Observation about hash-table.

Dhruv Matani dhruvbird@gmx.net
Fri May 7 15:05:00 GMT 2004


On Fri, 2004-05-07 at 20:09, Dhruv Matani wrote:
> Hello everyone,
> 	I noticed that the hash-table uses chaining for its purposes. However,
> insertion is not thread-safe, but can be made so quite easily IMHO. Now,
> when the pointers for the vector and the link node are being set the
> following should ensure safety:
> 
> struct node;
> vector<node*> vpn(bucket_size);
> 
> void insert(const_ref value)
> {
> 	int bkt = //Bucket number.
> 	node* current = new node(value);
> 	node* tmp = current;
> 	atomic_exchange_after_deref(current, &vpn[bkt]);
> 	tmp->next = current;
> }
> 
> 
> Should this do the trick, or is something wrong?

Which I just realized is not as simple as I initially thought, because
the hash-table inserts values within a bucket in sorted order, as
opposed to just a stack like insertion as I initially thought :-(


> 
-- 
        -Dhruv Matani.
http://www.geocities.com/dhruvbird/

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