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Try to call Less() fewer times when iterating #49

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Try to call Less() fewer times when iterating #49

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47669d1
cache stopindex to avoid much less fucntion call
a180285 Dec 31, 2022
b79fb31
Remove test code
a180285 Dec 31, 2022
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26 changes: 19 additions & 7 deletions btree.go
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Original file line number Diff line number Diff line change
Expand Up @@ -504,13 +504,18 @@ const (
// "greaterThan" or "lessThan" queries.
func (n *node) iterate(dir direction, start, stop Item, includeStart bool, hit bool, iter ItemIterator) (bool, bool) {
var ok, found bool
var index int
var index, stopIndex int
switch dir {
case ascend:
if start != nil {
index, _ = n.items.find(start)
}
for i := index; i < len(n.items); i++ {
if stop != nil {
stopIndex, _ = n.items.find(stop)
} else {
stopIndex = len(n.items)
}
for i := index; i < stopIndex; i++ {
if len(n.children) > 0 {
if hit, ok = n.children[i].iterate(dir, start, stop, includeStart, hit, iter); !ok {
return hit, false
Expand All @@ -521,15 +526,12 @@ func (n *node) iterate(dir direction, start, stop Item, includeStart bool, hit b
continue
}
hit = true
if stop != nil && !n.items[i].Less(stop) {
return hit, false
}
if !iter(n.items[i]) {
return hit, false
}
}
if len(n.children) > 0 {
if hit, ok = n.children[len(n.children)-1].iterate(dir, start, stop, includeStart, hit, iter); !ok {
if hit, ok = n.children[stopIndex].iterate(dir, start, stop, includeStart, hit, iter); !ok {
return hit, false
}
}
Expand All @@ -542,6 +544,16 @@ func (n *node) iterate(dir direction, start, stop Item, includeStart bool, hit b
} else {
index = len(n.items) - 1
}

if stop != nil {
stopIndex, found = n.items.find(stop)
if found {
stopIndex += 1
}
} else {
stopIndex = 0
}

for i := index; i >= 0; i-- {
if start != nil && !n.items[i].Less(start) {
if !includeStart || hit || start.Less(n.items[i]) {
Expand All @@ -562,7 +574,7 @@ func (n *node) iterate(dir direction, start, stop Item, includeStart bool, hit b
}
}
if len(n.children) > 0 {
if hit, ok = n.children[0].iterate(dir, start, stop, includeStart, hit, iter); !ok {
if hit, ok = n.children[stopIndex].iterate(dir, start, stop, includeStart, hit, iter); !ok {
return hit, false
}
}
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29 changes: 18 additions & 11 deletions btree_generic.go
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Original file line number Diff line number Diff line change
Expand Up @@ -499,13 +499,18 @@ func empty[T any]() optionalItem[T] {
// "greaterThan" or "lessThan" queries.
func (n *node[T]) iterate(dir direction, start, stop optionalItem[T], includeStart bool, hit bool, iter ItemIteratorG[T]) (bool, bool) {
var ok, found bool
var index int
var index, stopIndex int
switch dir {
case ascend:
if start.valid {
index, _ = n.items.find(start.item, n.cow.less)
}
for i := index; i < len(n.items); i++ {
if stop.valid {
stopIndex, _ = n.items.find(stop.item, n.cow.less)
} else {
stopIndex = len(n.items)
}
for i := index; i < stopIndex; i++ {
if len(n.children) > 0 {
if hit, ok = n.children[i].iterate(dir, start, stop, includeStart, hit, iter); !ok {
return hit, false
Expand All @@ -516,15 +521,12 @@ func (n *node[T]) iterate(dir direction, start, stop optionalItem[T], includeSta
continue
}
hit = true
if stop.valid && !n.cow.less(n.items[i], stop.item) {
return hit, false
}
if !iter(n.items[i]) {
return hit, false
}
}
if len(n.children) > 0 {
if hit, ok = n.children[len(n.children)-1].iterate(dir, start, stop, includeStart, hit, iter); !ok {
if hit, ok = n.children[stopIndex].iterate(dir, start, stop, includeStart, hit, iter); !ok {
return hit, false
}
}
Expand All @@ -537,7 +539,15 @@ func (n *node[T]) iterate(dir direction, start, stop optionalItem[T], includeSta
} else {
index = len(n.items) - 1
}
for i := index; i >= 0; i-- {
if stop.valid {
stopIndex, found = n.items.find(stop.item, n.cow.less)
if found {
stopIndex += 1
}
} else {
stopIndex = 0
}
for i := index; i >= stopIndex; i-- {
if start.valid && !n.cow.less(n.items[i], start.item) {
if !includeStart || hit || n.cow.less(start.item, n.items[i]) {
continue
Expand All @@ -548,16 +558,13 @@ func (n *node[T]) iterate(dir direction, start, stop optionalItem[T], includeSta
return hit, false
}
}
if stop.valid && !n.cow.less(stop.item, n.items[i]) {
return hit, false // continue
}
hit = true
if !iter(n.items[i]) {
return hit, false
}
}
if len(n.children) > 0 {
if hit, ok = n.children[0].iterate(dir, start, stop, includeStart, hit, iter); !ok {
if hit, ok = n.children[stopIndex].iterate(dir, start, stop, includeStart, hit, iter); !ok {
return hit, false
}
}
Expand Down