dirent.h

/*
* Dirent interface for Microsoft Visual Studio
*
* Copyright (C) 2006-2012 Toni Ronkko
* This file is part of dirent.  Dirent may be freely distributed
* under the MIT license.  For all details and documentation, see
* https://github.com/tronkko/dirent
*/
#ifndef DIRENT_H
#define DIRENT_H

/*
* Include windows.h without Windows Sockets 1.1 to prevent conflicts with
* Windows Sockets 2.0.
*/
#ifndef WIN32_LEAN_AND_MEAN
#   define WIN32_LEAN_AND_MEAN
#endif
#include <windows.h>

#include <stdio.h>
#include <stdarg.h>
#include <wchar.h>
#include <string.h>
#include <stdlib.h>
#include <malloc.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>

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

/* Indicates that d_namlen field is available in dirent structure */
#define _DIRENT_HAVE_D_NAMLEN

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

/* File type and permission flags for stat(), general mask */
#if !defined(S_IFMT)
#   define S_IFMT _S_IFMT
#endif

/* Directory bit */
#if !defined(S_IFDIR)
#   define S_IFDIR _S_IFDIR
#endif

/* Character device bit */
#if !defined(S_IFCHR)
#   define S_IFCHR _S_IFCHR
#endif

/* Pipe bit */
#if !defined(S_IFFIFO)
#   define S_IFFIFO _S_IFFIFO
#endif

/* Regular file bit */
#if !defined(S_IFREG)
#   define S_IFREG _S_IFREG
#endif

/* Read permission */
#if !defined(S_IREAD)
#   define S_IREAD _S_IREAD
#endif

/* Write permission */
#if !defined(S_IWRITE)
#   define S_IWRITE _S_IWRITE
#endif

/* Execute permission */
#if !defined(S_IEXEC)
#   define S_IEXEC _S_IEXEC
#endif

/* Pipe */
#if !defined(S_IFIFO)
#   define S_IFIFO _S_IFIFO
#endif

/* Block device */
#if !defined(S_IFBLK)
#   define S_IFBLK 0
#endif

/* Link */
#if !defined(S_IFLNK)
#   define S_IFLNK 0
#endif

/* Socket */
#if !defined(S_IFSOCK)
#   define S_IFSOCK 0
#endif

/* Read user permission */
#if !defined(S_IRUSR)
#   define S_IRUSR S_IREAD
#endif

/* Write user permission */
#if !defined(S_IWUSR)
#   define S_IWUSR S_IWRITE
#endif

/* Execute user permission */
#if !defined(S_IXUSR)
#   define S_IXUSR 0
#endif

/* Read group permission */
#if !defined(S_IRGRP)
#   define S_IRGRP 0
#endif

/* Write group permission */
#if !defined(S_IWGRP)
#   define S_IWGRP 0
#endif

/* Execute group permission */
#if !defined(S_IXGRP)
#   define S_IXGRP 0
#endif

/* Read others permission */
#if !defined(S_IROTH)
#   define S_IROTH 0
#endif

/* Write others permission */
#if !defined(S_IWOTH)
#   define S_IWOTH 0
#endif

/* Execute others permission */
#if !defined(S_IXOTH)
#   define S_IXOTH 0
#endif

/* Maximum length of file name */
#if !defined(PATH_MAX)
#   define PATH_MAX MAX_PATH
#endif
#if !defined(FILENAME_MAX)
#   define FILENAME_MAX MAX_PATH
#endif
#if !defined(NAME_MAX)
#   define NAME_MAX FILENAME_MAX
#endif

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

/* 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.
*/
#if !defined(S_ISFIFO)
#   define S_ISFIFO(mode) (((mode) & S_IFMT) == S_IFIFO)
#endif
#if !defined(S_ISDIR)
#   define S_ISDIR(mode) (((mode) & S_IFMT) == S_IFDIR)
#endif
#if !defined(S_ISREG)
#   define S_ISREG(mode) (((mode) & S_IFMT) == S_IFREG)
#endif
#if !defined(S_ISLNK)
#   define S_ISLNK(mode) (((mode) & S_IFMT) == S_IFLNK)
#endif
#if !defined(S_ISSOCK)
#   define S_ISSOCK(mode) (((mode) & S_IFMT) == S_IFSOCK)
#endif
#if !defined(S_ISCHR)
#   define S_ISCHR(mode) (((mode) & S_IFMT) == S_IFCHR)
#endif
#if !defined(S_ISBLK)
#   define S_ISBLK(mode) (((mode) & S_IFMT) == S_IFBLK)
#endif

/* Return the exact length of the file name without zero terminator */
#define _D_EXACT_NAMLEN(p) ((p)->d_namlen)

/* Return the maximum size of a file name */
#define _D_ALLOC_NAMLEN(p) ((PATH_MAX)+1)


#ifdef __cplusplus
extern "C" {
#endif


	/* Wide-character version */
	struct _wdirent {
		/* Always zero */
		long d_ino;

		/* File position within stream */
		long d_off;

		/* Structure size */
		unsigned short d_reclen;

		/* Length of name without \0 */
		size_t d_namlen;

		/* File type */
		int d_type;

		/* File name */
		wchar_t d_name[PATH_MAX + 1];
	};
	typedef struct _wdirent _wdirent;

	struct _WDIR {
		/* Current directory entry */
		struct _wdirent ent;

		/* Private file data */
		WIN32_FIND_DATAW data;

		/* True if data is valid */
		int cached;

		/* Win32 search handle */
		HANDLE handle;

		/* Initial directory name */
		wchar_t *patt;
	};
	typedef struct _WDIR _WDIR;

	/* Multi-byte character version */
	struct dirent {
		/* Always zero */
		long d_ino;

		/* File position within stream */
		long d_off;

		/* Structure size */
		unsigned short d_reclen;

		/* Length of name without \0 */
		size_t d_namlen;

		/* File type */
		int d_type;

		/* File name */
		char d_name[PATH_MAX + 1];
	};
	typedef struct dirent dirent;

	struct DIR {
		struct dirent ent;
		struct _WDIR *wdirp;
	};
	typedef struct DIR DIR;


	/* Dirent functions */
	static DIR *opendir(const char *dirname);
	static _WDIR *_wopendir(const wchar_t *dirname);

	static struct dirent *readdir(DIR *dirp);
	static struct _wdirent *_wreaddir(_WDIR *dirp);

	static int readdir_r(
		DIR *dirp, struct dirent *entry, struct dirent **result);
	static int _wreaddir_r(
		_WDIR *dirp, struct _wdirent *entry, struct _wdirent **result);

	static int closedir(DIR *dirp);
	static int _wclosedir(_WDIR *dirp);

	static void rewinddir(DIR* dirp);
	static void _wrewinddir(_WDIR* dirp);

	static int scandir(const char *dirname, struct dirent ***namelist,
		int(*filter)(const struct dirent*),
		int(*compare)(const void *, const void *));

	static int alphasort(const struct dirent **a, const struct dirent **b);

	static int versionsort(const struct dirent **a, const struct dirent **b);


	/* For compatibility with Symbian */
#define wdirent _wdirent
#define WDIR _WDIR
#define wopendir _wopendir
#define wreaddir _wreaddir
#define wclosedir _wclosedir
#define wrewinddir _wrewinddir


	/* Internal utility functions */
	static WIN32_FIND_DATAW *dirent_first(_WDIR *dirp);
	static WIN32_FIND_DATAW *dirent_next(_WDIR *dirp);

	static int dirent_mbstowcs_s(
		size_t *pReturnValue,
		wchar_t *wcstr,
		size_t sizeInWords,
		const char *mbstr,
		size_t count);

	static int dirent_wcstombs_s(
		size_t *pReturnValue,
		char *mbstr,
		size_t sizeInBytes,
		const wchar_t *wcstr,
		size_t count);

	static void dirent_set_errno(int error);


	/*
	* Open directory stream DIRNAME for read and return a pointer to the
	* internal working area that is used to retrieve individual directory
	* entries.
	*/
	static _WDIR*
		_wopendir(
			const wchar_t *dirname)
	{
		_WDIR *dirp = NULL;
		int error;

		/* Must have directory name */
		if (dirname == NULL || dirname[0] == '\0') {
			dirent_set_errno(ENOENT);
			return NULL;
		}

		/* Allocate new _WDIR structure */
		dirp = (_WDIR*)malloc(sizeof(struct _WDIR));
		if (dirp != NULL) {
			DWORD n;

			/* Reset _WDIR structure */
			dirp->handle = INVALID_HANDLE_VALUE;
			dirp->patt = NULL;
			dirp->cached = 0;

			/* Compute the length of full path plus zero terminator
			*
			* Note that on WinRT there's no way to convert relative paths
			* into absolute paths, so just assume it is an absolute path.
			*/
#       if defined(WINAPI_FAMILY) && (WINAPI_FAMILY == WINAPI_FAMILY_PHONE_APP)
			n = wcslen(dirname);
#       else
			n = GetFullPathNameW(dirname, 0, NULL, NULL);
#       endif

			/* Allocate room for absolute directory name and search pattern */
			dirp->patt = (wchar_t*)malloc(sizeof(wchar_t) * n + 16);
			if (dirp->patt) {

				/*
				* Convert relative directory name to an absolute one.  This
				* allows rewinddir() to function correctly even when current
				* working directory is changed between opendir() and rewinddir().
				*
				* Note that on WinRT there's no way to convert relative paths
				* into absolute paths, so just assume it is an absolute path.
				*/
#           if defined(WINAPI_FAMILY) && (WINAPI_FAMILY == WINAPI_FAMILY_PHONE_APP)
				wcsncpy_s(dirp->patt, n + 1, dirname, n);
#           else
				n = GetFullPathNameW(dirname, n, dirp->patt, NULL);
#           endif
				if (n > 0) {
					wchar_t *p;

					/* Append search pattern \* to the directory name */
					p = dirp->patt + n;
					if (dirp->patt < p) {
						switch (p[-1]) {
						case '\\':
						case '/':
						case ':':
							/* Directory ends in path separator, e.g. c:\temp\ */
							/*NOP*/;
							break;

						default:
							/* Directory name doesn't end in path separator */
							*p++ = '\\';
						}
					}
					*p++ = '*';
					*p = '\0';

					/* Open directory stream and retrieve the first entry */
					if (dirent_first(dirp)) {
						/* Directory stream opened successfully */
						error = 0;
					}
					else {
						/* Cannot retrieve first entry */
						error = 1;
						dirent_set_errno(ENOENT);
					}

				}
				else {
					/* Cannot retrieve full path name */
					dirent_set_errno(ENOENT);
					error = 1;
				}

			}
			else {
				/* Cannot allocate memory for search pattern */
				error = 1;
			}

		}
		else {
			/* Cannot allocate _WDIR structure */
			error = 1;
		}

		/* Clean up in case of error */
		if (error  &&  dirp) {
			_wclosedir(dirp);
			dirp = NULL;
		}

		return dirp;
	}

	/*
	* Read next directory entry.
	*
	* Returns pointer to static directory entry which may be overwritten by
	* subsequent calls to _wreaddir().
	*/
	static struct _wdirent*
		_wreaddir(
			_WDIR *dirp)
	{
		struct _wdirent *entry;

		/*
		* Read directory entry to buffer.  We can safely ignore the return value
		* as entry will be set to NULL in case of error.
		*/
		(void)_wreaddir_r(dirp, &dirp->ent, &entry);

		/* Return pointer to statically allocated directory entry */
		return entry;
	}

	/*
	* Read next directory entry.
	*
	* Returns zero on success.  If end of directory stream is reached, then sets
	* result to NULL and returns zero.
	*/
	static int
		_wreaddir_r(
			_WDIR *dirp,
			struct _wdirent *entry,
			struct _wdirent **result)
	{
		WIN32_FIND_DATAW *datap;

		/* Read next directory entry */
		datap = dirent_next(dirp);
		if (datap) {
			size_t n;
			DWORD attr;

			/*
			* Copy file name as wide-character string.  If the file name is too
			* long to fit in to the destination buffer, then truncate file name
			* to PATH_MAX characters and zero-terminate the buffer.
			*/
			n = 0;
			while (n < PATH_MAX  &&  datap->cFileName[n] != 0) {
				entry->d_name[n] = datap->cFileName[n];
				n++;
			}
			entry->d_name[n] = 0;

			/* Length of file name excluding zero terminator */
			entry->d_namlen = n;

			/* File type */
			attr = datap->dwFileAttributes;
			if ((attr & FILE_ATTRIBUTE_DEVICE) != 0) {
				entry->d_type = DT_CHR;
			}
			else if ((attr & FILE_ATTRIBUTE_DIRECTORY) != 0) {
				entry->d_type = DT_DIR;
			}
			else {
				entry->d_type = DT_REG;
			}

			/* Reset dummy fields */
			entry->d_ino = 0;
			entry->d_off = 0;
			entry->d_reclen = sizeof(struct _wdirent);

			/* Set result address */
			*result = entry;

		}
		else {

			/* Return NULL to indicate end of directory */
			*result = NULL;

		}

		return /*OK*/0;
	}

	/*
	* Close directory stream opened by opendir() function.  This invalidates the
	* DIR structure as well as any directory entry read previously by
	* _wreaddir().
	*/
	static int
		_wclosedir(
			_WDIR *dirp)
	{
		int ok;
		if (dirp) {

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

			/* Release search pattern */
			if (dirp->patt) {
				free(dirp->patt);
				dirp->patt = NULL;
			}

			/* Release directory structure */
			free(dirp);
			ok = /*success*/0;

		}
		else {

			/* Invalid directory stream */
			dirent_set_errno(EBADF);
			ok = /*failure*/-1;

		}
		return ok;
	}

	/*
	* Rewind directory stream such that _wreaddir() returns the very first
	* file name again.
	*/
	static void
		_wrewinddir(
			_WDIR* dirp)
	{
		if (dirp) {
			/* Release existing search handle */
			if (dirp->handle != INVALID_HANDLE_VALUE) {
				FindClose(dirp->handle);
			}

			/* Open new search handle */
			dirent_first(dirp);
		}
	}

	/* Get first directory entry (internal) */
	static WIN32_FIND_DATAW*
		dirent_first(
			_WDIR *dirp)
	{
		WIN32_FIND_DATAW *datap;

		/* Open directory and retrieve the first entry */
		dirp->handle = FindFirstFileExW(
			dirp->patt, FindExInfoStandard, &dirp->data,
			FindExSearchNameMatch, NULL, 0);
		if (dirp->handle != INVALID_HANDLE_VALUE) {

			/* a directory entry is now waiting in memory */
			datap = &dirp->data;
			dirp->cached = 1;

		}
		else {

			/* Failed to re-open directory: no directory entry in memory */
			dirp->cached = 0;
			datap = NULL;

		}
		return datap;
	}

	/*
	* Get next directory entry (internal).
	*
	* Returns
	*/
	static WIN32_FIND_DATAW*
		dirent_next(
			_WDIR *dirp)
	{
		WIN32_FIND_DATAW *p;

		/* Get next directory entry */
		if (dirp->cached != 0) {

			/* A valid directory entry already in memory */
			p = &dirp->data;
			dirp->cached = 0;

		}
		else if (dirp->handle != INVALID_HANDLE_VALUE) {

			/* Get the next directory entry from stream */
			if (FindNextFileW(dirp->handle, &dirp->data) != FALSE) {
				/* Got a file */
				p = &dirp->data;
			}
			else {
				/* The very last entry has been processed or an error occurred */
				FindClose(dirp->handle);
				dirp->handle = INVALID_HANDLE_VALUE;
				p = NULL;
			}

		}
		else {

			/* End of directory stream reached */
			p = NULL;

		}

		return p;
	}

	/*
	* Open directory stream using plain old C-string.
	*/
	static DIR*
		opendir(
			const char *dirname)
	{
		struct DIR *dirp;
		int error;

		/* Must have directory name */
		if (dirname == NULL || dirname[0] == '\0') {
			dirent_set_errno(ENOENT);
			return NULL;
		}

		/* Allocate memory for DIR structure */
		dirp = (DIR*)malloc(sizeof(struct DIR));
		if (dirp) {
			wchar_t wname[PATH_MAX + 1];
			size_t n;

			/* Convert directory name to wide-character string */
			error = dirent_mbstowcs_s(
				&n, wname, PATH_MAX + 1, dirname, PATH_MAX + 1);
			if (!error) {

				/* Open directory stream using wide-character name */
				dirp->wdirp = _wopendir(wname);
				if (dirp->wdirp) {
					/* Directory stream opened */
					error = 0;
				}
				else {
					/* Failed to open directory stream */
					error = 1;
				}

			}
			else {
				/*
				* Cannot convert file name to wide-character string.  This
				* occurs if the string contains invalid multi-byte sequences or
				* the output buffer is too small to contain the resulting
				* string.
				*/
				error = 1;
			}

		}
		else {
			/* Cannot allocate DIR structure */
			error = 1;
		}

		/* Clean up in case of error */
		if (error  &&  dirp) {
			free(dirp);
			dirp = NULL;
		}

		return dirp;
	}

	/*
	* Read next directory entry.
	*/
	static struct dirent*
		readdir(
			DIR *dirp)
	{
		struct dirent *entry;

		/*
		* Read directory entry to buffer.  We can safely ignore the return value
		* as entry will be set to NULL in case of error.
		*/
		(void)readdir_r(dirp, &dirp->ent, &entry);

		/* Return pointer to statically allocated directory entry */
		return entry;
	}

	/*
	* Read next directory entry into called-allocated buffer.
	*
	* Returns zero on success.  If the end of directory stream is reached, then
	* sets result to NULL and returns zero.
	*/
	static int
		readdir_r(
			DIR *dirp,
			struct dirent *entry,
			struct dirent **result)
	{
		WIN32_FIND_DATAW *datap;

		/* Read next directory entry */
		datap = dirent_next(dirp->wdirp);
		if (datap) {
			size_t n;
			int error;

			/* Attempt to convert file name to multi-byte string */
			error = dirent_wcstombs_s(
				&n, entry->d_name, PATH_MAX + 1, datap->cFileName, PATH_MAX + 1);

			/*
			* If the file name cannot be represented by a multi-byte string,
			* then attempt to use old 8+3 file name.  This allows traditional
			* Unix-code to access some file names despite of unicode
			* characters, although file names may seem unfamiliar to the user.
			*
			* Be ware that the code below cannot come up with a short file
			* name unless the file system provides one.  At least
			* VirtualBox shared folders fail to do this.
			*/
			if (error  &&  datap->cAlternateFileName[0] != '\0') {
				error = dirent_wcstombs_s(
					&n, entry->d_name, PATH_MAX + 1,
					datap->cAlternateFileName, PATH_MAX + 1);
			}

			if (!error) {
				DWORD attr;

				/* Length of file name excluding zero terminator */
				entry->d_namlen = n - 1;

				/* File attributes */
				attr = datap->dwFileAttributes;
				if ((attr & FILE_ATTRIBUTE_DEVICE) != 0) {
					entry->d_type = DT_CHR;
				}
				else if ((attr & FILE_ATTRIBUTE_DIRECTORY) != 0) {
					entry->d_type = DT_DIR;
				}
				else {
					entry->d_type = DT_REG;
				}

				/* Reset dummy fields */
				entry->d_ino = 0;
				entry->d_off = 0;
				entry->d_reclen = sizeof(struct dirent);

			}
			else {

				/*
				* Cannot convert file name to multi-byte string so construct
				* an erroneous directory entry and return that.  Note that
				* we cannot return NULL as that would stop the processing
				* of directory entries completely.
				*/
				entry->d_name[0] = '?';
				entry->d_name[1] = '\0';
				entry->d_namlen = 1;
				entry->d_type = DT_UNKNOWN;
				entry->d_ino = 0;
				entry->d_off = -1;
				entry->d_reclen = 0;

			}

			/* Return pointer to directory entry */
			*result = entry;

		}
		else {

			/* No more directory entries */
			*result = NULL;

		}

		return /*OK*/0;
	}

	/*
	* Close directory stream.
	*/
	static int
		closedir(
			DIR *dirp)
	{
		int ok;
		if (dirp) {

			/* Close wide-character directory stream */
			ok = _wclosedir(dirp->wdirp);
			dirp->wdirp = NULL;

			/* Release multi-byte character version */
			free(dirp);

		}
		else {

			/* Invalid directory stream */
			dirent_set_errno(EBADF);
			ok = /*failure*/-1;

		}
		return ok;
	}

	/*
	* Rewind directory stream to beginning.
	*/
	static void
		rewinddir(
			DIR* dirp)
	{
		/* Rewind wide-character string directory stream */
		_wrewinddir(dirp->wdirp);
	}

	/*
	* Scan directory for entries.
	*/
	static int
		scandir(
			const char *dirname,
			struct dirent ***namelist,
			int(*filter)(const struct dirent*),
			int(*compare)(const void*, const void*))
	{
		struct dirent **files = NULL;
		size_t size = 0;
		size_t allocated = 0;
		const size_t init_size = 1;
		DIR *dir = NULL;
		struct dirent *entry;
		struct dirent *tmp = NULL;
		size_t i;
		int result = 0;

		/* Open directory stream */
		dir = opendir(dirname);
		if (dir) {

			/* Read directory entries to memory */
			while (1) {

				/* Enlarge pointer table to make room for another pointer */
				if (size >= allocated) {
					void *p;
					size_t num_entries;

					/* Compute number of entries in the enlarged pointer table */
					if (size < init_size) {
						/* Allocate initial pointer table */
						num_entries = init_size;
					}
					else {
						/* Double the size */
						num_entries = size * 2;
					}

					/* Allocate first pointer table or enlarge existing table */
					p = realloc(files, sizeof(void*) * num_entries);
					if (p != NULL) {
						/* Got the memory */
						files = (dirent**)p;
						allocated = num_entries;
					}
					else {
						/* Out of memory */
						result = -1;
						break;
					}

				}

				/* Allocate room for temporary directory entry */
				if (tmp == NULL) {
					tmp = (struct dirent*) malloc(sizeof(struct dirent));
					if (tmp == NULL) {
						/* Cannot allocate temporary directory entry */
						result = -1;
						break;
					}
				}

				/* Read directory entry to temporary area */
				if (readdir_r(dir, tmp, &entry) == /*OK*/0) {

					/* Did we get an entry? */
					if (entry != NULL) {
						int pass;

						/* Determine whether to include the entry in result */
						if (filter) {
							/* Let the filter function decide */
							pass = filter(tmp);
						}
						else {
							/* No filter function, include everything */
							pass = 1;
						}

						if (pass) {
							/* Store the temporary entry to pointer table */
							files[size++] = tmp;
							tmp = NULL;

							/* Keep up with the number of files */
							result++;
						}

					}
					else {

						/*
						* End of directory stream reached => sort entries and
						* exit.
						*/
						qsort(files, size, sizeof(void*), compare);
						break;

					}

				}
				else {
					/* Error reading directory entry */
					result = /*Error*/ -1;
					break;
				}

			}

		}
		else {
			/* Cannot open directory */
			result = /*Error*/ -1;
		}

		/* Release temporary directory entry */
		if (tmp) {
			free(tmp);
		}

		/* Release allocated memory on error */
		if (result < 0) {
			for (i = 0; i < size; i++) {
				free(files[i]);
			}
			free(files);
			files = NULL;
		}

		/* Close directory stream */
		if (dir) {
			closedir(dir);
		}

		/* Pass pointer table to caller */
		if (namelist) {
			*namelist = files;
		}
		return result;
	}

	/* Alphabetical sorting */
	static int
		alphasort(
			const struct dirent **a, const struct dirent **b)
	{
		return strcoll((*a)->d_name, (*b)->d_name);
	}

	/* Sort versions */
	static int
		versionsort(
			const struct dirent **a, const struct dirent **b)
	{
		/* FIXME: implement strverscmp and use that */
		return alphasort(a, b);
	}


	/* Convert multi-byte string to wide character string */
	static int
		dirent_mbstowcs_s(
			size_t *pReturnValue,
			wchar_t *wcstr,
			size_t sizeInWords,
			const char *mbstr,
			size_t count)
	{
		int error;

#if defined(_MSC_VER)  &&  _MSC_VER >= 1400

		/* Microsoft Visual Studio 2005 or later */
		error = mbstowcs_s(pReturnValue, wcstr, sizeInWords, mbstr, count);

#else

		/* Older Visual Studio or non-Microsoft compiler */
		size_t n;

		/* Convert to wide-character string (or count characters) */
		n = mbstowcs(wcstr, mbstr, sizeInWords);
		if (!wcstr || n < count) {

			/* Zero-terminate output buffer */
			if (wcstr  &&  sizeInWords) {
				if (n >= sizeInWords) {
					n = sizeInWords - 1;
				}
				wcstr[n] = 0;
			}

			/* Length of resulting multi-byte string WITH zero terminator */
			if (pReturnValue) {
				*pReturnValue = n + 1;
			}

			/* Success */
			error = 0;

		}
		else {

			/* Could not convert string */
			error = 1;

		}

#endif

		return error;
	}

	/* Convert wide-character string to multi-byte string */
	static int
		dirent_wcstombs_s(
			size_t *pReturnValue,
			char *mbstr,
			size_t sizeInBytes, /* max size of mbstr */
			const wchar_t *wcstr,
			size_t count)
	{
		int error;

#if defined(_MSC_VER)  &&  _MSC_VER >= 1400

		/* Microsoft Visual Studio 2005 or later */
		error = wcstombs_s(pReturnValue, mbstr, sizeInBytes, wcstr, count);

#else

		/* Older Visual Studio or non-Microsoft compiler */
		size_t n;

		/* Convert to multi-byte string (or count the number of bytes needed) */
		n = wcstombs(mbstr, wcstr, sizeInBytes);
		if (!mbstr || n < count) {

			/* Zero-terminate output buffer */
			if (mbstr  &&  sizeInBytes) {
				if (n >= sizeInBytes) {
					n = sizeInBytes - 1;
				}
				mbstr[n] = '\0';
			}

			/* Length of resulting multi-bytes string WITH zero-terminator */
			if (pReturnValue) {
				*pReturnValue = n + 1;
			}

			/* Success */
			error = 0;

		}
		else {

			/* Cannot convert string */
			error = 1;

		}

#endif

		return error;
	}

	/* Set errno variable */
	static void
		dirent_set_errno(
			int error)
	{
#if defined(_MSC_VER)  &&  _MSC_VER >= 1400

		/* Microsoft Visual Studio 2005 and later */
		_set_errno(error);

#else

		/* Non-Microsoft compiler or older Microsoft compiler */
		errno = error;

#endif
	}


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