/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Copyright 2018 Danny Robson <danny@nerdcruft.net>
 */

#ifndef CRUFT_UTIL_JOB_SEMAPHORE_HPP
#define CRUFT_UTIL_JOB_SEMAPHORE_HPP

#include <atomic>

namespace util::job {
    /// Explicitly does not conform to BasicLockable.
    class semaphore {
    public:
        semaphore (int initial);
        semaphore ();

        semaphore (const semaphore&) = delete;
        semaphore& operator= (const semaphore&) = delete;
        semaphore (semaphore&&) = delete;
        semaphore& operator= (semaphore&&) = delete;

        int acquire (void);
        int acquire (int count);
        int release (void);

        auto   lock (void) { return acquire (); }
        auto unlock (void) { return release (); }

        int value (void) const;

        int operator++ (void);
        int operator-- (void);

    private:
        std::atomic<int> m_value;
    };
};

#endif