Implement Count for bitArray and sparseBitArray

bitarray/bitarray.go

@@ -202,6 +202,15 @@ func (ba *bitArray) ClearBit(k uint64) error {
  return nil
 }
 
+// Count returns the number of set bits in this array.
+func (ba *bitArray) Count() uint64 {
+ count := 0
+ for _, block := range ba.blocks {
+ count += bits.OnesCount64(uint64(block))
+ }
+ return uint64(count)
+}
+
 // Or will bitwise or two bit arrays and return a new bit array
 // representing the result.
 func (ba *bitArray) Or(other BitArray) BitArray {

bitarray/sparse_bitarray.go

@@ -16,7 +16,10 @@ limitations under the License.
 
 package bitarray
 
-import "sort"
+import (
+ "math/bits"
+ "sort"
+)
 
 // uintSlice is an alias for a slice of ints. Len, Swap, and Less
 // are exported to fulfill an interface needed for the search
@@ -243,6 +246,15 @@ func (sba *sparseBitArray) Equals(other BitArray) bool {
  return true
 }
 
+// Count returns the number of set bits in this array.
+func (sba *sparseBitArray) Count() uint64 {
+ count := 0
+ for _, block := range sba.blocks {
+ count += bits.OnesCount64(uint64(block))
+ }
+ return uint64(count)
+}
+
 // Or will perform a bitwise or operation with the provided bitarray and
 // return a new result bitarray.
 func (sba *sparseBitArray) Or(other BitArray) BitArray {