func (b *bucket) getDummy(index uint32) *bucket {
key := Dummykey(index)
for {
pred, curr := b.find(key)
if (*node)(curr).Key == key {
return &bucket{
head: curr,
}
} else {
dummy := &node{
Key: key,
next: (*node)(pred).next,
}
if taggedptr.CompareAndSwap(&(*node)(pred).next, curr, unsafe.Pointer(dummy), 0, 0) {
return &bucket{
head: unsafe.Pointer(dummy),
}
} else {
continue
}
}
}
return nil
}
// Add item to list.
func (b *bucket) add(newNode *node) bool {
for {
pred, curr := b.find(newNode.Key)
if (*node)(curr).Key == newNode.Key {
newNode.next = (*node)(curr).next
} else {
newNode.next = curr
}
return taggedptr.CompareAndSwap(&(*node)(pred).next, curr, unsafe.Pointer(newNode), 0, 0)
}
}
// Remove item from the list.
func (b *bucket) remove(key uint32) bool {
for {
pred, curr := b.find(key)
if (*node)(curr).Key != key {
return false
} else {
succ := taggedptr.GetPointer((*node)(curr).next)
if !taggedptr.AttemptTag(&(*node)(curr).next, succ, 1) {
continue
}
taggedptr.CompareAndSwap(&(*node)(pred).next, curr, succ, 0, 0)
return true
}
}
}
func (b *bucket) find(key uint32) (unsafe.Pointer, unsafe.Pointer) {
pred := b.head
curr := taggedptr.GetPointer((*node)(b.head).next)
Retry:
for {
succ, tag := taggedptr.Get((*node)(curr).next)
for tag != 0 {
if !taggedptr.CompareAndSwap(&(*node)(pred).next, curr, succ, 0, 0) {
continue Retry
}
curr = succ
succ = taggedptr.GetPointer((*node)(curr).next)
}
if (*node)(curr).Key >= key {
return pred, curr
}
pred = curr
curr = succ
}
}