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One additional optimization to the routine just committed, which 

avoids pushing space tiles and processing them just so it can pop
them off the stack and deallocate the memory.
This commit is contained in:
Tim Edwards 2021-12-31 22:25:22 -05:00
parent f81560557b
commit abc4b263a5
1 changed files with 31 additions and 10 deletions
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41
select/selOps.c
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@ -682,10 +682,19 @@ selShortFindNext(tile, pnum, ldest, mask)
else if (!SplitDirection(tile) && fdir == GEO_WEST) goto srchleft;
}
/* As a small optimization, check for space tiles and avoid going
* through the hoops of allocating a structure and pushing it on the
* stack. This check is not rigorous, but it saves time for the
* most common case.
*/
for (tp = RT(tile); RIGHT(tp) > LEFT(tile); tp = BL(tp))
{
sd = NewSD(cost + 1, tp, pnum, GEO_NORTH, lmask);
STACKPUSH(sd, ShortStack);
if (TiGetTypeExact(tp) != TT_SPACE)
{
sd = NewSD(cost + 1, tp, pnum, GEO_NORTH, lmask);
STACKPUSH(sd, ShortStack);
}
}
/* Search left */
@ -699,8 +708,11 @@ srchleft:
for (tp = BL(tile); BOTTOM(tp) < TOP(tile); tp = RT(tp))
{
sd = NewSD(cost + 1, tp, pnum, GEO_WEST, lmask);
STACKPUSH(sd, ShortStack);
if (TiGetTypeExact(tp) != TT_SPACE)
{
sd = NewSD(cost + 1, tp, pnum, GEO_WEST, lmask);
STACKPUSH(sd, ShortStack);
}
}
/* Search bottom */
@ -714,8 +726,11 @@ srchbot:
for (tp = LB(tile); LEFT(tp) < RIGHT(tile); tp = TR(tp))
{
sd = NewSD(cost + 1, tp, pnum, GEO_SOUTH, lmask);
STACKPUSH(sd, ShortStack);
if (TiGetTypeExact(tp) != TT_SPACE)
{
sd = NewSD(cost + 1, tp, pnum, GEO_SOUTH, lmask);
STACKPUSH(sd, ShortStack);
}
}
/* Search right */
@ -729,8 +744,11 @@ srchright:
for (tp = TR(tile); TOP(tp) > BOTTOM(tile); tp = LB(tp))
{
sd = NewSD(cost + 1, tp, pnum, GEO_EAST, lmask);
STACKPUSH(sd, ShortStack);
if (TiGetTypeExact(tp) != TT_SPACE)
{
sd = NewSD(cost + 1, tp, pnum, GEO_EAST, lmask);
STACKPUSH(sd, ShortStack);
}
}
/* Search other connecting planes */
@ -747,8 +765,11 @@ donesrch:
{
tp = SelectDef->cd_planes[p]->pl_hint;
GOTOPOINT(tp, &tile->ti_ll);
sd = NewSD(cost + 1, tp, p, GEO_CENTER, lmask);
STACKPUSH(sd, ShortStack);
if (TiGetTypeExact(tp) != TT_SPACE)
{
sd = NewSD(cost + 1, tp, p, GEO_CENTER, lmask);
STACKPUSH(sd, ShortStack);
}
}
}
}