• Ondrej Pokorny (64/64) Aug 21 2012 Hi,
• Ondrej Pokorny (3/3) Aug 21 2012 Could you remove this double repost please?
• Ondrej Pokorny (2/2) Aug 21 2012 Ignore this doulbe post, please.

"Ondrej Pokorny" <pokorny.ondrej gmail.com> writes:

Hi,

there is in chapter 13.16.2 in last paragraph before SharedList 
code listing:
... The idea is first to mark that pointer as “logically 
deleted” by setting its bit to zero, and then ...

and later:

T* setlsb(T)(T* p) {
    return cast(T*) (cast(size_t) p | 1);
}

now to SharedList source code. Could possibly someone give me a 
hand and helps explain me this algorithm?
I hope nobody will be offended if i repost it from here 
(http://www.informit.com/articles/article.aspx?p=1609144&seqNum=16) 
in my book is same version:

shared struct SharedList(T) {
    shared struct Node {
       private T _payload;
       private Node * _next;

        property shared(Node)* next() {
          return clearlsb(_next);
       }

       bool removeAfter() {
          shared(Node)* thisNext, afterNext;
          // Step 1: set the lsb of _next for the node to delete
          do {
             thisNext = next;
             if (!thisNext) return false;
             afterNext = thisNext.next;
          } while (!cas(&thisNext._next, afterNext, 
setlsb(afterNext)));
          // Step 2: excise the node to delete
          if (!cas(&_next, thisNext, afterNext)) {
             afterNext = thisNext._next;
             while (!haslsb(afterNext)) {
                thisNext._next = thisNext._next.next;
          }
          _next = afterNext;
       }
    }

    void insertAfter(T value) {
       auto newNode = new Node(value);
       for (;;) {
          // Attempt to find an insertion point
          auto n = _next;
          while (n && haslsb(n)) {
             n = n._next;
          }
          // Found a possible insertion point, attempt insert
          auto afterN = n._next;
          newNode._next = afterN;
          if (cas(&n._next, afterN, newNode)) {
             break;
          }
       }
     }
   }

   private Node * _root;

   void pushFront(T value) {
      ... // Same as for Stack.push
   }

   shared(T)* popFront() {
      ... // Same as for Stack.pop
   }
}

"Ondrej Pokorny" <pokorny.ondrej gmail.com> writes:

Could you remove this double repost please?

Thanks.

Ondrej

"Ondrej Pokorny" <pokorny.ondrej gmail.com> writes:

Ignore this doulbe post, please.

Ondrej