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micro optimization to bitmap difference

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Todd Gruben 2017-09-18 10:30:19 -05:00 • committed by Travis
parent 50dab75c82
commit 3f3cc60531
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2 changed files with 21 additions and 10 deletions
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21
roaring/roaring.go
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@ -422,24 +422,25 @@ func (b *Bitmap) Difference(other *Bitmap) *Bitmap {
ki, ci := b.keys, b.containers
kj, cj := other.keys, other.containers
ni, nj := len(ki), len(kj)
i, j := 0, 0
for {
var key uint64
var container *container
ni, nj := len(ki), len(kj)
if ni == 0 { // eof(i)
if ni == i { // eof(i)
break
} else if nj == 0 || ki[0] < kj[0] { // eof(j) or i < j
key, container = ki[0], ci[0].clone()
ki, ci = ki[1:], ci[1:]
} else if nj == j || ki[i] < kj[j] { // eof(j) or i < j
key, container = ki[i], ci[i].clone()
i++
output.keys = append(output.keys, key)
output.containers = append(output.containers, container)
} else if nj > 0 && ki[0] > kj[0] { // i > j
kj, cj = kj[1:], cj[1:]
} else if nj > j && ki[i] > kj[j] { // i > j
j++
} else { // i == j
key, container = ki[0], difference(ci[0], cj[0])
ki, ci = ki[1:], ci[1:]
kj, cj = kj[1:], cj[1:]
key, container = ki[i], difference(ci[i], cj[j])
i++
j++
output.keys = append(output.keys, key)
output.containers = append(output.containers, container)
}

10
roaring/roaring_test.go
View file

@ -24,6 +24,7 @@ import (
"testing"
"testing/quick"
"github.com/pilosa/pilosa"
"github.com/pilosa/pilosa/roaring"
_ "github.com/pilosa/pilosa/test"
)
@ -487,6 +488,15 @@ func TestBitmap_Difference(t *testing.T) {
}
}
func TestBitmap_Difference2(t *testing.T) {
bm0 := roaring.NewBitmap(0, 1, 2, 131072, 262144, pilosa.SliceWidth+5, pilosa.SliceWidth+7)
bm1 := roaring.NewBitmap(2, 3, 100000, 262144, 2*pilosa.SliceWidth+1)
result := bm0.Difference(bm1)
if !reflect.DeepEqual(result.Slice(), []uint64{0, 1, 131072, pilosa.SliceWidth + 5, pilosa.SliceWidth + 7}) {
t.Fatalf("unexpected : %v", result.Slice())
}
}
func TestBitmap_Difference_Empty(t *testing.T) {
bm0 := roaring.NewBitmap(0, 2683177)
bm1 := roaring.NewBitmap()