ff.c

stm32-SDIO+FatFS文件系统txt-int-ascii

const BYTE LfnOfs[] = {1,3,5,7,9,14,16,18,20,22,24,28,30};	/* Offset of LFN chars in the directory entry */


static
int cmp_lfn (			/* 1:Matched, 0:Not matched */
	WCHAR *lfnbuf,		/* Pointer to the LFN to be compared */
	BYTE *dir			/* Pointer to the directory entry containing a part of LFN */
)
{
	int i, s;
	WCHAR wc, uc;


	i = ((dir[LDIR_Ord] & 0xBF) - 1) * 13;	/* Get offset in the LFN buffer */
	s = 0; wc = 1;
	do {
		uc = LD_WORD(dir+LfnOfs[s]);	/* Pick an LFN character from the entry */
		if (wc) {	/* Last char has not been processed */
			wc = ff_wtoupper(uc);		/* Convert it to upper case */
			if (i >= _MAX_LFN || wc != ff_wtoupper(lfnbuf[i++]))	/* Compare it */
				return 0;				/* Not matched */
		} else {
			if (uc != 0xFFFF) return 0;	/* Check filler */
		}
	} while (++s < 13);				/* Repeat until all chars in the entry are checked */

	if ((dir[LDIR_Ord] & 0x40) && wc && lfnbuf[i])	/* Last segment matched but different length */
		return 0;

	return 1;						/* The part of LFN matched */
}



static
int pick_lfn (			/* 1:Succeeded, 0:Buffer overflow */
	WCHAR *lfnbuf,		/* Pointer to the Unicode-LFN buffer */
	BYTE *dir			/* Pointer to the directory entry */
)
{
	int i, s;
	WCHAR wc, uc;


	i = ((dir[LDIR_Ord] & 0x3F) - 1) * 13;	/* Offset in the LFN buffer */

	s = 0; wc = 1;
	do {
		uc = LD_WORD(dir+LfnOfs[s]);		/* Pick an LFN character from the entry */
		if (wc) {	/* Last char has not been processed */
			if (i >= _MAX_LFN) return 0;	/* Buffer overflow? */
			lfnbuf[i++] = wc = uc;			/* Store it */
		} else {
			if (uc != 0xFFFF) return 0;		/* Check filler */
		}
	} while (++s < 13);						/* Read all character in the entry */

	if (dir[LDIR_Ord] & 0x40) {				/* Put terminator if it is the last LFN part */
		if (i >= _MAX_LFN) return 0;		/* Buffer overflow? */
		lfnbuf[i] = 0;
	}

	return 1;
}


#if !_FS_READONLY
static
void fit_lfn (
	const WCHAR *lfnbuf,	/* Pointer to the LFN buffer */
	BYTE *dir,				/* Pointer to the directory entry */
	BYTE ord,				/* LFN order (1-20) */
	BYTE sum				/* SFN sum */
)
{
	int i, s;
	WCHAR wc;


	dir[LDIR_Chksum] = sum;			/* Set check sum */
	dir[LDIR_Attr] = AM_LFN;		/* Set attribute. LFN entry */
	dir[LDIR_Type] = 0;
	ST_WORD(dir+LDIR_FstClusLO, 0);

	i = (ord - 1) * 13;				/* Get offset in the LFN buffer */
	s = wc = 0;
	do {
		if (wc != 0xFFFF) wc = lfnbuf[i++];	/* Get an effective char */
		ST_WORD(dir+LfnOfs[s], wc);	/* Put it */
		if (!wc) wc = 0xFFFF;		/* Padding chars following last char */
	} while (++s < 13);
	if (wc == 0xFFFF || !lfnbuf[i]) ord |= 0x40;	/* Bottom LFN part is the start of LFN sequence */
	dir[LDIR_Ord] = ord;			/* Set the LFN order */
}

#endif
#endif



/*-----------------------------------------------------------------------*/
/* Create numbered name                                                  */
/*-----------------------------------------------------------------------*/
#if _USE_LFN
void gen_numname (
	BYTE *dst,			/* Pointer to generated SFN */
	const BYTE *src,	/* Pointer to source SFN to be modified */
	const WCHAR *lfn,	/* Pointer to LFN */
	WORD seq			/* Sequence number */
)
{
	BYTE ns[8], c;
	int i, j;


	mem_cpy(dst, src, 11);

	if (seq > 5) {	/* On many collisions, generate a hash number instead of sequential number */
		do seq = (seq >> 1) + (seq << 15) + (WORD)*lfn++; while (*lfn);
	}

	/* itoa */
	i = 7;
	do {
		c = (seq % 16) + '0';
		if (c > '9') c += 7;
		ns[i--] = c;
		seq /= 16;
	} while (seq);
	ns[i] = '~';

	/* Append the number */
	for (j = 0; j < i && dst[j] != ' '; j++) {
		if (IsDBCS1(dst[j])) {
			if (j == i - 1) break;
			j++;
		}
	}
	do {
		dst[j++] = (i < 8) ? ns[i++] : ' ';
	} while (j < 8);
}
#endif




/*-----------------------------------------------------------------------*/
/* Calculate sum of an SFN                                               */
/*-----------------------------------------------------------------------*/
#if _USE_LFN
static
BYTE sum_sfn (
	const BYTE *dir		/* Ptr to directory entry */
)
{
	BYTE sum = 0;
	int n = 11;

	do sum = (sum >> 1) + (sum << 7) + *dir++; while (--n);
	return sum;
}
#endif




/*-----------------------------------------------------------------------*/
/* Directory handling - Find an object in the directory                  */
/*-----------------------------------------------------------------------*/

static
FRESULT dir_find (
	DIR *dj			/* Pointer to the directory object linked to the file name */
)
{
	FRESULT res;
	BYTE c, *dir;
#if _USE_LFN
	BYTE a, ord, sum;
#endif

	res = dir_sdi(dj, 0);			/* Rewind directory object */
	if (res != FR_OK) return res;

#if _USE_LFN
	ord = sum = 0xFF;
#endif
	do {
		res = move_window(dj->fs, dj->sect);
		if (res != FR_OK) break;
		dir = dj->dir;					/* Ptr to the directory entry of current index */
		c = dir[DIR_Name];
		if (c == 0) { res = FR_NO_FILE; break; }	/* Reached to end of table */
#if _USE_LFN	/* LFN configuration */
		a = dir[DIR_Attr] & AM_MASK;
		if (c == 0xE5 || ((a & AM_VOL) && a != AM_LFN)) {	/* An entry without valid data */
			ord = 0xFF;
		} else {
			if (a == AM_LFN) {			/* An LFN entry is found */
				if (dj->lfn) {
					if (c & 0x40) {		/* Is it start of LFN sequence? */
						sum = dir[LDIR_Chksum];
						c &= 0xBF; ord = c;	/* LFN start order */
						dj->lfn_idx = dj->index;
					}
					/* Check validity of the LFN entry and compare it with given name */
					ord = (c == ord && sum == dir[LDIR_Chksum] && cmp_lfn(dj->lfn, dir)) ? ord - 1 : 0xFF;
				}
			} else {					/* An SFN entry is found */
				if (!ord && sum == sum_sfn(dir)) break;	/* LFN matched? */
				ord = 0xFF; dj->lfn_idx = 0xFFFF;	/* Reset LFN sequence */
				if (!(dj->fn[NS] & NS_LOSS) && !mem_cmp(dir, dj->fn, 11)) break;	/* SFN matched? */
			}
		}
#else		/* Non LFN configuration */
		if (!(dir[DIR_Attr] & AM_VOL) && !mem_cmp(dir, dj->fn, 11)) /* Is it a valid entry? */
			break;
#endif
		res = dir_next(dj, 0);		/* Next entry */
	} while (res == FR_OK);

	return res;
}




/*-----------------------------------------------------------------------*/
/* Read an object from the directory                                     */
/*-----------------------------------------------------------------------*/
#if _FS_MINIMIZE <= 1
static
FRESULT dir_read (
	DIR *dj			/* Pointer to the directory object that pointing the entry to be read */
)
{
	FRESULT res;
	BYTE c, *dir;
#if _USE_LFN
	BYTE a, ord = 0xFF, sum = 0xFF;
#endif

	res = FR_NO_FILE;
	while (dj->sect) {
		res = move_window(dj->fs, dj->sect);
		if (res != FR_OK) break;
		dir = dj->dir;					/* Ptr to the directory entry of current index */
		c = dir[DIR_Name];
		if (c == 0) { res = FR_NO_FILE; break; }	/* Reached to end of table */
#if _USE_LFN	/* LFN configuration */
		a = dir[DIR_Attr] & AM_MASK;
		if (c == 0xE5 || (!_FS_RPATH && c == '.') || ((a & AM_VOL) && a != AM_LFN)) {	/* An entry without valid data */
			ord = 0xFF;
		} else {
			if (a == AM_LFN) {			/* An LFN entry is found */
				if (c & 0x40) {			/* Is it start of LFN sequence? */
					sum = dir[LDIR_Chksum];
					c &= 0xBF; ord = c;
					dj->lfn_idx = dj->index;
				}
				/* Check LFN validity and capture it */
				ord = (c == ord && sum == dir[LDIR_Chksum] && pick_lfn(dj->lfn, dir)) ? ord - 1 : 0xFF;
			} else {					/* An SFN entry is found */
				if (ord || sum != sum_sfn(dir))	/* Is there a valid LFN? */
					dj->lfn_idx = 0xFFFF;		/* It has no LFN. */
				break;
			}
		}
#else		/* Non LFN configuration */
		if (c != 0xE5 && (_FS_RPATH || c != '.') && !(dir[DIR_Attr] & AM_VOL))	/* Is it a valid entry? */
			break;
#endif
		res = dir_next(dj, 0);				/* Next entry */
		if (res != FR_OK) break;
	}

	if (res != FR_OK) dj->sect = 0;

	return res;
}
#endif



/*-----------------------------------------------------------------------*/
/* Register an object to the directory                                   */
/*-----------------------------------------------------------------------*/
#if !_FS_READONLY
static
FRESULT dir_register (	/* FR_OK:Successful, FR_DENIED:No free entry or too many SFN collision, FR_DISK_ERR:Disk error */
	DIR *dj				/* Target directory with object name to be created */
)
{
	FRESULT res;
	BYTE c, *dir;
#if _USE_LFN	/* LFN configuration */
	WORD n, ne, is;
	BYTE sn[12], *fn, sum;
	WCHAR *lfn;


	fn = dj->fn; lfn = dj->lfn;
	mem_cpy(sn, fn, 12);

	if (_FS_RPATH && (sn[NS] & NS_DOT)) return FR_INVALID_NAME;	/* Cannot create dot entry */

	if (sn[NS] & NS_LOSS) {			/* When LFN is out of 8.3 format, generate a numbered name */
		fn[NS] = 0; dj->lfn = 0;			/* Find only SFN */
		for (n = 1; n < 100; n++) {
			gen_numname(fn, sn, lfn, n);	/* Generate a numbered name */
			res = dir_find(dj);				/* Check if the name collides with existing SFN */
			if (res != FR_OK) break;
		}
		if (n == 100) return FR_DENIED;		/* Abort if too many collisions */
		if (res != FR_NO_FILE) return res;	/* Abort if the result is other than 'not collided' */
		fn[NS] = sn[NS]; dj->lfn = lfn;
	}

	if (sn[NS] & NS_LFN) {			/* When LFN is to be created, reserve an SFN + LFN entries. */
		for (ne = 0; lfn[ne]; ne++) ;
		ne = (ne + 25) / 13;
	} else {						/* Otherwise reserve only an SFN entry. */
		ne = 1;
	}

	/* Reserve contiguous entries */
	res = dir_sdi(dj, 0);
	if (res != FR_OK) return res;
	n = is = 0;
	do {
		res = move_window(dj->fs, dj->sect);
		if (res != FR_OK) break;
		c = *dj->dir;				/* Check the entry status */
		if (c == 0xE5 || c == 0) {	/* Is it a blank entry? */
			if (n == 0) is = dj->index;	/* First index of the contiguous entry */
			if (++n == ne) break;	/* A contiguous entry that required count is found */
		} else {
			n = 0;					/* Not a blank entry. Restart to search */
		}
		res = dir_next(dj, 1);		/* Next entry with table stretch */
	} while (res == FR_OK);

	if (res == FR_OK && ne > 1) {	/* Initialize LFN entry if needed */
		res = dir_sdi(dj, is);
		if (res == FR_OK) {
			sum = sum_sfn(dj->fn);	/* Sum of the SFN tied to the LFN */
			ne--;
			do {					/* Store LFN entries in bottom first */
				res = move_window(dj->fs, dj->sect);
				if (res != FR_OK) break;
				fit_lfn(dj->lfn, dj->dir, (BYTE)ne, sum);
				dj->fs->wflag = 1;
				res = dir_next(dj, 0);	/* Next entry */
			} while (res == FR_OK && --ne);
		}
	}

#else	/* Non LFN configuration */
	res = dir_sdi(dj, 0);
	if (res == FR_OK) {
		do {	/* Find a blank entry for the SFN */
			res = move_window(dj->fs, dj->sect);
			if (res != FR_OK) break;
			c = *dj->dir;
			if (c == 0xE5 || c == 0) break;	/* Is it a blank entry? */
			res = dir_next(dj, 1);			/* Next entry with table stretch */
		} while (res == FR_OK);
	}
#endif

	if (res == FR_OK) {		/* Initialize the SFN entry */
		res = move_window(dj->fs, dj->sect);
		if (res == FR_OK) {
			dir = dj->dir;
			mem_set(dir, 0, 32);		/* Clean the entry */
			mem_cpy(dir, dj->fn, 11);	/* Put SFN */
#if _USE_LFN
			dir[DIR_NTres] = *(dj->fn+NS) & (NS_BODY | NS_EXT);	/* Put NT flag */
#endif
			dj->fs->wflag = 1;
		}
	}

	return res;
}
#endif /* !_FS_READONLY */




/*-----------------------------------------------------------------------*/
/* Remove an object from the directory                                   */
/*-----------------------------------------------------------------------*/
#if !_FS_READONLY && !_FS_MINIMIZE
static
FRESULT dir_remove (	/* FR_OK: Successful, FR_DISK_ERR: A disk error */
	DIR *dj				/* Directory object pointing the entry to be removed */
)
{
	FRESULT res;
#if _USE_LFN	/* LFN configuration */
	WORD i;

	i = dj->index;	/* SFN index */
	res = dir_sdi(dj, (WORD)((dj->lfn_idx == 0xFFFF) ? i : dj->lfn_idx));	/* Goto the SFN or top of the LFN entries */
	if (res == FR_OK) {
		do {
			res = move_window(dj->fs, dj->sect);
			if (res != FR_OK) break;
			*dj->dir = 0xE5;			/* Mark the entry "deleted" */
			dj->fs->wflag = 1;
			if (dj->index >= i) break;	/* When reached SFN, all entries of the object has been deleted. */