/*
 * dirent.h - dirent API for Microsoft Visual Studio
 *
 * Copyright (C) 2006-2012 Toni Ronkko
 *
 * 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 TONI RONKKO 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.
 *
 * $Id: dirent.h,v 1.20 2014/03/19 17:52:23 tronkko Exp $
 */
#ifndef DIRENT_MSVC_H
#define DIRENT_MSVC_H

#include <windows.h>

#if _MSC_VER >= 1900
#include <../ucrt/stdio.h>
#include <../ucrt/wchar.h>
#include <../ucrt/string.h>
#include <../ucrt/stdlib.h>
#include <../ucrt/sys/types.h>
#include <../ucrt/errno.h>
#else
#include <../include/stdio.h>
#include <../include/wchar.h>
#include <../include/string.h>
#include <../include/stdlib.h>
#include <../include/sys/types.h>
#include <../include/errno.h>
#endif

#include <stdarg.h>
#include <sys/stat.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

/* 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

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

/* Return number of bytes needed to store d_namlen */
#define _D_ALLOC_NAMLEN(p)(PATH_MAX)

/* Wide-character version */
struct _wdirent {
	long d_ino;                         /* Always zero */
	unsigned short d_reclen;            /* Structure size */
	size_t d_namlen;                    /* Length of name without \0 */
	int d_type;                         /* File type */
	wchar_t d_name[PATH_MAX];           /* File name */
};
typedef struct _wdirent _wdirent;

struct _WDIR {
	struct _wdirent ent;                /* Current directory entry */
	WIN32_FIND_DATAW data;              /* Private file data */
	int cached;                         /* True if data is valid */
	HANDLE handle;                      /* Win32 search handle */
	wchar_t *patt;                      /* Initial directory name */
};
typedef struct _WDIR _WDIR;

static _WDIR *_wopendir(const wchar_t *dirname);
static struct _wdirent *_wreaddir(_WDIR *dirp);
static int _wclosedir(_WDIR *dirp);
static void _wrewinddir(_WDIR* dirp);

/* Multi-byte character versions */
struct dirent {
	long d_ino;                         /* Always zero */
	unsigned short d_reclen;            /* Structure size */
	size_t d_namlen;                    /* Length of name without \0 */
	int d_type;                         /* File type */
	char d_name[PATH_MAX];              /* File name */
};
typedef struct dirent dirent;

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

static DIR *opendir(const char *dirname);
static struct dirent *readdir(DIR *dirp);
static int closedir(DIR *dirp);
static void rewinddir(DIR* dirp);

/* 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);

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

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

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

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

		/* Compute the length of full path plus zero terminator */
		n = GetFullPathNameW(dirname, 0, NULL, NULL);

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

			/*
			 * Convert relative directory name to an absolute one.  This
			 * allows rewinddir() to function correctly even when current
			 * working directory is changed between opendir() and rewinddir().
			 */
			n = GetFullPathNameW(dirname, n, dirp->patt, NULL);
			if (n > 0) {
				wchar_t *p;

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

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

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

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

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

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

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

	return dirp;
}

/*
 * Read next directory entry.  The directory entry is returned in dirent
 * structure in the d_name field.  Individual directory entries returned by
 * this function include regular files, sub-directories, pseudo-directories
 * "." and ".." as well as volume labels, hidden files and system files.
 */
static struct _wdirent*
_wreaddir(_WDIR *dirp)
{
	WIN32_FIND_DATAW *datap;
	struct _wdirent *entp;

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

		/* Pointer to directory entry to return */
		entp = &dirp->ent;

		/*
		 * 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 + 1 < PATH_MAX  &&  datap->cFileName[n] != 0) {
			entp->d_name[n] = datap->cFileName[n];
			n++;
		}
		dirp->ent.d_name[n] = 0;

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

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

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

	} else {

		/* Last directory entry read */
		entp = NULL;

	}

	return entp;
}

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

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

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

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

	} else {
		/* Invalid directory stream */
		_set_errno(EBADF);
		ok = /*failure*/-1;
	}
	return ok;
}

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

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

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

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

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

	} else {

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

	}
	return datap;
}

/* Get next directory entry(internal) */
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 occured */
			FindClose(dirp->handle);
			dirp->handle = INVALID_HANDLE_VALUE;
			p = NULL;
		}

	} else {

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

	}

	return p;
}

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

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

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

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

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

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

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

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

	return dirp;
}

/*
 * Read next directory entry.
 *
 * When working with text consoles, please note that file names returned by
 * readdir() are represented in the default ANSI code page while any output to
 * console is typically formatted on another code page.  Thus, non-ASCII
 * characters in file names will not usually display correctly on console.  The
 * problem can be fixed in two ways:(1) change the character set of console
 * to 1252 using chcp utility and use Lucida Console font, or(2) use
 * _cprintf function when writing to console.  The _cprinf() will re-encode
 * ANSI strings to the console code page so many non-ASCII characters will
 * display correcly.
 */
static struct dirent*
readdir(DIR *dirp)
{
	WIN32_FIND_DATAW *datap;
	struct dirent *entp;

	/* 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, dirp->ent.d_name, PATH_MAX, datap->cFileName, PATH_MAX);

		/*
		 * 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, dirp->ent.d_name, PATH_MAX,
			    datap->cAlternateFileName, PATH_MAX);
		}

		if (!error) {
			DWORD attr;

			/* Initialize directory entry for return */
			entp = &dirp->ent;

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

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

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

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

	} else {
		/* No more directory entries */
		entp = NULL;
	}

	return entp;
}

/*
 * 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 */
		_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);
}

/* 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)
{
	return mbstowcs_s(pReturnValue, wcstr, sizeInWords, mbstr, count);
}

/* 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)
{
	return wcstombs_s(pReturnValue, mbstr, sizeInBytes, wcstr, count);
}

#endif /*DIRENT_H*/