tff.c

基于AVR UC/OS-II的FAT32文件系统。

	BYTE sc;
	FRESULT res;
	FATFS *fs = fp->fs;


	res = validate(fs, fp->id);
	if (res) return res;
	if (fp->flag & FA__ERROR) return FR_RW_ERROR;
	if (ofs > fp->fsize) ofs = fp->fsize;	/* Clip offset by file size */
	fp->fptr = ofs; fp->sect_clust = 1; 	/* Re-initialize file pointer */

	/* Seek file pinter if needed */
	if (ofs) {
		ofs = (ofs - 1) / 512;				/* Calcurate current sector */
		sc = fs->sects_clust;				/* Number of sectors in a cluster */
		fp->sect_clust = sc - ((BYTE)ofs % sc);	/* Calcurate sector counter */
		ofs /= sc;							/* Number of clusters to skip */
		clust = fp->org_clust;				/* Seek to current cluster */
		while (ofs--)
			clust = get_cluster(clust);
		if (clust < 2 || clust >= fs->max_clust)
			goto fk_error;
		fp->curr_clust = clust;
		fp->curr_sect = clust2sect(clust) + sc - fp->sect_clust;	/* Current sector */
	}

	return FR_OK;

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




/*-----------------------------------------------------------------------*/
/* Synchronize between File and Disk                                     */
/*-----------------------------------------------------------------------*/

#if _FS_READONLY == 0
FRESULT f_sync (
	FIL *fp		/* Pointer to the file object */
)
{
	BYTE *ptr;
	FRESULT res;
	FATFS *fs = fp->fs;


	res = validate(fs, fp->id);
	if (res) return res;

	/* Has the file been written? */
	if (fp->flag & FA__WRITTEN) {
		/* Update the directory entry */
		if (!move_window(fp->dir_sect))
			return FR_RW_ERROR;
		ptr = fp->dir_ptr;
		*(ptr+11) |= AM_ARC;					/* Set archive bit */
		ST_DWORD(ptr+28, fp->fsize);			/* Update file size */
		ST_WORD(ptr+26, fp->org_clust);			/* Update start cluster */
#if _FAT32 != 0
		ST_WORD(ptr+20, fp->org_clust >> 16);
#endif
		ST_DWORD(ptr+22, get_fattime());		/* Updated time */
		fs->winflag = 1;
		fp->flag &= ~FA__WRITTEN;
	}
	if (!move_window(0)) return FR_RW_ERROR;

	return FR_OK;
}
#endif /* _FS_READONLY */




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

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


#if _FS_READONLY == 0
	res = f_sync(fp);
#else
	res = validate(fp->fs, fp->id);
#endif
	if (res == FR_OK)
		fp->fs = NULL;

	return res;
}




#if _FS_MINIMIZE <= 1
/*-----------------------------------------------------------------------*/
/* Create a directroy object                                             */
/*-----------------------------------------------------------------------*/

FRESULT f_opendir (
	DIR *dirobj,		/* Pointer to directory object to create */
	const char *path	/* Pointer to the directory path */
)
{
	BYTE *dir;
	char fn[8+3+1];
	FRESULT res;
	FATFS *fs = FatFs;


	if ((res = auto_mount(&path, 0)) != FR_OK)
		return res;
	res = trace_path(dirobj, fn, path, &dir);	/* Trace the directory path */

	if (res == FR_OK) {						/* Trace completed */
		if (dir != NULL) {					/* It is not a root dir */
			if (*(dir+11) & AM_DIR) {		/* The entry is a directory */
#if _FAT32 != 0
				dirobj->clust = ((DWORD)LD_WORD(dir+20) << 16) | LD_WORD(dir+26);
#else
				dirobj->clust = LD_WORD(dir+26);
#endif
				dirobj->sect = clust2sect(dirobj->clust);
				dirobj->index = 0;
			} else {						/* The entry is not a directory */
				res = FR_NO_FILE;
			}
		}
		dirobj->id = ~fs->id;
	}
	return res;
}




/*-----------------------------------------------------------------------*/
/* Read Directory Entry in Sequense                                      */
/*-----------------------------------------------------------------------*/

FRESULT f_readdir (
	DIR *dirobj,		/* Pointer to the directory object */
	FILINFO *finfo		/* Pointer to file information to return */
)
{
	BYTE *dir, c;
	FRESULT res;
	FATFS *fs = dirobj->fs;


	res = validate(fs, dirobj->id);
	if (res) return res;

	finfo->fname[0] = 0;
	while (dirobj->sect) {
		if (!move_window(dirobj->sect))
			return FR_RW_ERROR;
		dir = &fs->win[(dirobj->index & 15) * 32];		/* pointer to the directory entry */
		c = *dir;
		if (c == 0) break;								/* Has it reached to end of dir? */
		if (c != 0xE5 && c != '.' && !(*(dir+11) & AM_VOL))	/* Is it a valid entry? */
			get_fileinfo(finfo, dir);
		if (!next_dir_entry(dirobj)) dirobj->sect = 0;	/* Next entry */
		if (finfo->fname[0]) break;						/* Found valid entry */
	}

	return FR_OK;
}




#if _FS_MINIMIZE == 0
/*-----------------------------------------------------------------------*/
/* Get File Status                                                       */
/*-----------------------------------------------------------------------*/

FRESULT f_stat (
	const char *path,	/* Pointer to the file path */
	FILINFO *finfo		/* Pointer to file information to return */
)
{
	BYTE *dir;
	char fn[8+3+1];
	FRESULT res;
	DIR dirobj;


	if ((res = auto_mount(&path, 0)) != FR_OK)
		return res;
	res = trace_path(&dirobj, fn, path, &dir);	/* Trace the file path */

	if (res == FR_OK)							/* Trace completed */
		get_fileinfo(finfo, dir);

	return res;
}




#if _FS_READONLY == 0
/*-----------------------------------------------------------------------*/
/* Get Number of Free Clusters                                           */
/*-----------------------------------------------------------------------*/

FRESULT f_getfree (
	const char *drv,	/* Logical drive number */
	DWORD *nclust,		/* Pointer to the double word to return number of free clusters */
	FATFS **fatfs		/* Pointer to pointer to the file system object to return */
)
{
	DWORD n, sect;
	CLUST clust;
	BYTE fat, f, *p;
	FRESULT res;
	FATFS *fs;


	/* Get drive number */
	if ((res = auto_mount(&drv, 0)) != FR_OK)
		return res;
	*fatfs = fs = FatFs;

	/* Count number of free clusters */
	fat = fs->fs_type;
	n = 0;
	if (fat == FS_FAT12) {
		clust = 2;
		do {
			if ((WORD)get_cluster(clust) == 0) n++;
		} while (++clust < fs->max_clust);
	} else {
		clust = fs->max_clust;
		sect = fs->fatbase;
		f = 0; p = 0;
		do {
			if (!f) {
				if (!move_window(sect++)) return FR_RW_ERROR;
				p = fs->win;
			}
			if (_FAT32 == 0 || fat == FS_FAT16) {
				if (LD_WORD(p) == 0) n++;
				p += 2; f += 1;
			} else {
				if (LD_DWORD(p) == 0) n++;
				p += 4; f += 2;
			}
		} while (--clust);
	}

	*nclust = n;
	return FR_OK;
}




/*-----------------------------------------------------------------------*/
/* Delete a File or a Directory                                          */
/*-----------------------------------------------------------------------*/

FRESULT f_unlink (
	const char *path			/* Pointer to the file or directory path */
)
{
	BYTE *dir, *sdir;
	DWORD dsect;
	char fn[8+3+1];
	CLUST dclust;
	FRESULT res;
	DIR dirobj;
	FATFS *fs = FatFs;


	if ((res = auto_mount(&path, 1)) != FR_OK)
		return res;
	res = trace_path(&dirobj, fn, path, &dir);	/* Trace the file path */

	if (res != FR_OK) return res;				/* Trace failed */
	if (dir == NULL) return FR_NO_FILE;			/* It is a root directory */
	if (*(dir+11) & AM_RDO) return FR_DENIED;	/* It is a R/O item */
	dsect = fs->winsect;
#if _FAT32 != 0
	dclust = ((DWORD)LD_WORD(dir+20) << 16) | LD_WORD(dir+26);
#else
	dclust = LD_WORD(dir+26);
#endif
	if (*(dir+11) & AM_DIR) {					/* It is a sub-directory */
		dirobj.clust = dclust;					/* Check if the sub-dir is empty or not */
		dirobj.sect = clust2sect(dclust);
		dirobj.index = 0;
		do {
			if (!move_window(dirobj.sect)) return FR_RW_ERROR;
			sdir = &fs->win[(dirobj.index & 15) * 32];
			if (*sdir == 0) break;
			if (!(*sdir == 0xE5 || *sdir == '.') && !(*(sdir+11) & AM_VOL))
				return FR_DENIED;	/* The directory is not empty */
		} while (next_dir_entry(&dirobj));
	}

	if (!move_window(dsect)) return FR_RW_ERROR;	/* Mark the directory entry 'deleted' */
	*dir = 0xE5; 
	fs->winflag = 1;
	if (!remove_chain(dclust)) return FR_RW_ERROR;	/* Remove the cluster chain */
	if (!move_window(0)) return FR_RW_ERROR;

	return FR_OK;
}




/*-----------------------------------------------------------------------*/
/* Create a Directory                                                    */
/*-----------------------------------------------------------------------*/

FRESULT f_mkdir (
	const char *path		/* Pointer to the directory path */
)
{
	BYTE *dir, *w, n;
	char fn[8+3+1];
	DWORD sect, dsect, tim;
	CLUST dclust, pclust;
	FRESULT res;
	DIR dirobj;
	FATFS *fs = FatFs;


	if ((res = auto_mount(&path, 1)) != FR_OK)
		return res;
	res = trace_path(&dirobj, fn, path, &dir);	/* Trace the file path */

	if (res == FR_OK) return FR_DENIED;		/* Any file or directory is already existing */
	if (res != FR_NO_FILE) return res;

	dir = reserve_direntry(&dirobj);		/* Reserve a directory entry */
	if (dir == NULL) return FR_DENIED;
	sect = fs->winsect;
	dsect = clust2sect(dclust = create_chain(0));	/* Get a new cluster for new directory */
	if (!dsect) return FR_DENIED;
	if (!move_window(0)) return 0;

	w = fs->win;
	memset(w, 0, 512);						/* Initialize the directory table */
	for (n = fs->sects_clust - 1; n; n--) {
		if (disk_write(0, w, dsect+n, 1) != RES_OK)
			return FR_RW_ERROR;
	}

	fs->winsect = dsect;					/* Create dot directories */
	memset(w, ' ', 8+3);
	*w = '.'; *(w+11) = AM_DIR;
	tim = get_fattime(); ST_DWORD(w+22, tim);
	memcpy(w+32, w, 32); *(w+33) = '.';
	pclust = dirobj.sclust;
	ST_WORD(w+32+26, pclust);
	ST_WORD(w   +26, dclust);
#if _FAT32 != 0
	if (fs->fs_type == FS_FAT32 && pclust == fs->dirbase) pclust = 0;
	ST_WORD(w+32+20, pclust >> 16);
	ST_WORD(w   +20, dclust >> 16);
#endif
	fs->winflag = 1;

	if (!move_window(sect)) return FR_RW_ERROR;
	memcpy(dir, fn, 8+3);		/* Initialize the new entry */
	*(dir+11) = AM_DIR;
	*(dir+12) = fn[11];
	memset(dir+13, 0, 32-13);
	ST_DWORD(dir+22, tim);		/* Crated time */
	ST_WORD(dir+26, dclust);	/* Table start cluster */
#if _FAT32 != 0
	ST_WORD(dir+20, dclust >> 16);
#endif
	fs->winflag = 1;

	if (!move_window(0)) return FR_RW_ERROR;

	return FR_OK;
}




/*-----------------------------------------------------------------------*/
/* Change File Attribute                                                 */
/*-----------------------------------------------------------------------*/

FRESULT f_chmod (
	const char *path,	/* Pointer to the file path */
	BYTE value,			/* Attribute bits */
	BYTE mask			/* Attribute mask to change */
)
{
	FRESULT res;
	BYTE *dir;
	DIR dirobj;
	char fn[8+3+1];
	FATFS *fs = FatFs;


	if ((res = auto_mount(&path, 1)) != FR_OK)
		return res;
	res = trace_path(&dirobj, fn, path, &dir);	/* Trace the file path */

	if (res == FR_OK) {			/* Trace completed */
		if (dir == NULL) {
			res = FR_NO_FILE;
		} else {
			mask &= AM_RDO|AM_HID|AM_SYS|AM_ARC;	/* Valid attribute mask */
			*(dir+11) = (value & mask) | (*(dir+11) & ~mask);	/* Apply attribute change */
			fs->winflag = 1;
			if (!move_window(0)) res = FR_RW_ERROR;
		}
	}
	return res;
}




/*-----------------------------------------------------------------------*/
/* Rename File/Directory                                                 */
/*-----------------------------------------------------------------------*/

FRESULT f_rename (
	const char *path_old,	/* Pointer to the old name */
	const char *path_new	/* Pointer to the new name */
)
{
	FRESULT res;
	DWORD sect_old;
	BYTE *dir_old, *dir_new, direntry[32-11];
	DIR dirobj;
	char fn[8+3+1];
	FATFS *fs = FatFs;


	if ((res = auto_mount(&path_old, 1)) != FR_OK)
		return res;
	res = trace_path(&dirobj, fn, path_old, &dir_old);	/* Check old object */

	if (res != FR_OK) return res;			/* The old object is not found */
	if (!dir_old) return FR_NO_FILE;
	sect_old = fs->winsect;					/* Save the object information */
	memcpy(direntry, dir_old+11, 32-11);

	res = trace_path(&dirobj, fn, path_new, &dir_new);	/* Check new object */
	if (res == FR_OK) return FR_DENIED;		/* The new object name is already existing */
	if (res != FR_NO_FILE) return res;

	dir_new = reserve_direntry(&dirobj);	/* Reserve a directory entry */
	if (dir_new == NULL) return FR_DENIED;
	memcpy(dir_new+11, direntry, 32-11);	/* Create new entry */
	memcpy(dir_new, fn, 8+3);
	*(dir_new+12) = fn[11];
	fs->winflag = 1;

	if (!move_window(sect_old)) return FR_RW_ERROR;	/* Remove old entry */
	*dir_old = 0xE5;
	fs->winflag = 1;
	if (!move_window(0)) return FR_RW_ERROR;

	return FR_OK;
}

#endif /* _FS_READONLY */
#endif /* _FS_MINIMIZE == 0 */
#endif /* _FS_MINIMIZE <= 1 */