windows: import tronkko's dirent.h

Win32 compatible version of dirent.h microsoft just don't seem to be
able to include themselves.

MIT license, same as lws, link to original github project in the header

1 files changed, 1160 insertions, 0 deletions

diff --git a/win32port/dirent/dirent-win32.h b/win32port/dirent/dirent-win32.h
new file mode 100644
index 00000000..f7a46daf
--- /dev/null
+++ b/win32port/dirent/dirent-win32.h
@@ -0,0 +1,1160 @@
+/*
+ * 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 <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 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);
+
+
+/* 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;
+    DWORD n;
+    wchar_t *p;
+
+    /* 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) {
+        return NULL;
+    }
+
+    /* 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 WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
+    /* Desktop */
+    n = GetFullPathNameW (dirname, 0, NULL, NULL);
+#else
+    /* WinRT */
+    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;
+}
+
+/*
+ * 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);
+        }
+
+        /* Release search pattern */
+        free (dirp->patt);
+
+        /* 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;
+    DWORD error;
+
+    /* 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 open directory: no directory entry in memory */
+        dirp->cached = 0;
+        datap = NULL;
+
+        /* Set error code */
+        error = GetLastError ();
+        switch (error) {
+        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);
+        }
+
+    }
+    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;
+
+    /* 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) {
+        return NULL;
+    }
+    {
+        int error;
+        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) {
+            /*
+             * 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.
+             */
+            goto exit_free;
+        }
+
+
+        /* Open directory stream using wide-character name */
+        dirp->wdirp = _wopendir (wname);
+        if (!dirp->wdirp) {
+            goto exit_free;
+        }
+
+    }
+
+    /* Success */
+    return dirp;
+
+    /* Failure */
+exit_free:
+    free (dirp);
+    return NULL;
+}
+
+/*
+ * 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 struct dirent**, const struct dirent**))
+{
+    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*),
+                        (int (*) (const void*, const void*)) compare);
+                    break;
+
+                }
+
+            } else {
+                /* Error reading directory entry */
+                result = /*Error*/ -1;
+                break;
+            }
+
+        }
+
+    } else {
+        /* Cannot open directory */
+        result = /*Error*/ -1;
+    }
+
+    /* Release temporary directory entry */
+    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*/