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Inlined much of getFATblock() into link_fat. Saves the idx reference. 

The second call (for a FAT12 entry that is divided in two sectors)
can be much simpler, no need to recalculate.


git-svn-id: https://svn.code.sf.net/p/freedos/svn/kernel/trunk@907 6ac86273-5f31-0410-b378-82cca8765d1b
This commit is contained in:
Bart Oldeman 2004-04-30 14:05:14 +00:00
parent bfe9252c2b
commit 126ef5cec9
1 changed files with 53 additions and 55 deletions
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108
kernel/fattab.c
View File

@ -51,60 +51,9 @@ int ISFAT32(struct dpb FAR * dpbp)
} }
#endif #endif
/* idx is a pointer to an index which is the nibble offset of the FAT struct buffer FAR *getFATblock(struct dpb FAR * dpbp, CLUSTER clussec)
entry within the sector for FAT12, or word offset for FAT16, or
dword offset for FAT32 */
struct buffer FAR *getFATblock(CLUSTER clussec, struct dpb FAR * dpbp,
unsigned *idx)
{ {
unsigned secdiv; struct buffer FAR *bp = getblock(clussec, dpbp->dpb_unit);
struct buffer FAR *bp;
CLUSTER max_cluster = dpbp->dpb_size;
#ifdef WITHFAT32
if (ISFAT32(dpbp))
max_cluster = dpbp->dpb_xsize;
#endif
if (clussec <= 1 || clussec > max_cluster)
{
put_string("run CHKDSK: trying to access invalid cluster 0x");
#ifdef WITHFAT32
put_unsigned((unsigned)(clussec >> 16), 16, 4);
#endif
put_unsigned((unsigned)(clussec & 0xffffu), 16, 4);
put_console('\n');
return NULL;
}
secdiv = dpbp->dpb_secsize;
if (ISFAT12(dpbp))
{
clussec = (unsigned)clussec * 3;
secdiv *= 2;
}
else /* FAT16 or FAT32 */
{
secdiv /= 2;
#ifdef WITHFAT32
if (ISFAT32(dpbp))
secdiv /= 2;
#endif
}
if (idx)
*idx = (unsigned)(clussec % secdiv);
clussec /= secdiv;
clussec += dpbp->dpb_fatstrt;
#ifdef WITHFAT32
if (ISFAT32(dpbp) && (dpbp->dpb_xflags & FAT_NO_MIRRORING))
{
/* we must modify the active fat,
it's number is in the 0-3 bits of dpb_xflags */
clussec += (dpbp->dpb_xflags & 0xf) * dpbp->dpb_xfatsize;
}
#endif
bp = getblock(clussec, dpbp->dpb_unit);
if (bp) if (bp)
{ {
@ -175,9 +124,58 @@ CLUSTER link_fat(struct dpb FAR * dpbp, CLUSTER Cluster1,
{ {
struct buffer FAR *bp; struct buffer FAR *bp;
unsigned idx; unsigned idx;
unsigned secdiv;
CLUSTER clussec = Cluster1;
CLUSTER max_cluster = dpbp->dpb_size;
#ifdef WITHFAT32
if (ISFAT32(dpbp))
max_cluster = dpbp->dpb_xsize;
#endif
if (clussec <= 1 || clussec > max_cluster)
{
put_string("run CHKDSK: trying to access invalid cluster 0x");
#ifdef WITHFAT32
put_unsigned((unsigned)(clussec >> 16), 16, 4);
#endif
put_unsigned((unsigned)(clussec & 0xffffu), 16, 4);
put_console('\n');
return NULL;
}
secdiv = dpbp->dpb_secsize;
if (ISFAT12(dpbp))
{
clussec = (unsigned)clussec * 3;
secdiv *= 2;
}
else /* FAT16 or FAT32 */
{
secdiv /= 2;
#ifdef WITHFAT32
if (ISFAT32(dpbp))
secdiv /= 2;
#endif
}
/* idx is a pointer to an index which is the nibble offset of the FAT
entry within the sector for FAT12, or word offset for FAT16, or
dword offset for FAT32 */
idx = (unsigned)(clussec % secdiv);
clussec /= secdiv;
clussec += dpbp->dpb_fatstrt;
#ifdef WITHFAT32
if (ISFAT32(dpbp) && (dpbp->dpb_xflags & FAT_NO_MIRRORING))
{
/* we must modify the active fat,
it's number is in the 0-3 bits of dpb_xflags */
clussec += (dpbp->dpb_xflags & 0xf) * dpbp->dpb_xfatsize;
}
#endif
/* Get the block that this cluster is in */ /* Get the block that this cluster is in */
bp = getFATblock(Cluster1, dpbp, &idx); bp = getFATblock(dpbp, clussec);
if (bp == NULL) if (bp == NULL)
return 1; /* the only error code possible here */ return 1; /* the only error code possible here */
@ -208,7 +206,7 @@ CLUSTER link_fat(struct dpb FAR * dpbp, CLUSTER Cluster1,
if (idx >= (unsigned)dpbp->dpb_secsize - 1) if (idx >= (unsigned)dpbp->dpb_secsize - 1)
{ {
bp1 = getFATblock((unsigned)Cluster1 + 1, dpbp, NULL); bp1 = getFATblock(dpbp, (unsigned)clussec + 1);
if (bp1 == 0) if (bp1 == 0)
return 1; /* the only error code possible here */ return 1; /* the only error code possible here */