/*****************************************************************************
* dirent.h - dirent API for Microsoft Visual Studio
*
* Copyright (C) 2006 Toni Ronkko
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* ``Software''), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL TONI RONKKO BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
* Mar 15, 2011, Toni Ronkko
* Defined FILE_ATTRIBUTE_DEVICE for MSVC 6.0.
*
* Aug 11, 2010, Toni Ronkko
* Added d_type and d_namlen fields to dirent structure.  The former is
* especially useful for determining whether directory entry represents a
* file or a directory.  For more information, see
* http://www.delorie.com/gnu/docs/glibc/libc_270.html
*
* Aug 11, 2010, Toni Ronkko
* Improved conformance to the standards.  For example, errno is now set
* properly on failure and assert() is never used.  Thanks to Peter Brockam
* for suggestions.
*
* Aug 11, 2010, Toni Ronkko
* Fixed a bug in rewinddir(): when using relative directory names, change
* of working directory no longer causes rewinddir() to fail.
*
* Dec 15, 2009, John Cunningham
* Added rewinddir member function
*
* Jan 18, 2008, Toni Ronkko
* Using FindFirstFileA and WIN32_FIND_DATAA to avoid converting string
* between multi-byte and unicode representations.  This makes the
* code simpler and also allows the code to be compiled under MingW.  Thanks
* to Azriel Fasten for the suggestion.
*
* Mar 4, 2007, Toni Ronkko
* Bug fix: due to the strncpy_s() function this file only compiled in
* Visual Studio 2005.  Using the new string functions only when the
* compiler version allows.
*
* Nov  2, 2006, Toni Ronkko
* Major update: removed support for Watcom C, MS-DOS and Turbo C to
* simplify the file, updated the code to compile cleanly on Visual
* Studio 2005 with both unicode and multi-byte character strings,
* removed rewinddir() as it had a bug.
*
* Aug 20, 2006, Toni Ronkko
* Removed all remarks about MSVC 1.0, which is antiqued now.  Simplified
* comments by removing SGML tags.
*
* May 14 2002, Toni Ronkko
* Embedded the function definitions directly to the header so that no
* source modules need to be included in the Visual Studio project.  Removed
* all the dependencies to other projects so that this very header can be
* used independently.
*
* May 28 1998, Toni Ronkko
* First version.
*****************************************************************************/
#ifndef DIRENT_H
#define DIRENT_H

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>

/* Entries missing from MSVC 6.0 */
#if !defined(FILE_ATTRIBUTE_DEVICE)
# define FILE_ATTRIBUTE_DEVICE 0x40
#endif

/* File type and permission flags for stat() */
#if defined(_MSC_VER)  &&  !defined(S_IREAD)
# define S_IFMT   _S_IFMT                      /* file type mask */
# define S_IFDIR  _S_IFDIR                     /* directory */
# define S_IFCHR  _S_IFCHR                     /* character device */
# define S_IFFIFO _S_IFFIFO                    /* pipe */
# define S_IFREG  _S_IFREG                     /* regular file */
# define S_IREAD  _S_IREAD                     /* read permission */
# define S_IWRITE _S_IWRITE                    /* write permission */
# define S_IEXEC  _S_IEXEC                     /* execute permission */
#endif
#define S_IFBLK   -1                            /* block device */
#define S_IFLNK   -2                            /* link */
//#define S_IFSOCK  0                            /* socket */

#if defined(_MSC_VER)
# define S_IRUSR  S_IREAD                      /* read, user */
# define S_IWUSR  S_IWRITE                     /* write, user */
# define S_IXUSR  0                            /* execute, user */
# define S_IRGRP  0                            /* read, group */
# define S_IWGRP  0                            /* write, group */
# define S_IXGRP  0                            /* execute, group */
# define S_IROTH  0                            /* read, others */
# define S_IWOTH  0                            /* write, others */
# define S_IXOTH  0                            /* execute, others */
#endif

/* Indicates that d_type field is available in dirent structure */
#define _DIRENT_HAVE_D_TYPE

/* File type flags for d_type */
#define DT_UNKNOWN  0
#define DT_REG      S_IFREG
#define DT_DIR      S_IFDIR
#define DT_FIFO     S_IFFIFO
#define DT_SOCK     S_IFSOCK
#define DT_CHR      S_IFCHR
#define DT_BLK      S_IFBLK

/* Macros for converting between st_mode and d_type */
#define IFTODT(mode) ((mode) & S_IFMT)
#define DTTOIF(type) (type)

/*
* File type macros.  Note that block devices, sockets and links cannot be
* distinguished on Windows and the macros S_ISBLK, S_ISSOCK and S_ISLNK are
* only defined for compatibility.  These macros should always return false
* on Windows.
*/
#define	S_ISFIFO(mode) (((mode) & S_IFMT) == S_IFFIFO)
#define	S_ISDIR(mode)  (((mode) & S_IFMT) == S_IFDIR)
#define	S_ISREG(mode)  (((mode) & S_IFMT) == S_IFREG)
#define	S_ISLNK(mode)  (((mode) & S_IFMT) == S_IFLNK)
#define	S_ISSOCK(mode) (((mode) & S_IFMT) == S_IFSOCK)
#define	S_ISCHR(mode)  (((mode) & S_IFMT) == S_IFCHR)
#define	S_ISBLK(mode)  (((mode) & S_IFMT) == S_IFBLK)

#ifdef __cplusplus
extern "C" {
#endif


	typedef struct dirent
	{
		char d_name[MAX_PATH + 1];                  /* File name */
		size_t d_namlen;                            /* Length of name without \0 */
		int d_type;                                 /* File type */
	} dirent;


	typedef struct DIR
	{
		dirent           curentry;                  /* Current directory entry */
		WIN32_FIND_DATAA find_data;                 /* Private file data */
		int              cached;                    /* True if data is valid */
		HANDLE           search_handle;             /* Win32 search handle */
		char             patt[MAX_PATH + 3];        /* Initial directory name */
	} DIR;


	/* Forward declarations */
	static DIR *opendir(const char *dirname);
	static struct dirent *readdir(DIR *dirp);
	static int closedir(DIR *dirp);
	static void rewinddir(DIR* dirp);


	/* Use the new safe string functions introduced in Visual Studio 2005 */
#if defined(_MSC_VER) && _MSC_VER >= 1400
# define DIRENT_STRNCPY(dest,src,size) strncpy_s((dest),(size),(src),_TRUNCATE)
#else
# define DIRENT_STRNCPY(dest,src,size) strncpy((dest),(src),(size))
#endif

	/* Set errno variable */
#if defined(_MSC_VER)
#define DIRENT_SET_ERRNO(x) _set_errno (x)
#else
#define DIRENT_SET_ERRNO(x) (errno = (x))
#endif


	/*****************************************************************************
	* Open directory stream DIRNAME for read and return a pointer to the
	* internal working area that is used to retrieve individual directory
	* entries.
	*/
	static DIR *opendir(const char *dirname)
	{
		DIR *dirp;

		/* ensure that the resulting search pattern will be a valid file name */
		if (dirname == NULL) {
			DIRENT_SET_ERRNO(ENOENT);
			return NULL;
		}
		if (strlen(dirname) + 3 >= MAX_PATH) {
			DIRENT_SET_ERRNO(ENAMETOOLONG);
			return NULL;
		}

		/* construct new DIR structure */
		dirp = (DIR*)malloc(sizeof(struct DIR));
		if (dirp != NULL) {
			int error;

			/*
			* Convert relative directory name to an absolute one.  This
			* allows rewinddir() to function correctly when the current working
			* directory is changed between opendir() and rewinddir().
			*/
			if (GetFullPathNameA(dirname, MAX_PATH, dirp->patt, NULL)) {
				char *p;

				/* append the search pattern "\\*\0" to the directory name */
				p = strchr(dirp->patt, '\0');
				if (dirp->patt < p  &&  *(p - 1) != '\\'  &&  *(p - 1) != ':') {
					*p++ = '\\';
				}
				*p++ = '*';
				*p = '\0';

				/* open directory stream and retrieve the first entry */
				dirp->search_handle = FindFirstFileA(dirp->patt, &dirp->find_data);
				if (dirp->search_handle != INVALID_HANDLE_VALUE) {
					/* a directory entry is now waiting in memory */
					dirp->cached = 1;
					error = 0;
				}
				else {
					/* search pattern is not a directory name? */
					DIRENT_SET_ERRNO(ENOENT);
					error = 1;
				}
			}
			else {
				/* buffer too small */
				DIRENT_SET_ERRNO(ENOMEM);
				error = 1;
			}

			if (error) {
				free(dirp);
				dirp = NULL;
			}
		}

		return dirp;
	}


	/*****************************************************************************
	* Read a directory entry, and return a pointer to a dirent structure
	* containing the name of the entry in d_name field.  Individual directory
	* entries returned by this very function include regular files,
	* sub-directories, pseudo-directories "." and "..", but also volume labels,
	* hidden files and system files may be returned.
	*/
	static struct dirent *readdir(DIR *dirp)
	{
		DWORD attr;
		if (dirp == NULL) {
			/* directory stream did not open */
			DIRENT_SET_ERRNO(EBADF);
			return NULL;
		}

		/* get next directory entry */
		if (dirp->cached != 0) {
			/* a valid directory entry already in memory */
			dirp->cached = 0;
		}
		else {
			/* get the next directory entry from stream */
			if (dirp->search_handle == INVALID_HANDLE_VALUE) {
				return NULL;
			}
			if (FindNextFileA(dirp->search_handle, &dirp->find_data) == FALSE) {
				/* the very last entry has been processed or an error occured */
				FindClose(dirp->search_handle);
				dirp->search_handle = INVALID_HANDLE_VALUE;
				return NULL;
			}
		}

		/* copy as a multibyte character string */
		DIRENT_STRNCPY(dirp->curentry.d_name,
			dirp->find_data.cFileName,
			sizeof(dirp->curentry.d_name));
		dirp->curentry.d_name[MAX_PATH] = '\0';

		/* compute the length of name */
		dirp->curentry.d_namlen = strlen(dirp->curentry.d_name);

		/* determine file type */
		attr = dirp->find_data.dwFileAttributes;
		if ((attr & FILE_ATTRIBUTE_DEVICE) != 0) {
			dirp->curentry.d_type = DT_CHR;
		}
		else if ((attr & FILE_ATTRIBUTE_DIRECTORY) != 0) {
			dirp->curentry.d_type = DT_DIR;
		}
		else {
			dirp->curentry.d_type = DT_REG;
		}
		return &dirp->curentry;
	}


	/*****************************************************************************
	* Close directory stream opened by opendir() function.  Close of the
	* directory stream invalidates the DIR structure as well as any previously
	* read directory entry.
	*/
	static int closedir(DIR *dirp)
	{
		if (dirp == NULL) {
			/* invalid directory stream */
			DIRENT_SET_ERRNO(EBADF);
			return -1;
		}

		/* release search handle */
		if (dirp->search_handle != INVALID_HANDLE_VALUE) {
			FindClose(dirp->search_handle);
			dirp->search_handle = INVALID_HANDLE_VALUE;
		}

		/* release directory structure */
		free(dirp);
		return 0;
	}


	/*****************************************************************************
	* Resets the position of the directory stream to which dirp refers to the
	* beginning of the directory.  It also causes the directory stream to refer
	* to the current state of the corresponding directory, as a call to opendir()
	* would have done.  If dirp does not refer to a directory stream, the effect
	* is undefined.
	*/
	static void rewinddir(DIR* dirp)
	{
		if (dirp != NULL) {
			/* release search handle */
			if (dirp->search_handle != INVALID_HANDLE_VALUE) {
				FindClose(dirp->search_handle);
			}

			/* open new search handle and retrieve the first entry */
			dirp->search_handle = FindFirstFileA(dirp->patt, &dirp->find_data);
			if (dirp->search_handle != INVALID_HANDLE_VALUE) {
				/* a directory entry is now waiting in memory */
				dirp->cached = 1;
			}
			else {
				/* failed to re-open directory: no directory entry in memory */
				dirp->cached = 0;
			}
		}
	}


#ifdef __cplusplus
}
#endif
#endif /*DIRENT_H*/
