/* Directory entry code for Window platforms.
Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
2007, 2008, 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
This file is part of GNU Make.

GNU Make is free software; you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation; either version 3 of the License, or (at your option) any later
version.

GNU Make is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program.  If not, see <http://www.gnu.org/licenses/>.  */


#include <config.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include "dirent.h"


DIR*
opendir(const char* pDirName)
{
	struct stat sb;
	DIR*	pDir;
	char*	pEndDirName;
	int	nBufferLen;

	/* sanity checks */
	if (!pDirName) {
		errno = EINVAL;
		return NULL;
	}
	if (stat(pDirName, &sb) != 0) {
		errno = ENOENT;
		return NULL;
	}
	if ((sb.st_mode & S_IFMT) != S_IFDIR) {
		errno = ENOTDIR;
		return NULL;
	}

	/* allocate a DIR structure to return */
	pDir = (DIR *) malloc(sizeof (DIR));

	if (!pDir)
		return NULL;

	/* input directory name length */
	nBufferLen = strlen(pDirName);

	/* copy input directory name to DIR buffer */
	strcpy(pDir->dir_pDirectoryName, pDirName);

	/* point to end of the copied directory name */
	pEndDirName = &pDir->dir_pDirectoryName[nBufferLen - 1];

	/* if directory name did not end in '/' or '\', add '/' */
	if ((*pEndDirName != '/') && (*pEndDirName != '\\')) {
		pEndDirName++;
		*pEndDirName = '/';
	}

	/* now append the wildcard character to the buffer */
	pEndDirName++;
	*pEndDirName = '*';
	pEndDirName++;
	*pEndDirName = '\0';

	/* other values defaulted */
	pDir->dir_nNumFiles = 0;
	pDir->dir_hDirHandle = INVALID_HANDLE_VALUE;
	pDir->dir_ulCookie = __DIRENT_COOKIE;

	return pDir;
}

void
closedir(DIR *pDir)
{
	/* got a valid pointer? */
	if (!pDir) {
		errno = EINVAL;
		return;
	}

	/* sanity check that this is a DIR pointer */
	if (pDir->dir_ulCookie != __DIRENT_COOKIE) {
		errno = EINVAL;
		return;
	}

	/* close the WINDOWS32 directory handle */
	if (pDir->dir_hDirHandle != INVALID_HANDLE_VALUE)
		FindClose(pDir->dir_hDirHandle);

	free(pDir);

	return;
}

struct dirent *
readdir(DIR* pDir)
{
	WIN32_FIND_DATA wfdFindData;

	if (!pDir) {
		errno = EINVAL;
		return NULL;
	}

	/* sanity check that this is a DIR pointer */
	if (pDir->dir_ulCookie != __DIRENT_COOKIE) {
		errno = EINVAL;
		return NULL;
	}

	if (pDir->dir_nNumFiles == 0) {
		pDir->dir_hDirHandle = FindFirstFile(pDir->dir_pDirectoryName, &wfdFindData);
		if (pDir->dir_hDirHandle == INVALID_HANDLE_VALUE)
			return NULL;
	} else if (!FindNextFile(pDir->dir_hDirHandle, &wfdFindData))
			return NULL;

	/* bump count for next call to readdir() or telldir() */
	pDir->dir_nNumFiles++;

	/* fill in struct dirent values */
	pDir->dir_sdReturn.d_ino = (ino_t)-1;
	strcpy(pDir->dir_sdReturn.d_name, wfdFindData.cFileName);

	return &pDir->dir_sdReturn;
}

void
rewinddir(DIR* pDir)
{
	if (!pDir) {
		errno = EINVAL;
		return;
	}

	/* sanity check that this is a DIR pointer */
	if (pDir->dir_ulCookie != __DIRENT_COOKIE) {
		errno = EINVAL;
		return;
	}

	/* close the WINDOWS32 directory handle */
	if (pDir->dir_hDirHandle != INVALID_HANDLE_VALUE)
		if (!FindClose(pDir->dir_hDirHandle))
			errno = EBADF;

	/* reset members which control readdir() */
	pDir->dir_hDirHandle = INVALID_HANDLE_VALUE;
	pDir->dir_nNumFiles = 0;

	return;
}

int
telldir(DIR* pDir)
{
	if (!pDir) {
		errno = EINVAL;
		return -1;
	}

	/* sanity check that this is a DIR pointer */
	if (pDir->dir_ulCookie != __DIRENT_COOKIE) {
		errno = EINVAL;
		return -1;
	}

	/* return number of times readdir() called */
	return pDir->dir_nNumFiles;
}

void
seekdir(DIR* pDir, long nPosition)
{
	if (!pDir)
		return;

	/* sanity check that this is a DIR pointer */
	if (pDir->dir_ulCookie != __DIRENT_COOKIE)
		return;

	/* go back to beginning of directory */
	rewinddir(pDir);

	/* loop until we have found position we care about */
	for (--nPosition; nPosition && readdir(pDir); nPosition--);

	/* flag invalid nPosition value */
	if (nPosition)
		errno = EINVAL;

	return;
}