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Author: lemire

README.md

@@ -66,6 +66,13 @@ func main() {
 	rb3 := gocroaring.New(1, 5)
 	rb3.Or(rb1)
 
+        // prints 1, 3, 4, 5, 1000
+        i := rb3.Iterator()
+        for i.HasNext() {
+          fmt.Println(i.Next())
+        }
+        fmt.Println()
+
 	fmt.Println(rb3.ToArray())
 	fmt.Println(rb3)
 

gocroaring.go

@@ -12,12 +12,11 @@ import "C"
 import (
 	"bytes"
 	"errors"
-	"strconv"
 	"runtime"
+	"strconv"
+  "unsafe"
 )
 
-import "unsafe"
-
 const CRoaringMajor = C.ROARING_VERSION_MAJOR
 const CRoaringMinor = C.ROARING_VERSION_MINOR
 const CRoaringRevision = C.ROARING_VERSION_REVISION
@@ -185,6 +184,53 @@ func (rb *Bitmap) SerializedSizeInBytes() int {
 	return int(C.roaring_bitmap_portable_size_in_bytes(rb.cpointer))
 }
 
+// IntIterable allows you to iterate over the values in a Bitmap
+type IntIterable interface {
+	HasNext() bool
+	Next() uint32
+}
+
+type intIterator struct {
+	pointertonext *C.roaring_uint32_iterator_t
+	current       uint32
+	has_next      bool
+}
+
+// Iterator creates a new IntIterable to iterate over the integers contained in the bitmap, in sorted order
+func (rb *Bitmap) Iterator() IntIterable {
+	return newIntIterator(rb)
+}
+
+// HasNext returns true if there are more integers to iterate over
+func (ii *intIterator) HasNext() bool {
+	return ii.has_next
+}
+
+// Next returns the next integer
+func (ii *intIterator) Next() uint32 {
+	answer := ii.current
+	ii.has_next = bool(ii.pointertonext.has_value)
+	ii.current = uint32(ii.pointertonext.current_value)
+	C.roaring_advance_uint32_iterator(ii.pointertonext)
+	return answer
+}
+
+func freeIntIterator(a *intIterator) {
+	C.roaring_free_uint32_iterator(a.pointertonext)
+}
+
+func newIntIterator(a *Bitmap) *intIterator {
+	p := new(intIterator)
+	p.pointertonext = C.roaring_create_iterator(a.cpointer)
+	p.has_next = bool(p.pointertonext.has_value)
+	p.current = uint32(p.pointertonext.current_value)
+	if p.has_next {
+		C.roaring_advance_uint32_iterator(p.pointertonext)
+	}
+	runtime.SetFinalizer(p, freeIntIterator)
+	return p
+}
+
 // Write writes a serialized version of this bitmap to stream (you should have enough space)
 func (rb *Bitmap) Write(b []byte) error {
 	if len(b) < rb.SerializedSizeInBytes() {
@@ -204,19 +250,19 @@ func (rb *Bitmap) ToArray() []uint32 {
 
 // String creates a string representation of the Bitmap
 func (rb *Bitmap) String() string {
-  arr := rb.ToArray() // todo: replace with an iterator
-  var buffer bytes.Buffer
+	arr := rb.ToArray() // todo: replace with an iterator
+	var buffer bytes.Buffer
 	start := []byte("{")
 	buffer.Write(start)
-  l := len(arr)
-  for counter,i := range arr {
+	l := len(arr)
+	for counter, i := range arr {
 		// to avoid exhausting the memory
 		if counter > 0x40000 {
 			buffer.WriteString("...")
 			break
 		}
 		buffer.WriteString(strconv.FormatInt(int64(i), 10))
-		if counter + 1 < l { // there is more
+		if counter+1 < l { // there is more
 			buffer.WriteString(",")
 		}
 	}

gocroaring_test.go

@@ -6,7 +6,7 @@ import (
 )
 
 func TestDisplayVersion(t *testing.T) {
-  fmt.Printf("CRoaring %v.%v.%v\n", CRoaringMajor, CRoaringMinor, CRoaringRevision)
+	fmt.Printf("CRoaring %v.%v.%v\n", CRoaringMajor, CRoaringMinor, CRoaringRevision)
 }
 
 // go test -run MemoryUsage
@@ -16,7 +16,7 @@ func TestMemoryUsage(t *testing.T) {
 		bitmap.Add(uint32(i) * 10)
 	}
 	sb := bitmap.SerializedSizeInBytes()
-	memoryAlloc := 8 *  1024 * 1024
+	memoryAlloc := 8 * 1024 * 1024
 	howmany := (memoryAlloc + sb - 1) / sb
 	fmt.Println("size in kB of one bitmap ", sb/(1024), "; number of copies = ", howmany, "; total alloc: ", howmany*sb/(1024), "kB")
 	for i := 0; i < howmany; i++ {
@@ -96,6 +96,12 @@ func TestFancier(t *testing.T) {
 	fmt.Println(rb1)
 	rb3.Add(5)
 	rb3.Or(rb1)
+  // prints 3, 4, 5, 1000
+  i := rb3.Iterator()
+  for i.HasNext() {
+  fmt.Println(i.Next())
+  }
+  fmt.Println()
 	fmt.Println(rb3.ToArray())
 	fmt.Println(rb3)
 	rb4 := FastOr(rb1, rb2, rb3)
@@ -112,8 +118,8 @@ func TestFancier(t *testing.T) {
 }
 
 func TestString(t *testing.T) {
-  ans := New(1,2,3).String()
-  fmt.Println(ans)
+	ans := New(1, 2, 3).String()
+	fmt.Println(ans)
 	if ans != "{1,2,3}" {
 		t.Errorf("bad string ")
 	}