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fix bitmapCountRange and test

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had been thinking that index 0 was the most significant bit, but based on the
bitmapAdd function, it must be the least significant bit
This commit is contained in:
Matt Jaffee 2017-05-19 15:15:23 -05:00
parent fb4651cdb8
commit c0ddbe0e3f
2 changed files with 22 additions and 24 deletions
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6
roaring/roaring.go
View file

@ -907,13 +907,13 @@ func (c *container) bitmapCountRange(start, end uint32) int {
// Special case when start and end fall in the same word.
if i == j {
offi, offj := start%64, 64-end%64
n += popcount((c.bitmap[i] << offi) >> (offj + offi))
n += popcount((c.bitmap[i] >> offi) << (offj + offi))
return int(n)
}
// Count partial starting word.
if off := start % 64; off != 0 {
n += popcount(c.bitmap[i] << off)
n += popcount(c.bitmap[i] >> off)
i++
}
@ -925,7 +925,7 @@ func (c *container) bitmapCountRange(start, end uint32) int {
// Count partial ending word.
if int(j) < len(c.bitmap) {
if off := 64 - (end % 64); off != 0 {
n += popcount(c.bitmap[j] >> off)
n += popcount(c.bitmap[j] << off)
}
}

40
roaring/roaring_internal_test.go
View file

@ -5,27 +5,25 @@ import (
)
func TestBitmapCountRange(t *testing.T) {
c := container{bitmap: []uint64{1}}
cnt := c.bitmapCountRange(63, 65)
if cnt != 1 {
t.Fatalf("count of %v from 63 to 65 should be 1, but got %v", c.bitmap, cnt)
c := container{}
tests := []struct {
start uint32
end uint32
bitmap []uint64
exp int
}{
{start: 0, end: 1, bitmap: []uint64{1}, exp: 1},
{start: 2, end: 7, bitmap: []uint64{0xFFFFFFFFFFFFFF18}, exp: 2},
{start: 67, end: 68, bitmap: []uint64{0, 0x8}, exp: 1},
{start: 1, end: 68, bitmap: []uint64{0x3, 0x8, 0xF}, exp: 2},
{start: 1, end: 258, bitmap: []uint64{0xF, 0x8, 0xA, 0x4, 0xFFFFFFFFFFFFFFFF}, exp: 9},
{start: 66, end: 71, bitmap: []uint64{0xF, 0xFFFFFFFFFFFFFF18}, exp: 2},
{start: 63, end: 64, bitmap: []uint64{0x8000000000000000}, exp: 1},
}
c = container{bitmap: []uint64{0, 0x8000000000000000}}
cnt = c.bitmapCountRange(65, 66)
if cnt != 0 {
t.Fatalf("count of %v from 65 to 66 should be 0, but got %v", c.bitmap, cnt)
}
c = container{bitmap: []uint64{0, 0xF000000000000000}}
cnt = c.bitmapCountRange(65, 66)
if cnt != 1 {
t.Fatalf("count of %v from 65 to 66 should be 1, but got %v", c.bitmap, cnt)
}
c = container{bitmap: []uint64{0x1, 0xFF00000000000000}}
cnt = c.bitmapCountRange(62, 66)
if cnt != 3 {
t.Fatalf("count of %v from 62 to 66 should be 3, but got %v", c.bitmap, cnt)
for i, test := range tests {
c.bitmap = test.bitmap
if ret := c.bitmapCountRange(test.start, test.end); ret != test.exp {
t.Fatalf("test #%v count of %v from %v to %v should be %v but got %v", i, test.bitmap, test.start, test.end, test.exp, ret)
}
}
}