLastError();
	}

	DWORD last_error = 0;

	for (;;) {
		if (FindNextFile(hFile, &ffd) == 0) {
			DWORD rc;
			rc = GetLastError();
			if (rc == ERROR_NO_MORE_FILES) {
				break;
			}

			last_error = rc;
			break;
		}

		fputws(ffd.cFileName, stdout);
		fputwc(L'\n', stdout);
	}

	FindClose(hFile);

	return last_error;
}

wchar_t *get_pattern(const wchar_t *dirname, const size_t namelen)
{
	const wchar_t wildcard[] = L"*.*";
	const size_t wc_len = sizeof(wildcard)/sizeof(wildcard[0]);

	size_t dstlen;
	BOOL need_sep;

	dstlen = namelen + wc_len;
	need_sep = dirname[namelen-1] != L'\\';
	if (need_sep) {
		dstlen++;
	}

	wchar_t *pattern;

	pattern = (wchar_t*)malloc(dstlen * sizeof(wchar_t));
	if (pattern == NULL) {
		fputws(L"out of memory\n", stderr);
		abort();
	}

	wcscpy(pattern, dirname);

	size_t wc_pos = namelen;
	if (need_sep) {
		pattern[wc_pos] = L'\\';
		wc_pos++;
	}

	wcscpy(pattern + wc_pos, wildcard);
	pattern[dstlen] = L'\0';

	return pattern;
}

int wmain(int argc, const wchar_t **argv)
{
	if (setlocale(LC_ALL, "") == NULL) {
		fputws(L"setlocale failed\n", stderr);
		abort();
	}

	wchar_t *pattern;
	BOOL allocated;

	switch (argc) {
	case 2:
		size_t namelen = wcslen(argv[1]);
		if (namelen > 0) {
			pattern = get_pattern(argv[1], namelen);
			allocated = TRUE;
			break;
		}
		// fall through
	case 1:
		pattern = L".\\*.*";
		allocated = FALSE;
		break;
	default:
		fputws(L"wrong number of arguments.\n", stderr);
		return 2;
	}

	fputws(pattern, stdout);
	fputwc(L'\n', stdout);
	fflush(stdout);

	DWORD rc;
	rc = print_matching(pattern);
	if (rc != 0) {
		print_sys_error(rc);
	}

	if (allocated) {
		free(pattern);
	}

	if (rc == 0) {
		return 0;
	}

	return 1;
}