ff.c

FAT16 Microchip Application not for PIC24F

	/* Initialize allocation information */
	fs->free_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(fs->drive, 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(fs->drive) & 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 >= _DRIVES) return FR_INVALID_DRIVE;

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

	FatFs[drv] = 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, &dj.fs, (BYTE)(mode & (FA_WRITE|FA_CREATE_ALWAYS|FA_OPEN_ALWAYS|FA_CREATE_NEW)));
#else
	mode &= FA_READ;
	res = auto_mount(&path, &dj.fs, 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)) {
		DWORD ps, rs;
		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 it (R/O or DIR) */
				return FR_DENIED;
			if (mode & FA_CREATE_ALWAYS) {		/* Resize it to zero if needed */
				rs = ((DWORD)LD_WORD(&dir[DIR_FstClusHI]) << 16) | LD_WORD(&dir[DIR_FstClusLO]);	/* Get start cluster */
				ST_WORD(&dir[DIR_FstClusHI], 0);	/* cluster = 0 */
				ST_WORD(&dir[DIR_FstClusLO], 0);
				ST_DWORD(&dir[DIR_FileSize], 0);	/* size = 0 */
				dj.fs->winflag = 1;
				ps = dj.fs->winsect;			/* Remove the cluster chain */
				if (!remove_chain(dj.fs, rs) || !move_window(dj.fs, ps))
					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 */
			ps = get_fattime();
			ST_DWORD(&dir[DIR_CrtTime], ps);	/* 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 */
		((DWORD)LD_WORD(&dir[DIR_FstClusHI]) << 16) | LD_WORD(&dir[DIR_FstClusLO]);
	fp->fsize = LD_DWORD(&dir[DIR_FileSize]);	/* File size */
	fp->fptr = 0; fp->csect = 255;		/* File pointer */
	fp->curr_sect = 0;
	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 clust, sect, remain;
	UINT rcnt, cc;
	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 % SS(fp->fs)) == 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->fs, fp->curr_clust);
				if (clust < 2 || clust >= fp->fs->max_clust) goto fr_error;
				fp->curr_clust = clust;				/* Update current cluster */
				fp->csect = 0;						/* Reset sector address in the cluster */
			}
			sect = clust2sect(fp->fs, fp->curr_clust) + fp->csect;	/* Get current sector */
			cc = btr / SS(fp->fs);					/* When remaining bytes >= sector size, */
			if (cc) {								/* Read maximum contiguous sectors directly */
				if (fp->csect + cc > fp->fs->csize)	/* Clip at cluster boundary */
					cc = fp->fs->csize - fp->csect;
				if (disk_read(fp->fs->drive, rbuff, sect, (BYTE)cc) != RES_OK)
					goto fr_error;
				fp->csect += (BYTE)cc;				/* Next sector address in the cluster */
				rcnt = SS(fp->fs) * cc;				/* Number of bytes transferred */
				continue;
			}
			if (sect != fp->curr_sect) {			/* Is window offset changed? */
#if !_FS_READONLY
				if (fp->flag & FA__DIRTY) {			/* Write back file I/O buffer if needed */
					if (disk_write(fp->fs->drive, fp->buffer, fp->curr_sect, 1) != RES_OK)
						goto fr_error;
					fp->flag &= (BYTE)~FA__DIRTY;
				}
#endif
				if (disk_read(fp->fs->drive, fp->buffer, sect, 1) != RES_OK)	/* Fill file I/O buffer with file data */
					goto fr_error;
				fp->curr_sect = sect;
			}
			fp->csect++;							/* Next sector address in the cluster */
		}
		rcnt = SS(fp->fs) - (fp->fptr % SS(fp->fs));	/* Get partial sector from file I/O buffer */
		if (rcnt > btr) rcnt = btr;
		memcpy(rbuff, &fp->buffer[fp->fptr % SS(fp->fs)], rcnt);
	}

	return FR_OK;

fr_error:	/* Abort this file due to an unrecoverable error */
	fp->flag |= FA__ERROR;
	return FR_RW_ERROR;
}




#if !_FS_READONLY
/*-----------------------------------------------------------------------*/
/* Write File                                                            */
/*-----------------------------------------------------------------------*/

FRESULT f_write (
	FIL *fp,			/* Pointer to the file object */
	const void *buff,	/* Pointer to the data to be written */
	UINT btw,			/* Number of bytes to write */
	UINT *bw			/* Pointer to number of bytes written */
)
{
	FRESULT res;
	DWORD clust, sect;
	UINT wcnt, cc;
	const BYTE *wbuff = buff;


	*bw = 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_WRITE)) return FR_DENIED;	/* Check access mode */
	if (fp->fsize + btw < fp->fsize) return FR_OK;	/* File size cannot reach 4GB */

	for ( ;  btw;									/* Repeat until all data transferred */
		wbuff += wcnt, fp->fptr += wcnt, *bw += wcnt, btw -= wcnt) {
		if ((fp->fptr % SS(fp->fs)) == 0) {			/* On the sector boundary? */
			if (fp->csect >= fp->fs->csize) {		/* On the cluster boundary? */
				if (fp->fptr == 0) {				/* On the top of the file? */
					clust = fp->org_clust;			/* Follow from the origin */
					if (clust == 0)					/* When there is no cluster chain, */
						fp->org_clust = clust = create_chain(fp->fs, 0);	/* Create a new cluster chain */
				} else {							/* Middle or end of the file */
					clust = create_chain(fp->fs, fp->curr_clust);			/* Trace or streach cluster chain */
				}
				if (clust == 0) break;				/* Could not allocate a new cluster (disk full) */
				if (clust == 1 || clust >= fp->fs->max_clust) goto fw_error;
				fp->curr_clust = clust;				/* Update current cluster */
				fp->csect = 0;						/* Reset sector address in the cluster */
			}
			sect = clust2sect(fp->fs, fp->curr_clust) + fp->csect;	/* Get current sector */
			cc = btw / SS(fp->fs);					/* When remaining bytes >= sector size, */
			if (cc) {								/* Write maximum contiguous sectors directly */
				if (fp->csect + cc > fp->fs->csize)	/* Clip at cluster boundary */
					cc = fp->fs->csize - fp->csect;
				if (disk_write(fp->fs->drive, wbuff, sect, (BYTE)cc) != RES_OK)
					goto fw_error;
				fp->csect += (BYTE)cc;				/* Next sector address in the cluster */
				wcnt = SS(fp->fs) * cc;				/* Number of bytes transferred */
				continue;
			}
			if (sect != fp->curr_sect) {			/* Is window offset changed? */
				if (fp->flag & FA__DIRTY) {			/* Write back file I/O buffer if needed */
					if (disk_write(fp->fs->drive, fp->buffer, fp->curr_sect, 1) != RES_OK)
						goto fw_error;
					fp->flag &= (BYTE)~FA__DIRTY;
				}
				if (fp->fptr < fp->fsize &&  		/* Fill file I/O buffer with file data */
					disk_read(fp->fs->drive, fp->buffer, sect, 1) != RES_OK)
						goto fw_error;
				fp->curr_sect = sect;
			}
			fp->csect++;							/* Next sector address in the cluster */
		}
		wcnt = SS(fp->fs) - (fp->fptr % SS(fp->fs));	/* Put partial sector into file I/O buffer */
		if (wcnt > btw) wcnt = btw;
		memcpy(&fp->buffer[fp->fptr % SS(fp->fs)], wbuff, wcnt);
		fp->flag |= FA__DIRTY;
	}

	if (fp->fptr > fp->fsize) fp->fsize = fp->fptr;	/* Update file size if needed */
	fp->flag |= FA__WRITTEN;						/* Set file changed flag */
	return FR_OK;

fw_error:	/* Abort this file due to an unrecoverable error */
	fp->flag |= FA__ERROR;
	return FR_RW_ERROR;
}




/*-----------------------------------------------------------------------*/
/* Synchronize the file object                                           */
/*-----------------------------------------------------------------------*/

FRESULT f_sync (
	FIL *fp		/* Pointer to the file object */
)
{
	FRESULT res;
	DWORD tim;
	BYTE *dir;


	res = validate(fp->fs, fp->id);		/* Check validity of the object */
	if (res == FR_OK) {
		if (fp->flag & FA__WRITTEN) {	/* Has the file been written? */
			/* Write back data buffer if needed */
			if (fp->flag & FA__DIRTY) {
				if (disk_write(fp->fs->drive, fp->buffer, fp->curr_sect, 1) != RES_OK)
					return FR_RW_ERROR;
				fp->flag &= (BYTE)~FA__DIRTY;
			}
			/* Update the directory entry */
			if (!move_window(fp->fs, fp->dir_sect))
				return FR_RW_ERROR;
			dir = fp->dir_ptr;
			dir[DIR_Attr] |= AM_ARC;						/* Set archive bit */
			ST_DWORD(&dir[DIR_FileSize], fp->fsize);		/* Update file size */
			ST_WORD(&dir[DIR_FstClusLO], fp->org_clust);	/* Update start cluster */
			ST_WORD(&dir[DIR_FstClusHI], fp->org_clust >> 16);
			tim = get_fattime();					/* Updated time */
			ST_DWORD(&dir[DIR_WrtTime], tim);
			fp->flag &= (BYTE)~FA__WRITTEN;
			res = sync(fp->fs);
		}
	}
	return res;
}

#endif /* !_FS_READONLY */




/*-----------------------------------------------------------------------*/
/* Close File                                                            */
/*-----------------------------------------------------------------------*/

FRESULT f_close (
	FIL *fp		/* Pointer to the file object to be closed */
)
{
	FRESULT res;


#if !_FS_READONLY
	res = f_sync(fp);
#else
	res = validate(fp->fs, fp->id);
#endif
	if (res == FR_OK) fp->fs = NULL;
	return res;
}




#if _FS_MINIMIZE <= 2
/*-----------------------------------------------------------------------*/