diff --git a/roaring/roaring.go b/roaring/roaring.go index 62f87d94b..97994c37a 100644 --- a/roaring/roaring.go +++ b/roaring/roaring.go @@ -2508,17 +2508,25 @@ func differenceRunArray(a, b *container) *container { // differenceRunBitmap computes the difference of an run from a bitmap. func differenceRunBitmap(a, b *container) *container { // If a is full, difference is the flip of b. - if a.runs[0].start == 0 && a.runs[0].last == 65535 { + if len(a.runs) > 0 && a.runs[0].start == 0 && a.runs[0].last == 65535 { return b.flipBitmap() } output := &container{container_type: ContainerRun} output.n = a.n + if len(a.runs) == 0 { + return output + } for j := 0; j < len(a.runs); j++ { run := a.runs[j] + add := true for bit := a.runs[j].start; bit <= a.runs[j].last; bit++ { if b.bitmapContains(bit) { output.n-- if run.start == bit { + if bit == 65535 { //overflow + add = false + } + run.start++ } else if bit == run.last { run.last-- @@ -2534,10 +2542,15 @@ func differenceRunBitmap(a, b *container) *container { break } } + + if bit == 65535 { //overflow + break + } } if run.start <= run.last { - output.runs = append(output.runs, run) - + if add { + output.runs = append(output.runs, run) + } } } diff --git a/roaring/roaring_internal_test.go b/roaring/roaring_internal_test.go index bdc08b649..b36723b26 100644 --- a/roaring/roaring_internal_test.go +++ b/roaring/roaring_internal_test.go @@ -1485,6 +1485,12 @@ func MakeBitmap(start []uint64) []uint64 { } return b } +func MakeLastBitSet() []uint64 { + obj := NewBitmap(65535) + c := obj.container(0) + c.arrayToBitmap() + return c.bitmap +} func TestDifferenceRunBitmap(t *testing.T) { a := &container{} @@ -1524,14 +1530,24 @@ func TestDifferenceRunBitmap(t *testing.T) { bitmap: MakeBitmap([]uint64{0x0, 0x8000000000000000}), exp: []interval16{{start: 0, last: 65}}, }, + { + runs: []interval16{{start: 1, last: 65535}}, + bitmap: MakeBitmap([]uint64{0x0000000000000001}), + exp: []interval16{{start: 1, last: 65535}}, + }, + { + runs: []interval16{{start: 0, last: 65533}, {start: 65535, last: 65535}}, + bitmap: MakeLastBitSet(), + exp: []interval16{{start: 0, last: 65533}}, + }, } for i, test := range tests { a.runs = test.runs - a.n = a.runCountRange(0, 100) + a.n = a.runCountRange(0, 65536) for i, v := range test.bitmap { b.bitmap[i] = v } - b.n = b.bitmapCountRange(0, 100) + b.n = b.bitmapCountRange(0, 65536) ret := differenceRunBitmap(a, b) if !reflect.DeepEqual(ret.runs, test.exp) { t.Fatalf("test #%v expected %v, but got %v", i, test.exp, ret.runs)