ff.c

stm32 红外万年历

/*-----------------------------------------------------------------------*/
/* FAT handling - Convert offset into cluster with link map table        */
/*-----------------------------------------------------------------------*/

#if _USE_FASTSEEK
static
DWORD clmt_clust (	/* <2:Error, >=2:Cluster number */
	FIL* fp,		/* Pointer to the file object */
	DWORD ofs		/* File offset to be converted to cluster# */
)
{
	DWORD cl, ncl, *tbl;


	tbl = fp->cltbl + 1;	/* Top of CLMT */
	cl = ofs / SS(fp->fs) / fp->fs->csize;	/* Cluster order from top of the file */
	for (;;) {
		ncl = *tbl++;			/* Number of cluters in the fragment */
		if (!ncl) return 0;		/* End of table? (error) */
		if (cl < ncl) break;	/* In this fragment? */
		cl -= ncl; tbl++;		/* Next fragment */
	}
	return cl + *tbl;	/* Return the cluster number */
}
#endif	/* _USE_FASTSEEK */



/*-----------------------------------------------------------------------*/
/* Directory handling - Set directory index                              */
/*-----------------------------------------------------------------------*/

static
FRESULT dir_sdi (
	DIR *dj,		/* Pointer to directory object */
	WORD idx		/* Directory index number */
)
{
	DWORD clst;
	WORD ic;


	dj->index = idx;
	clst = dj->sclust;
	if (clst == 1 || clst >= dj->fs->n_fatent)	/* Check start cluster range */
		return FR_INT_ERR;
	if (!clst && dj->fs->fs_type == FS_FAT32)	/* Replace cluster# 0 with root cluster# if in FAT32 */
		clst = dj->fs->dirbase;

	if (clst == 0) {	/* Static table (root-dir in FAT12/16) */
		dj->clust = clst;
		if (idx >= dj->fs->n_rootdir)		/* Index is out of range */
			return FR_INT_ERR;
		dj->sect = dj->fs->dirbase + idx / (SS(dj->fs) / SZ_DIR);	/* Sector# */
	}
	else {				/* Dynamic table (sub-dirs or root-dir in FAT32) */
		ic = SS(dj->fs) / SZ_DIR * dj->fs->csize;	/* Entries per cluster */
		while (idx >= ic) {	/* Follow cluster chain */
			clst = get_fat(dj->fs, clst);				/* Get next cluster */
			if (clst == 0xFFFFFFFF) return FR_DISK_ERR;	/* Disk error */
			if (clst < 2 || clst >= dj->fs->n_fatent)	/* Reached to end of table or int error */
				return FR_INT_ERR;
			idx -= ic;
		}
		dj->clust = clst;
		dj->sect = clust2sect(dj->fs, clst) + idx / (SS(dj->fs) / SZ_DIR);	/* Sector# */
	}

	dj->dir = dj->fs->win + (idx % (SS(dj->fs) / SZ_DIR)) * SZ_DIR;	/* Ptr to the entry in the sector */

	return FR_OK;	/* Seek succeeded */
}




/*-----------------------------------------------------------------------*/
/* Directory handling - Move directory index next                        */
/*-----------------------------------------------------------------------*/

static
FRESULT dir_next (	/* FR_OK:Succeeded, FR_NO_FILE:End of table, FR_DENIED:EOT and could not stretch */
	DIR *dj,		/* Pointer to directory object */
	int stretch		/* 0: Do not stretch table, 1: Stretch table if needed */
)
{
	DWORD clst;
	WORD i;


	i = dj->index + 1;
	if (!i || !dj->sect)	/* Report EOT when index has reached 65535 */
		return FR_NO_FILE;

	if (!(i % (SS(dj->fs) / SZ_DIR))) {	/* Sector changed? */
		dj->sect++;					/* Next sector */

		if (dj->clust == 0) {	/* Static table */
			if (i >= dj->fs->n_rootdir)	/* Report EOT when end of table */
				return FR_NO_FILE;
		}
		else {					/* Dynamic table */
			if (((i / (SS(dj->fs) / SZ_DIR)) & (dj->fs->csize - 1)) == 0) {	/* Cluster changed? */
				clst = get_fat(dj->fs, dj->clust);				/* Get next cluster */
				if (clst <= 1) return FR_INT_ERR;
				if (clst == 0xFFFFFFFF) return FR_DISK_ERR;
				if (clst >= dj->fs->n_fatent) {					/* When it reached end of dynamic table */
#if !_FS_READONLY
					BYTE c;
					if (!stretch) return FR_NO_FILE;			/* When do not stretch, report EOT */
					clst = create_chain(dj->fs, dj->clust);		/* Stretch cluster chain */
					if (clst == 0) return FR_DENIED;			/* No free cluster */
					if (clst == 1) return FR_INT_ERR;
					if (clst == 0xFFFFFFFF) return FR_DISK_ERR;
					/* Clean-up stretched table */
					if (move_window(dj->fs, 0)) return FR_DISK_ERR;	/* Flush active window */
					mem_set(dj->fs->win, 0, SS(dj->fs));			/* Clear window buffer */
					dj->fs->winsect = clust2sect(dj->fs, clst);	/* Cluster start sector */
					for (c = 0; c < dj->fs->csize; c++) {		/* Fill the new cluster with 0 */
						dj->fs->wflag = 1;
						if (move_window(dj->fs, 0)) return FR_DISK_ERR;
						dj->fs->winsect++;
					}
					dj->fs->winsect -= c;						/* Rewind window address */
#else
					return FR_NO_FILE;			/* Report EOT */
#endif
				}
				dj->clust = clst;				/* Initialize data for new cluster */
				dj->sect = clust2sect(dj->fs, clst);
			}
		}
	}

	dj->index = i;
	dj->dir = dj->fs->win + (i % (SS(dj->fs) / SZ_DIR)) * SZ_DIR;

	return FR_OK;
}




/*-----------------------------------------------------------------------*/
/* LFN handling - Test/Pick/Fit an LFN segment from/to directory entry   */
/*-----------------------------------------------------------------------*/
#if _USE_LFN
static
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 */
)
{
	UINT i, s;
	WCHAR wc, uc;


	i = ((dir[LDIR_Ord] & ~LLE) - 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] & LLE) && 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 */
)
{
	UINT 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] & LLE) {				/* 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 */
)
{
	UINT 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 |= LLE;	/* 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;
	UINT 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 (hexdecimal) */
	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;
	UINT 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;