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Add in place union

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This commit is contained in:
Richard Artoul 2018-11-28 14:46:15 -05:00
parent 82a9ef2059
commit b77c8a630b
1 changed files with 19 additions and 5 deletions
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24
roaring/roaring.go
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@ -396,9 +396,24 @@ func (b *Bitmap) Intersect(other *Bitmap) *Bitmap {
}
// Union returns the bitwise union of b and other.
func (b *Bitmap) Union(other *Bitmap) *Bitmap {
func (b *Bitmap) Union(others ...*Bitmap) *Bitmap {
output := NewBitmap()
output.UnionInPlace(others...)
return output
}
// UnionInPlace returns the bitwise union of b and other, modifying
// b in place.
func (b *Bitmap) UnionInPlace(others ...*Bitmap) {
for _, other := range others {
b.unionIntoTarget(other, b)
}
}
// unionIntoTarget stores the union of b and other into target. b and other will
// be left unchanged, but target will be modified in place. Used to share
// the union logic between the copy-on-write and in-place functions.
func (b *Bitmap) unionIntoTarget(other *Bitmap, target *Bitmap) {
iiter, _ := b.Containers.Iterator(0)
jiter, _ := other.Containers.Iterator(0)
i, j := iiter.Next(), jiter.Next()
@ -406,21 +421,20 @@ func (b *Bitmap) Union(other *Bitmap) *Bitmap {
kj, cj := jiter.Value()
for i || j {
if i && (!j || ki < kj) {
output.Containers.Put(ki, ci.Clone())
target.Containers.Put(ki, ci.Clone())
i = iiter.Next()
ki, ci = iiter.Value()
} else if j && (!i || ki > kj) {
output.Containers.Put(kj, cj.Clone())
target.Containers.Put(kj, cj.Clone())
j = jiter.Next()
kj, cj = jiter.Value()
} else { // ki == kj
output.Containers.Put(ki, union(ci, cj))
target.Containers.Put(ki, union(ci, cj))
i, j = iiter.Next(), jiter.Next()
ki, ci = iiter.Value()
kj, cj = jiter.Value()
}
}
return output
}
// Difference returns the difference of b and other.