Step down container index if next present container key is larger tha…

…n target container key

This means that previous value (if exist) must be always in the previous container

roaring.go

@@ -1935,13 +1935,14 @@ func (rb *Bitmap) PreviousValue(target uint32) int64 {
 	}
 
 	if rb.highlowcontainer.getKeyAtIndex(containerIndex) > originalKey {
-		return -1
+		// target absent, key of first container after target too high
+		containerIndex--
 	}
 
 	for containerIndex != -1 && prevValue == -1 {
 		containerKey := rb.highlowcontainer.getKeyAtIndex(containerIndex)
 		container := rb.highlowcontainer.getContainer(containerKey)
-		// if containerKey > orginalKey then we are past the container which mapped to the orignal key
+		// if containerKey > originalKey then we are past the container which mapped to the original key
 		// in that case we can just return the minimum from that container
 		var responseBit int
 		if containerKey < originalKey {

roaring_test.go

@@ -2973,6 +2973,17 @@ func TestNextAndPreviousValue(t *testing.T) {
 		}
 	})
 
+	t.Run("Absent target container", func(t *testing.T) {
+		bmp := BitmapOf(2, 3, 131072, MaxUint32)
+
+		assert.Equal(t, int64(3), bmp.PreviousValue(65536))
+		assert.Equal(t, int64(131072), bmp.PreviousValue(MaxUint32>>1))
+		assert.Equal(t, int64(131072), bmp.PreviousValue(MaxUint32-131071))
+
+		bmp = BitmapOf(131072)
+		assert.Equal(t, int64(-1), bmp.PreviousValue(65536))
+	})
+
 	t.Run("skipping with ranges", func(t *testing.T) {
 		bmp := New()
 		intervalEnd := 512