Squashed 'third_party/glog/' content from commit 9ef754a3023

git-subtree-dir: third_party/glog
git-subtree-split: 9ef754a3023e6fd10f20fe53dfca96dd898182e3

1 files changed, 1160 insertions, 0 deletions

diff --git a/src/windows/dirent.h b/src/windows/dirent.h
new file mode 100644
index 000000000000..f7a46dafcbf1
--- /dev/null
+++ b/src/windows/dirent.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*/