// insert key to MRU position
std::pair ret
= _map.insert( Val(key, LRUCacheH4Value(V(), _mru, NULL)) );

Val * inserted = &*ret.first;
if (_mru)
_mru->second._newer = inserted;
_mru = inserted;

// possibly update the LRU
if (!_lru)
_lru = _mru;
else if (!_lru->second._newer)
_lru->second._newer = _mru;

return inserted;
}

} // namespace lru

测试代码：

#include

#include "lru.hpp"

using namespace lru;
using namespace std;

int main()
{
typedef LRUCacheH4 CacheType;

CacheType tc(3);

tc.insert(1, 101);
tc.insert(2, 102);
tc.insert(3, 103);

tc.insert(2, 1002);

cout << tc[1] << endl;

cout << "================" << endl;

for (CacheType::const_iterator it = tc.mru_begin(); it != tc.end(); ++it)
cout << it.key() << " " << it.value() << endl;

cout << "================" << endl;

for (CacheType::const_iterator it = tc.lru_begin(); it != tc.end(); ++it)
cout << it.key() << " " << it.value() << endl;

system("PAUSE");
return 0;
}