diff -r 8aa7f885326e -r 2d83be3a0927 hotspot/src/share/vm/utilities/quickSort.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/utilities/quickSort.cpp	Tue Jun 28 14:23:27 2011 +0200
@@ -0,0 +1,218 @@
+/*
+ * 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() {
+  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;
+  }
+  return true;
+}
+
+#endif