version of dirent.c that is liked by both VC++ and MinGW

1 files changed, 1109 insertions, 454 deletions

diff --git a/src/lib/third_party/include/windows/dirent.h b/src/lib/third_party/include/windows/dirent.h
index de75def2f..fd1e81354 100644
--- a/src/lib/third_party/include/windows/dirent.h
+++ b/src/lib/third_party/include/windows/dirent.h
@@ -1,584 +1,1239 @@
 /*
-MIT License
-Copyright (c) 2019 win32ports
-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 THE
-AUTHORS OR COPYRIGHT HOLDERS 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.
-*/
-
-#pragma once
-
-#ifndef __DIRENT_H_9DE6B42C_8D0C_4D31_A8EF_8E4C30E6C46A__
-#define __DIRENT_H_9DE6B42C_8D0C_4D31_A8EF_8E4C30E6C46A__
-
-#ifndef _WIN32
-
-#pragma message("this dirent.h implementation is for Windows only!")
-
-#else /* _WIN32 */
-
-#ifdef __cplusplus
-extern "C" {
-#endif /* __cplusplus */
+ * Dirent interface for Microsoft Visual Studio
+ *
+ * Copyright (C) 1998-2019 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
+
+/* Hide warnings about unreferenced local functions */
+#if defined(__clang__)
+#	pragma clang diagnostic ignored "-Wunused-function"
+#elif defined(_MSC_VER)
+#	pragma warning(disable:4505)
+#elif defined(__GNUC__)
+#	pragma GCC diagnostic ignored "-Wunused-function"
+#endif
 
+/*
+ * 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 <stdint.h>
+#include <sys/stat.h>
 #include <errno.h>
+#include <ctype.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
 
-#include <Windows.h>
+/* File type and permission flags for stat(), general mask */
+#if !defined(S_IFMT)
+#	define S_IFMT _S_IFMT
+#endif
 
-#include <Shlwapi.h>
+/* Directory bit */
+#if !defined(S_IFDIR)
+#	define S_IFDIR _S_IFDIR
+#endif
 
-#ifdef _MSC_VER
-#pragma comment(lib, "Shlwapi.lib")
+/* Character device bit */
+#if !defined(S_IFCHR)
+#	define S_IFCHR _S_IFCHR
 #endif
 
-#ifndef NAME_MAX
-#define NAME_MAX 260
-#endif /* NAME_MAX */
+/* Pipe bit */
+#if !defined(S_IFFIFO)
+#	define S_IFFIFO _S_IFFIFO
+#endif
 
-#ifndef DT_UNKNOWN
+/* 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
+
+/*
+ * Symbolic link.  Be ware that S_IFLNK value and S_ISLNK() macro are only
+ * usable with dirent - they do not work with stat() function call!
+ */
+#if !defined(S_IFLNK)
+#	define S_IFLNK (_S_IFDIR | _S_IFREG)
+#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
+
+/* User full permissions */
+#if !defined(S_IRWXU)
+#	define S_IRWXU (S_IRUSR | S_IWUSR | S_IXUSR)
+#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
+
+/* Group full permissions */
+#if !defined(S_IRWXG)
+#	define S_IRWXG (S_IRGRP | S_IWGRP | S_IXGRP)
+#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
+
+/* Other full permissions */
+#if !defined(S_IRWXO)
+#	define S_IRWXO (S_IROTH | S_IWOTH | S_IXOTH)
+#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
-#endif /* DT_UNKNOWN */
+#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 and sockets cannot be
+ * distinguished on Windows, and the macros S_ISBLK and S_ISSOCK 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)
 
-#ifndef DT_FIFO
-#define DT_FIFO 1
-#endif /* DT_FIFO */
 
-#ifndef DT_CHR
-#define DT_CHR 2
-#endif /* DT_CHR */
+#ifdef __cplusplus
+extern "C" {
+#endif
 
-#ifndef DT_DIR
-#define DT_DIR 4
-#endif /* DT_DIR */
 
-#ifndef DT_BLK
-#define DT_BLK 6
-#endif /* DT_BLK */
+/* Wide-character version */
+struct _wdirent {
+	/* Always zero */
+	long d_ino;
 
-#ifndef DT_REG
-#define DT_REG 8
-#endif /* DT_REF */
+	/* Position of next file in a directory stream */
+	long d_off;
 
-#ifndef DT_LNK
-#define DT_LNK 10
-#endif /* DT_LNK */
+	/* Structure size */
+	unsigned short d_reclen;
 
-#ifndef DT_SOCK
-#define DT_SOCK 12
-#endif /* DT_SOCK */
+	/* Length of name without \0 */
+	size_t d_namlen;
 
-#ifndef DT_WHT
-#define DT_WHT 14
-#endif /* DT_WHT */
+	/* File type */
+	int d_type;
 
-#ifndef _DIRENT_HAVE_D_NAMLEN
-#define _DIRENT_HAVE_D_NAMLEN 1
-#endif /* _DIRENT_HAVE_D_NAMLEN */
+	/* File name */
+	wchar_t d_name[PATH_MAX+1];
+};
+typedef struct _wdirent _wdirent;
 
-#ifndef _DIRENT_HAVE_D_RECLEN
-#define _DIRENT_HAVE_D_RECLEN 1
-#endif /* _DIRENT_HAVE_D_RECLEN */
+struct _WDIR {
+	/* Current directory entry */
+	struct _wdirent ent;
 
-#ifndef _DIRENT_HAVE_D_OFF
-#define _DIRENT_HAVE_D_OFF 1
-#endif /* _DIRENT_HAVE_D_OFF */
+	/* Private file data */
+	WIN32_FIND_DATAW data;
 
-#ifndef _DIRENT_HAVE_D_TYPE 
-#define _DIRENT_HAVE_D_TYPE 1
-#endif /* _DIRENT_HAVE_D_TYPE  */
+	/* True if data is valid */
+	int cached;
 
-#ifndef NTFS_MAX_PATH
-#define NTFS_MAX_PATH 32768
-#endif /* NTFS_MAX_PATH */
+	/* True if next entry is invalid */
+	int invalid;
 
-#ifndef FSCTL_GET_REPARSE_POINT
-#define FSCTL_GET_REPARSE_POINT 0x900a8
-#endif /* FSCTL_GET_REPARSE_POINT */
+	/* Win32 search handle */
+	HANDLE handle;
 
-#ifndef FILE_NAME_NORMALIZED
-#define FILE_NAME_NORMALIZED 0
-#endif /* FILE_NAME_NORMALIZED */
+	/* Initial directory name */
+	wchar_t *patt;
+};
+typedef struct _WDIR _WDIR;
 
-typedef void* DIR;
+/* Multi-byte character version */
+struct dirent {
+	/* Always zero */
+	long d_ino;
 
-typedef struct ino_t
-{
-	unsigned long long serial;
-	unsigned char fileid[16];
-} __ino_t;
+	/* Position of next file in a directory stream */
+	long d_off;
 
-struct dirent
-{
-	__ino_t d_ino;
-	off_t d_off;
+	/* Structure size */
 	unsigned short d_reclen;
-	unsigned char d_namelen;
-	unsigned char d_type;
-	char d_name[NAME_MAX];
+
+	/* 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* entries;
-	intptr_t fd;
-	long int count;
-	long int index;
+struct DIR {
+	struct dirent ent;
+	struct _WDIR *wdirp;
 };
+typedef struct DIR DIR;
 
-static int closedir(DIR* dirp)
-{
-	struct __dir* data = NULL;
-	if (!dirp) {
-		errno = EBADF;
-		return -1;
-	}
-	data = (struct __dir*) dirp;
-	CloseHandle((HANDLE)data->fd);
-	free(data->entries);
-	free(data);
-	return 0;
-}
 
-static void __seterrno(int value)
-{
-#ifdef _MSC_VER
-	_set_errno(value);
-#else /* _MSC_VER */
-	errno = value;
-#endif /* _MSC_VER */
-}
+/* Dirent functions */
+static DIR *opendir(const char *dirname);
+static _WDIR *_wopendir(const wchar_t *dirname);
 
-static int __islink(const wchar_t * name, char * buffer)
-{
-	DWORD io_result = 0;
-	DWORD bytes_returned = 0;
-	HANDLE hFile = CreateFileW(name, 0, 0, NULL, OPEN_EXISTING,
-		FILE_FLAG_OPEN_REPARSE_POINT | FILE_FLAG_BACKUP_SEMANTICS, 0);
-	if (hFile == INVALID_HANDLE_VALUE)
-		return 0;
+static struct dirent *readdir(DIR *dirp);
+static struct _wdirent *_wreaddir(_WDIR *dirp);
 
-	io_result = DeviceIoControl(hFile, FSCTL_GET_REPARSE_POINT, NULL, 0,
-		buffer, MAXIMUM_REPARSE_DATA_BUFFER_SIZE, &bytes_returned, NULL);
+static int readdir_r(
+	DIR *dirp, struct dirent *entry, struct dirent **result);
+static int _wreaddir_r(
+	_WDIR *dirp, struct _wdirent *entry, struct _wdirent **result);
 
-	CloseHandle(hFile);
+static int closedir(DIR *dirp);
+static int _wclosedir(_WDIR *dirp);
 
-	if (io_result == 0)
-		return 0;
+static void rewinddir(DIR *dirp);
+static void _wrewinddir(_WDIR *dirp);
 
-	return ((REPARSE_GUID_DATA_BUFFER*)buffer)->ReparseTag == IO_REPARSE_TAG_SYMLINK;
-}
+static long telldir(DIR *dirp);
+static long _wtelldir(_WDIR *dirp);
+
+static void seekdir(DIR *dirp, long loc);
+static void _wseekdir(_WDIR *dirp, long loc);
+
+static int scandir(const char *dirname, struct dirent ***namelist,
+	int (*filter)(const struct dirent*),
+	int (*compare)(const struct dirent**, const struct dirent**));
+
+static int alphasort(const struct dirent **a, const struct dirent **b);
+
+static int versionsort(const struct dirent **a, const struct dirent **b);
 
-#pragma pack(push, 1)
+static int strverscmp(const char *a, const char *b);
 
-typedef struct dirent_FILE_ID_128
+/* For compatibility with Symbian */
+#define wdirent _wdirent
+#define WDIR _WDIR
+#define wopendir _wopendir
+#define wreaddir _wreaddir
+#define wclosedir _wclosedir
+#define wrewinddir _wrewinddir
+#define wtelldir _wtelldir
+#define wseekdir _wseekdir
+
+/* Compatibility with older Microsoft compilers and non-Microsoft compilers */
+#if !defined(_MSC_VER) || _MSC_VER < 1400
+#	define wcstombs_s dirent_wcstombs_s
+#	define mbstowcs_s dirent_mbstowcs_s
+#endif
+
+/* Optimize dirent_set_errno() away on modern Microsoft compilers */
+#if defined(_MSC_VER) && _MSC_VER >= 1400
+#	define dirent_set_errno _set_errno
+#endif
+
+
+/* Internal utility functions */
+static WIN32_FIND_DATAW *dirent_first(_WDIR *dirp);
+static WIN32_FIND_DATAW *dirent_next(_WDIR *dirp);
+static long dirent_hash(WIN32_FIND_DATAW *datap);
+
+#if !defined(_MSC_VER) || _MSC_VER < 1400
+static int dirent_mbstowcs_s(
+	size_t *pReturnValue, wchar_t *wcstr, size_t sizeInWords,
+	const char *mbstr, size_t count);
+#endif
+
+#if !defined(_MSC_VER) || _MSC_VER < 1400
+static int dirent_wcstombs_s(
+	size_t *pReturnValue, char *mbstr, size_t sizeInBytes,
+	const wchar_t *wcstr, size_t count);
+#endif
+
+#if !defined(_MSC_VER) || _MSC_VER < 1400
+static void dirent_set_errno(int error);
+#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 _WDIR *
+_wopendir(const wchar_t *dirname)
 {
-	BYTE Identifier[16];
+	wchar_t *p;
+
+	/* Must have directory name */
+	if (dirname == NULL || dirname[0] == '\0') {
+		dirent_set_errno(ENOENT);
+		return NULL;
+	}
+
+	/* Allocate new _WDIR structure */
+	_WDIR *dirp = (_WDIR*) malloc(sizeof(struct _WDIR));
+	if (!dirp)
+		return NULL;
+
+	/* Reset _WDIR structure */
+	dirp->handle = INVALID_HANDLE_VALUE;
+	dirp->patt = NULL;
+	dirp->cached = 0;
+	dirp->invalid = 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 WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
+	/* Desktop */
+	DWORD n = GetFullPathNameW(dirname, 0, NULL, NULL);
+#else
+	/* WinRT */
+	size_t n = wcslen(dirname);
+#endif
+
+	/* Allocate room for absolute directory name and search pattern */
+	dirp->patt = (wchar_t*) malloc(sizeof(wchar_t) * n + 16);
+	if (dirp->patt == NULL)
+		goto exit_closedir;
+
+	/*
+	 * 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 WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
+	/* Desktop */
+	n = GetFullPathNameW(dirname, n, dirp->patt, NULL);
+	if (n <= 0)
+		goto exit_closedir;
+#else
+	/* WinRT */
+	wcsncpy_s(dirp->patt, n+1, dirname, n);
+#endif
+
+	/* Append search pattern \* to the directory name */
+	p = dirp->patt + n;
+	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))
+		goto exit_closedir;
+
+	/* Success */
+	return dirp;
+
+	/* Failure */
+exit_closedir:
+	_wclosedir(dirp);
+	return NULL;
 }
-dirent_FILE_ID_128;
 
-typedef struct _dirent_FILE_ID_INFO
+/*
+ * 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)
 {
-	ULONGLONG VolumeSerialNumber;
-	dirent_FILE_ID_128 FileId;
+	/*
+	 * Read directory entry to buffer.  We can safely ignore the return
+	 * value as entry will be set to NULL in case of error.
+	 */
+	struct _wdirent *entry;
+	(void) _wreaddir_r(dirp, &dirp->ent, &entry);
+
+	/* Return pointer to statically allocated directory entry */
+	return entry;
 }
-dirent_FILE_ID_INFO;
 
-#pragma pack(pop)
+/*
+ * 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)
+{
+	/* Validate directory handle */
+	if (!dirp || dirp->handle == INVALID_HANDLE_VALUE || !dirp->patt) {
+		dirent_set_errno(EBADF);
+		*result = NULL;
+		return -1;
+	}
 
-typedef enum dirent_FILE_INFO_BY_HANDLE_CLASS
-{ dirent_FileIdInfo = 18 }
-dirent_FILE_INFO_BY_HANDLE_CLASS;
+	/* Read next directory entry */
+	WIN32_FIND_DATAW *datap = dirent_next(dirp);
+	if (!datap) {
+		/* Return NULL to indicate end of directory */
+		*result = NULL;
+		return /*OK*/0;
+	}
 
-static __ino_t __inode(const wchar_t* name)
-{
-	__ino_t value = { 0 };
-	BOOL result;
-	dirent_FILE_ID_INFO fileid;
-	BY_HANDLE_FILE_INFORMATION info;
-	typedef BOOL (__stdcall* pfnGetFileInformationByHandleEx)(HANDLE hFile,
-			dirent_FILE_INFO_BY_HANDLE_CLASS FileInformationClass,
-			LPVOID lpFileInformation, DWORD dwBufferSize);
-
-	HANDLE hKernel32 = GetModuleHandleW(L"kernel32.dll");
-	if (!hKernel32)
-		return value;
-
-	pfnGetFileInformationByHandleEx fnGetFileInformationByHandleEx = (pfnGetFileInformationByHandleEx) GetProcAddress(hKernel32, "GetFileInformationByHandleEx");
-	if (!fnGetFileInformationByHandleEx)
-		return value;
-
-	HANDLE hFile = CreateFileW(name, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, 0);
-	if (hFile == INVALID_HANDLE_VALUE)
-		return value;
-
-	result = fnGetFileInformationByHandleEx(hFile, dirent_FileIdInfo, &fileid, sizeof(fileid));
-	if (result)
-	{
-		value.serial = fileid.VolumeSerialNumber;
-		memcpy(value.fileid, fileid.FileId.Identifier, 16);
+	/*
+	 * 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.
+	 */
+	size_t i = 0;
+	while (i < PATH_MAX && datap->cFileName[i] != 0) {
+		entry->d_name[i] = datap->cFileName[i];
+		i++;
 	}
+	entry->d_name[i] = 0;
+
+	/* Length of file name excluding zero terminator */
+	entry->d_namlen = i;
+
+	/* Determine file type */
+	DWORD attr = datap->dwFileAttributes;
+	if ((attr & FILE_ATTRIBUTE_DEVICE) != 0)
+		entry->d_type = DT_CHR;
+	else if ((attr & FILE_ATTRIBUTE_REPARSE_POINT) != 0)
+		entry->d_type = DT_LNK;
+	else if ((attr & FILE_ATTRIBUTE_DIRECTORY) != 0)
+		entry->d_type = DT_DIR;
 	else
-	{
-		result = GetFileInformationByHandle(hFile, &info);
-		if(result)
-		{
-			value.serial = info.dwVolumeSerialNumber;
-			memcpy(value.fileid + 8, &info.nFileIndexHigh, 4);
-			memcpy(value.fileid + 12, &info.nFileIndexLow, 4);
-		}
+		entry->d_type = DT_REG;
+
+	/* Read the next directory entry to cache */
+	datap = dirent_next(dirp);
+	if (datap) {
+		/* Compute 31-bit hash of the next directory entry */
+		entry->d_off = dirent_hash(datap);
+
+		/* Push the next directory entry back to cache */
+		dirp->cached = 1;
+	} else {
+		/* End of directory stream */
+		entry->d_off = (long) ((~0UL) >> 1);
 	}
-	CloseHandle(hFile);
-	return value;
+
+	/* Reset other fields */
+	entry->d_ino = 0;
+	entry->d_reclen = sizeof(struct _wdirent);
+
+	/* Set result address */
+	*result = entry;
+	return /*OK*/0;
 }
 
-static DIR* __internal_opendir(wchar_t* wname, int size)
+/*
+ * 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)
 {
-	struct __dir* data = NULL;
-	struct dirent *tmp_entries = NULL;
-	static char default_char = '?';
-	static wchar_t* prefix = L"\\\\?\\";
-	static wchar_t* suffix = L"\\*.*";
-	static int extra_prefix = 4; /* use prefix "\\?\" to handle long file names */
-	static int extra_suffix = 4; /* use suffix "\*.*" to find everything */
-	WIN32_FIND_DATAW w32fd = { 0 };
-	HANDLE hFindFile = INVALID_HANDLE_VALUE;
-	static int grow_factor = 2;
-	char* buffer = NULL;
-
-	BOOL relative = PathIsRelativeW(wname + extra_prefix);
-
-	memcpy(wname + size - 1, suffix, sizeof(wchar_t) * extra_suffix);
-	wname[size + extra_suffix - 1] = 0;
-
-	if (relative) {
-		wname += extra_prefix;
-		size -= extra_prefix;
-	}
-	hFindFile = FindFirstFileW(wname, &w32fd);
-	if (INVALID_HANDLE_VALUE == hFindFile)
-	{
-		__seterrno(ENOENT);
-		return NULL;
+	if (!dirp) {
+		dirent_set_errno(EBADF);
+		return /*failure*/-1;
 	}
 
-	data = (struct __dir*) malloc(sizeof(struct __dir));
-	if (!data)
-		goto out_of_memory;
-	wname[size - 1] = 0;
-	data->fd = (intptr_t)CreateFileW(wname, 0, 0, NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, 0);
-	wname[size - 1] = L'\\';
-	data->count = 16;
-	data->index = 0;
-	data->entries = (struct dirent*) malloc(sizeof(struct dirent) * data->count);
-	if (!data->entries)
-		goto out_of_memory;
-	buffer = malloc(MAXIMUM_REPARSE_DATA_BUFFER_SIZE);
-	if (!buffer)
-		goto out_of_memory;
-	do
-	{
-		WideCharToMultiByte(CP_UTF8, 0, w32fd.cFileName, -1, data->entries[data->index].d_name, NAME_MAX, &default_char, NULL);
-
-		memcpy(wname + size, w32fd.cFileName, sizeof(wchar_t) * NAME_MAX);
-
-		if (((w32fd.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) == FILE_ATTRIBUTE_REPARSE_POINT) && __islink(wname, buffer))
-			data->entries[data->index].d_type = DT_LNK;
-		else if ((w32fd.dwFileAttributes & FILE_ATTRIBUTE_DEVICE) == FILE_ATTRIBUTE_DEVICE)
-			data->entries[data->index].d_type = DT_CHR;
-		else if ((w32fd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) == FILE_ATTRIBUTE_DIRECTORY)
-			data->entries[data->index].d_type = DT_DIR;
-		else
-			data->entries[data->index].d_type = DT_REG;
-
-		data->entries[data->index].d_ino = __inode(wname);
-		data->entries[data->index].d_reclen = sizeof(struct dirent);
-		data->entries[data->index].d_namelen = (unsigned char)wcslen(w32fd.cFileName);
-		data->entries[data->index].d_off = 0;
-
-		if (++data->index == data->count) {
-			tmp_entries = (struct dirent*) realloc(data->entries, sizeof(struct dirent) * data->count * grow_factor);
-			if (!tmp_entries)
-				goto out_of_memory;
-			data->entries = tmp_entries;
-			data->count *= grow_factor;
-		}
+	/*
+	 * Release search handle if we have one.  Being able to handle
+	 * partially initialized _WDIR structure allows us to use this
+	 * function to handle errors occuring within _wopendir.
+	 */
+	if (dirp->handle != INVALID_HANDLE_VALUE) {
+		FindClose(dirp->handle);
 	}
-	while (FindNextFileW(hFindFile, &w32fd) != 0);
-
-	free(buffer);
-	FindClose(hFindFile);
-
-	data->count = data->index;
-	data->index = 0;
-	return (DIR*)data;
-out_of_memory:
-	if (data)
-	{
-		if (INVALID_HANDLE_VALUE != (HANDLE)data->fd)
-			CloseHandle((HANDLE)data->fd);
-		free(data->entries);
-	}
-	free(buffer);
-	free(data);
-	if (INVALID_HANDLE_VALUE != hFindFile)
-		FindClose(hFindFile);
-	__seterrno(ENOMEM);
-	return NULL;
+
+	/*
+	 * Release search pattern.  Note that we don't need to care if
+	 * dirp->patt is NULL or not: function free is guaranteed to act
+	 * appropriately.
+	 */
+	free(dirp->patt);
+
+	/* Release directory structure */
+	free(dirp);
+	return /*success*/0;
 }
 
-static wchar_t* __get_buffer()
+/*
+ * Rewind directory stream such that _wreaddir() returns the very first
+ * file name again.
+ */
+static void _wrewinddir(_WDIR* dirp)
 {
-	wchar_t* name = malloc(sizeof(wchar_t) * (NTFS_MAX_PATH + NAME_MAX + 8));
-	if (name)
-		memcpy(name, L"\\\\?\\", sizeof(wchar_t) * 4);
-	return name;
+	/* Check directory pointer */
+	if (!dirp || dirp->handle == INVALID_HANDLE_VALUE || !dirp->patt)
+		return;
+
+	/* Release existing search handle */
+	FindClose(dirp->handle);
+
+	/* Open new search handle */
+	dirent_first(dirp);
 }
 
-static DIR* opendir(const char* name)
+/* Get first directory entry */
+static WIN32_FIND_DATAW *
+dirent_first(_WDIR *dirp)
 {
-	DIR* dirp = NULL;
-	wchar_t* wname = __get_buffer();
-	int size = 0;
-	if (!wname)
-	{
-		errno = ENOMEM;
-		return NULL;
-	}
-	size = MultiByteToWideChar(CP_UTF8, 0, name, -1, wname + 4, NTFS_MAX_PATH);
-	if (0 == size)
-	{
-		free(wname);
-		return NULL;
+	/* Open directory and retrieve the first entry */
+	dirp->handle = FindFirstFileExW(
+		dirp->patt, FindExInfoStandard, &dirp->data,
+		FindExSearchNameMatch, NULL, 0);
+	if (dirp->handle == INVALID_HANDLE_VALUE)
+		goto error;
+
+	/* A directory entry is now waiting in memory */
+	dirp->cached = 1;
+	return &dirp->data;
+
+error:
+	/* Failed to open directory: no directory entry in memory */
+	dirp->cached = 0;
+	dirp->invalid = 1;
+
+	/* Set error code */
+	DWORD errorcode = GetLastError();
+	switch (errorcode) {
+	case ERROR_ACCESS_DENIED:
+		/* No read access to directory */
+		dirent_set_errno(EACCES);
+		break;
+
+	case ERROR_DIRECTORY:
+		/* Directory name is invalid */
+		dirent_set_errno(ENOTDIR);
+		break;
+
+	case ERROR_PATH_NOT_FOUND:
+	default:
+		/* Cannot find the file */
+		dirent_set_errno(ENOENT);
 	}
-	dirp = __internal_opendir(wname, size + 4);
-	free(wname);
-	return dirp;
+	return NULL;
 }
 
-static DIR* _wopendir(const wchar_t* name)
+/* Get next directory entry */
+static WIN32_FIND_DATAW *
+dirent_next(_WDIR *dirp)
 {
-	DIR* dirp = NULL;
-	wchar_t* wname = __get_buffer();
-	int size = 0;
-	if (!wname)
-	{
-		errno = ENOMEM;
+	/* Return NULL if seek position was invalid */
+	if (dirp->invalid)
 		return NULL;
+
+	/* Is the next directory entry already in cache? */
+	if (dirp->cached) {
+		/* Yes, a valid directory entry found in memory */
+		dirp->cached = 0;
+		return &dirp->data;
 	}
-	size = (int)wcslen(name);
-	if (size > NTFS_MAX_PATH)
-	{
-		free(wname);
+
+	/* Read the next directory entry from stream */
+	if (FindNextFileW(dirp->handle, &dirp->data) == FALSE) {
+		/* End of directory stream */
 		return NULL;
 	}
-	memcpy(wname + 4, name, sizeof(wchar_t) * (size + 1));
-	dirp = __internal_opendir(wname, size + 5);
-	free(wname);
-	return dirp;
+
+	/* Success */
+	return &dirp->data;
 }
 
-static DIR* fdopendir(intptr_t fd)
+/*
+ * Compute 31-bit hash of file name.
+ *
+ * See djb2 at http://www.cse.yorku.ca/~oz/hash.html
+ */
+static long
+dirent_hash(WIN32_FIND_DATAW *datap)
 {
-	DIR* dirp = NULL;
-	wchar_t* wname = __get_buffer();
-	typedef DWORD (__stdcall * pfnGetFinalPathNameByHandleW)(
-			HANDLE hFile, LPWSTR lpszFilePath, DWORD cchFilePath, DWORD dwFlags);
-
-	HANDLE hKernel32 = GetModuleHandleW(L"kernel32.dll");
-	if (!hKernel32)
-	{
-		errno = EINVAL;
-		return NULL;
+	unsigned long hash = 5381;
+	unsigned long c;
+	const wchar_t *p = datap->cFileName;
+	const wchar_t *e = p + MAX_PATH;
+	while (p != e && (c = *p++) != 0) {
+		hash = (hash << 5) + hash + c;
 	}
 
-	pfnGetFinalPathNameByHandleW fnGetFinalPathNameByHandleW = (pfnGetFinalPathNameByHandleW) GetProcAddress(hKernel32, "GetFinalPathNameByHandleW");
-	if (!fnGetFinalPathNameByHandleW)
-	{
-		errno = EINVAL;
-		return NULL;
-	}
+	return (long) (hash & ((~0UL) >> 1));
+}
 
-	int size = 0;
-	if (!wname)
-	{
-		errno = ENOMEM;
+/* Open directory stream using plain old C-string */
+static DIR *opendir(const char *dirname)
+{
+	/* Must have directory name */
+	if (dirname == NULL || dirname[0] == '\0') {
+		dirent_set_errno(ENOENT);
 		return NULL;
 	}
-	size = fnGetFinalPathNameByHandleW((HANDLE) fd, wname + 4, NTFS_MAX_PATH, FILE_NAME_NORMALIZED);
-	if (0 == size)
-	{
-		free(wname);
-		errno = ENOTDIR;
+
+	/* Allocate memory for DIR structure */
+	struct DIR *dirp = (DIR*) malloc(sizeof(struct DIR));
+	if (!dirp)
 		return NULL;
-	}
-	dirp = __internal_opendir(wname, size + 5);
-	free(wname);
+
+	/* Convert directory name to wide-character string */
+	wchar_t wname[PATH_MAX + 1];
+	size_t n;
+	int error = mbstowcs_s(&n, wname, PATH_MAX + 1, dirname, PATH_MAX+1);
+	if (error)
+		goto exit_failure;
+
+	/* Open directory stream using wide-character name */
+	dirp->wdirp = _wopendir(wname);
+	if (!dirp->wdirp)
+		goto exit_failure;
+
+	/* Success */
 	return dirp;
+
+	/* Failure */
+exit_failure:
+	free(dirp);
+	return NULL;
 }
 
-static struct dirent* readdir(DIR* dirp)
+/* Read next directory entry */
+static struct dirent *
+readdir(DIR *dirp)
 {
-	struct __dir* data = (struct __dir*) dirp;
-	if (!data) {
-		errno = EBADF;
-		return NULL;
-	}
-	if (data->index < data->count)
-	{
-		return &data->entries[data->index++];
-	}
-	return NULL;
+	/*
+	 * Read directory entry to buffer.  We can safely ignore the return
+	 * value as entry will be set to NULL in case of error.
+	 */
+	struct dirent *entry;
+	(void) readdir_r(dirp, &dirp->ent, &entry);
+
+	/* Return pointer to statically allocated directory entry */
+	return entry;
 }
 
-static int readdir_r(DIR* dirp, struct dirent* entry, struct dirent**result)
+/*
+ * 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)
 {
-	struct __dir* data = (struct __dir*) dirp;
-	if (!data) {
-		return EBADF;
+	/* Read next directory entry */
+	WIN32_FIND_DATAW *datap = dirent_next(dirp->wdirp);
+	if (!datap) {
+		/* No more directory entries */
+		*result = NULL;
+		return /*OK*/0;
 	}
-	if (data->index < data->count)
-	{
-		if (entry)
-			memcpy(entry, &data->entries[data->index++], sizeof(struct dirent));
-		if (result)
-			*result = entry;
+
+	/* Attempt to convert file name to multi-byte string */
+	size_t n;
+	int error = 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 the program to
+	 * access files 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 = wcstombs_s(
+			&n, entry->d_name, PATH_MAX + 1,
+			datap->cAlternateFileName, PATH_MAX + 1);
 	}
-	else if (result)
-		*result = NULL;
-	return 0;
+
+	if (!error) {
+		/* Length of file name excluding zero terminator */
+		entry->d_namlen = n - 1;
+
+		/* Determine file type */
+		DWORD attr = datap->dwFileAttributes;
+		if ((attr & FILE_ATTRIBUTE_DEVICE) != 0)
+			entry->d_type = DT_CHR;
+		else if ((attr & FILE_ATTRIBUTE_REPARSE_POINT) != 0)
+			entry->d_type = DT_LNK;
+		else if ((attr & FILE_ATTRIBUTE_DIRECTORY) != 0)
+			entry->d_type = DT_DIR;
+		else
+			entry->d_type = DT_REG;
+
+		/* Get offset of next file */
+		datap = dirent_next(dirp->wdirp);
+		if (datap) {
+			/* Compute 31-bit hash of the next directory entry */
+			entry->d_off = dirent_hash(datap);
+
+			/* Push the next directory entry back to cache */
+			dirp->wdirp->cached = 1;
+		} else {
+			/* End of directory stream */
+			entry->d_off = (long) ((~0UL) >> 1);
+		}
+
+		/* Reset fields */
+		entry->d_ino = 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;
+	return /*OK*/0;
 }
 
-static void seekdir(DIR* dirp, long int offset)
+/* Close directory stream */
+static int
+closedir(DIR *dirp)
 {
-	if (dirp)
-	{
-		struct __dir* data = (struct __dir*) dirp;
-		data->index = (offset < data->count) ? offset : data->index;
-	}
+	int ok;
+
+	if (!dirp)
+		goto exit_failure;
+
+	/* Close wide-character directory stream */
+	ok = _wclosedir(dirp->wdirp);
+	dirp->wdirp = NULL;
+
+	/* Release multi-byte character version */
+	free(dirp);
+	return ok;
+
+exit_failure:
+	/* Invalid directory stream */
+	dirent_set_errno(EBADF);
+	return /*failure*/-1;
 }
 
-static void rewinddir(DIR* dirp)
+/* Rewind directory stream to beginning */
+static void
+rewinddir(DIR *dirp)
 {
-	seekdir(dirp, 0);
+	if (!dirp)
+		return;
+
+	/* Rewind wide-character string directory stream */
+	_wrewinddir(dirp->wdirp);
 }
 
-static long int telldir(DIR* dirp)
+/* Get position of directory stream */
+static long
+_wtelldir(_WDIR *dirp)
 {
-	if (!dirp) {
-		errno = EBADF;
-		return -1;
+	if (!dirp || dirp->handle == INVALID_HANDLE_VALUE) {
+		dirent_set_errno(EBADF);
+		return /*failure*/-1;
+	}
+
+	/* Read next file entry */
+	WIN32_FIND_DATAW *datap = dirent_next(dirp);
+	if (!datap) {
+		/* End of directory stream */
+		return (long) ((~0UL) >> 1);
 	}
-	return ((struct __dir*)dirp)->count;
+
+	/* Store file entry to cache for readdir() */
+	dirp->cached = 1;
+
+	/* Return the 31-bit hash code to be used as stream position */
+	return dirent_hash(datap);
 }
 
-static intptr_t dirfd(DIR * dirp)
+/* Get position of directory stream */
+static long
+telldir(DIR *dirp)
 {
 	if (!dirp) {
-		errno = EINVAL;
+		dirent_set_errno(EBADF);
 		return -1;
 	}
-	return ((struct __dir*)dirp)->fd;
+
+	return _wtelldir(dirp->wdirp);
+}
+
+/* Seek directory stream to offset */
+static void
+_wseekdir(_WDIR *dirp, long loc)
+{
+	if (!dirp)
+		return;
+	
+	/* Directory must be open */
+	if (dirp->handle == INVALID_HANDLE_VALUE)
+		goto exit_failure;
+
+	/* Ensure that seek position is valid */
+	if (loc < 0)
+		goto exit_failure;
+
+	/* Restart directory stream from the beginning */
+	FindClose(dirp->handle);
+	if (!dirent_first(dirp))
+		goto exit_failure;
+
+	/* Reset invalid flag so that we can read from the stream again */
+	dirp->invalid = 0;
+
+	/*
+	 * Read directory entries from the beginning until the hash matches a
+	 * file name.  Be ware that hash code is only 31 bits longs and
+	 * duplicates are possible: the hash code cannot return the position
+	 * with 100.00% accuracy! Moreover, the method is slow for large
+	 * directories.
+	 */
+	long hash;
+	do {
+		/* Read next directory entry */
+		WIN32_FIND_DATAW *datap = dirent_next(dirp);
+		if (!datap) {
+			/*
+			 * End of directory stream was reached before finding
+			 * the requested location.  Perhaps the file in
+			 * question was deleted or moved out of the directory.
+			 */
+			goto exit_failure;
+		}
+
+		/* Does the file name match the hash? */
+		hash = dirent_hash(datap);
+	} while (hash != loc);
+
+	/*
+	 * File name matches the hash!  Push the directory entry back to cache
+	 * from where next readdir() will return it.
+	 */
+	dirp->cached = 1;
+	dirp->invalid = 0;
+	return;
+
+exit_failure:
+	/* Ensure that readdir will return NULL */
+	dirp->invalid = 1;
 }
 
-static int scandir(const char* dirp, struct dirent*** namelist,
+/* Seek directory stream to offset */
+static void
+seekdir(DIR *dirp, long loc)
+{
+	if (!dirp)
+		return;
+
+	_wseekdir(dirp->wdirp, loc);
+}
+
+/* Scan directory for entries */
+static int
+scandir(
+	const char *dirname, struct dirent ***namelist,
 	int (*filter)(const struct dirent*),
-	int (*compar)(const struct dirent**, const struct dirent**))
+	int (*compare)(const struct dirent**, const struct dirent**))
 {
-	struct dirent ** entries = NULL, ** tmp_entries = NULL;
-	long int i = 0, index = 0, count = 16;
-	DIR * d = opendir(dirp);
-	struct __dir* data = (struct __dir*) d;
-	if (!data) {
-		closedir(d);
-		__seterrno(ENOENT);
-		return -1;
+	int result;
+
+	/* Open directory stream */
+	DIR *dir = opendir(dirname);
+	if (!dir) {
+		/* Cannot open directory */
+		return /*Error*/ -1;
 	}
-	entries = (struct dirent**) malloc(sizeof(struct dirent*) * count);
-	if (!entries)
-	{
-		closedir(d);
-		__seterrno(ENOMEM);
-		return -1;
+
+	/* Read directory entries to memory */
+	struct dirent *tmp = NULL;
+	struct dirent **files = NULL;
+	size_t size = 0;
+	size_t allocated = 0;
+	while (1) {
+		/* Allocate room for a temporary directory entry */
+		if (!tmp) {
+			tmp = (struct dirent*) malloc(sizeof(struct dirent));
+			if (!tmp)
+				goto exit_failure;
+		}
+
+		/* Read directory entry to temporary area */
+		struct dirent *entry;
+		if (readdir_r(dir, tmp, &entry) != /*OK*/0)
+			goto exit_failure;
+
+		/* Stop if we already read the last directory entry */
+		if (entry == NULL)
+			goto exit_success;
+
+		/* Determine whether to include the entry in results */
+		if (filter && !filter(tmp))
+			continue;
+
+		/* Enlarge pointer table to make room for another pointer */
+		if (size >= allocated) {
+			/* Compute number of entries in the new table */
+			size_t num_entries = size * 2 + 16;
+
+			/* Allocate new pointer table or enlarge existing */
+			void *p = realloc(files, sizeof(void*) * num_entries);
+			if (!p)
+				goto exit_failure;
+
+			/* Got the memory */
+			files = (dirent**) p;
+			allocated = num_entries;
+		}
+
+		/* Store the temporary entry to ptr table */
+		files[size++] = tmp;
+		tmp = NULL;
+	}
+
+exit_failure:
+	/* Release allocated entries */
+	for (size_t i = 0; i < size; i++) {
+		free(files[i]);
+	}
+
+	/* Release the pointer table */
+	free(files);
+	files = NULL;
+
+	/* Exit with error code */
+	result = /*error*/ -1;
+	goto exit_status;
+
+exit_success:
+	/* Sort directory entries */
+	if (size > 1 && compare) {
+		qsort(files, size, sizeof(void*),
+			(int (*) (const void*, const void*)) compare);
+	}
+
+	/* Pass pointer table to caller */
+	if (namelist)
+		*namelist = files;
+
+	/* Return the number of directory entries read */
+	result = (int) size;
+
+exit_status:
+	/* Release temporary directory entry, if we had one */
+	free(tmp);
+
+	/* Close directory stream */
+	closedir(dir);
+	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)
+{
+	return strverscmp((*a)->d_name, (*b)->d_name);
+}
+
+/* Compare strings */
+static int
+strverscmp(const char *a, const char *b)
+{
+	size_t i = 0;
+	size_t j;
+
+	/* Find first difference */
+	while (a[i] == b[i]) {
+		if (a[i] == '\0') {
+			/* No difference */
+			return 0;
+		}
+		++i;
 	}
-	for (i = 0; i < data->count; ++i)
-	{
-		if (!filter || filter(&data->entries[i]))
-		{
-			entries[index] = (struct dirent*) malloc(sizeof(struct dirent));
-			if (!entries[index])
-			{
-				closedir(d);
-				for (i = 0; i < index; ++i)
-					free(entries[index]);
-				free(entries);
-				__seterrno(ENOMEM);
+
+	/* Count backwards and find the leftmost digit */
+	j = i;
+	while (j > 0 && isdigit(a[j-1])) {
+		--j;
+	}
+
+	/* Determine mode of comparison */
+	if (a[j] == '0' || b[j] == '0') {
+		/* Find the next non-zero digit */
+		while (a[j] == '0' && a[j] == b[j]) {
+			j++;
+		}
+
+		/* String with more digits is smaller, e.g 002 < 01 */
+		if (isdigit(a[j])) {
+			if (!isdigit(b[j])) {
 				return -1;
 			}
-			memcpy(entries[index], &data->entries[i], sizeof(struct dirent));
-			if (++index == count)
-			{
-				tmp_entries = (struct dirent**)realloc(entries, sizeof(struct dirent*) * count * 2);
-				if (!tmp_entries)
-				{
-					closedir(d);
-					for (i = 0; i < index; ++i)
-						free(entries[index - 1]);
-					free(entries);
-					__seterrno(ENOMEM);
-					return -1;
-				}
-				entries = tmp_entries;
-				count *= 2;
-			}
+		} else if (isdigit(b[j])) {
+			return 1;
+		}
+	} else if (isdigit(a[j]) && isdigit(b[j])) {
+		/* Numeric comparison */
+		size_t k1 = j;
+		size_t k2 = j;
+
+		/* Compute number of digits in each string */
+		while (isdigit(a[k1])) {
+			k1++;
+		}
+		while (isdigit(b[k2])) {
+			k2++;
 		}
+
+		/* Number with more digits is bigger, e.g 999 < 1000 */
+		if (k1 < k2)
+			return -1;
+		else if (k1 > k2)
+			return 1;
 	}
-	qsort(entries, index, sizeof(struct dirent*), compar);
-	entries[index] = NULL;
-	if (namelist)
-		*namelist = entries;
-	closedir(d);
-	return 0;
+
+	/* Alphabetical comparison */
+	return (int) ((unsigned char) a[i]) - ((unsigned char) b[i]);
 }
 
-int alphasort(const void* a, const void* b)
+/* Convert multi-byte string to wide character string */
+#if !defined(_MSC_VER) || _MSC_VER < 1400
+static int
+dirent_mbstowcs_s(
+	size_t *pReturnValue, wchar_t *wcstr,
+	size_t sizeInWords, const char *mbstr, size_t count)
 {
-	struct dirent** dira = (struct dirent**)a, **dirb = (struct dirent**)b;
-	if (!dira || !dirb)
-		return 0;
-	return strcoll((*dira)->d_name, (*dirb)->d_name);
+	/* Older Visual Studio or non-Microsoft compiler */
+	size_t n = mbstowcs(wcstr, mbstr, sizeInWords);
+	if (wcstr && n >= count)
+		return /*error*/ 1;
+
+	/* Zero-terminate output buffer */
+	if (wcstr && sizeInWords) {
+		if (n >= sizeInWords)
+			n = sizeInWords - 1;
+		wcstr[n] = 0;
+	}
+
+	/* Length of multi-byte string with zero terminator */
+	if (pReturnValue) {
+		*pReturnValue = n + 1;
+	}
+
+	/* Success */
+	return 0;
 }
+#endif
 
-static int __strverscmp(const char* s1, const char* s2)
+/* Convert wide-character string to multi-byte string */
+#if !defined(_MSC_VER) || _MSC_VER < 1400
+static int
+dirent_wcstombs_s(
+	size_t *pReturnValue, char *mbstr,
+	size_t sizeInBytes, const wchar_t *wcstr, size_t count)
 {
-	return alphasort(s1, s2);
+	/* Older Visual Studio or non-Microsoft compiler */
+	size_t n = wcstombs(mbstr, wcstr, sizeInBytes);
+	if (mbstr && n >= count)
+		return /*error*/1;
+
+	/* 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 */
+	return 0;
 }
+#endif
 
-int versionsort(const void* a, const void* b)
+/* Set errno variable */
+#if !defined(_MSC_VER) || _MSC_VER < 1400
+static void
+dirent_set_errno(int error)
 {
-	struct dirent** dira = (struct dirent**)a, ** dirb = (struct dirent**)b;
-	if (!dira || !dirb)
-		return 0;
-	return __strverscmp((*dira)->d_name, (*dirb)->d_name);
+	/* Non-Microsoft compiler or older Microsoft compiler */
+	errno = error;
 }
+#endif
 
 #ifdef __cplusplus
 }
-#endif /* __cplusplus */
-
-#endif /* _WIN32 */
-
-#endif /* __DIRENT_H_9DE6B42C_8D0C_4D31_A8EF_8E4C30E6C46A__ */
+#endif
+#endif /*DIRENT_H*/