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performance enhancement for Difference

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This commit is contained in:
Todd Gruben 2014-07-28 19:22:48 +00:00
parent 671036432f
commit 4190b720dc
2 changed files with 17 additions and 4 deletions
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17
index/bitmap.go
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@ -121,6 +121,14 @@ func BlockArray_intersection(a *BlockArray, b *BlockArray) BlockArray {
return o
}
func BlockArray_difference(a *BlockArray, b *BlockArray) BlockArray {
var o = BlockArray{}
for i, _ := range a.Block {
o.Block[i] = a.Block[i] &^ b.Block[i]
}
return o
}
func (s *BlockArray) set_bit(BlockIndex uint8, bit uint8) bool {
val := s.Block[BlockIndex] & (1 << bit)
s.Block[BlockIndex] |= 1 << bit
@ -295,9 +303,14 @@ func Difference(a_bm IBitmap, b_bm IBitmap) IBitmap {
b = b.Next()
} else if a.Item().Key == b.Item().Key {
var a_node = a.Item()
var b_node = BlockArray_invert(&b.Item().Value) //probably need to copy this out
var o = BlockArray_intersection(&a_node.Value, &b_node)
//var b_node = BlockArray_invert(&b.Item().Value) //probably need to copy this out
//var o = BlockArray_intersection(&a_node.Value, &b_node)
var b_node = b.Item().Value
var o = BlockArray_difference(&a_node.Value, &b_node)
var o_node = &Chunk{a_node.Key, o}
//could not add if all zero
if o_node.Value.bitcount() > 0 {
output.AddChunk(o_node)

4
index/storage_test.go
View file

@ -6,7 +6,7 @@ import (
// "io/ioutil"
// "time"
"github.com/davecgh/go-spew/spew"
. "github.com/smartystreets/goconvey/convey"
)
@ -58,7 +58,7 @@ func TestStorage(t *testing.T) {
fmt.Println("FETCH")
bm, _ := storage.Fetch(bitmap_id, db, frame, slice)
spew.Dump(bm)
//spew.Dump(bm)
SetBit(bm, 0)
SetBit(bm, 1)
SetBit(bm, 2)