/*
 * Copyright (C) 2016 Linaro Limited. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

/*
 * Description:     Tracks performance of String intrinsics, Java, and native methods.
 * Main Focus:      Looped memory compare.
 * Secondary Focus: Array access.
 *
 */

package org.linaro.benchmarks.micro;

import java.lang.StringBuilder;
import java.lang.System;
import java.util.Random;
import org.openjdk.jmh.annotations.*;
import java.util.concurrent.TimeUnit;

@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@State(Scope.Benchmark)

public class StringOps {

  private static int RANDOM_STRING_8 = 0;
  private static int RANDOM_STRING_16 = 1;
  private static int RANDOM_STRING_32 = 2;
  private static int RANDOM_STRING_128 = 3;
  private static int RANDOM_STRING_512 = 4;
  private static int NUM_LENGTH_TESTS = 5;

  private static char MIN_RANDOM_CHAR = 65;
  private static char MAX_RANDOM_CHAR = 123;
  private static char searchChar;

  /* Intentionally use the same seed each time for consistency across benchmark runs. */
  private static int SAME_SEED = 0;

  /* Random string data. */
  private static Random rnd = new Random(SAME_SEED);
  private static String[] stringData = new String[NUM_LENGTH_TESTS];

  /* Same random string data as above for comparing different instances of the same char data. */
  private static Random rndAlt = new Random(SAME_SEED);
  private static String[] stringDataAlt = new String[NUM_LENGTH_TESTS];

  /* Benchmark results cache for preventing DCE. */
  private static boolean[] stringEqualsResults = new boolean[NUM_LENGTH_TESTS];
  private static boolean[] stringEqualsIgnoreCaseResults = new boolean[NUM_LENGTH_TESTS];
  private static boolean[] stringContentEqualsResults = new boolean[NUM_LENGTH_TESTS];
  private static int[] stringCompareToResults = new int[NUM_LENGTH_TESTS];
  private static int[] stringCompareToIgnoreCaseResults = new int[NUM_LENGTH_TESTS];
  private static boolean[] stringRegionMatchesResults = new boolean[NUM_LENGTH_TESTS];
  private static boolean[] stringRegionMatchesIgnoreCaseResults = new boolean[NUM_LENGTH_TESTS];
  private static char stringCharAtResult;
  private static int stringIndexOfResult;
  private static int stringIndexOfAfterResult;
  private static String[] stringNewStringFromBytesResult = new String[NUM_LENGTH_TESTS];
  private static String[] stringNewStringFromCharsResult = new String[NUM_LENGTH_TESTS];
  private static String[] stringNewStringFromStringResult = new String[NUM_LENGTH_TESTS];
  private static String[] stringGetCharsNoCheckResult = new String[NUM_LENGTH_TESTS];

  private static char []chars_8 = new char[8];
  private static char []chars_16 = new char[16];
  private static char []chars_32 = new char[32];
  private static char []chars_128 = new char[128];
  private static char []chars_512 = new char[512];

  private static String generateRandomString(int len, Random rnd) {
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < len - 1; i++) {
      /* Compose random string data from upper and lower case english alphabet entries plus a few
       * harmless characters in-between. */
      sb.append(Character.valueOf((char)(MIN_RANDOM_CHAR +
                                         rnd.nextInt(MAX_RANDOM_CHAR - MIN_RANDOM_CHAR))));
    }
    sb.append(Character.valueOf(MAX_RANDOM_CHAR));
    return sb.toString();
  }

  private static void generateRandomStrings(Random rnd, String[] output) {
    output[RANDOM_STRING_8] = generateRandomString(8, rnd);
    output[RANDOM_STRING_16] = generateRandomString(16, rnd);
    output[RANDOM_STRING_32] = generateRandomString(32, rnd);
    output[RANDOM_STRING_128] = generateRandomString(128, rnd);
    output[RANDOM_STRING_512] = generateRandomString(512, rnd);
  }

  static {
    searchChar = MAX_RANDOM_CHAR;
    generateRandomStrings(rnd, stringData);
    generateRandomStrings(rndAlt, stringDataAlt);
  }

  /**
   * String.equals
   */

  @Benchmark
  public void jmhTimeStringEqualsSmall() {
    stringEqualsResults[RANDOM_STRING_8]
      ^= stringData[RANDOM_STRING_8].equals(stringDataAlt[RANDOM_STRING_8]);
    stringEqualsResults[RANDOM_STRING_16]
      ^= stringData[RANDOM_STRING_16].equals(stringDataAlt[RANDOM_STRING_16]);
    stringEqualsResults[RANDOM_STRING_32]
      ^= stringData[RANDOM_STRING_32].equals(stringDataAlt[RANDOM_STRING_32]);
  }

  @Benchmark
  public void jmhTimeStringEqualsLarge() {
    stringEqualsResults[RANDOM_STRING_128]
      ^= stringData[RANDOM_STRING_128].equals(stringDataAlt[RANDOM_STRING_128]);
    stringEqualsResults[RANDOM_STRING_512]
      ^= stringData[RANDOM_STRING_512].equals(stringDataAlt[RANDOM_STRING_512]);
  }

  /**
   * String.equalsIgnoreCase
   */

  @Benchmark
  public void jmhTimeStringEqualsIgnoreCaseSmall() {
    stringEqualsIgnoreCaseResults[RANDOM_STRING_8]
      ^= stringData[RANDOM_STRING_8].equalsIgnoreCase(
              stringDataAlt[RANDOM_STRING_8]);
    stringEqualsIgnoreCaseResults[RANDOM_STRING_16]
      ^= stringData[RANDOM_STRING_16].equalsIgnoreCase(
              stringDataAlt[RANDOM_STRING_16]);
    stringEqualsIgnoreCaseResults[RANDOM_STRING_32]
      ^= stringData[RANDOM_STRING_32].equalsIgnoreCase(
              stringDataAlt[RANDOM_STRING_32]);
  }

  @Benchmark
  public void jmhTimeStringEqualsIgnoreCaseLarge() {
    stringEqualsIgnoreCaseResults[RANDOM_STRING_128]
      ^= stringData[RANDOM_STRING_128].equalsIgnoreCase(
              stringDataAlt[RANDOM_STRING_128]);
    stringEqualsIgnoreCaseResults[RANDOM_STRING_512]
      ^= stringData[RANDOM_STRING_512].equalsIgnoreCase(
              stringDataAlt[RANDOM_STRING_512]);
  }

  /**
   * String.contentEquals
   */

  @Benchmark
  public void jmhTimeStringContentEqualsSmall() {
    stringContentEqualsResults[RANDOM_STRING_8]
      ^= stringData[RANDOM_STRING_8].contentEquals(
              stringDataAlt[RANDOM_STRING_8]);
    stringContentEqualsResults[RANDOM_STRING_16]
      ^= stringData[RANDOM_STRING_16].contentEquals(
              stringDataAlt[RANDOM_STRING_16]);
    stringContentEqualsResults[RANDOM_STRING_32]
      ^= stringData[RANDOM_STRING_32].contentEquals(
              stringDataAlt[RANDOM_STRING_32]);
  }

  @Benchmark
  public void jmhTimeStringContentEqualsLarge() {
    stringContentEqualsResults[RANDOM_STRING_128]
      ^= stringData[RANDOM_STRING_128].contentEquals(
              stringDataAlt[RANDOM_STRING_128]);
    stringContentEqualsResults[RANDOM_STRING_512]
      ^= stringData[RANDOM_STRING_512].contentEquals(
              stringDataAlt[RANDOM_STRING_512]);
  }

  /**
   * String.compareTo
   */

  @Benchmark
  public void jmhTimeStringCompareToSmall() {
    stringCompareToResults[RANDOM_STRING_8]
      += stringData[RANDOM_STRING_8].compareTo(stringDataAlt[RANDOM_STRING_8]);
    stringCompareToResults[RANDOM_STRING_16]
      += stringData[RANDOM_STRING_16].compareTo(stringDataAlt[RANDOM_STRING_16]);
    stringCompareToResults[RANDOM_STRING_32]
      += stringData[RANDOM_STRING_32].compareTo(stringDataAlt[RANDOM_STRING_32]);
  }

  @Benchmark
  public void jmhTimeStringCompareToLarge() {
    stringCompareToResults[RANDOM_STRING_128]
      += stringData[RANDOM_STRING_128].compareTo(stringDataAlt[RANDOM_STRING_128]);
    stringCompareToResults[RANDOM_STRING_512]
      += stringData[RANDOM_STRING_512].compareTo(stringDataAlt[RANDOM_STRING_512]);
  }

  /**
   * String.compareToIgnoreCase
   */

  @Benchmark
  public void jmhTimeStringCompareToIgnoreCaseSmall() {
    stringCompareToIgnoreCaseResults[RANDOM_STRING_8]
      += stringData[RANDOM_STRING_8].compareToIgnoreCase(
              stringDataAlt[RANDOM_STRING_8]);
    stringCompareToIgnoreCaseResults[RANDOM_STRING_16]
      += stringData[RANDOM_STRING_16].compareToIgnoreCase(
              stringDataAlt[RANDOM_STRING_16]);
    stringCompareToIgnoreCaseResults[RANDOM_STRING_32]
      += stringData[RANDOM_STRING_32].compareToIgnoreCase(
              stringDataAlt[RANDOM_STRING_32]);
  }

  @Benchmark
  public void jmhTimeStringCompareToIgnoreCaseLarge() {
    stringCompareToIgnoreCaseResults[RANDOM_STRING_128]
      += stringData[RANDOM_STRING_128].compareToIgnoreCase(
              stringDataAlt[RANDOM_STRING_128]);
    stringCompareToIgnoreCaseResults[RANDOM_STRING_512]
      += stringData[RANDOM_STRING_512].compareToIgnoreCase(
              stringDataAlt[RANDOM_STRING_512]);
  }

  /**
   * String.regionMatches
   */

  @Benchmark
  public void jmhTimeStringRegionMatchesSmall() {
    stringRegionMatchesResults[RANDOM_STRING_8]
      ^= stringData[RANDOM_STRING_8].regionMatches(
              0, stringDataAlt[RANDOM_STRING_8], 0, 8);
    stringRegionMatchesResults[RANDOM_STRING_16]
      ^= stringData[RANDOM_STRING_16].regionMatches(
              0, stringDataAlt[RANDOM_STRING_16], 0, 16);
    stringRegionMatchesResults[RANDOM_STRING_32]
      ^= stringData[RANDOM_STRING_32].regionMatches(
              0, stringDataAlt[RANDOM_STRING_32], 0, 32);
  }

  @Benchmark
  public void jmhTimeStringRegionMatchesLarge() {
    stringRegionMatchesResults[RANDOM_STRING_128]
      ^= stringData[RANDOM_STRING_128].regionMatches(
              0, stringDataAlt[RANDOM_STRING_128], 0, 128);
    stringRegionMatchesResults[RANDOM_STRING_512]
      ^= stringData[RANDOM_STRING_512].regionMatches(
              0, stringDataAlt[RANDOM_STRING_512], 0, 512);
  }

  /**
   * String.regionMatches
   */

  @Benchmark
  public void jmhTimeStringRegionMatchesIgnoreCaseSmall() {
    stringRegionMatchesIgnoreCaseResults[RANDOM_STRING_8]
      ^= stringData[RANDOM_STRING_8].regionMatches(
              true, 0, stringDataAlt[RANDOM_STRING_8], 0, 8);
    stringRegionMatchesIgnoreCaseResults[RANDOM_STRING_16]
      ^= stringData[RANDOM_STRING_16].regionMatches(
              true, 0, stringDataAlt[RANDOM_STRING_16], 0, 16);
    stringRegionMatchesIgnoreCaseResults[RANDOM_STRING_32]
      ^= stringData[RANDOM_STRING_32].regionMatches(
              true, 0, stringDataAlt[RANDOM_STRING_32], 0, 32);
  }

  @Benchmark
  public void jmhTimeStringRegionMatchesIgnoreCaseLarge() {
    stringRegionMatchesIgnoreCaseResults[RANDOM_STRING_128]
      ^= stringData[RANDOM_STRING_128].regionMatches(
              true, 0, stringDataAlt[RANDOM_STRING_128], 0, 128);
    stringRegionMatchesIgnoreCaseResults[RANDOM_STRING_512]
      ^= stringData[RANDOM_STRING_512].regionMatches(
              true, 0, stringDataAlt[RANDOM_STRING_512], 0, 512);
  }

  /**
   * String.charAt
   */

  @Benchmark
  public void jmhTimeStringCharAt() {
    for (int j = 0; j < 512; j++) {
      stringCharAtResult = stringData[RANDOM_STRING_512].charAt(j);
    }
  }

  /**
   * String.indexOf
   */

  @Benchmark
  public void jmhTimeStringIndexOfSmall() {
    stringIndexOfResult += stringData[RANDOM_STRING_8].indexOf(searchChar);
    stringIndexOfResult += stringData[RANDOM_STRING_16].indexOf(searchChar);
    stringIndexOfResult += stringData[RANDOM_STRING_32].indexOf(searchChar);
  }

  @Benchmark
  public void jmhTimeStringIndexOfLarge() {
    stringIndexOfResult += stringData[RANDOM_STRING_128].indexOf(searchChar);
    stringIndexOfResult += stringData[RANDOM_STRING_512].indexOf(searchChar);
  }

  /**
   * String.indexOfAfter
   */

  @Benchmark
  public void jmhTimeStringIndexOfAfterSmall() {
    stringIndexOfAfterResult += stringData[RANDOM_STRING_8].indexOf(searchChar, 1);
    stringIndexOfAfterResult += stringData[RANDOM_STRING_16].indexOf(searchChar, 1);
    stringIndexOfAfterResult += stringData[RANDOM_STRING_32].indexOf(searchChar, 1);
  }

  @Benchmark
  public void jmhTimeStringIndexOfAfterLarge() {
    stringIndexOfAfterResult += stringData[RANDOM_STRING_128].indexOf(searchChar, 1);
    stringIndexOfAfterResult += stringData[RANDOM_STRING_512].indexOf(searchChar, 1);
  }

  /**
   * NewStringFromBytes
   */

  @Benchmark
  public void jmhTimeStringNewStringFromBytesSmall() {
    byte[] bytes = stringData[RANDOM_STRING_8].getBytes();
    stringNewStringFromBytesResult[RANDOM_STRING_8] = new String(bytes);
    byte[] bytes2 = stringData[RANDOM_STRING_16].getBytes();
    stringNewStringFromBytesResult[RANDOM_STRING_16] = new String(bytes2);
    byte[] bytes3 = stringData[RANDOM_STRING_32].getBytes();
    stringNewStringFromBytesResult[RANDOM_STRING_32] = new String(bytes3);
  }

  @Benchmark
  public void jmhTimeStringNewStringFromBytesLarge() {
    byte[] bytes = stringData[RANDOM_STRING_128].getBytes();
    stringNewStringFromBytesResult[RANDOM_STRING_128] = new String(bytes);
    byte[] bytes2 = stringData[RANDOM_STRING_512].getBytes();
    stringNewStringFromBytesResult[RANDOM_STRING_512] = new String(bytes2);
  }

  /**
   * NewStringFromChars
   */

  @Benchmark
  public void jmhTimeStringNewStringFromCharsSmall() {
    char[] chars = new char[8];
    stringData[RANDOM_STRING_8].getChars(0, 8, chars, 0);
    stringNewStringFromCharsResult[RANDOM_STRING_8] = new String(chars);
    char[] chars2 = new char[16];
    stringData[RANDOM_STRING_16].getChars(0, 16, chars2, 0);
    stringNewStringFromCharsResult[RANDOM_STRING_16] = new String(chars2);
    char[] chars3 = new char[32];
    stringData[RANDOM_STRING_32].getChars(0, 32, chars3, 0);
    stringNewStringFromCharsResult[RANDOM_STRING_32] = new String(chars3);
  }

  @Benchmark
  public void jmhTimeStringNewStringFromCharsLarge() {
    char[] chars = new char[128];
    stringData[RANDOM_STRING_128].getChars(0, 128, chars, 0);
    stringNewStringFromCharsResult[RANDOM_STRING_128] = new String(chars);
    char[] chars2 = new char[512];
    stringData[RANDOM_STRING_512].getChars(0, 512, chars2, 0);
    stringNewStringFromCharsResult[RANDOM_STRING_512] = new String(chars2);
  }

  /**
   * NewStringFromString
   */

  @Benchmark
  public void jmhTimeStringNewStringFromStringSmall() {
    stringNewStringFromStringResult[RANDOM_STRING_8] =
        new String(stringData[RANDOM_STRING_8]);
    stringNewStringFromStringResult[RANDOM_STRING_16] =
        new String(stringData[RANDOM_STRING_16]);
    stringNewStringFromStringResult[RANDOM_STRING_32] =
        new String(stringData[RANDOM_STRING_32]);
  }

  @Benchmark
  public void jmhTimeStringNewStringFromStringLarge() {
    stringNewStringFromStringResult[RANDOM_STRING_128] =
        new String(stringData[RANDOM_STRING_128]);
    stringNewStringFromStringResult[RANDOM_STRING_512] =
        new String(stringData[RANDOM_STRING_512]);
  }

  /**
   * String.getCharsNoCheck
   */

  @Benchmark
  public void jmhTimeStringGetCharsNoCheckSmall() {
    stringData[RANDOM_STRING_8].getChars(0, 8, chars_8, 0);
    stringGetCharsNoCheckResult[RANDOM_STRING_8] = new String(chars_8);
    stringData[RANDOM_STRING_16].getChars(0, 16, chars_16, 0);
    stringGetCharsNoCheckResult[RANDOM_STRING_16] = new String(chars_16);
    stringData[RANDOM_STRING_32].getChars(0, 32, chars_32, 0);
    stringGetCharsNoCheckResult[RANDOM_STRING_32] = new String(chars_32);
  }

  @Benchmark
  public void jmhTimeStringGetCharsNoCheckLarge() {
    stringData[RANDOM_STRING_128].getChars(0, 128, chars_128, 0);
    stringGetCharsNoCheckResult[RANDOM_STRING_128] = new String(chars_128);
    stringData[RANDOM_STRING_512].getChars(0, 512, chars_512, 0);
    stringGetCharsNoCheckResult[RANDOM_STRING_512] = new String(chars_512);
  }
}