/*

 * Copyright (c) 2011, 2017, 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

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 */

#include "precompiled.hpp"

#include "memory/allocation.inline.hpp"

#include "runtime/os.hpp"

#include "utilities/quickSort.hpp"

#include "unittest.hpp"

static int test_comparator(int a, int b) {

  if (a == b) {

    return 0;

  }

  if (a < b) {

    return -1;

  }

  return 1;

}

static bool compare_arrays(int* actual, int* expected, size_t length) {

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

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

      return false;

    }

  }

  return true;

}

template <class C>

static bool sort_and_compare(int* arrayToSort, int* expectedResult, size_t length, C comparator, bool idempotent = false) {

  QuickSort::sort(arrayToSort, length, comparator, idempotent);

  return compare_arrays(arrayToSort, expectedResult, length);

}

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;

}

extern "C" {

  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;

  }

}

TEST(QuickSort, quicksort) {

  {

    int* test_array = NULL;

    int* expected_array = NULL;

    EXPECT_TRUE(sort_and_compare(test_array, expected_array, 0, test_comparator));

  }

  {

    int test_array[] = {3};

    int expected_array[] = {3};

    EXPECT_TRUE(sort_and_compare(test_array, expected_array, 1, test_comparator));

  }

  {

    int test_array[] = {3,2};

    int expected_array[] = {2,3};

    EXPECT_TRUE(sort_and_compare(test_array, expected_array, 2, test_comparator));

  }

  {

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

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

    EXPECT_TRUE(sort_and_compare(test_array, expected_array, 3, test_comparator));

  }

  {

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

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

    EXPECT_TRUE(sort_and_compare(test_array, expected_array, 4, test_comparator));

  }

  {

    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};

    EXPECT_TRUE(sort_and_compare(test_array, expected_array, 10, test_comparator));

  }

  {

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

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

    EXPECT_TRUE(sort_and_compare(test_array, expected_array, 4, test_comparator));

  }

  {

    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};

    EXPECT_TRUE(sort_and_compare(test_array, expected_array, 10, test_comparator));

  }

  {

    // one of the random arrays that found an issue in the partition 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};

    EXPECT_TRUE(sort_and_compare(test_array, expected_array, 42, test_comparator));

  }

  {

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

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

    EXPECT_TRUE(sort_and_compare(test_array, expected_array, 4, test_even_odd_comparator));

  }

}

TEST(QuickSort, idempotent) {

  {

    // 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};

    EXPECT_TRUE(sort_and_compare(test_array, expected_array, 3, test_even_odd_comparator, true));

  }

  {

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

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

    EXPECT_TRUE(sort_and_compare(test_array, expected_array, 6, test_even_odd_comparator, true));

  }

  {

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

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

    EXPECT_TRUE(sort_and_compare(test_array, expected_array, 6, test_even_odd_comparator, true));

  }

  {

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

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

    EXPECT_TRUE(sort_and_compare(test_array, expected_array, 6, test_even_odd_comparator, true));

  }

  {

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

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

    EXPECT_TRUE(sort_and_compare(test_array, expected_array, 6, test_even_odd_comparator, true));

  }

  {

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

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

    EXPECT_TRUE(sort_and_compare(test_array, expected_array, 6, test_even_odd_comparator, true));

  }

  {

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

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

    EXPECT_TRUE(sort_and_compare(test_array, expected_array, 6, test_even_odd_comparator, true));

  }

}

TEST(QuickSort, random) {

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

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

    int* test_array = NEW_C_HEAP_ARRAY(int, length, mtInternal);

    int* expected_array = NEW_C_HEAP_ARRAY(int, length, mtInternal);

    for (size_t 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);

    EXPECT_TRUE(sort_and_compare(test_array, expected_array, length, test_comparator));

    // 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.

    QuickSort::sort(expected_array, length, test_even_odd_comparator, true);

    QuickSort::sort(test_array, length, test_even_odd_comparator, true);

    EXPECT_TRUE(compare_arrays(test_array, expected_array, length));

    QuickSort::sort(test_array, length, test_even_odd_comparator, true);

    EXPECT_TRUE(compare_arrays(test_array, expected_array, length));

    FREE_C_HEAP_ARRAY(int, test_array);

    FREE_C_HEAP_ARRAY(int, expected_array);

  }

}