utilmm: utilmm: cached_fn.hh Source File

00001 /* -*- C++ -*-
00002  * $Id: cached_fn.hh 957 2005-03-07 16:01:20Z sjoyeux $
00003  */
00004 #ifndef UTILMM_FUNCTIONAL_CACHED_FN_HEADER
00005 # define UTILMM_FUNCTIONAL_CACHED_FN_HEADER
00006 
00007 #include "utilmm/config/config.h"
00008 #include "utilmm/hash/hash_map.hh"
00009 
00010 namespace utilmm {
00011 
00058   template< typename Arg, typename Ret, class Hash=hash<Arg>,
00059             class Equal=std::equal_to<Arg> >
00060   class cached_fn
00061     :public std::unary_function<Arg, Ret> {
00062   private:
00063     typedef hash_map<Arg, Ret, Hash, Equal> cache_type;
00064     typedef typename arg_traits<Arg>::type arg_type;
00065     
00066     cache_type the_cache;
00067     
00068   protected:
00078     virtual Ret call(Arg const &arg) =0;
00079 
00080   public:
00085     cached_fn() {}
00087     virtual ~cached_fn() {}
00088 
00103     Ret const &operator()(arg_type arg);
00104 
00111     void empty_cache() {
00112       the_cache.clear();
00113     }
00114     
00119     size_t cache_size() const {
00120       return the_cache.size();
00121     }
00122   }; // struct utilmm::cached_fn<>
00123 
00124 } // namespace utilmm
00125 
00126 # define IN_UTILMM_FUNCTIONAL_CACHED_FN_HEADER
00127 #include "utilmm/functional/bits/cached_fn.tcc" 
00128 # undef IN_UTILMM_FUNCTIONAL_CACHED_FN_HEADER 
00129 #endif // UTILMM_FUNCTIONAL_CACHED_FN_HEADER
00130