Merge pull request #500 from rogpeppe-contrib/unsetiterator-open-range

use open range for UnsetIterator

Author: lemire

iter.go

@@ -32,7 +32,7 @@ func Backward(b *Bitmap) func(func(uint32) bool) {
 // The iterator becomes invalid if the bitmap is modified (e.g., with Add or Remove).
 func Unset(b *Bitmap, min, max uint32) func(func(uint32) bool) {
 	return func(yield func(uint32) bool) {
-		it := b.UnsetIterator(min, max)
+		it := b.UnsetIterator(uint64(min), uint64(max)+1)
 		for it.HasNext() {
 			if !yield(it.Next()) {
 				return

iter_test.go

@@ -315,7 +315,7 @@ func TestUnsetIteratorPeekable(t *testing.T) {
 		b.AddInt(5)
 		b.AddInt(8)
 
-		it := b.UnsetIterator(3, 10)
+		it := b.UnsetIterator(3, 11)
 
 		// First value should be 3
 		assert.True(t, it.HasNext())
@@ -357,7 +357,7 @@ func TestUnsetIteratorPeekable(t *testing.T) {
 		b.AddInt(8)
 		b.AddInt(12)
 
-		it := b.UnsetIterator(1, 15)
+		it := b.UnsetIterator(1, 16)
 
 		// Skip to values >= 7
 		it.AdvanceIfNeeded(7)
@@ -394,7 +394,7 @@ func TestUnsetIteratorPeekable(t *testing.T) {
 		b := New()
 		b.AddInt(5)
 
-		it := b.UnsetIterator(10, 15)
+		it := b.UnsetIterator(10, 16)
 
 		// Try to advance to a value before our range start
 		it.AdvanceIfNeeded(5)
@@ -408,7 +408,7 @@ func TestUnsetIteratorPeekable(t *testing.T) {
 		b := New()
 		b.AddInt(5)
 
-		it := b.UnsetIterator(10, 15)
+		it := b.UnsetIterator(10, 16)
 
 		// Advance beyond our range
 		it.AdvanceIfNeeded(20)
@@ -420,7 +420,7 @@ func TestUnsetIteratorPeekable(t *testing.T) {
 	t.Run("advance if needed on current value", func(t *testing.T) {
 		b := New()
 		b.AddRange(0, 0x10000)
-		iter := b.UnsetIterator(0, 0x10002)
+		iter := b.UnsetIterator(0, 0x10003)
 		var got []uint32
 		prev := uint32(0)
 		for len(got) < 10 {
@@ -439,7 +439,7 @@ func TestUnsetIteratorPeekable(t *testing.T) {
 		b := New()
 		b.AddInt(5) // Set bit in middle of range
 
-		it := b.UnsetIterator(5, 5) // Range contains only the set bit
+		it := b.UnsetIterator(5, 6) // Range contains only the set bit
 
 		// Should have no values
 		assert.False(t, it.HasNext())
@@ -454,7 +454,7 @@ func TestUnsetIteratorPeekable(t *testing.T) {
 		b := New()
 		b.Add(4294967294) // Set the value before max
 
-		it := b.UnsetIterator(4294967294, 4294967295)
+		it := b.UnsetIterator(4294967294, 4294967296)
 
 		// Should have 4294967295 (max uint32) as it's unset
 		assert.True(t, it.HasNext())
@@ -469,7 +469,7 @@ func TestUnsetIteratorPeekable(t *testing.T) {
 		b := New()
 		b.Add(4294967295) // Set max uint32
 
-		it := b.UnsetIterator(4294967294, 4294967295)
+		it := b.UnsetIterator(4294967294, 4294967296)
 
 		// Should have 4294967294 as it's unset, but not 4294967295
 		assert.True(t, it.HasNext())

roaring.go

@@ -743,20 +743,25 @@ func (ii *manyIntIterator) Initialize(a *Bitmap) {
 }
 
 type unsetIterator struct {
-	min, max uint32
-	current  uint64 // use uint64 to avoid overflow
-	it       IntPeekable
-	hasNext  bool
+	start, end uint64
+	current    uint64
+	it         IntPeekable
+	hasNext    bool
 }
 
-// Initialize configures the unset iterator to iterate over values in [min, max] that are not in the bitmap
-func (ui *unsetIterator) Initialize(b *Bitmap, min, max uint32) {
-	ui.min = min
-	ui.max = max
-	ui.current = uint64(min)
+// Initialize configures the unset iterator to iterate over values in [start, end) that are not in the bitmap
+func (ui *unsetIterator) Initialize(b *Bitmap, start, end uint64) {
+	if end > 0x100000000 {
+		panic("end > 0x100000000")
+	}
+	ui.start = start
+	ui.end = end
+	ui.current = start
 	ui.it = b.Iterator()
-	// Advance to first value >= min
-	ui.it.AdvanceIfNeeded(min)
+	// Advance to first value >= start
+	if start <= MaxUint32 {
+		ui.it.AdvanceIfNeeded(uint32(start))
+	}
 	ui.updateHasNext()
 }
 
@@ -776,16 +781,16 @@ func (ui *unsetIterator) Next() uint32 {
 }
 
 func (ui *unsetIterator) updateHasNext() {
-	for ui.current <= uint64(ui.max) {
+	for ui.current < ui.end {
 		if !ui.it.HasNext() {
 			// No more set bits, we have values to yield
 			ui.hasNext = true
 			return
 		}
 
 		nextSet := ui.it.PeekNext()
-		if nextSet > ui.max {
-			// Next set bit is beyond our range, we have values to yield
+		if uint64(nextSet) >= ui.end {
+			// Next set bit is at or beyond our range, we have values to yield
 			ui.hasNext = true
 			return
 		}
@@ -818,8 +823,8 @@ func (ui *unsetIterator) AdvanceIfNeeded(minval uint32) {
 		return // Already at or past minval
 	}
 
-	if minval > ui.max {
-		// Beyond our range, no more values
+	if uint64(minval) >= ui.end {
+		// At or beyond our range, no more values
 		ui.hasNext = false
 		return
 	}
@@ -915,11 +920,11 @@ func (rb *Bitmap) ManyIterator() ManyIntIterable {
 	return p
 }
 
-// UnsetIterator creates a new IntPeekable to iterate over values in the range [min, max] that are NOT contained in the bitmap.
+// UnsetIterator creates a new IntPeekable to iterate over values in the range [start, end) that are NOT contained in the bitmap.
 // The iterator becomes invalid if the bitmap is modified (e.g., with Add or Remove).
-func (rb *Bitmap) UnsetIterator(min, max uint32) IntPeekable {
+func (rb *Bitmap) UnsetIterator(start, end uint64) IntPeekable {
 	p := new(unsetIterator)
-	p.Initialize(rb, min, max)
+	p.Initialize(rb, start, end)
 	return p
 }