UnsetIterator: address review comments

Signed-off-by: Roger Peppe <rogpeppe@gmail.com>

Author: rogpeppe

arraycontainer.go

@@ -62,56 +62,8 @@ func (ac *arrayContainer) getManyIterator() manyIterable {
 	return &shortIterator{ac.content, 0}
 }
 
-type arrayContainerUnsetIterator struct {
-	content []uint16
-	pos     int
-	nextVal int
-}
-
-func (acui *arrayContainerUnsetIterator) next() uint16 {
-	val := acui.nextVal
-	acui.nextVal++
-	for acui.pos < len(acui.content) && uint16(acui.nextVal) == acui.content[acui.pos] {
-		acui.nextVal++
-		acui.pos++
-	}
-	return uint16(val)
-}
-
-func (acui *arrayContainerUnsetIterator) hasNext() bool {
-	return acui.nextVal < 65536
-}
-
-func (acui *arrayContainerUnsetIterator) peekNext() uint16 {
-	return uint16(acui.nextVal)
-}
-
-func (acui *arrayContainerUnsetIterator) advanceIfNeeded(minval uint16) {
-	if !acui.hasNext() || acui.peekNext() >= minval {
-		return
-	}
-	acui.nextVal = int(minval)
-	acui.pos = binarySearch(acui.content, minval)
-	if acui.pos < 0 {
-		acui.pos = -acui.pos - 1
-	}
-	for acui.pos < len(acui.content) && uint16(acui.nextVal) == acui.content[acui.pos] {
-		acui.nextVal++
-		acui.pos++
-	}
-}
-
-func newArrayContainerUnsetIterator(a *arrayContainer) *arrayContainerUnsetIterator {
-	acui := &arrayContainerUnsetIterator{content: a.content, pos: 0, nextVal: 0}
-	for acui.pos < len(acui.content) && uint16(acui.nextVal) == acui.content[acui.pos] {
-		acui.nextVal++
-		acui.pos++
-	}
-	return acui
-}
-
 func (ac *arrayContainer) getUnsetIterator() shortPeekable {
-	return newArrayContainerUnsetIterator(ac)
+	return newArrayContainerUnsetIterator(ac.content)
 }
 
 func (ac *arrayContainer) minimum() uint16 {

roaring.go

@@ -812,7 +812,7 @@ func (iui *unsetIterator) init() {
 	c := iui.highlowcontainer.getContainerAtIndex(iui.containerIndex)
 	switch t := c.(type) {
 	case *arrayContainer:
-		iui.arrayUnsetIter = *newArrayContainerUnsetIterator(t)
+		iui.arrayUnsetIter = *newArrayContainerUnsetIterator(t.content)
 		iui.iter = &iui.arrayUnsetIter
 	case *runContainer16:
 		iui.runUnsetIter = *t.newRunUnsetIterator16()

runcontainer.go

@@ -2002,7 +2002,7 @@ func (rui *runUnsetIterator16) hasNext() bool {
 func (rui *runUnsetIterator16) next() uint16 {
 	val := rui.nextVal
 	rui.nextVal++
-	if rui.curIndex < len(rui.rc.iv) && uint16(rui.nextVal) == rui.rc.iv[rui.curIndex].start {
+	if rui.curIndex < len(rui.rc.iv) && uint16(rui.nextVal) >= rui.rc.iv[rui.curIndex].start {
 		rui.nextVal = int(rui.rc.iv[rui.curIndex].start) + int(rui.rc.iv[rui.curIndex].length) + 1
 		rui.curIndex++
 	}

shortiterator.go

@@ -50,3 +50,53 @@ func (si *reverseIterator) next() uint16 {
 	si.loc--
 	return a
 }
+
+type arrayContainerUnsetIterator struct {
+	content []uint16
+	// pos is the index of the next set bit that is >= nextVal.
+	// When nextVal reaches content[pos], pos is incremented.
+	pos     int
+	nextVal int
+}
+
+func (acui *arrayContainerUnsetIterator) next() uint16 {
+	val := acui.nextVal
+	acui.nextVal++
+	for acui.pos < len(acui.content) && uint16(acui.nextVal) >= acui.content[acui.pos] {
+		acui.nextVal++
+		acui.pos++
+	}
+	return uint16(val)
+}
+
+func (acui *arrayContainerUnsetIterator) hasNext() bool {
+	return acui.nextVal < 65536
+}
+
+func (acui *arrayContainerUnsetIterator) peekNext() uint16 {
+	return uint16(acui.nextVal)
+}
+
+func (acui *arrayContainerUnsetIterator) advanceIfNeeded(minval uint16) {
+	if !acui.hasNext() || acui.peekNext() >= minval {
+		return
+	}
+	acui.nextVal = int(minval)
+	acui.pos = binarySearch(acui.content, minval)
+	if acui.pos < 0 {
+		acui.pos = -acui.pos - 1
+	}
+	for acui.pos < len(acui.content) && uint16(acui.nextVal) >= acui.content[acui.pos] {
+		acui.nextVal++
+		acui.pos++
+	}
+}
+
+func newArrayContainerUnsetIterator(content []uint16) *arrayContainerUnsetIterator {
+	acui := &arrayContainerUnsetIterator{content: content, pos: 0, nextVal: 0}
+	for acui.pos < len(acui.content) && uint16(acui.nextVal) >= acui.content[acui.pos] {
+		acui.nextVal++
+		acui.pos++
+	}
+	return acui
+}