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	/*
	* Copyright (c) 2009, 2015, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code 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
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package sun.java2d.marlin;

	/**
	* MergeSort adapted from (OpenJDK 8) java.util.Array.legacyMergeSort(Object[])
	* to swap two arrays at the same time (x & y)
	* and use external auxiliary storage for temporary arrays
	*/
	final class MergeSort {

	// insertion sort threshold
	public static final int INSERTION_SORT_THRESHOLD = 14;

	/**
	* Modified merge sort:
	* Input arrays are in both auxX/auxY (sorted: 0 to insertionSortIndex)
	* and x/y (unsorted: insertionSortIndex to toIndex)
	* Outputs are stored in x/y arrays
	*/
	static void mergeSortNoCopy(final int[] x, final int[] y,
	final int[] auxX, final int[] auxY,
	final int toIndex,
	final int insertionSortIndex)
	{
	if ((toIndex > x.length) \|\| (toIndex > y.length)
	\|\| (toIndex > auxX.length) \|\| (toIndex > auxY.length)) {
	// explicit check to avoid bound checks within hot loops (below):
	throw new ArrayIndexOutOfBoundsException("bad arguments: toIndex="
	+ toIndex);
	}

	// sort second part only using merge / insertion sort
	// in auxiliary storage (auxX/auxY)
	mergeSort(x, y, x, auxX, y, auxY, insertionSortIndex, toIndex);

	// final pass to merge both
	// Merge sorted parts (auxX/auxY) into x/y arrays
	if ((insertionSortIndex == 0)
	\|\| (auxX[insertionSortIndex - 1] <= auxX[insertionSortIndex])) {
	// System.out.println("mergeSortNoCopy: ordered");
	// 34 occurences
	// no initial left part or both sublists (auxX, auxY) are sorted:
	// copy back data into (x, y):
	System.arraycopy(auxX, 0, x, 0, toIndex);
	System.arraycopy(auxY, 0, y, 0, toIndex);
	return;
	}

	for (int i = 0, p = 0, q = insertionSortIndex; i < toIndex; i++) {
	if ((q >= toIndex) \|\| ((p < insertionSortIndex)
	&& (auxX[p] <= auxX[q]))) {
	x[i] = auxX[p];
	y[i] = auxY[p];
	p++;
	} else {
	x[i] = auxX[q];
	y[i] = auxY[q];
	q++;
	}
	}
	}

	/**
	* Src is the source array that starts at index 0
	* Dest is the (possibly larger) array destination with a possible offset
	* low is the index in dest to start sorting
	* high is the end index in dest to end sorting
	*/
	private static void mergeSort(final int[] refX, final int[] refY,
	final int[] srcX, final int[] dstX,
	final int[] srcY, final int[] dstY,
	final int low, final int high)
	{
	final int length = high - low;

	/*
	* Tuning parameter: list size at or below which insertion sort
	* will be used in preference to mergesort.
	*/
	if (length <= INSERTION_SORT_THRESHOLD) {
	// Insertion sort on smallest arrays
	dstX[low] = refX[low];
	dstY[low] = refY[low];

	for (int i = low + 1, j = low, x, y; i < high; j = i++) {
	x = refX[i];
	y = refY[i];

	while (dstX[j] > x) {
	// swap element
	dstX[j + 1] = dstX[j];
	dstY[j + 1] = dstY[j];
	if (j-- == low) {
	break;
	}
	}
	dstX[j + 1] = x;
	dstY[j + 1] = y;
	}
	return;
	}

	// Recursively sort halves of dest into src

	// note: use signed shift (not >>>) for performance
	// as indices are small enough to exceed Integer.MAX_VALUE
	final int mid = (low + high) >> 1;

	mergeSort(refX, refY, dstX, srcX, dstY, srcY, low, mid);
	mergeSort(refX, refY, dstX, srcX, dstY, srcY, mid, high);

	// If arrays are inverted ie all(A) > all(B) do swap A and B to dst
	if (srcX[high - 1] <= srcX[low]) {
	// System.out.println("mergeSort: inverse ordered");
	// 1561 occurences
	final int left = mid - low;
	final int right = high - mid;
	final int off = (left != right) ? 1 : 0;
	// swap parts:
	System.arraycopy(srcX, low, dstX, mid + off, left);
	System.arraycopy(srcX, mid, dstX, low, right);
	System.arraycopy(srcY, low, dstY, mid + off, left);
	System.arraycopy(srcY, mid, dstY, low, right);
	return;
	}

	// If arrays are already sorted, just copy from src to dest. This is an
	// optimization that results in faster sorts for nearly ordered lists.
	if (srcX[mid - 1] <= srcX[mid]) {
	// System.out.println("mergeSort: ordered");
	// 14 occurences
	System.arraycopy(srcX, low, dstX, low, length);
	System.arraycopy(srcY, low, dstY, low, length);
	return;
	}

	// Merge sorted halves (now in src) into dest
	for (int i = low, p = low, q = mid; i < high; i++) {
	if ((q >= high) \|\| ((p < mid) && (srcX[p] <= srcX[q]))) {
	dstX[i] = srcX[p];
	dstY[i] = srcY[p];
	p++;
	} else {
	dstX[i] = srcX[q];
	dstY[i] = srcY[q];
	q++;
	}
	}
	}

	private MergeSort() {
	}
	}

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