cluster_priority_queue.h

/*
 * Copyright © 2015-2023 Synthstrom Audible Limited
 *
 * This file is part of The Synthstrom Audible Deluge Firmware.
 *
 * The Synthstrom Audible Deluge Firmware is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software Foundation,
 * either version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program.
 * If not, see <https://www.gnu.org/licenses/>.
 */
 
#pragma once
 
#include "util/containers.h"
#include <cstdint>
#include <limits>
 
class Cluster;
 
class ClusterPriorityQueue {
    using Priority = uint32_t;
 
public:
    ClusterPriorityQueue() = default;
 
    Error push(Cluster& cluster, uint32_t priorityRating);
    constexpr Cluster& front() const { return *priority_map_.begin()->second; }
 
    constexpr void pop() {
        auto it = priority_map_.begin();
        priority_map_.erase(it);
        queued_clusters_.erase(it->second);
    }
 
    constexpr bool empty() const { return queued_clusters_.empty() || priority_map_.empty(); }
    constexpr size_t erase(Cluster& cluster) {
        if (auto search = queued_clusters_.find(&cluster); search != queued_clusters_.end()) {
            priority_map_.erase({search->second, &cluster});
            queued_clusters_.erase(&cluster);
            return 1;
        }
        return 0;
    }
 
    /* This is currently a consequence of how priorities are calculated (using full 32bits) next-gen getPriorityRating
     * should return an int32_t */
    constexpr bool hasAnyLowestPriority() const {
        return !priority_map_.empty() && priority_map_.rbegin()->first == std::numeric_limits<uint32_t>::max();
    }
 
private:
    deluge::fast_set<std::pair<Priority, Cluster*>> priority_map_;
    deluge::fast_unordered_map<Cluster*, Priority> queued_clusters_;
};