sing-box/common/domain/set.go

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2022-07-02 14:55:10 +00:00
package domain
import (
"math/bits"
)
const prefixLabel = '\r'
// mod from https://github.com/openacid/succinct
type succinctSet struct {
leaves, labelBitmap []uint64
labels []byte
ranks, selects []int32
}
func newSuccinctSet(keys []string) *succinctSet {
ss := &succinctSet{}
lIdx := 0
type qElt struct{ s, e, col int }
queue := []qElt{{0, len(keys), 0}}
for i := 0; i < len(queue); i++ {
elt := queue[i]
if elt.col == len(keys[elt.s]) {
// a leaf node
elt.s++
setBit(&ss.leaves, i, 1)
}
for j := elt.s; j < elt.e; {
frm := j
for ; j < elt.e && keys[j][elt.col] == keys[frm][elt.col]; j++ {
}
queue = append(queue, qElt{frm, j, elt.col + 1})
ss.labels = append(ss.labels, keys[frm][elt.col])
setBit(&ss.labelBitmap, lIdx, 0)
lIdx++
}
setBit(&ss.labelBitmap, lIdx, 1)
lIdx++
}
ss.init()
return ss
}
func (ss *succinctSet) Has(key string) bool {
var nodeId, bmIdx int
for i := 0; i < len(key); i++ {
currentChar := key[i]
for ; ; bmIdx++ {
if getBit(ss.labelBitmap, bmIdx) != 0 {
return false
}
nextLabel := ss.labels[bmIdx-nodeId]
if nextLabel == prefixLabel {
return true
}
if nextLabel == currentChar {
break
}
}
nodeId = countZeros(ss.labelBitmap, ss.ranks, bmIdx+1)
bmIdx = selectIthOne(ss.labelBitmap, ss.ranks, ss.selects, nodeId-1) + 1
}
if getBit(ss.leaves, nodeId) != 0 {
return true
}
for ; ; bmIdx++ {
if getBit(ss.labelBitmap, bmIdx) != 0 {
return false
}
if ss.labels[bmIdx-nodeId] == prefixLabel {
return true
}
}
}
func setBit(bm *[]uint64, i int, v int) {
for i>>6 >= len(*bm) {
*bm = append(*bm, 0)
}
(*bm)[i>>6] |= uint64(v) << uint(i&63)
}
func getBit(bm []uint64, i int) uint64 {
return bm[i>>6] & (1 << uint(i&63))
}
func (ss *succinctSet) init() {
ss.selects, ss.ranks = indexSelect32R64(ss.labelBitmap)
}
func countZeros(bm []uint64, ranks []int32, i int) int {
a, _ := rank64(bm, ranks, int32(i))
return i - int(a)
}
func selectIthOne(bm []uint64, ranks, selects []int32, i int) int {
a, _ := select32R64(bm, selects, ranks, int32(i))
return int(a)
}
func rank64(words []uint64, rindex []int32, i int32) (int32, int32) {
wordI := i >> 6
j := uint32(i & 63)
n := rindex[wordI]
w := words[wordI]
c1 := n + int32(bits.OnesCount64(w&mask[j]))
return c1, int32(w>>uint(j)) & 1
}
func indexRank64(words []uint64, opts ...bool) []int32 {
trailing := false
if len(opts) > 0 {
trailing = opts[0]
}
l := len(words)
if trailing {
l++
}
idx := make([]int32, l)
n := int32(0)
for i := 0; i < len(words); i++ {
idx[i] = n
n += int32(bits.OnesCount64(words[i]))
}
if trailing {
idx[len(words)] = n
}
return idx
}
func select32R64(words []uint64, selectIndex, rankIndex []int32, i int32) (int32, int32) {
a := int32(0)
l := int32(len(words))
wordI := selectIndex[i>>5] >> 6
for ; rankIndex[wordI+1] <= i; wordI++ {
}
w := words[wordI]
ww := w
base := wordI << 6
findIth := int(i - rankIndex[wordI])
offset := int32(0)
ones := bits.OnesCount32(uint32(ww))
if ones <= findIth {
findIth -= ones
offset |= 32
ww >>= 32
}
ones = bits.OnesCount16(uint16(ww))
if ones <= findIth {
findIth -= ones
offset |= 16
ww >>= 16
}
ones = bits.OnesCount8(uint8(ww))
if ones <= findIth {
a = int32(select8Lookup[(ww>>5)&(0x7f8)|uint64(findIth-ones)]) + offset + 8
} else {
a = int32(select8Lookup[(ww&0xff)<<3|uint64(findIth)]) + offset
}
a += base
w &= rMaskUpto[a&63]
if w != 0 {
return a, base + int32(bits.TrailingZeros64(w))
}
wordI++
for ; wordI < l; wordI++ {
w = words[wordI]
if w != 0 {
return a, wordI<<6 + int32(bits.TrailingZeros64(w))
}
}
return a, l << 6
}
func indexSelect32R64(words []uint64) ([]int32, []int32) {
l := len(words) << 6
sidx := make([]int32, 0, len(words))
ith := -1
for i := 0; i < l; i++ {
if words[i>>6]&(1<<uint(i&63)) != 0 {
ith++
if ith&31 == 0 {
sidx = append(sidx, int32(i))
}
}
}
// clone to reduce cap to len
sidx = append(sidx[:0:0], sidx...)
return sidx, indexRank64(words, true)
}
func init() {
initMasks()
initSelectLookup()
}
var (
mask [65]uint64
rMaskUpto [64]uint64
)
func initMasks() {
for i := 0; i < 65; i++ {
mask[i] = (1 << uint(i)) - 1
}
var maskUpto [64]uint64
for i := 0; i < 64; i++ {
maskUpto[i] = (1 << uint(i+1)) - 1
rMaskUpto[i] = ^maskUpto[i]
}
}
var select8Lookup [256 * 8]uint8
func initSelectLookup() {
for i := 0; i < 256; i++ {
w := uint8(i)
for j := 0; j < 8; j++ {
// x-th 1 in w
// if x-th 1 is not found, it is 8
x := bits.TrailingZeros8(w)
w &= w - 1
select8Lookup[i*8+j] = uint8(x)
}
}
}