LRUCache
Demostration of LRUCache
LRUCache.cpp
#include <Core/Core.h>
using namespace Upp;
struct MakeFactorial : LRUCache<double, int>::Maker {
int n;
virtual int Key() const {
return n;
}
virtual int Make(double& object) const {
LOG("Computing factorial of " << n); // only to show that values are cached
object = 1;
for(int i = 1; i <= n; i++)
object *= i;
return 1; // 'Size' of created object
}
};
double GetFactorialCached(int num)
{
#ifdef MULTITHREADED // need to serialize access to cache
static StaticMutex cm;
Mutex::Lock __(cm);
#endif
static LRUCache<double, int> cache;
MakeFactorial f;
f.n = num;
double result = cache.Get(f);
cache.Shrink(20); // cache only 20 values
return result;
}
CONSOLE_APP_MAIN
{
DUMP(GetFactorialCached(20));
DUMP(GetFactorialCached(30));
DUMP(GetFactorialCached(20)); // this one should be retrieved from the cache
}
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