memory pool and rb-tree

[Steven Schveighoffer]

"Jeff" wrote
> Hi,
>
> i'm learning D and i'm trying to translate my C++ code to D. But i hit 
> some problems.
>
> My C++ code looks like:
>
> struct spot_rec
> {
> char id[20];
> int  value1;
> int  value2;
> int  value3;
> bool changed;
>
> spot_rec() {...}; //init
> const spot_rec& operator=(const spot_rec& r) {...}; //copy-operator
> };
>
> struct less_spot_record : public std::binary_function<spot_rec *,spot_rec 
> *,bool>
> {
>  bool operator()(const spot_rec *a, const spot_rec *b) const { return 
> stricmp(a->id, b->id); }
> };
>
> typedef set < spot_rec*, less_spot_record >  TableSpotRecords;
> typedef set < spot_rec*, less_spot_record >::iterator 
> TableSpotRecordsIter;
>
> boost::my_object_pool< spot_rec > pool_spot_rec;
> TableSpotRecords table_spot_rec;  //ordered RB-Tree
>
> bool shutdown = false;
> int thread_save_data()
> {
> while(!shutdown)
> {
> TableSpotRecordsIter iter = table_spot_rec.begin();
> while(iter != table_spot_rec.end())
> {
> spot_rec *r = *iter;
> if(r->changed)
> {
> mutex.lock();
> save_record(r);
> r->changed = false;
> mutex.unlock();
> }
> if(shutdown) return 0;
> ++iter; // is thread save
> }
> }
> return 0;
> }
>
> void update_spot(spot_rec *r)
> {
>    TableSpotRecordsIter iter = table_spot_rec.find(r);
>    if(iter==table_spot_rec.end())
> {   //add new record
> spot_rec *p = pool_spot_rec.construct();
> *p = *r;
> table_spot_rec.insert(p) // is thread save
> }
> else
> { //update record
> spot_rec *p = *iter;
> mutex.lock();
> *p = *r;
> mutex.unlock();
> }
> }
>
> main
> {
> create_thread(thread_save_data);
> ...
> //read from udp socket
> char buf[1024];
> while( recvfrom(socket,buf,sizeof(buf),from,fromlen)>0 )
> {
> spot_rec r;
> if(parse_record(buf,r))
> update_spot(&r);
> }
>
> shutdown=true;
> join_thread();
> table_spot_rec.purge_memory();
> ...
> }
>
> This program processes realtime data.
> I can't find a D replacement for boost::my_object_pool and stlport-set.
> I looked at tango and dcollections, but i can't find any example that use 
> RB-Trees and where i can set my own compare function.
>
> Can somebody help me?

As far as TreeSet in dcollections, you can replace the compare function 
(although, I admit the docs aren't fully filled out, there should eventually 
be a tutorial that covers this kind of stuff):

int myCompare(ref spot_rec sr1, ref spot_rec sr2) {/*your compare impl 
here*/}
...
TreeSet!(spot_rec).Impl.parameters p;
p.compareFunction = &myCompare;
auto tset = new TreeSet!(spot_rec)(p);

That's kinda ugly, I probably should work on the syntax to make that 
easier...  but it does work :)

-Steve