/*
 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
 * 
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * The contents of this file are subject to the terms of either the Universal Permissive License
 * v 1.0 as shown at http://oss.oracle.com/licenses/upl
 *
 * or the following license:
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted
 * provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice, this list of conditions
 * and the following disclaimer.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
 * conditions and the following disclaimer in the documentation and/or other materials provided with
 * the distribution.
 * 
 * 3. Neither the name of the copyright holder nor the names of its contributors may be used to
 * endorse or promote products derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
 * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.openjdk.jmc.greychart.providers;

import org.openjdk.jmc.greychart.impl.SamplePoint;

/**
 * A buffer for stacking several sample series for the {@link IntermediateStackingProvider}.
 * <p>
 * Each bucket represents the sum of the values added to it.
 */
public final class StackingBuffer extends AbstractSampler {
	public StackingBuffer(int size) {
		super(size);
	}

	private int prevIndex = Integer.MAX_VALUE;
	private double previousY;

	public void startSeries() {
		prevIndex = Integer.MAX_VALUE;
	}

	public void addNonNormalizedDataPoint(int index, double currentY) {
		SamplePoint sp = getSamplePoint(index);
		sp.count++;
		sp.y += currentY;
		for (int x = prevIndex; x < index; x++) {
			SamplePoint samplePoint = getSamplePoint(x);
			samplePoint.y += previousY + (currentY - previousY) / (index - prevIndex) * (x - prevIndex);
		}
		prevIndex = index + 1;
		previousY = currentY;
		invalidateStatistics();
	}
}
