/*

 * Copyright (c) 2011, 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.

 *

 */

#include "precompiled.hpp"

#include "utilities/quickSort.hpp"

#ifndef PRODUCT

// Unit tests

#include "runtime/os.hpp"

#include <stdlib.h>

static int test_comparator(int a, int b) {

  if (a == b) {

    return 0;

  }

  if (a < b) {

    return -1;

  }

  return 1;

}

static int test_even_odd_comparator(int a, int b) {

  bool a_is_odd = (a % 2) == 1;

  bool b_is_odd = (b % 2) == 1;

  if (a_is_odd == b_is_odd) {

    return 0;

  }

  if (a_is_odd) {

    return -1;

  }

  return 1;

}

static int test_stdlib_comparator(const void* a, const void* b) {

  int ai = *(int*)a;

  int bi = *(int*)b;

  if (ai == bi) {

    return 0;

  }

  if (ai < bi) {

    return -1;

  }

  return 1;

}

void QuickSort::print_array(const char* prefix, int* array, int length) {

  tty->print("%s:", prefix);

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

    tty->print(" %d", array[i]);

  }

  tty->print_cr("");

}

bool QuickSort::compare_arrays(int* actual, int* expected, int length) {

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

    if (actual[i] != expected[i]) {

      print_array("Sorted array  ", actual, length);

      print_array("Expected array", expected, length);

      return false;

    }

  }

  return true;

}

template <class C>

bool QuickSort::sort_and_compare(int* arrayToSort, int* expectedResult, int length, C comparator, bool idempotent) {

  sort<int, C>(arrayToSort, length, comparator, idempotent);

  return compare_arrays(arrayToSort, expectedResult, length);

}

bool QuickSort::test_quick_sort() {

#if 0

  tty->print_cr("test_quick_sort\n");

  {

    int* test_array = NULL;

    int* expected_array = NULL;

    assert(sort_and_compare(test_array, expected_array, 0, test_comparator), "Empty array not handled");

  }

  {

    int test_array[] = {3};

    int expected_array[] = {3};

    assert(sort_and_compare(test_array, expected_array, 1, test_comparator), "Single value array not handled");

  }

  {

    int test_array[] = {3,2};

    int expected_array[] = {2,3};

    assert(sort_and_compare(test_array, expected_array, 2, test_comparator), "Array with 2 values not correctly sorted");

  }

  {

    int test_array[] = {3,2,1};

    int expected_array[] = {1,2,3};

    assert(sort_and_compare(test_array, expected_array, 3, test_comparator), "Array with 3 values not correctly sorted");

  }

  {

    int test_array[] = {4,3,2,1};

    int expected_array[] = {1,2,3,4};

    assert(sort_and_compare(test_array, expected_array, 4, test_comparator), "Array with 4 values not correctly sorted");

  }

  {

    int test_array[] = {7,1,5,3,6,9,8,2,4,0};

    int expected_array[] = {0,1,2,3,4,5,6,7,8,9};

    assert(sort_and_compare(test_array, expected_array, 10, test_comparator), "Array with 10 values not correctly sorted");

  }

  {

    int test_array[] = {4,4,1,4};

    int expected_array[] = {1,4,4,4};

    assert(sort_and_compare(test_array, expected_array, 4, test_comparator), "3 duplicates not sorted correctly");

  }

  {

    int test_array[] = {0,1,2,3,4,5,6,7,8,9};

    int expected_array[] = {0,1,2,3,4,5,6,7,8,9};

    assert(sort_and_compare(test_array, expected_array, 10, test_comparator), "Already sorted array not correctly sorted");

  }

  {

    // one of the random arrays that found an issue in the partion method.

    int test_array[] = {76,46,81,8,64,56,75,11,51,55,11,71,59,27,9,64,69,75,21,25,39,40,44,32,7,8,40,41,24,78,24,74,9,65,28,6,40,31,22,13,27,82};

    int expected_array[] = {6,7,8,8,9,9,11,11,13,21,22,24,24,25,27,27,28,31,32,39,40,40,40,41,44,46,51,55,56,59,64,64,65,69,71,74,75,75,76,78,81,82};

    assert(sort_and_compare(test_array, expected_array, 42, test_comparator), "Not correctly sorted");

  }

  {

    int test_array[] = {2,8,1,4};

    int expected_array[] = {1,4,2,8};

    assert(sort_and_compare(test_array, expected_array, 4, test_even_odd_comparator), "Even/odd not sorted correctly");

  }

  {  // Some idempotent tests

    {

      // An array of lenght 3 is only sorted by find_pivot. Make sure that it is idempotent.

      int test_array[] = {1,4,8};

      int expected_array[] = {1,4,8};

      assert(sort_and_compare(test_array, expected_array, 3, test_even_odd_comparator, true), "Even/odd not idempotent");

    }

    {

      int test_array[] = {1,7,9,4,8,2};

      int expected_array[] = {1,7,9,4,8,2};

      assert(sort_and_compare(test_array, expected_array, 6, test_even_odd_comparator, true), "Even/odd not idempotent");

    }

    {

      int test_array[] = {1,9,7,4,2,8};

      int expected_array[] = {1,9,7,4,2,8};

      assert(sort_and_compare(test_array, expected_array, 6, test_even_odd_comparator, true), "Even/odd not idempotent");

    }

    {

      int test_array[] = {7,9,1,2,8,4};

      int expected_array[] = {7,9,1,2,8,4};

      assert(sort_and_compare(test_array, expected_array, 6, test_even_odd_comparator, true), "Even/odd not idempotent");

    }

    {

      int test_array[] = {7,1,9,2,4,8};

      int expected_array[] = {7,1,9,2,4,8};

      assert(sort_and_compare(test_array, expected_array, 6, test_even_odd_comparator, true), "Even/odd not idempotent");

    }

    {

      int test_array[] = {9,1,7,4,8,2};

      int expected_array[] = {9,1,7,4,8,2};

      assert(sort_and_compare(test_array, expected_array, 6, test_even_odd_comparator, true), "Even/odd not idempotent");

    }

    {

      int test_array[] = {9,7,1,4,2,8};

      int expected_array[] = {9,7,1,4,2,8};

      assert(sort_and_compare(test_array, expected_array, 6, test_even_odd_comparator, true), "Even/odd not idempotent");

    }

  }

  // test sorting random arrays

  for (int i = 0; i < 1000; i++) {

    int length = os::random() % 100;

    int* test_array = new int[length];

    int* expected_array = new int[length];

    for (int j = 0; j < length; j++) {

        // Choose random values, but get a chance of getting duplicates

        test_array[j] = os::random() % (length * 2);

        expected_array[j] = test_array[j];

    }

    // Compare sorting to stdlib::qsort()

    qsort(expected_array, length, sizeof(int), test_stdlib_comparator);

    assert(sort_and_compare(test_array, expected_array, length, test_comparator), "Random array not correctly sorted");

    // Make sure sorting is idempotent.

    // Both test_array and expected_array are sorted by the test_comparator.

    // Now sort them once with the test_even_odd_comparator. Then sort the

    // test_array one more time with test_even_odd_comparator and verify that

    // it is idempotent.

    sort(expected_array, length, test_even_odd_comparator, true);

    sort(test_array, length, test_even_odd_comparator, true);

    assert(compare_arrays(test_array, expected_array, length), "Sorting identical arrays rendered different results");

    sort(test_array, length, test_even_odd_comparator, true);

    assert(compare_arrays(test_array, expected_array, length), "Sorting already sorted array changed order of elements - not idempotent");

    delete[] test_array;

    delete[] expected_array;

  }

#endif

  return true;

}

#endif