/*

 * Copyright (c) 2009, 2012, 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.

 *

 * 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.

 */

import java.util.*;

import java.nio.*;

import java.nio.charset.*;

import java.util.concurrent.*;

import java.util.regex.Pattern;

/**

 * Usage: java StringCodingBenchmark

 * [-Diterations=N] [-Dsize=N] [-Dsubsize=N] [-Dmaxchar=N]

 * [-Dfilter=REGEXP] [-DSecurityManager=true]

 */

public class StrCodingBenchmark {

    abstract static class Job {

        private final String name;

        public Job(String name) { this.name = name; }

        public String name() { return name; }

        public abstract void work() throws Throwable;

    }

    private static void collectAllGarbage() {

        final java.util.concurrent.CountDownLatch drained

            = new java.util.concurrent.CountDownLatch(1);

        try {

            System.gc();        // enqueue finalizable objects

            new Object() { protected void finalize() {

                drained.countDown(); }};

            System.gc();        // enqueue detector

            drained.await();    // wait for finalizer queue to drain

            System.gc();        // cleanup finalized objects

        } catch (InterruptedException e) { throw new Error(e); }

    }

    /**

     * Runs each job for long enough that all the runtime compilers

     * have had plenty of time to warm up, i.e. get around to

     * compiling everything worth compiling.

     * Returns array of average times per job per run.

     */

    public static long[] time0(Job ... jobs) throws Throwable {

        //final long warmupNanos = 10L * 1000L * 1000L * 1000L;

        final long warmupNanos = 100L * 100L;

        long[] nanoss = new long[jobs.length];

        for (int i = 0; i < jobs.length; i++) {

            collectAllGarbage();

            long t0 = System.nanoTime();

            long t;

            int j = 0;

            do { jobs[i].work(); j++; }

            while ((t = System.nanoTime() - t0) < warmupNanos);

            nanoss[i] = t/j;

        }

        return nanoss;

    }

    public static long[] time(Job ... jobs) throws Throwable {

        long[] warmup = time0(jobs); // Warm up run

        long[] nanoss = time0(jobs); // Real timing run

        long[] milliss = new long[jobs.length];

        double[] ratios = new double[jobs.length];

        final String nameHeader   = "Method";

        final String millisHeader = "Millis";

        final String ratioHeader  = "Ratio";

        int nameWidth   = nameHeader.length();

        int millisWidth = millisHeader.length();

        int ratioWidth  = ratioHeader.length();

        for (int i = 0; i < jobs.length; i++) {

            nameWidth = Math.max(nameWidth, jobs[i].name().length());

            milliss[i] = nanoss[i]/(1000L * 1000L);

            millisWidth = Math.max(millisWidth,

                                   String.format("%d", milliss[i]).length());

            ratios[i] = (double) nanoss[i] / (double) nanoss[0];

            ratioWidth = Math.max(ratioWidth,

                                  String.format("%.3f", ratios[i]).length());

        }

        String format = String.format("%%-%ds %%%dd %n",

                                      nameWidth, millisWidth);

        String headerFormat = String.format("%%-%ds %%%ds%n",

                                            nameWidth, millisWidth);

        System.out.printf(headerFormat, "Method", "Millis");

        // Print out absolute and relative times, calibrated against first job

        for (int i = 0; i < jobs.length; i++)

            System.out.printf(format, jobs[i].name(), milliss[i], ratios[i]);

        return milliss;

    }

    public static Job[] filter(Pattern filter, Job[] jobs) {

        if (filter == null) return jobs;

        Job[] newJobs = new Job[jobs.length];

        int n = 0;

        for (Job job : jobs)

            if (filter.matcher(job.name()).find())

                newJobs[n++] = job;

        // Arrays.copyOf not available in JDK 5

        Job[] ret = new Job[n];

        System.arraycopy(newJobs, 0, ret, 0, n);

        return ret;

    }

    static class PermissiveSecurityManger extends SecurityManager {

        @Override public void checkPermission(java.security.Permission p) {

        }

    }

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

        final int itrs = Integer.getInteger("iterations", 100000);

        final int size       = Integer.getInteger("size", 2048);

        final int subsize    = Integer.getInteger("subsize", 128);

        final int maxchar    = Integer.getInteger("maxchar", 128);

        final String regex = System.getProperty("filter");

        final Pattern filter = (regex == null) ? null : Pattern.compile(regex);

        final boolean useSecurityManager = Boolean.getBoolean("SecurityManager");

        if (useSecurityManager)

            System.setSecurityManager(new PermissiveSecurityManger());

        final Random rnd = new Random();

        for (Charset charset:  Charset.availableCharsets().values()) {

            if (!("ISO-8859-1".equals(charset.name()) ||

                  "US-ASCII".equals(charset.name()) ||

                  charset.newDecoder() instanceof sun.nio.cs.SingleByte.Decoder))

                continue;

            final String csn = charset.name();

            final Charset cs = charset;

            final StringBuilder sb = new StringBuilder();

            {

                final CharsetEncoder enc = cs.newEncoder();

                for (int i = 0; i < size; ) {

                    char c = (char) rnd.nextInt(maxchar);

                    if (enc.canEncode(c)) {

                        sb.append(c);

                        i++;

                    }

                }

            }

            final String string = sb.toString();

            final byte[] bytes  = string.getBytes(cs);

            System.out.printf("%n--------%s---------%n", csn);

            for (int sz = 4; sz <= 2048; sz *= 2) {

                System.out.printf("   [len=%d]%n", sz);

                final byte[] bs  = Arrays.copyOf(bytes, sz);

                final String str = new String(bs, csn);

                Job[] jobs = {

                    new Job("String decode: csn") {

                    public void work() throws Throwable {

                        for (int i = 0; i < itrs; i++)

                            new String(bs, csn);

                    }},

                    new Job("String decode: cs") {

                    public void work() throws Throwable {

                        for (int i = 0; i < itrs; i++)

                            new String(bs, cs);

                    }},

                    new Job("String encode: csn") {

                    public void work() throws Throwable {

                        for (int i = 0; i < itrs; i++)

                                str.getBytes(csn);

                    }},

                    new Job("String encode: cs") {

                    public void work() throws Throwable {

                         for (int i = 0; i < itrs; i++)

                          str.getBytes(cs);

                    }},

                };

                time(filter(filter, jobs));

            }

        }

    }

}