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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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/*
 * @test
 * @summary Testing that, faced with a given (possibly odd) mapping address of class space, the encoding
 *          scheme fits the address
 * @requires vm.bits == 64 & !vm.graal.enabled & vm.debug == true
 * @requires vm.flagless
 * @library /test/lib
 * @modules java.base/jdk.internal.misc
 *          java.management
 * @run driver CompressedClassPointersEncodingScheme
 */

import jdk.test.lib.Platform;
import jdk.test.lib.process.OutputAnalyzer;
import jdk.test.lib.process.ProcessTools;
import jtreg.SkippedException;

import java.io.IOException;

public class CompressedClassPointersEncodingScheme {

    private static void test(long forceAddress, long classSpaceSize, long expectedEncodingBase, int expectedEncodingShift) throws IOException {
        String forceAddressString = String.format("0x%016X", forceAddress).toLowerCase();
        String expectedEncodingBaseString = String.format("0x%016X", expectedEncodingBase).toLowerCase();
        ProcessBuilder pb = ProcessTools.createLimitedTestJavaProcessBuilder(
                "-Xshare:off", // to make CompressedClassSpaceBaseAddress work
                "-XX:+UnlockDiagnosticVMOptions",
                "-XX:-UseCompressedOops", // keep VM from optimizing heap location
                "-XX:CompressedClassSpaceBaseAddress=" + forceAddress,
                "-XX:CompressedClassSpaceSize=" + classSpaceSize,
                "-Xmx128m",
                "-Xlog:metaspace*",
                "-version");
        OutputAnalyzer output = new OutputAnalyzer(pb.start());

        output.reportDiagnosticSummary();

        // We ignore cases where we were not able to map at the force address
        if (output.contains("reserving class space failed")) {
            throw new SkippedException("Skipping because we cannot force ccs to " + forceAddressString);
        }

        output.shouldHaveExitValue(0);
        output.shouldContain("Narrow klass base: " + expectedEncodingBaseString + ", Narrow klass shift: " + expectedEncodingShift);
    }

    final static long K = 1024;
    final static long M = K * 1024;
    final static long G = M * 1024;
    public static void main(String[] args) throws Exception {
        // Test ccs nestling right at the end of the 4G range
        // Expecting base=0, shift=0
        test(4 * G - 128 * M, 128 * M, 0, 0);

        // add more...

    }
}