/*
* get_refcount_el() --- given an block number, try to find refcount
* information in the sorted list. If the create flag is set,
* and we can't find an entry, create one in the sorted list.
*/
static struct ea_refcount_el *get_refcount_el(ext2_refcount_t refcount,
ea_key_t ea_key, int create)
{
int low, high, mid;
if (!refcount || !refcount->list)
return 0;
retry:
low = 0;
high = (int) refcount->count-1;
if (create && ((refcount->count == 0) ||
(ea_key > refcount->list[high].ea_key))) {
if (refcount->count >= refcount->size)
refcount_collapse(refcount);
return insert_refcount_el(refcount, ea_key,
(unsigned) refcount->count);
}
if (refcount->count == 0)
return 0;
if (refcount->cursor >= refcount->count)
refcount->cursor = 0;
if (ea_key == refcount->list[refcount->cursor].ea_key)
return &refcount->list[refcount->cursor++];
#ifdef DEBUG
printf("Non-cursor get_refcount_el: %u\n", ea_key);
#endif
while (low <= high) {
mid = (low+high)/2;
if (ea_key == refcount->list[mid].ea_key) {
refcount->cursor = mid+1;
return &refcount->list[mid];
}
if (ea_key < refcount->list[mid].ea_key)
high = mid-1;
else
low = mid+1;
}
/*
* If we need to create a new entry, it should be right at
* low (where high will be left at low-1).
*/
if (create) {
if (refcount->count >= refcount->size) {
refcount_collapse(refcount);
if (refcount->count < refcount->size)
goto retry;
}
return insert_refcount_el(refcount, ea_key, low);
}
return 0;
}
static struct ea_refcount_el *get_refcount_el(ext2_refcount_t refcount,
blk_t blk, int create)
{
float range;
int low, high, mid;
blk_t lowval, highval;
if (!refcount || !refcount->list)
return 0;
retry:
low = 0;
high = (int) refcount->count-1;
if (create && ((refcount->count == 0) ||
(blk > refcount->list[high].ea_blk))) {
if (refcount->count >= refcount->size)
refcount_collapse(refcount);
return insert_refcount_el(refcount, blk,
(unsigned) refcount->count);
}
if (refcount->count == 0)
return 0;
if (refcount->cursor >= refcount->count)
refcount->cursor = 0;
if (blk == refcount->list[refcount->cursor].ea_blk)
return &refcount->list[refcount->cursor++];
#ifdef DEBUG
printf("Non-cursor get_refcount_el: %u\n", blk);
#endif
while (low <= high) {
#if 0
mid = (low+high)/2;
#else
if (low == high)
mid = low;
else {
/* Interpolate for efficiency */
lowval = refcount->list[low].ea_blk;
highval = refcount->list[high].ea_blk;
if (blk < lowval)
range = 0;
else if (blk > highval)
range = 1;
else
range = ((float) (blk - lowval)) /
(highval - lowval);
mid = low + ((int) (range * (high-low)));
}
#endif
if (blk == refcount->list[mid].ea_blk) {
refcount->cursor = mid+1;
return &refcount->list[mid];
}
if (blk < refcount->list[mid].ea_blk)
high = mid-1;
else
low = mid+1;
}
/*
* If we need to create a new entry, it should be right at
* low (where high will be left at low-1).
*/
if (create) {
if (refcount->count >= refcount->size) {
refcount_collapse(refcount);
if (refcount->count < refcount->size)
goto retry;
}
return insert_refcount_el(refcount, blk, low);
}
return 0;
}
