wvstringcache.cc

/*
 * Worldvisions Weaver Software:
 *   Copyright (C) 2005 Net Integration Technologies, Inc.
 *
 * Definition for the WvStringCache class.  See wvstringcache.h.
 */
#include "wvstringcache.h"
#include "wvstringlist.h"
 
WvStringTable *WvStringCache::t;
int WvStringCache::refcount;
size_t WvStringCache::clean_threshold;
 
WvStringCache::WvStringCache()
{
    refcount++;
    if (!t)
    {
        t = new WvStringTable;
        clean_threshold = 0;
    }
}
 
 
WvStringCache::~WvStringCache()
{
    refcount--;
    if (!refcount)
    {
        delete t;
        t = NULL;
        clean_threshold = 0;
    }
    else
        clean();
}
    
 
WvString WvStringCache::get(WvStringParm s)
{
    // return s; // disable cache
    WvString *ret = (*t)[s];
    if (ret)
    {
        // printf("found(%s)\n", s.cstr());
        return *ret;
    }
    else
    {
        // printf("  new(%s)\n", s.cstr());
        ret = new WvString(s);
        t->add(ret, true);
        return *ret;
    }
}
 
 
void WvStringCache::clean()
{
    // do we actually need to clean yet?  Skip it if we haven't added too
    // many items since the last clean, since cleaning is pretty slow.
    if (t->count() < clean_threshold)
        return;
    
    WvStringList l;
    
    // use a two-stage process so the iterator doesn't get messed up
    // FIXME: this might actually be unnecessary with WvScatterHash, but
    // someone should actually confirm that before taking this out.
    {
        WvStringTable::Iter i(*t);
        for (i.rewind(); i.next(); )
        {
            if (i->is_unique()) // last remaining instance
            {
                // printf("CLEANUP(%s)\n", i->cstr());
                l.append(i.ptr(), false);
            }
        }
    }
    
//    printf("CLEANUP-1: %d elements at start (%d to remove)\n",
//         (int)t->count(), (int)l.count());
    
    {
        WvStringList::Iter i(l);
        for (i.rewind(); i.next(); )
            t->remove(i.ptr());
    }
    
    clean_threshold = t->count() + t->count()/10 + 1;
    
//    printf("CLEANUP-2: %d elements left (thres=%d).\n", 
//         (int)t->count(), (int)clean_threshold);
}