if (c <= ')') goto md_l1;			/* Accept ! # $ % & ' ( ) */
		if (c <= ',') break;				/* Reject * + , */
		if (c <= '9') goto md_l1;			/* Accept - 0-9 */
		if (c <= '?') break;				/* Reject : ; < = > ? */
		if (!(a & 1)) {	/* These checks are not applied to S-JIS 2nd byte */
			if (c == '|') break;			/* Reject | */
			if (c >= '[' && c <= ']') break;/* Reject [ \ ] */
			if (_USE_NTFLAG && c >= 'A' && c <= 'Z')
				(t == 8) ? (b &= 0xF7) : (b &= 0xEF);
			if (c >= 'a' && c <= 'z') {		/* Convert to upper case */
				c -= 0x20;
				if (_USE_NTFLAG) (t == 8) ? (a |= 0x08) : (a |= 0x10);
			}
		}
	md_l1:
		a &= 0xFE;
	md_l2:
		if (n >= t) break;
		dirname[n++] = c;
	}
	return 1;
}



/*-----------------------------------------------------------------------*/
/* Trace a file path                                                     */
/*-----------------------------------------------------------------------*/

static
FRESULT trace_path (	/* FR_OK(0): successful, !=0: error code */
	DIR *dj,			/* Pointer to directory object to return last directory */
	char *fn,			/* Pointer to last segment name to return */
	const char *path,	/* Full-path string to trace a file or directory */
	BYTE **dir			/* Pointer to pointer to found entry to retutn */
)
{
	CLUST clust;
	char ds;
	BYTE *dptr = NULL;
	FATFS *fs = FatFs;

	/* Initialize directory object */
	dj->fs = fs;
	clust = fs->dirbase;
#if _FAT32
	if (fs->fs_type == FS_FAT32) {
		dj->clust = dj->sclust = clust;
		dj->sect = clust2sect(clust);
	} else
#endif
	{
		dj->clust = dj->sclust = 0;
		dj->sect = clust;
	}
	dj->index = 0;

	if (*path == '\0') {							/* Null path means the root directory */
		*dir = NULL; return FR_OK;
	}

	for (;;) {
		ds = make_dirfile(&path, fn);					/* Get a paragraph into fn[] */
		if (ds == 1) return FR_INVALID_NAME;
		for (;;) {
			if (!move_window(dj->sect)) return FR_RW_ERROR;
			dptr = &fs->win[(dj->index & 15) * 32];		/* Pointer to the directory entry */
			if (dptr[DIR_Name] == 0)					/* Has it reached to end of dir? */
				return !ds ? FR_NO_FILE : FR_NO_PATH;
			if (dptr[DIR_Name] != 0xE5					/* Matched? */
				&& !(dptr[DIR_Attr] & AM_VOL)
				&& !memcmp(&dptr[DIR_Name], fn, 8+3) ) break;
			if (!next_dir_entry(dj))					/* Next directory pointer */
				return !ds ? FR_NO_FILE : FR_NO_PATH;
		}
		if (!ds) { *dir = dptr; return FR_OK; }			/* Matched with end of path */
		if (!(dptr[DIR_Attr] & AM_DIR)) return FR_NO_PATH;	/* Cannot trace because it is a file */
		clust =											/* Get cluster# of the directory */
#if _FAT32
			((DWORD)LD_WORD(&dptr[DIR_FstClusHI]) << 16) |
#endif
			LD_WORD(&dptr[DIR_FstClusLO]);
		dj->clust = dj->sclust = clust;				/* Restart scannig with the new directory */
		dj->sect = clust2sect(clust);
		dj->index = 2;
	}
}



/*-----------------------------------------------------------------------*/
/* Reserve a directory entry                                             */
/*-----------------------------------------------------------------------*/

#if !_FS_READONLY
static
FRESULT reserve_direntry (	/* FR_OK: successful, FR_DENIED: no free entry, FR_RW_ERROR: a disk error occured */
	DIR *dj,				/* Target directory to create new entry */
	BYTE **dir				/* Pointer to pointer to created entry to retutn */
)
{
	CLUST clust;
	DWORD sector;
	BYTE c, n, *dptr;
	FATFS *fs = dj->fs;


	/* Re-initialize directory object */
	clust = dj->sclust;
	if (clust != 0) {	/* Dyanmic directory table */
		dj->clust = clust;
		dj->sect = clust2sect(clust);
	} else {			/* Static directory table */
		dj->sect = fs->dirbase;
	}
	dj->index = 0;

	do {
		if (!move_window(dj->sect)) return FR_RW_ERROR;
		dptr = &fs->win[(dj->index & 15) * 32];	/* Pointer to the directory entry */
		c = dptr[DIR_Name];
		if (c == 0 || c == 0xE5) {			/* Found an empty entry! */
			*dir = dptr; return FR_OK;
		}
	} while (next_dir_entry(dj));			/* Next directory pointer */
	/* Reached to end of the directory table */

	/* Abort when static table or could not stretch dynamic table */
	if (clust == 0 || !(clust = create_chain(dj->clust))) return FR_DENIED;
	if (clust == 1 || !move_window(0)) return FR_RW_ERROR;

	fs->winsect = sector = clust2sect(clust);	/* Cleanup the expanded table */
	memset(fs->win, 0, 512U);
	for (n = fs->csize; n; n--) {
		if (disk_write(0, fs->win, sector, 1) != RES_OK)
			return FR_RW_ERROR;
		sector++;
	}
	fs->winflag = 1;
	*dir = fs->win;
	return FR_OK;
}
#endif /* !_FS_READONLY */




/*-----------------------------------------------------------------------*/
/* Load boot record and check if it is an FAT boot record                */
/*-----------------------------------------------------------------------*/

static
BYTE check_fs (	/* 0:The FAT boot record, 1:Valid boot record but not an FAT, 2:Not a boot record or error */
	DWORD sect	/* Sector# to check if it is an FAT boot record or not */
)
{
	FATFS *fs = FatFs;

	if (disk_read(0, fs->win, sect, 1) != RES_OK)	/* Load boot record */
		return 2;
	if (LD_WORD(&fs->win[BS_55AA]) != 0xAA55)		/* Check record signature */
		return 2;

	if (!memcmp(&fs->win[BS_FilSysType], "FAT", 3))	/* Check FAT signature */
		return 0;
#if _FAT32
	if (!memcmp(&fs->win[BS_FilSysType32], "FAT32", 5) && !(fs->win[BPB_ExtFlags] & 0x80))
		return 0;
#endif
	return 1;
}




/*-----------------------------------------------------------------------*/
/* Make sure that the file system is valid                               */
/*-----------------------------------------------------------------------*/

static
FRESULT auto_mount (	/* FR_OK(0): successful, !=0: any error occured */
	const char **path,	/* Pointer to pointer to the path name (drive number) */
	BYTE chk_wp			/* !=0: Check media write protection for write access */
)
{
	BYTE fmt;
	DSTATUS stat;
	DWORD bootsect, fatsize, totalsect, maxclust;
	const char *p = *path;
	FATFS *fs;


	while (*p == ' ') p++;	/* Strip leading spaces */
	if (*p == '/') p++;		/* Strip heading slash */
	*path = p;				/* Return pointer to the path name */

	/* Is the file system object registered? */
	fs = FatFs;
	if (!fs) return FR_NOT_ENABLED;

	if (fs->fs_type) {						/* If the logical drive has been mounted */
		stat = disk_status(0);
		if (!(stat & STA_NOINIT)) {			/* and physical drive is kept initialized (has not been changed), */
#if !_FS_READONLY
			if (chk_wp && (stat & STA_PROTECT))	/* Check write protection if needed */
				return FR_WRITE_PROTECTED;
#endif
			return FR_OK;					/* The file system object is valid */
		}
	}

	/* The logical drive must be re-mounted. Following code attempts to mount the logical drive */

	memset(fs, 0, sizeof(FATFS));		/* Clean-up the file system object */
	stat = disk_initialize(0);			/* Initialize low level disk I/O layer */
	if (stat & STA_NOINIT)				/* Check if the drive is ready */
		return FR_NOT_READY;
#if !_FS_READONLY
	if (chk_wp && (stat & STA_PROTECT))	/* Check write protection if needed */
		return FR_WRITE_PROTECTED;
#endif

	/* Search FAT partition on the drive */
	fmt = check_fs(bootsect = 0);		/* Check sector 0 as an SFD format */
	if (fmt == 1) {						/* Not an FAT boot record, it may be patitioned */
		/* Check a partition listed in top of the partition table */
		if (fs->win[MBR_Table+4]) {						/* Is the 1st partition existing? */
			bootsect = LD_DWORD(&fs->win[MBR_Table+8]);	/* Partition offset in LBA */
			fmt = check_fs(bootsect);					/* Check the partition */
		}
	}
	if (fmt || LD_WORD(&fs->win[BPB_BytsPerSec]) != 512U)	/* No valid FAT patition is found */
		return FR_NO_FILESYSTEM;

	/* Initialize the file system object */
	fatsize = LD_WORD(&fs->win[BPB_FATSz16]);			/* Number of sectors per FAT */
	if (!fatsize) fatsize = LD_DWORD(&fs->win[BPB_FATSz32]);
	fs->sects_fat = (CLUST)fatsize;
	fs->n_fats = fs->win[BPB_NumFATs];					/* Number of FAT copies */
	fatsize *= fs->n_fats;								/* (Number of sectors in FAT area) */
	fs->fatbase = bootsect + LD_WORD(&fs->win[BPB_RsvdSecCnt]);	/* FAT start sector (lba) */
	fs->csize = fs->win[BPB_SecPerClus];				/* Number of sectors per cluster */
	fs->n_rootdir = LD_WORD(&fs->win[BPB_RootEntCnt]);	/* Nmuber of root directory entries */
	totalsect = LD_WORD(&fs->win[BPB_TotSec16]);		/* Number of sectors on the file system */
	if (!totalsect) totalsect = LD_DWORD(&fs->win[BPB_TotSec32]);
	fs->max_clust = maxclust = (totalsect				/* max_clust = Last cluster# + 1 */
		- LD_WORD(&fs->win[BPB_RsvdSecCnt]) - fatsize - fs->n_rootdir / 16
		) / fs->csize + 2;

	fmt = FS_FAT12;										/* Determine the FAT sub type */
	if (maxclust >= 0xFF7) fmt = FS_FAT16;
	if (maxclust >= 0xFFF7)
#if !_FAT32
		return FR_NO_FILESYSTEM;
#else
		fmt = FS_FAT32;
	if (fmt == FS_FAT32)
		fs->dirbase = LD_DWORD(&fs->win[BPB_RootClus]);	/* Root directory start cluster */
	else
#endif
		fs->dirbase = fs->fatbase + fatsize;			/* Root directory start sector (lba) */
	fs->database = fs->fatbase + fatsize + fs->n_rootdir / 16;	/* Data start sector (lba) */

#if !_FS_READONLY
	/* Initialize allocation information */
	fs->free_clust = (CLUST)0xFFFFFFFF;
#if _USE_FSINFO
	/* Get fsinfo if needed */
	if (fmt == FS_FAT32) {
		fs->fsi_sector = bootsect + LD_WORD(&fs->win[BPB_FSInfo]);
		if (disk_read(0, fs->win, fs->fsi_sector, 1) == RES_OK &&
			LD_WORD(&fs->win[BS_55AA]) == 0xAA55 &&
			LD_DWORD(&fs->win[FSI_LeadSig]) == 0x41615252 &&
			LD_DWORD(&fs->win[FSI_StrucSig]) == 0x61417272) {
			fs->last_clust = LD_DWORD(&fs->win[FSI_Nxt_Free]);
			fs->free_clust = LD_DWORD(&fs->win[FSI_Free_Count]);
		}
	}
#endif
#endif

	fs->fs_type = fmt;			/* FAT syb-type */
	fs->id = ++fsid;			/* File system mount ID */
	return FR_OK;
}




/*-----------------------------------------------------------------------*/
/* Check if the file/dir object is valid or not                          */
/*-----------------------------------------------------------------------*/

static
FRESULT validate (		/* FR_OK(0): The object is valid, !=0: Invalid */
	const FATFS *fs,	/* Pointer to the file system object */
	WORD id				/* Member id of the target object to be checked */
)
{
	if (!fs || !fs->fs_type || fs->id != id)
		return FR_INVALID_OBJECT;
	if (disk_status(0) & STA_NOINIT)
		return FR_NOT_READY;

	return FR_OK;
}




/*--------------------------------------------------------------------------

   Public Functions

--------------------------------------------------------------------------*/


/*-----------------------------------------------------------------------*/
/* Mount/Unmount a Locical Drive                                         */
/*-----------------------------------------------------------------------*/

FRESULT f_mount (
	BYTE drv,		/* Logical drive number to be mounted/unmounted */
	FATFS *fs		/* Pointer to new file system object (NULL for unmount)*/
)
{
	if (drv) return FR_INVALID_DRIVE;

	if (FatFs) FatFs->fs_type = 0;	/* Clear old object */

	FatFs = fs;					/* Register and clear new object */
	if (fs) fs->fs_type = 0;

	return FR_OK;
}




/*-----------------------------------------------------------------------*/
/* Open or Create a File                                                 */
/*-----------------------------------------------------------------------*/

FRESULT f_open (
	FIL *fp,			/* Pointer to the blank file object */
	const char *path,	/* Pointer to the file name */
	BYTE mode			/* Access mode and file open mode flags */
)
{
	FRESULT res;
	DIR dj;
	BYTE *dir;
	char fn[8+3+1];


	fp->fs = NULL;		/* Clear file object */
#if !_FS_READONLY
	mode &= (FA_READ|FA_WRITE|FA_CREATE_ALWAYS|FA_OPEN_ALWAYS|FA_CREATE_NEW);
	res = auto_mount(&path, (BYTE)(mode & (FA_WRITE|FA_CREATE_ALWAYS|FA_OPEN_ALWAYS|FA_CREATE_NEW)));
#else
	mode &= FA_READ;
	res = auto_mount(&path, 0);
#endif
	if (res != FR_OK) return res;
	res = trace_path(&dj, fn, path, &dir);	/* Trace the file path */

#if !_FS_READONLY
	/* Create or Open a File */
	if (mode & (FA_CREATE_ALWAYS|FA_OPEN_ALWAYS|FA_CREATE_NEW)) {
		CLUST rs;
		DWORD dw;
		if (res != FR_OK) {		/* No file, create new */
			if (res != FR_NO_FILE) return res;
			res = reserve_direntry(&dj, &dir);
			if (res != FR_OK) return res;
			memset(dir, 0, 32);		/* Initialize the new entry with open name */
			memcpy(&dir[DIR_Name], fn, 8+3);
			dir[DIR_NTres] = fn[11];
			mode |= FA_CREATE_ALWAYS;
		}
		else {					/* Any object is already existing */
			if (mode & FA_CREATE_NEW)			/* Cannot create new */
				return FR_EXIST;
			if (!dir || (dir[DIR_Attr] & (AM_RDO|AM_DIR)))	/* Cannot overwrite (R/O or DIR) */
				return FR_DENIED;
			if (mode & FA_CREATE_ALWAYS) {		/* Resize it to zero */
#if _FAT32
				rs = ((DWORD)LD_WORD(&dir[DIR_FstClusHI]) << 16) | LD_WORD(&dir[DIR_FstClusLO]);
				ST_WORD(&dir[DIR_FstClusHI], 0);
#else
				rs = LD_WORD(&dir[DIR_FstClusLO]);
#endif
				ST_WORD(&dir[DIR_FstClusLO], 0);	/* cluster = 0 */
				ST_DWORD(&dir[DIR_FileSize], 0);	/* size = 0 */
				dj.fs->winflag = 1;
				dw = dj.fs->winsect;			/* Remove the cluster chain */
				if (!remove_chain(rs) || !move_window(dw))
					return FR_RW_ERROR;
				dj.fs->last_clust = rs - 1;		/* Reuse the cluster hole */
			}
		}
		if (mode & FA_CREATE_ALWAYS) {
			dir[DIR_Attr] = 0;					/* Reset attribute */
			dw = get_fattime();
			ST_DWORD(&dir[DIR_CrtTime], dw);	/* Created time */
			dj.fs->winflag = 1;
			mode |= FA__WRITTEN;				/* Set file changed flag */
		}
	}
	/* Open an existing file */
	else {
#endif /* !_FS_READONLY */
		if (res != FR_OK) return res;			/* Trace failed */
		if (!dir || (dir[DIR_Attr] & AM_DIR))	/* It is a directory */
			return FR_NO_FILE;
#if !_FS_READONLY
		if ((mode & FA_WRITE) && (dir[DIR_Attr] & AM_RDO)) /* R/O violation */
			return FR_DENIED;
	}
	fp->dir_sect = dj.fs->winsect;		/* Pointer to the directory entry */
	fp->dir_ptr = dir;
#endif
	fp->flag = mode;					/* File access mode */
	fp->org_clust =						/* File start cluster */
#if _FAT32
		((DWORD)LD_WORD(&dir[DIR_FstClusHI]) << 16) |
#endif
		LD_WORD(&dir[DIR_FstClusLO]);
	fp->fsize = LD_DWORD(&dir[DIR_FileSize]);	/* File size */
	fp->fptr = 0; fp->csect = 255;		/* File pointer */
	fp->fs = dj.fs; fp->id = dj.fs->id;	/* Owner file system object of the file */

	return FR_OK;
}




/*-----------------------------------------------------------------------*/
/* Read File                                                             */
/*-----------------------------------------------------------------------*/

FRESULT f_read (
	FIL *fp, 		/* Pointer to the file object */
	void *buff,		/* Pointer to data buffer */
	UINT btr,		/* Number of bytes to read */
	UINT *br		/* Pointer to number of bytes read */
)
{
	FRESULT res;
	DWORD sect, remain;
	UINT rcnt, cc;
	CLUST clust;
	BYTE *rbuff = buff;


	*br = 0;
	res = validate(fp->fs, fp->id);					/* Check validity of the object */
	if (res != FR_OK) return res;
	if (fp->flag & FA__ERROR) return FR_RW_ERROR;	/* Check error flag */
	if (!(fp->flag & FA_READ)) return FR_DENIED;	/* Check access mode */
	remain = fp->fsize - fp->fptr;
	if (btr > remain) btr = (UINT)remain;			/* Truncate btr by remaining bytes */

	for ( ;  btr;									/* Repeat until all data transferred */
		rbuff += rcnt, fp->fptr += rcnt, *br += rcnt, btr -= rcnt) {
		if ((fp->fptr % 512U) == 0) {				/* On the sector boundary? */
			if (fp->csect >= fp->fs->csize) {		/* On the cluster boundary? */
				clust = (fp->fptr == 0) ?			/* On the top of the file? */
					fp->org_clust : get_cluster(fp->curr_clust);