You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
323 lines
6.2 KiB
323 lines
6.2 KiB
package common
|
|
|
|
import (
|
|
"encoding/binary"
|
|
"fmt"
|
|
"strings"
|
|
"sync"
|
|
)
|
|
|
|
type BitArray struct {
|
|
mtx sync.Mutex
|
|
Bits int `json:"bits"` // NOTE: persisted via reflect, must be exported
|
|
Elems []uint64 `json:"elems"` // NOTE: persisted via reflect, must be exported
|
|
}
|
|
|
|
// There is no BitArray whose Size is 0. Use nil instead.
|
|
func NewBitArray(bits int) *BitArray {
|
|
if bits <= 0 {
|
|
return nil
|
|
}
|
|
return &BitArray{
|
|
Bits: bits,
|
|
Elems: make([]uint64, (bits+63)/64),
|
|
}
|
|
}
|
|
|
|
func (bA *BitArray) Size() int {
|
|
if bA == nil {
|
|
return 0
|
|
}
|
|
return bA.Bits
|
|
}
|
|
|
|
// NOTE: behavior is undefined if i >= bA.Bits
|
|
func (bA *BitArray) GetIndex(i int) bool {
|
|
if bA == nil {
|
|
return false
|
|
}
|
|
bA.mtx.Lock()
|
|
defer bA.mtx.Unlock()
|
|
return bA.getIndex(i)
|
|
}
|
|
|
|
func (bA *BitArray) getIndex(i int) bool {
|
|
if i >= bA.Bits {
|
|
return false
|
|
}
|
|
return bA.Elems[i/64]&(uint64(1)<<uint(i%64)) > 0
|
|
}
|
|
|
|
// NOTE: behavior is undefined if i >= bA.Bits
|
|
func (bA *BitArray) SetIndex(i int, v bool) bool {
|
|
if bA == nil {
|
|
return false
|
|
}
|
|
bA.mtx.Lock()
|
|
defer bA.mtx.Unlock()
|
|
return bA.setIndex(i, v)
|
|
}
|
|
|
|
func (bA *BitArray) setIndex(i int, v bool) bool {
|
|
if i >= bA.Bits {
|
|
return false
|
|
}
|
|
if v {
|
|
bA.Elems[i/64] |= (uint64(1) << uint(i%64))
|
|
} else {
|
|
bA.Elems[i/64] &= ^(uint64(1) << uint(i%64))
|
|
}
|
|
return true
|
|
}
|
|
|
|
func (bA *BitArray) Copy() *BitArray {
|
|
if bA == nil {
|
|
return nil
|
|
}
|
|
bA.mtx.Lock()
|
|
defer bA.mtx.Unlock()
|
|
return bA.copy()
|
|
}
|
|
|
|
func (bA *BitArray) copy() *BitArray {
|
|
c := make([]uint64, len(bA.Elems))
|
|
copy(c, bA.Elems)
|
|
return &BitArray{
|
|
Bits: bA.Bits,
|
|
Elems: c,
|
|
}
|
|
}
|
|
|
|
func (bA *BitArray) copyBits(bits int) *BitArray {
|
|
c := make([]uint64, (bits+63)/64)
|
|
copy(c, bA.Elems)
|
|
return &BitArray{
|
|
Bits: bits,
|
|
Elems: c,
|
|
}
|
|
}
|
|
|
|
// Returns a BitArray of larger bits size.
|
|
func (bA *BitArray) Or(o *BitArray) *BitArray {
|
|
if bA == nil && o == nil {
|
|
return nil
|
|
}
|
|
if bA == nil && o != nil {
|
|
return o.Copy()
|
|
}
|
|
if o == nil {
|
|
return bA.Copy()
|
|
}
|
|
bA.mtx.Lock()
|
|
defer bA.mtx.Unlock()
|
|
c := bA.copyBits(MaxInt(bA.Bits, o.Bits))
|
|
for i := 0; i < len(c.Elems); i++ {
|
|
c.Elems[i] |= o.Elems[i]
|
|
}
|
|
return c
|
|
}
|
|
|
|
// Returns a BitArray of smaller bit size.
|
|
func (bA *BitArray) And(o *BitArray) *BitArray {
|
|
if bA == nil || o == nil {
|
|
return nil
|
|
}
|
|
bA.mtx.Lock()
|
|
defer bA.mtx.Unlock()
|
|
return bA.and(o)
|
|
}
|
|
|
|
func (bA *BitArray) and(o *BitArray) *BitArray {
|
|
c := bA.copyBits(MinInt(bA.Bits, o.Bits))
|
|
for i := 0; i < len(c.Elems); i++ {
|
|
c.Elems[i] &= o.Elems[i]
|
|
}
|
|
return c
|
|
}
|
|
|
|
func (bA *BitArray) Not() *BitArray {
|
|
if bA == nil {
|
|
return nil // Degenerate
|
|
}
|
|
bA.mtx.Lock()
|
|
defer bA.mtx.Unlock()
|
|
c := bA.copy()
|
|
for i := 0; i < len(c.Elems); i++ {
|
|
c.Elems[i] = ^c.Elems[i]
|
|
}
|
|
return c
|
|
}
|
|
|
|
func (bA *BitArray) Sub(o *BitArray) *BitArray {
|
|
if bA == nil || o == nil {
|
|
// TODO: Decide if we should do 1's complement here?
|
|
return nil
|
|
}
|
|
bA.mtx.Lock()
|
|
defer bA.mtx.Unlock()
|
|
if bA.Bits > o.Bits {
|
|
c := bA.copy()
|
|
for i := 0; i < len(o.Elems)-1; i++ {
|
|
c.Elems[i] &= ^c.Elems[i]
|
|
}
|
|
i := len(o.Elems) - 1
|
|
if i >= 0 {
|
|
for idx := i * 64; idx < o.Bits; idx++ {
|
|
// NOTE: each individual GetIndex() call to o is safe.
|
|
c.setIndex(idx, c.getIndex(idx) && !o.GetIndex(idx))
|
|
}
|
|
}
|
|
return c
|
|
} else {
|
|
return bA.and(o.Not()) // Note degenerate case where o == nil
|
|
}
|
|
}
|
|
|
|
func (bA *BitArray) IsEmpty() bool {
|
|
if bA == nil {
|
|
return true // should this be opposite?
|
|
}
|
|
bA.mtx.Lock()
|
|
defer bA.mtx.Unlock()
|
|
for _, e := range bA.Elems {
|
|
if e > 0 {
|
|
return false
|
|
}
|
|
}
|
|
return true
|
|
}
|
|
|
|
func (bA *BitArray) IsFull() bool {
|
|
if bA == nil {
|
|
return true
|
|
}
|
|
bA.mtx.Lock()
|
|
defer bA.mtx.Unlock()
|
|
|
|
// Check all elements except the last
|
|
for _, elem := range bA.Elems[:len(bA.Elems)-1] {
|
|
if (^elem) != 0 {
|
|
return false
|
|
}
|
|
}
|
|
|
|
// Check that the last element has (lastElemBits) 1's
|
|
lastElemBits := (bA.Bits+63)%64 + 1
|
|
lastElem := bA.Elems[len(bA.Elems)-1]
|
|
return (lastElem+1)&((uint64(1)<<uint(lastElemBits))-1) == 0
|
|
}
|
|
|
|
func (bA *BitArray) PickRandom() (int, bool) {
|
|
if bA == nil {
|
|
return 0, false
|
|
}
|
|
bA.mtx.Lock()
|
|
defer bA.mtx.Unlock()
|
|
|
|
length := len(bA.Elems)
|
|
if length == 0 {
|
|
return 0, false
|
|
}
|
|
randElemStart := RandIntn(length)
|
|
for i := 0; i < length; i++ {
|
|
elemIdx := ((i + randElemStart) % length)
|
|
if elemIdx < length-1 {
|
|
if bA.Elems[elemIdx] > 0 {
|
|
randBitStart := RandIntn(64)
|
|
for j := 0; j < 64; j++ {
|
|
bitIdx := ((j + randBitStart) % 64)
|
|
if (bA.Elems[elemIdx] & (uint64(1) << uint(bitIdx))) > 0 {
|
|
return 64*elemIdx + bitIdx, true
|
|
}
|
|
}
|
|
PanicSanity("should not happen")
|
|
}
|
|
} else {
|
|
// Special case for last elem, to ignore straggler bits
|
|
elemBits := bA.Bits % 64
|
|
if elemBits == 0 {
|
|
elemBits = 64
|
|
}
|
|
randBitStart := RandIntn(elemBits)
|
|
for j := 0; j < elemBits; j++ {
|
|
bitIdx := ((j + randBitStart) % elemBits)
|
|
if (bA.Elems[elemIdx] & (uint64(1) << uint(bitIdx))) > 0 {
|
|
return 64*elemIdx + bitIdx, true
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return 0, false
|
|
}
|
|
|
|
func (bA *BitArray) String() string {
|
|
if bA == nil {
|
|
return "nil-BitArray"
|
|
}
|
|
bA.mtx.Lock()
|
|
defer bA.mtx.Unlock()
|
|
return bA.stringIndented("")
|
|
}
|
|
|
|
func (bA *BitArray) StringIndented(indent string) string {
|
|
if bA == nil {
|
|
return "nil-BitArray"
|
|
}
|
|
bA.mtx.Lock()
|
|
defer bA.mtx.Unlock()
|
|
return bA.stringIndented(indent)
|
|
}
|
|
|
|
func (bA *BitArray) stringIndented(indent string) string {
|
|
|
|
lines := []string{}
|
|
bits := ""
|
|
for i := 0; i < bA.Bits; i++ {
|
|
if bA.getIndex(i) {
|
|
bits += "X"
|
|
} else {
|
|
bits += "_"
|
|
}
|
|
if i%100 == 99 {
|
|
lines = append(lines, bits)
|
|
bits = ""
|
|
}
|
|
if i%10 == 9 {
|
|
bits += " "
|
|
}
|
|
if i%50 == 49 {
|
|
bits += " "
|
|
}
|
|
}
|
|
if len(bits) > 0 {
|
|
lines = append(lines, bits)
|
|
}
|
|
return fmt.Sprintf("BA{%v:%v}", bA.Bits, strings.Join(lines, indent))
|
|
}
|
|
|
|
func (bA *BitArray) Bytes() []byte {
|
|
bA.mtx.Lock()
|
|
defer bA.mtx.Unlock()
|
|
|
|
numBytes := (bA.Bits + 7) / 8
|
|
bytes := make([]byte, numBytes)
|
|
for i := 0; i < len(bA.Elems); i++ {
|
|
elemBytes := [8]byte{}
|
|
binary.LittleEndian.PutUint64(elemBytes[:], bA.Elems[i])
|
|
copy(bytes[i*8:], elemBytes[:])
|
|
}
|
|
return bytes
|
|
}
|
|
|
|
// NOTE: other bitarray o is not locked when reading,
|
|
// so if necessary, caller must copy or lock o prior to calling Update.
|
|
// If bA is nil, does nothing.
|
|
func (bA *BitArray) Update(o *BitArray) {
|
|
if bA == nil || o == nil {
|
|
return
|
|
}
|
|
bA.mtx.Lock()
|
|
defer bA.mtx.Unlock()
|
|
|
|
copy(bA.Elems, o.Elems)
|
|
}
|