package eu.faircode.email;

/*
    This file is part of FairEmail.

    FairEmail 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.

    FairEmail 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 FairEmail.  If not, see <http://www.gnu.org/licenses/>.

    Copyright 2018-2022 by Marcel Bokhorst (M66B)
*/

public class RingBuffer<T> {
    private T[] buffer;
    private int count = 0;
    private int out = 0;
    private int in = 0;

    public RingBuffer(int capacity) {
        buffer = (T[]) new Object[capacity];
    }

    public synchronized void push(T item) {
        if (count == buffer.length)
            pop();

        buffer[in] = item;
        in = (in + 1) % buffer.length;
        count++;
    }

    public synchronized T pop() {
        T item = buffer[out];
        buffer[out] = null;
        count--;
        out = (out + 1) % buffer.length;
        return item;
    }

    public synchronized boolean isEmpty() {
        return (count == 0);
    }

    public synchronized int size() {
        return count;
    }
}