utils/wvstringcache.cc

   1 /*
   2  * Worldvisions Weaver Software:
   3  *   Copyright (C) 2005 Net Integration Technologies, Inc.
   4  *
   5  * Definition for the WvStringCache class.  See wvstringcache.h.
   6  */
   7 #include "wvstringcache.h"
   8 #include "wvstringlist.h"
   9
  10 WvStringTable *WvStringCache::t;
  11 int WvStringCache::refcount;
  12 size_t WvStringCache::clean_threshold;
  13
  14 WvStringCache::WvStringCache()
  15 {
  16     refcount++;
  17     if (!t)
  18     {
  19         t = new WvStringTable;
  20         clean_threshold = 0;
  21     }
  22 }
  23
  24
  25 WvStringCache::~WvStringCache()
  26 {
  27     refcount--;
  28     if (!refcount)
  29     {
  30         delete t;
  31         t = NULL;
  32         clean_threshold = 0;
  33     }
  34     else
  35         clean();
  36 }
  37
  38
  39 WvString WvStringCache::get(WvStringParm s)
  40 {
  41     // return s; // disable cache
  42     WvString *ret = (*t)[s];
  43     if (ret)
  44     {
  45         // printf("found(%s)\n", s.cstr());
  46         return *ret;
  47     }
  48     else
  49     {
  50         // printf("  new(%s)\n", s.cstr());
  51         ret = new WvString(s);
  52         t->add(ret, true);
  53         return *ret;
  54     }
  55 }
  56
  57
  58 void WvStringCache::clean()
  59 {
  60     // do we actually need to clean yet?  Skip it if we haven't added too
  61     // many items since the last clean, since cleaning is pretty slow.
  62     if (t->count() < clean_threshold)
  63         return;
  64
  65     WvStringList l;
  66
  67     // use a two-stage process so the iterator doesn't get messed up
  68     // FIXME: this might actually be unnecessary with WvScatterHash, but
  69     // someone should actually confirm that before taking this out.
  70     {
  71         WvStringTable::Iter i(*t);
  72         for (i.rewind(); i.next(); )
  73         {
  74             if (i->is_unique()) // last remaining instance
  75             {
  76                 // printf("CLEANUP(%s)\n", i->cstr());
  77                 l.append(i.ptr(), false);
  78             }
  79         }
  80     }
  81
  82 //    printf("CLEANUP-1: %d elements at start (%d to remove)\n",
  83 //         (int)t->count(), (int)l.count());
  84
  85     {
  86         WvStringList::Iter i(l);
  87         for (i.rewind(); i.next(); )
  88             t->remove(i.ptr());
  89     }
  90
  91     clean_threshold = t->count() + t->count()/10 + 1;
  92
  93 //    printf("CLEANUP-2: %d elements left (thres=%d).\n",
  94 //         (int)t->count(), (int)clean_threshold);
  95 }
  96
  97