Files
OpenSpace/modules/volume/linearlrucache.inl
2024-02-06 15:53:24 +01:00

86 lines
3.7 KiB
C++

/*****************************************************************************************
* *
* OpenSpace *
* *
* Copyright (c) 2014-2024 *
* *
* Permission is hereby granted, free of charge, to any person obtaining a copy of this *
* software and associated documentation files (the "Software"), to deal in the Software *
* without restriction, including without limitation the rights to use, copy, modify, *
* merge, publish, distribute, sublicense, and/or sell copies of the Software, and to *
* permit persons to whom the Software is furnished to do so, subject to the following *
* conditions: *
* *
* The above copyright notice and this permission notice shall be included in all copies *
* or substantial portions of the Software. *
* *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, *
* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A *
* PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT *
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF *
* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE *
* OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
****************************************************************************************/
namespace openspace::volume {
template <typename ValueType>
LinearLruCache<ValueType>::LinearLruCache(size_t capacity, size_t nIndices)
: _tracker()
, _cache(nIndices, { nullptr, _tracker.end() })
, _capacity(capacity)
{}
template <typename ValueType>
bool LinearLruCache<ValueType>::has(size_t key) const {
return _cache[key].first != nullptr;
}
template <typename ValueType>
void LinearLruCache<ValueType>::set(size_t key, ValueType value) {
auto prev = _cache[key];
if (prev.first != nullptr) {
prev.first = value;
const std::list<size_t>::iterator trackerIter = prev.second;
_tracker.splice(_tracker.end(), _tracker, trackerIter);
}
else {
insert(key, value);
}
}
template <typename ValueType>
ValueType& LinearLruCache<ValueType>::use(size_t key) {
auto& pair = _cache[key];
const std::list<size_t>::iterator trackerIter = pair.second;
_tracker.splice(_tracker.end(), _tracker, trackerIter);
return pair.first;
}
template <typename ValueType>
ValueType& LinearLruCache<ValueType>::get(size_t key) {
return _cache[key].first;
}
template <typename ValueType>
void LinearLruCache<ValueType>::evict() {
_cache[_tracker.front()] = make_pair(nullptr, _tracker.end());
_tracker.pop_front();
}
template <typename ValueType>
size_t LinearLruCache<ValueType>::capacity() const {
return _capacity;
}
template <typename ValueType>
void LinearLruCache<ValueType>::insert(size_t key, const ValueType& value) {
if (_tracker.size() == _capacity) {
evict();
}
auto iter = _tracker.insert(_tracker.end(), key);
_cache[key] = { value, iter };
}
} // namespace openspace::volume