Avoid unneeded slice allocations for addOffset

arraycontainer.go

@@ -1007,7 +1007,7 @@ func (ac *arrayContainer) containerType() contype {
 	return arrayContype
 }
 
-func (ac *arrayContainer) addOffset(x uint16) []container {
+func (ac *arrayContainer) addOffset(x uint16) (container, container) {
 	low := &arrayContainer{}
 	high := &arrayContainer{}
 	for _, val := range ac.content {
@@ -1018,5 +1018,5 @@ func (ac *arrayContainer) addOffset(x uint16) []container {
 			low.content = append(low.content, lowbits(y))
 		}
 	}
-	return []container{low, high}
+	return low, high
 }

arraycontainer_test.go

@@ -69,18 +69,18 @@ func TestArrayOffset(t *testing.T) {
 		v = v.iaddReturnMinimized(n)
 		expected[i] = int(n) + int(offtest)
 	}
-	w := v.addOffset(offtest)
-	w0card := w[0].getCardinality()
-	w1card := w[1].getCardinality()
+	l, h := v.addOffset(offtest)
+	w0card := l.getCardinality()
+	w1card := h.getCardinality()
 
 	assert.Equal(t, 3, w0card+w1card)
 
 	wout := make([]int, len(nums))
 	for i := 0; i < w0card; i++ {
-		wout[i] = w[0].selectInt(uint16(i))
+		wout[i] = l.selectInt(uint16(i))
 	}
 	for i := 0; i < w1card; i++ {
-		wout[i+w0card] = w[1].selectInt(uint16(i)) + 65536
+		wout[i+w0card] = h.selectInt(uint16(i)) + 65536
 	}
 	for i, x := range wout {
 		assert.Equal(t, expected[i], x)

bitmapcontainer.go

@@ -1125,7 +1125,7 @@ func (bc *bitmapContainer) containerType() contype {
 	return bitmapContype
 }
 
-func (bc *bitmapContainer) addOffset(x uint16) []container {
+func (bc *bitmapContainer) addOffset(x uint16) (container, container) {
 	low := newBitmapContainer()
 	high := newBitmapContainer()
 	b := uint32(x) >> 6
@@ -1150,5 +1150,5 @@ func (bc *bitmapContainer) addOffset(x uint16) []container {
 	}
 	low.computeCardinality()
 	high.computeCardinality()
-	return []container{low, high}
+	return low, high
 }

bitmapcontainer_test.go

@@ -221,18 +221,18 @@ func TestBitmapOffset(t *testing.T) {
 		v.iadd(n)
 		expected[i] = int(n) + int(offtest)
 	}
-	w := v.addOffset(offtest)
-	w0card := w[0].getCardinality()
-	w1card := w[1].getCardinality()
+	l, h := v.addOffset(offtest)
+	w0card := l.getCardinality()
+	w1card := h.getCardinality()
 
 	assert.Equal(t, v.getCardinality(), w0card+w1card)
 
 	wout := make([]int, len(nums))
 	for i := 0; i < w0card; i++ {
-		wout[i] = w[0].selectInt(uint16(i))
+		wout[i] = l.selectInt(uint16(i))
 	}
 	for i := 0; i < w1card; i++ {
-		wout[i+w0card] = w[1].selectInt(uint16(i)) + 65536
+		wout[i+w0card] = h.selectInt(uint16(i)) + 65536
 	}
 
 	for i, x := range wout {

roaring.go

@@ -545,9 +545,9 @@ func AddOffset64(x *Bitmap, offset int64) (answer *Bitmap) {
 			key += containerOffset
 
 			c := x.highlowcontainer.getContainerAtIndex(pos)
-			offsetted := c.addOffset(inOffset)
+			lo, hi := c.addOffset(inOffset)
 
-			if !offsetted[0].isEmpty() && (key >= 0 && key <= MaxUint16) {
+			if !lo.isEmpty() && (key >= 0 && key <= MaxUint16) {
 				curSize := answer.highlowcontainer.size()
 				lastkey := int32(0)
 
@@ -557,15 +557,15 @@ func AddOffset64(x *Bitmap, offset int64) (answer *Bitmap) {
 
 				if curSize > 0 && lastkey == key {
 					prev := answer.highlowcontainer.getContainerAtIndex(curSize - 1)
-					orrseult := prev.ior(offsetted[0])
+					orrseult := prev.ior(lo)
 					answer.highlowcontainer.setContainerAtIndex(curSize-1, orrseult)
 				} else {
-					answer.highlowcontainer.appendContainer(uint16(key), offsetted[0], false)
+					answer.highlowcontainer.appendContainer(uint16(key), lo, false)
 				}
 			}
 
-			if !offsetted[1].isEmpty() && ((key+1) >= 0 && (key+1) <= MaxUint16) {
-				answer.highlowcontainer.appendContainer(uint16(key+1), offsetted[1], false)
+			if !hi.isEmpty() && ((key+1) >= 0 && (key+1) <= MaxUint16) {
+				answer.highlowcontainer.appendContainer(uint16(key+1), hi, false)
 			}
 		}
 	}

roaringarray.go

@@ -9,7 +9,7 @@ import (
 )
 
 type container interface {
-	addOffset(uint16) []container
+	addOffset(uint16) (container, container)
 
 	clone() container
 	and(container) container

runcontainer.go

@@ -2582,7 +2582,7 @@ func (rc *runContainer16) serializedSizeInBytes() int {
 	return 2 + len(rc.iv)*4
 }
 
-func (rc *runContainer16) addOffset(x uint16) []container {
+func (rc *runContainer16) addOffset(x uint16) (container, container) {
 	low := newRunContainer16()
 	high := newRunContainer16()
 
@@ -2600,5 +2600,5 @@ func (rc *runContainer16) addOffset(x uint16) []container {
 			high.iv = append(high.iv, interval16{uint16(val & 0xffff), iv.length})
 		}
 	}
-	return []container{low, high}
+	return low, high
 }

runcontainer_test.go

@@ -80,9 +80,9 @@ func TestRleInterval16s(t *testing.T) {
 func TestRunOffset(t *testing.T) {
 	v := newRunContainer16TakeOwnership([]interval16{newInterval16Range(34, 39)})
 	offtest := uint16(65500)
-	w := v.addOffset(offtest)
-	w0card := w[0].getCardinality()
-	w1card := w[1].getCardinality()
+	l, h := v.addOffset(offtest)
+	w0card := l.getCardinality()
+	w1card := h.getCardinality()
 
 	if w0card+w1card != 6 {
 		t.Errorf("Bogus cardinality.")
@@ -91,10 +91,10 @@ func TestRunOffset(t *testing.T) {
 	expected := []int{65534, 65535, 65536, 65537, 65538, 65539}
 	wout := make([]int, len(expected))
 	for i := 0; i < w0card; i++ {
-		wout[i] = w[0].selectInt(uint16(i))
+		wout[i] = l.selectInt(uint16(i))
 	}
 	for i := 0; i < w1card; i++ {
-		wout[i+w0card] = w[1].selectInt(uint16(i)) + 65536
+		wout[i+w0card] = h.selectInt(uint16(i)) + 65536
 	}
 
 	for i, x := range wout {