lokinet/llarp/util/decaying_hashset.hpp
2019-12-30 15:52:10 -05:00

69 lines
1.5 KiB
C++

#ifndef LLARP_UTIL_DECAYING_HASHSET_HPP
#define LLARP_UTIL_DECAYING_HASHSET_HPP
#include <util/time.hpp>
#include <unordered_map>
namespace llarp
{
namespace util
{
template < typename Val_t, typename Hash_t = typename Val_t::Hash >
struct DecayingHashSet
{
DecayingHashSet(llarp_time_t cacheInterval = 5000)
: m_CacheInterval(cacheInterval)
{
}
/// determine if we have v contained in our decayiny hashset
bool
Contains(const Val_t& v) const
{
return m_Values.find(v) != m_Values.end();
}
/// return true if inserted
/// return false if not inserted
bool
Insert(const Val_t& v, llarp_time_t now = 0)
{
if(Contains(v))
return false;
if(now == 0)
now = llarp::time_now_ms();
m_Values.emplace(v, now + m_CacheInterval);
return true;
}
/// decay hashset entries
void
Decay(llarp_time_t now = 0)
{
if(now == 0)
now = llarp::time_now_ms();
auto itr = m_Values.begin();
while(itr != m_Values.end())
{
if(itr->second <= now)
itr = m_Values.erase(itr);
else
++itr;
}
}
llarp_time_t
DecayInterval() const
{
return m_CacheInterval;
}
private:
const llarp_time_t m_CacheInterval;
std::unordered_map< Val_t, llarp_time_t, Hash_t > m_Values;
};
} // namespace util
} // namespace llarp
#endif