simdjson/windows/toni_ronnko_dirent.h

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