58cc0014e1
Adds a generic C++ based caching library to support material external modules. This is a template based library which means there is nothing to build or link. The only modification is to the CMakeLists.txt file to enable integration with FreeCAD, Original source: https://github.com/goldsborough/lru-cache
58 lines
2.0 KiB
C++
58 lines
2.0 KiB
C++
/// The MIT License (MIT)
|
|
/// Copyright (c) 2016 Peter Goldsborough
|
|
///
|
|
/// 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.
|
|
|
|
#include <chrono>
|
|
#include <iostream>
|
|
|
|
#include "lru/lru.hpp"
|
|
|
|
using namespace std::chrono_literals;
|
|
|
|
using Cache = LRU::TimedCache<int, int>;
|
|
|
|
int fibonacci(int n, Cache& cache) {
|
|
if (n < 2) return 1;
|
|
|
|
// We internally keep track of the last accessed key, meaning a
|
|
// `contains(key)` + `lookup(key)` sequence will involve only a single hash
|
|
// table lookup.
|
|
if (cache.contains(n)) return cache[n];
|
|
|
|
auto value = fibonacci(n - 1, cache) + fibonacci(n - 2, cache);
|
|
|
|
// Caches are 100% move-aware and we have implemented
|
|
// `unordered_map` style emplacement and insertion.
|
|
cache.emplace(n, value);
|
|
|
|
return value;
|
|
}
|
|
|
|
int fibonacci(int n) {
|
|
// Use a time to live of 100ms. This means that 100ms after insertion, a key
|
|
// will be said to have "expired" and `contains(key)` will return false.
|
|
Cache cache(100ms);
|
|
return fibonacci(n, cache);
|
|
}
|
|
|
|
auto main() -> int {
|
|
std::cout << fibonacci(32) << std::endl;
|
|
}
|