/*

 * Copyright (c) 2016, 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,

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/* @test

 * @bug 8164102

 * @run main/othervm -ea -esa test.java.lang.invoke.CountedLoopIterationCountsTest

 */

package test.java.lang.invoke;

import java.lang.invoke.MethodHandle;

import java.lang.invoke.MethodHandles;

import java.lang.invoke.MethodType;

public class CountedLoopIterationCountsTest {

    public static void main(String[] args) throws Throwable {

        run(1, -10, 0);

        run(1, 0, 0);

        run(Integer.MAX_VALUE - 1, Integer.MIN_VALUE + 10, 0);

        run(Integer.MIN_VALUE, Integer.MIN_VALUE + 4, 4);

        run(Integer.MAX_VALUE - 2, Integer.MAX_VALUE - 1, 1);

        run(Integer.MAX_VALUE - 1, 0, 0);

        run(Integer.MAX_VALUE - 1, 10, 0);

        run(Integer.MAX_VALUE - 1, -10, 0);

        run(Integer.MAX_VALUE, Integer.MIN_VALUE + 10, 0);

        run(Integer.MAX_VALUE - 1, Integer.MAX_VALUE, 1);

        run(Integer.MAX_VALUE, Integer.MAX_VALUE, 0);

        if (failed) {

            throw new AssertionError("one or more tests failed");

        }

    }

    static boolean failed = false;

    private static void run(int start, int end, int expectedIterations) throws Throwable {

        System.out.println("run from " + start + " to " + end);

        MethodHandle loop = MethodHandles.countedLoop(

                MethodHandles.constant(int.class, start), // iterate from given start (inclusive) ...

                MethodHandles.constant(int.class, end),   // ... to given end (exclusive)

                MH_m1,                                    // initialise loop variable to -1

                MH_step);                                 // increment loop counter by one in each iteration

        // The loop variable's value, and hence the loop result, will be "number of iterations" minus one.

        int r = (int) loop.invoke();

        if (r + 1 != expectedIterations) {

            System.out.println("expected " + expectedIterations + " iterations, but got " + r);

            failed = true;

        }

    }

    static int step(int stepCount, int counter) {

        return stepCount + 1;

    }

    static final MethodHandle MH_m1;

    static final MethodHandle MH_step;

    static {

        try {

            MH_m1 = MethodHandles.constant(int.class, -1);

            MH_step = MethodHandles.lookup().findStatic(CountedLoopIterationCountsTest.class, "step",

                    MethodType.methodType(int.class, int.class, int.class));

        } catch (Throwable t) {

            throw new ExceptionInInitializerError(t);

        }

    }

}