6804124: Replace "modified mergesort" in java.util.Arrays.sort with timsort
Summary: Easy port of timsort from android
Reviewed-by: martin
--- a/jdk/make/java/java/FILES_java.gmk Wed Jul 29 13:56:15 2009 -0700
+++ b/jdk/make/java/java/FILES_java.gmk Wed Jul 29 14:24:19 2009 -0700
@@ -250,6 +250,8 @@
java/util/IdentityHashMap.java \
java/util/EnumMap.java \
java/util/Arrays.java \
+ java/util/TimSort.java \
+ java/util/ComparableTimSort.java \
java/util/ConcurrentModificationException.java \
java/util/ServiceLoader.java \
java/util/ServiceConfigurationError.java \
--- a/jdk/src/share/classes/java/util/Arrays.java Wed Jul 29 13:56:15 2009 -0700
+++ b/jdk/src/share/classes/java/util/Arrays.java Wed Jul 29 14:24:19 2009 -0700
@@ -1065,29 +1065,103 @@
(x[b] > x[c] ? b : x[a] > x[c] ? c : a));
}
+ /**
+ * Old merge sort implementation can be selected (for
+ * compatibility with broken comparators) using a system property.
+ * Cannot be a static boolean in the enclosing class due to
+ * circular dependencies. To be removed in a future release.
+ */
+ static final class LegacyMergeSort {
+ private static final boolean userRequested =
+ java.security.AccessController.doPrivileged(
+ new sun.security.action.GetBooleanAction(
+ "java.util.Arrays.useLegacyMergeSort")).booleanValue();
+ }
+
+ /*
+ * If this platform has an optimizing VM, check whether ComparableTimSort
+ * offers any performance benefit over TimSort in conjunction with a
+ * comparator that returns:
+ * {@code ((Comparable)first).compareTo(Second)}.
+ * If not, you are better off deleting ComparableTimSort to
+ * eliminate the code duplication. In other words, the commented
+ * out code below is the preferable implementation for sorting
+ * arrays of Comparables if it offers sufficient performance.
+ */
+
+// /**
+// * A comparator that implements the natural ordering of a group of
+// * mutually comparable elements. Using this comparator saves us
+// * from duplicating most of the code in this file (one version for
+// * Comparables, one for explicit Comparators).
+// */
+// private static final Comparator<Object> NATURAL_ORDER =
+// new Comparator<Object>() {
+// @SuppressWarnings("unchecked")
+// public int compare(Object first, Object second) {
+// return ((Comparable<Object>)first).compareTo(second);
+// }
+// };
+//
+// public static void sort(Object[] a) {
+// sort(a, 0, a.length, NATURAL_ORDER);
+// }
+//
+// public static void sort(Object[] a, int fromIndex, int toIndex) {
+// sort(a, fromIndex, toIndex, NATURAL_ORDER);
+// }
/**
- * Sorts the specified array of objects into ascending order, according to
- * the {@linkplain Comparable natural ordering}
- * of its elements. All elements in the array
- * must implement the {@link Comparable} interface. Furthermore, all
- * elements in the array must be <i>mutually comparable</i> (that is,
- * <tt>e1.compareTo(e2)</tt> must not throw a <tt>ClassCastException</tt>
- * for any elements <tt>e1</tt> and <tt>e2</tt> in the array).<p>
+ * Sorts the specified array of objects into ascending order, according
+ * to the {@linkplain Comparable natural ordering} of its elements.
+ * All elements in the array must implement the {@link Comparable}
+ * interface. Furthermore, all elements in the array must be
+ * <i>mutually comparable</i> (that is, {@code e1.compareTo(e2)} must
+ * not throw a {@code ClassCastException} for any elements {@code e1}
+ * and {@code e2} in the array).
+ *
+ * <p>This sort is guaranteed to be <i>stable</i>: equal elements will
+ * not be reordered as a result of the sort.
*
- * This sort is guaranteed to be <i>stable</i>: equal elements will
- * not be reordered as a result of the sort.<p>
+ * <p>Implementation note: This implementation is a stable, adaptive,
+ * iterative mergesort that requires far fewer than n lg(n) comparisons
+ * when the input array is partially sorted, while offering the
+ * performance of a traditional mergesort when the input array is
+ * randomly ordered. If the input array is nearly sorted, the
+ * implementation requires approximately n comparisons. Temporary
+ * storage requirements vary from a small constant for nearly sorted
+ * input arrays to n/2 object references for randomly ordered input
+ * arrays.
*
- * The sorting algorithm is a modified mergesort (in which the merge is
- * omitted if the highest element in the low sublist is less than the
- * lowest element in the high sublist). This algorithm offers guaranteed
- * n*log(n) performance.
+ * <p>The implementation takes equal advantage of ascending and
+ * descending order in its input array, and can take advantage of
+ * ascending and descending order in different parts of the the same
+ * input array. It is well-suited to merging two or more sorted arrays:
+ * simply concatenate the arrays and sort the resulting array.
+ *
+ * <p>The implementation was adapted from Tim Peters's list sort for Python
+ * (<a href="http://svn.python.org/projects/python/trunk/Objects/listsort.txt">
+ * TimSort</a>). It uses techiques from Peter McIlroy's "Optimistic
+ * Sorting and Information Theoretic Complexity", in Proceedings of the
+ * Fourth Annual ACM-SIAM Symposium on Discrete Algorithms, pp 467-474,
+ * January 1993.
*
* @param a the array to be sorted
- * @throws ClassCastException if the array contains elements that are not
- * <i>mutually comparable</i> (for example, strings and integers).
+ * @throws ClassCastException if the array contains elements that are not
+ * <i>mutually comparable</i> (for example, strings and integers)
+ * @throws IllegalArgumentException (optional) if the natural
+ * ordering of the array elements is found to violate the
+ * {@link Comparable} contract
*/
public static void sort(Object[] a) {
+ if (LegacyMergeSort.userRequested)
+ legacyMergeSort(a);
+ else
+ ComparableTimSort.sort(a);
+ }
+
+ /** To be removed in a future release. */
+ private static void legacyMergeSort(Object[] a) {
Object[] aux = a.clone();
mergeSort(aux, a, 0, a.length, 0);
}
@@ -1097,34 +1171,63 @@
* ascending order, according to the
* {@linkplain Comparable natural ordering} of its
* elements. The range to be sorted extends from index
- * <tt>fromIndex</tt>, inclusive, to index <tt>toIndex</tt>, exclusive.
- * (If <tt>fromIndex==toIndex</tt>, the range to be sorted is empty.) All
+ * {@code fromIndex}, inclusive, to index {@code toIndex}, exclusive.
+ * (If {@code fromIndex==toIndex}, the range to be sorted is empty.) All
* elements in this range must implement the {@link Comparable}
* interface. Furthermore, all elements in this range must be <i>mutually
- * comparable</i> (that is, <tt>e1.compareTo(e2)</tt> must not throw a
- * <tt>ClassCastException</tt> for any elements <tt>e1</tt> and
- * <tt>e2</tt> in the array).<p>
+ * comparable</i> (that is, {@code e1.compareTo(e2)} must not throw a
+ * {@code ClassCastException} for any elements {@code e1} and
+ * {@code e2} in the array).
+ *
+ * <p>This sort is guaranteed to be <i>stable</i>: equal elements will
+ * not be reordered as a result of the sort.
*
- * This sort is guaranteed to be <i>stable</i>: equal elements will
- * not be reordered as a result of the sort.<p>
+ * <p>Implementation note: This implementation is a stable, adaptive,
+ * iterative mergesort that requires far fewer than n lg(n) comparisons
+ * when the input array is partially sorted, while offering the
+ * performance of a traditional mergesort when the input array is
+ * randomly ordered. If the input array is nearly sorted, the
+ * implementation requires approximately n comparisons. Temporary
+ * storage requirements vary from a small constant for nearly sorted
+ * input arrays to n/2 object references for randomly ordered input
+ * arrays.
*
- * The sorting algorithm is a modified mergesort (in which the merge is
- * omitted if the highest element in the low sublist is less than the
- * lowest element in the high sublist). This algorithm offers guaranteed
- * n*log(n) performance.
+ * <p>The implementation takes equal advantage of ascending and
+ * descending order in its input array, and can take advantage of
+ * ascending and descending order in different parts of the the same
+ * input array. It is well-suited to merging two or more sorted arrays:
+ * simply concatenate the arrays and sort the resulting array.
+ *
+ * <p>The implementation was adapted from Tim Peters's list sort for Python
+ * (<a href="http://svn.python.org/projects/python/trunk/Objects/listsort.txt">
+ * TimSort</a>). It uses techiques from Peter McIlroy's "Optimistic
+ * Sorting and Information Theoretic Complexity", in Proceedings of the
+ * Fourth Annual ACM-SIAM Symposium on Discrete Algorithms, pp 467-474,
+ * January 1993.
*
* @param a the array to be sorted
* @param fromIndex the index of the first element (inclusive) to be
* sorted
* @param toIndex the index of the last element (exclusive) to be sorted
- * @throws IllegalArgumentException if <tt>fromIndex > toIndex</tt>
- * @throws ArrayIndexOutOfBoundsException if <tt>fromIndex < 0</tt> or
- * <tt>toIndex > a.length</tt>
- * @throws ClassCastException if the array contains elements that are
- * not <i>mutually comparable</i> (for example, strings and
- * integers).
+ * @throws IllegalArgumentException if {@code fromIndex > toIndex} or
+ * (optional) if the natural ordering of the array elements is
+ * found to violate the {@link Comparable} contract
+ * @throws ArrayIndexOutOfBoundsException if {@code fromIndex < 0} or
+ * {@code toIndex > a.length}
+ * @throws ClassCastException if the array contains elements that are
+ * not <i>mutually comparable</i> (for example, strings and
+ * integers).
*/
public static void sort(Object[] a, int fromIndex, int toIndex) {
+ if (LegacyMergeSort.userRequested)
+ legacyMergeSort(a, fromIndex, toIndex);
+ else
+ ComparableTimSort.sort(a, fromIndex, toIndex);
+ }
+
+ /** To be removed in a future release. */
+ private static void legacyMergeSort(Object[] a,
+ int fromIndex, int toIndex) {
rangeCheck(a.length, fromIndex, toIndex);
Object[] aux = copyOfRange(a, fromIndex, toIndex);
mergeSort(aux, a, fromIndex, toIndex, -fromIndex);
@@ -1133,6 +1236,7 @@
/**
* Tuning parameter: list size at or below which insertion sort will be
* used in preference to mergesort or quicksort.
+ * To be removed in a future release.
*/
private static final int INSERTIONSORT_THRESHOLD = 7;
@@ -1142,6 +1246,7 @@
* low is the index in dest to start sorting
* high is the end index in dest to end sorting
* off is the offset to generate corresponding low, high in src
+ * To be removed in a future release.
*/
private static void mergeSort(Object[] src,
Object[] dest,
@@ -1197,25 +1302,53 @@
* Sorts the specified array of objects according to the order induced by
* the specified comparator. All elements in the array must be
* <i>mutually comparable</i> by the specified comparator (that is,
- * <tt>c.compare(e1, e2)</tt> must not throw a <tt>ClassCastException</tt>
- * for any elements <tt>e1</tt> and <tt>e2</tt> in the array).<p>
+ * {@code c.compare(e1, e2)} must not throw a {@code ClassCastException}
+ * for any elements {@code e1} and {@code e2} in the array).
+ *
+ * <p>This sort is guaranteed to be <i>stable</i>: equal elements will
+ * not be reordered as a result of the sort.
*
- * This sort is guaranteed to be <i>stable</i>: equal elements will
- * not be reordered as a result of the sort.<p>
+ * <p>Implementation note: This implementation is a stable, adaptive,
+ * iterative mergesort that requires far fewer than n lg(n) comparisons
+ * when the input array is partially sorted, while offering the
+ * performance of a traditional mergesort when the input array is
+ * randomly ordered. If the input array is nearly sorted, the
+ * implementation requires approximately n comparisons. Temporary
+ * storage requirements vary from a small constant for nearly sorted
+ * input arrays to n/2 object references for randomly ordered input
+ * arrays.
*
- * The sorting algorithm is a modified mergesort (in which the merge is
- * omitted if the highest element in the low sublist is less than the
- * lowest element in the high sublist). This algorithm offers guaranteed
- * n*log(n) performance.
+ * <p>The implementation takes equal advantage of ascending and
+ * descending order in its input array, and can take advantage of
+ * ascending and descending order in different parts of the the same
+ * input array. It is well-suited to merging two or more sorted arrays:
+ * simply concatenate the arrays and sort the resulting array.
+ *
+ * <p>The implementation was adapted from Tim Peters's list sort for Python
+ * (<a href="http://svn.python.org/projects/python/trunk/Objects/listsort.txt">
+ * TimSort</a>). It uses techiques from Peter McIlroy's "Optimistic
+ * Sorting and Information Theoretic Complexity", in Proceedings of the
+ * Fourth Annual ACM-SIAM Symposium on Discrete Algorithms, pp 467-474,
+ * January 1993.
*
* @param a the array to be sorted
* @param c the comparator to determine the order of the array. A
- * <tt>null</tt> value indicates that the elements'
+ * {@code null} value indicates that the elements'
* {@linkplain Comparable natural ordering} should be used.
- * @throws ClassCastException if the array contains elements that are
- * not <i>mutually comparable</i> using the specified comparator.
+ * @throws ClassCastException if the array contains elements that are
+ * not <i>mutually comparable</i> using the specified comparator
+ * @throws IllegalArgumentException (optional) if the comparator is
+ * found to violate the {@link Comparator} contract
*/
public static <T> void sort(T[] a, Comparator<? super T> c) {
+ if (LegacyMergeSort.userRequested)
+ legacyMergeSort(a, c);
+ else
+ TimSort.sort(a, c);
+ }
+
+ /** To be removed in a future release. */
+ private static <T> void legacyMergeSort(T[] a, Comparator<? super T> c) {
T[] aux = a.clone();
if (c==null)
mergeSort(aux, a, 0, a.length, 0);
@@ -1226,36 +1359,65 @@
/**
* Sorts the specified range of the specified array of objects according
* to the order induced by the specified comparator. The range to be
- * sorted extends from index <tt>fromIndex</tt>, inclusive, to index
- * <tt>toIndex</tt>, exclusive. (If <tt>fromIndex==toIndex</tt>, the
+ * sorted extends from index {@code fromIndex}, inclusive, to index
+ * {@code toIndex}, exclusive. (If {@code fromIndex==toIndex}, the
* range to be sorted is empty.) All elements in the range must be
* <i>mutually comparable</i> by the specified comparator (that is,
- * <tt>c.compare(e1, e2)</tt> must not throw a <tt>ClassCastException</tt>
- * for any elements <tt>e1</tt> and <tt>e2</tt> in the range).<p>
+ * {@code c.compare(e1, e2)} must not throw a {@code ClassCastException}
+ * for any elements {@code e1} and {@code e2} in the range).
+ *
+ * <p>This sort is guaranteed to be <i>stable</i>: equal elements will
+ * not be reordered as a result of the sort.
*
- * This sort is guaranteed to be <i>stable</i>: equal elements will
- * not be reordered as a result of the sort.<p>
+ * <p>Implementation note: This implementation is a stable, adaptive,
+ * iterative mergesort that requires far fewer than n lg(n) comparisons
+ * when the input array is partially sorted, while offering the
+ * performance of a traditional mergesort when the input array is
+ * randomly ordered. If the input array is nearly sorted, the
+ * implementation requires approximately n comparisons. Temporary
+ * storage requirements vary from a small constant for nearly sorted
+ * input arrays to n/2 object references for randomly ordered input
+ * arrays.
*
- * The sorting algorithm is a modified mergesort (in which the merge is
- * omitted if the highest element in the low sublist is less than the
- * lowest element in the high sublist). This algorithm offers guaranteed
- * n*log(n) performance.
+ * <p>The implementation takes equal advantage of ascending and
+ * descending order in its input array, and can take advantage of
+ * ascending and descending order in different parts of the the same
+ * input array. It is well-suited to merging two or more sorted arrays:
+ * simply concatenate the arrays and sort the resulting array.
+ *
+ * <p>The implementation was adapted from Tim Peters's list sort for Python
+ * (<a href="http://svn.python.org/projects/python/trunk/Objects/listsort.txt">
+ * TimSort</a>). It uses techiques from Peter McIlroy's "Optimistic
+ * Sorting and Information Theoretic Complexity", in Proceedings of the
+ * Fourth Annual ACM-SIAM Symposium on Discrete Algorithms, pp 467-474,
+ * January 1993.
*
* @param a the array to be sorted
* @param fromIndex the index of the first element (inclusive) to be
* sorted
* @param toIndex the index of the last element (exclusive) to be sorted
* @param c the comparator to determine the order of the array. A
- * <tt>null</tt> value indicates that the elements'
+ * {@code null} value indicates that the elements'
* {@linkplain Comparable natural ordering} should be used.
* @throws ClassCastException if the array contains elements that are not
* <i>mutually comparable</i> using the specified comparator.
- * @throws IllegalArgumentException if <tt>fromIndex > toIndex</tt>
- * @throws ArrayIndexOutOfBoundsException if <tt>fromIndex < 0</tt> or
- * <tt>toIndex > a.length</tt>
+ * @throws IllegalArgumentException if {@code fromIndex > toIndex} or
+ * (optional) if the comparator is found to violate the
+ * {@link Comparator} contract
+ * @throws ArrayIndexOutOfBoundsException if {@code fromIndex < 0} or
+ * {@code toIndex > a.length}
*/
public static <T> void sort(T[] a, int fromIndex, int toIndex,
Comparator<? super T> c) {
+ if (LegacyMergeSort.userRequested)
+ legacyMergeSort(a, fromIndex, toIndex, c);
+ else
+ TimSort.sort(a, fromIndex, toIndex, c);
+ }
+
+ /** To be removed in a future release. */
+ private static <T> void legacyMergeSort(T[] a, int fromIndex, int toIndex,
+ Comparator<? super T> c) {
rangeCheck(a.length, fromIndex, toIndex);
T[] aux = copyOfRange(a, fromIndex, toIndex);
if (c==null)
@@ -1270,6 +1432,7 @@
* low is the index in dest to start sorting
* high is the end index in dest to end sorting
* off is the offset into src corresponding to low in dest
+ * To be removed in a future release.
*/
private static void mergeSort(Object[] src,
Object[] dest,
--- a/jdk/src/share/classes/java/util/Collections.java Wed Jul 29 13:56:15 2009 -0700
+++ b/jdk/src/share/classes/java/util/Collections.java Wed Jul 29 14:24:19 2009 -0700
@@ -100,23 +100,42 @@
/**
* Sorts the specified list into ascending order, according to the
- * <i>natural ordering</i> of its elements. All elements in the list must
- * implement the <tt>Comparable</tt> interface. Furthermore, all elements
- * in the list must be <i>mutually comparable</i> (that is,
- * <tt>e1.compareTo(e2)</tt> must not throw a <tt>ClassCastException</tt>
- * for any elements <tt>e1</tt> and <tt>e2</tt> in the list).<p>
+ * {@linkplain Comparable natural ordering} of its elements.
+ * All elements in the list must implement the {@link Comparable}
+ * interface. Furthermore, all elements in the list must be
+ * <i>mutually comparable</i> (that is, {@code e1.compareTo(e2)}
+ * must not throw a {@code ClassCastException} for any elements
+ * {@code e1} and {@code e2} in the list).
*
- * This sort is guaranteed to be <i>stable</i>: equal elements will
- * not be reordered as a result of the sort.<p>
+ * <p>This sort is guaranteed to be <i>stable</i>: equal elements will
+ * not be reordered as a result of the sort.
+ *
+ * <p>The specified list must be modifiable, but need not be resizable.
*
- * The specified list must be modifiable, but need not be resizable.<p>
+ * <p>Implementation note: This implementation is a stable, adaptive,
+ * iterative mergesort that requires far fewer than n lg(n) comparisons
+ * when the input array is partially sorted, while offering the
+ * performance of a traditional mergesort when the input array is
+ * randomly ordered. If the input array is nearly sorted, the
+ * implementation requires approximately n comparisons. Temporary
+ * storage requirements vary from a small constant for nearly sorted
+ * input arrays to n/2 object references for randomly ordered input
+ * arrays.
*
- * The sorting algorithm is a modified mergesort (in which the merge is
- * omitted if the highest element in the low sublist is less than the
- * lowest element in the high sublist). This algorithm offers guaranteed
- * n log(n) performance.
+ * <p>The implementation takes equal advantage of ascending and
+ * descending order in its input array, and can take advantage of
+ * ascending and descending order in different parts of the the same
+ * input array. It is well-suited to merging two or more sorted arrays:
+ * simply concatenate the arrays and sort the resulting array.
*
- * This implementation dumps the specified list into an array, sorts
+ * <p>The implementation was adapted from Tim Peters's list sort for Python
+ * (<a href="http://svn.python.org/projects/python/trunk/Objects/listsort.txt">
+ * TimSort</a>). It uses techiques from Peter McIlroy's "Optimistic
+ * Sorting and Information Theoretic Complexity", in Proceedings of the
+ * Fourth Annual ACM-SIAM Symposium on Discrete Algorithms, pp 467-474,
+ * January 1993.
+ *
+ * <p>This implementation dumps the specified list into an array, sorts
* the array, and iterates over the list resetting each element
* from the corresponding position in the array. This avoids the
* n<sup>2</sup> log(n) performance that would result from attempting
@@ -126,8 +145,10 @@
* @throws ClassCastException if the list contains elements that are not
* <i>mutually comparable</i> (for example, strings and integers).
* @throws UnsupportedOperationException if the specified list's
- * list-iterator does not support the <tt>set</tt> operation.
- * @see Comparable
+ * list-iterator does not support the {@code set} operation.
+ * @throws IllegalArgumentException (optional) if the implementation
+ * detects that the natural ordering of the list elements is
+ * found to violate the {@link Comparable} contract
*/
public static <T extends Comparable<? super T>> void sort(List<T> list) {
Object[] a = list.toArray();
@@ -143,19 +164,38 @@
* Sorts the specified list according to the order induced by the
* specified comparator. All elements in the list must be <i>mutually
* comparable</i> using the specified comparator (that is,
- * <tt>c.compare(e1, e2)</tt> must not throw a <tt>ClassCastException</tt>
- * for any elements <tt>e1</tt> and <tt>e2</tt> in the list).<p>
+ * {@code c.compare(e1, e2)} must not throw a {@code ClassCastException}
+ * for any elements {@code e1} and {@code e2} in the list).
*
- * This sort is guaranteed to be <i>stable</i>: equal elements will
- * not be reordered as a result of the sort.<p>
+ * <p>This sort is guaranteed to be <i>stable</i>: equal elements will
+ * not be reordered as a result of the sort.
+ *
+ * <p>The specified list must be modifiable, but need not be resizable.
*
- * The sorting algorithm is a modified mergesort (in which the merge is
- * omitted if the highest element in the low sublist is less than the
- * lowest element in the high sublist). This algorithm offers guaranteed
- * n log(n) performance.
+ * <p>Implementation note: This implementation is a stable, adaptive,
+ * iterative mergesort that requires far fewer than n lg(n) comparisons
+ * when the input array is partially sorted, while offering the
+ * performance of a traditional mergesort when the input array is
+ * randomly ordered. If the input array is nearly sorted, the
+ * implementation requires approximately n comparisons. Temporary
+ * storage requirements vary from a small constant for nearly sorted
+ * input arrays to n/2 object references for randomly ordered input
+ * arrays.
*
- * The specified list must be modifiable, but need not be resizable.
- * This implementation dumps the specified list into an array, sorts
+ * <p>The implementation takes equal advantage of ascending and
+ * descending order in its input array, and can take advantage of
+ * ascending and descending order in different parts of the the same
+ * input array. It is well-suited to merging two or more sorted arrays:
+ * simply concatenate the arrays and sort the resulting array.
+ *
+ * <p>The implementation was adapted from Tim Peters's list sort for Python
+ * (<a href="http://svn.python.org/projects/python/trunk/Objects/listsort.txt">
+ * TimSort</a>). It uses techiques from Peter McIlroy's "Optimistic
+ * Sorting and Information Theoretic Complexity", in Proceedings of the
+ * Fourth Annual ACM-SIAM Symposium on Discrete Algorithms, pp 467-474,
+ * January 1993.
+ *
+ * <p>This implementation dumps the specified list into an array, sorts
* the array, and iterates over the list resetting each element
* from the corresponding position in the array. This avoids the
* n<sup>2</sup> log(n) performance that would result from attempting
@@ -163,13 +203,14 @@
*
* @param list the list to be sorted.
* @param c the comparator to determine the order of the list. A
- * <tt>null</tt> value indicates that the elements' <i>natural
+ * {@code null} value indicates that the elements' <i>natural
* ordering</i> should be used.
* @throws ClassCastException if the list contains elements that are not
* <i>mutually comparable</i> using the specified comparator.
* @throws UnsupportedOperationException if the specified list's
- * list-iterator does not support the <tt>set</tt> operation.
- * @see Comparator
+ * list-iterator does not support the {@code set} operation.
+ * @throws IllegalArgumentException (optional) if the comparator is
+ * found to violate the {@link Comparator} contract
*/
public static <T> void sort(List<T> list, Comparator<? super T> c) {
Object[] a = list.toArray();
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/util/ComparableTimSort.java Wed Jul 29 14:24:19 2009 -0700
@@ -0,0 +1,895 @@
+/*
+ * Copyright 2009 Google Inc. 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. Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package java.util;
+
+/**
+ * This is a near duplicate of {@link TimSort}, modified for use with
+ * arrays of objects that implement {@link Comparable}, instead of using
+ * explicit comparators.
+ *
+ * <p>If you are using an optimizing VM, you may find that ComparableTimSort
+ * offers no performance benefit over TimSort in conjunction with a
+ * comparator that simply returns {@code ((Comparable)first).compareTo(Second)}.
+ * If this is the case, you are better off deleting ComparableTimSort to
+ * eliminate the code duplication. (See Arrays.java for details.)
+ *
+ * @author Josh Bloch
+ */
+class ComparableTimSort {
+ /**
+ * This is the minimum sized sequence that will be merged. Shorter
+ * sequences will be lengthened by calling binarySort. If the entire
+ * array is less than this length, no merges will be performed.
+ *
+ * This constant should be a power of two. It was 64 in Tim Peter's C
+ * implementation, but 32 was empirically determined to work better in
+ * this implementation. In the unlikely event that you set this constant
+ * to be a number that's not a power of two, you'll need to change the
+ * {@link #minRunLength} computation.
+ *
+ * If you decrease this constant, you must change the stackLen
+ * computation in the TimSort constructor, or you risk an
+ * ArrayOutOfBounds exception. See listsort.txt for a discussion
+ * of the minimum stack length required as a function of the length
+ * of the array being sorted and the minimum merge sequence length.
+ */
+ private static final int MIN_MERGE = 32;
+
+ /**
+ * The array being sorted.
+ */
+ private final Object[] a;
+
+ /**
+ * When we get into galloping mode, we stay there until both runs win less
+ * often than MIN_GALLOP consecutive times.
+ */
+ private static final int MIN_GALLOP = 7;
+
+ /**
+ * This controls when we get *into* galloping mode. It is initialized
+ * to MIN_GALLOP. The mergeLo and mergeHi methods nudge it higher for
+ * random data, and lower for highly structured data.
+ */
+ private int minGallop = MIN_GALLOP;
+
+ /**
+ * Maximum initial size of tmp array, which is used for merging. The array
+ * can grow to accommodate demand.
+ *
+ * Unlike Tim's original C version, we do not allocate this much storage
+ * when sorting smaller arrays. This change was required for performance.
+ */
+ private static final int INITIAL_TMP_STORAGE_LENGTH = 256;
+
+ /**
+ * Temp storage for merges.
+ */
+ private Object[] tmp;
+
+ /**
+ * A stack of pending runs yet to be merged. Run i starts at
+ * address base[i] and extends for len[i] elements. It's always
+ * true (so long as the indices are in bounds) that:
+ *
+ * runBase[i] + runLen[i] == runBase[i + 1]
+ *
+ * so we could cut the storage for this, but it's a minor amount,
+ * and keeping all the info explicit simplifies the code.
+ */
+ private int stackSize = 0; // Number of pending runs on stack
+ private final int[] runBase;
+ private final int[] runLen;
+
+ /**
+ * Creates a TimSort instance to maintain the state of an ongoing sort.
+ *
+ * @param a the array to be sorted
+ */
+ private ComparableTimSort(Object[] a) {
+ this.a = a;
+
+ // Allocate temp storage (which may be increased later if necessary)
+ int len = a.length;
+ @SuppressWarnings({"unchecked", "UnnecessaryLocalVariable"})
+ Object[] newArray = new Object[len < 2 * INITIAL_TMP_STORAGE_LENGTH ?
+ len >>> 1 : INITIAL_TMP_STORAGE_LENGTH];
+ tmp = newArray;
+
+ /*
+ * Allocate runs-to-be-merged stack (which cannot be expanded). The
+ * stack length requirements are described in listsort.txt. The C
+ * version always uses the same stack length (85), but this was
+ * measured to be too expensive when sorting "mid-sized" arrays (e.g.,
+ * 100 elements) in Java. Therefore, we use smaller (but sufficiently
+ * large) stack lengths for smaller arrays. The "magic numbers" in the
+ * computation below must be changed if MIN_MERGE is decreased. See
+ * the MIN_MERGE declaration above for more information.
+ */
+ int stackLen = (len < 120 ? 5 :
+ len < 1542 ? 10 :
+ len < 119151 ? 19 : 40);
+ runBase = new int[stackLen];
+ runLen = new int[stackLen];
+ }
+
+ /*
+ * The next two methods (which are package private and static) constitute
+ * the entire API of this class. Each of these methods obeys the contract
+ * of the public method with the same signature in java.util.Arrays.
+ */
+
+ static void sort(Object[] a) {
+ sort(a, 0, a.length);
+ }
+
+ static void sort(Object[] a, int lo, int hi) {
+ rangeCheck(a.length, lo, hi);
+ int nRemaining = hi - lo;
+ if (nRemaining < 2)
+ return; // Arrays of size 0 and 1 are always sorted
+
+ // If array is small, do a "mini-TimSort" with no merges
+ if (nRemaining < MIN_MERGE) {
+ int initRunLen = countRunAndMakeAscending(a, lo, hi);
+ binarySort(a, lo, hi, lo + initRunLen);
+ return;
+ }
+
+ /**
+ * March over the array once, left to right, finding natural runs,
+ * extending short natural runs to minRun elements, and merging runs
+ * to maintain stack invariant.
+ */
+ ComparableTimSort ts = new ComparableTimSort(a);
+ int minRun = minRunLength(nRemaining);
+ do {
+ // Identify next run
+ int runLen = countRunAndMakeAscending(a, lo, hi);
+
+ // If run is short, extend to min(minRun, nRemaining)
+ if (runLen < minRun) {
+ int force = nRemaining <= minRun ? nRemaining : minRun;
+ binarySort(a, lo, lo + force, lo + runLen);
+ runLen = force;
+ }
+
+ // Push run onto pending-run stack, and maybe merge
+ ts.pushRun(lo, runLen);
+ ts.mergeCollapse();
+
+ // Advance to find next run
+ lo += runLen;
+ nRemaining -= runLen;
+ } while (nRemaining != 0);
+
+ // Merge all remaining runs to complete sort
+ assert lo == hi;
+ ts.mergeForceCollapse();
+ assert ts.stackSize == 1;
+ }
+
+ /**
+ * Sorts the specified portion of the specified array using a binary
+ * insertion sort. This is the best method for sorting small numbers
+ * of elements. It requires O(n log n) compares, but O(n^2) data
+ * movement (worst case).
+ *
+ * If the initial part of the specified range is already sorted,
+ * this method can take advantage of it: the method assumes that the
+ * elements from index {@code lo}, inclusive, to {@code start},
+ * exclusive are already sorted.
+ *
+ * @param a the array in which a range is to be sorted
+ * @param lo the index of the first element in the range to be sorted
+ * @param hi the index after the last element in the range to be sorted
+ * @param start the index of the first element in the range that is
+ * not already known to be sorted (@code lo <= start <= hi}
+ */
+ @SuppressWarnings("fallthrough")
+ private static void binarySort(Object[] a, int lo, int hi, int start) {
+ assert lo <= start && start <= hi;
+ if (start == lo)
+ start++;
+ for ( ; start < hi; start++) {
+ @SuppressWarnings("unchecked")
+ Comparable<Object> pivot = (Comparable) a[start];
+
+ // Set left (and right) to the index where a[start] (pivot) belongs
+ int left = lo;
+ int right = start;
+ assert left <= right;
+ /*
+ * Invariants:
+ * pivot >= all in [lo, left).
+ * pivot < all in [right, start).
+ */
+ while (left < right) {
+ int mid = (left + right) >>> 1;
+ if (pivot.compareTo(a[mid]) < 0)
+ right = mid;
+ else
+ left = mid + 1;
+ }
+ assert left == right;
+
+ /*
+ * The invariants still hold: pivot >= all in [lo, left) and
+ * pivot < all in [left, start), so pivot belongs at left. Note
+ * that if there are elements equal to pivot, left points to the
+ * first slot after them -- that's why this sort is stable.
+ * Slide elements over to make room to make room for pivot.
+ */
+ int n = start - left; // The number of elements to move
+ // Switch is just an optimization for arraycopy in default case
+ switch(n) {
+ case 2: a[left + 2] = a[left + 1];
+ case 1: a[left + 1] = a[left];
+ break;
+ default: System.arraycopy(a, left, a, left + 1, n);
+ }
+ a[left] = pivot;
+ }
+ }
+
+ /**
+ * Returns the length of the run beginning at the specified position in
+ * the specified array and reverses the run if it is descending (ensuring
+ * that the run will always be ascending when the method returns).
+ *
+ * A run is the longest ascending sequence with:
+ *
+ * a[lo] <= a[lo + 1] <= a[lo + 2] <= ...
+ *
+ * or the longest descending sequence with:
+ *
+ * a[lo] > a[lo + 1] > a[lo + 2] > ...
+ *
+ * For its intended use in a stable mergesort, the strictness of the
+ * definition of "descending" is needed so that the call can safely
+ * reverse a descending sequence without violating stability.
+ *
+ * @param a the array in which a run is to be counted and possibly reversed
+ * @param lo index of the first element in the run
+ * @param hi index after the last element that may be contained in the run.
+ It is required that @code{lo < hi}.
+ * @return the length of the run beginning at the specified position in
+ * the specified array
+ */
+ @SuppressWarnings("unchecked")
+ private static int countRunAndMakeAscending(Object[] a, int lo, int hi) {
+ assert lo < hi;
+ int runHi = lo + 1;
+ if (runHi == hi)
+ return 1;
+
+ // Find end of run, and reverse range if descending
+ if (((Comparable) a[runHi++]).compareTo(a[lo]) < 0) { // Descending
+ while(runHi < hi && ((Comparable) a[runHi]).compareTo(a[runHi - 1]) < 0)
+ runHi++;
+ reverseRange(a, lo, runHi);
+ } else { // Ascending
+ while (runHi < hi && ((Comparable) a[runHi]).compareTo(a[runHi - 1]) >= 0)
+ runHi++;
+ }
+
+ return runHi - lo;
+ }
+
+ /**
+ * Reverse the specified range of the specified array.
+ *
+ * @param a the array in which a range is to be reversed
+ * @param lo the index of the first element in the range to be reversed
+ * @param hi the index after the last element in the range to be reversed
+ */
+ private static void reverseRange(Object[] a, int lo, int hi) {
+ hi--;
+ while (lo < hi) {
+ Object t = a[lo];
+ a[lo++] = a[hi];
+ a[hi--] = t;
+ }
+ }
+
+ /**
+ * Returns the minimum acceptable run length for an array of the specified
+ * length. Natural runs shorter than this will be extended with
+ * {@link #binarySort}.
+ *
+ * Roughly speaking, the computation is:
+ *
+ * If n < MIN_MERGE, return n (it's too small to bother with fancy stuff).
+ * Else if n is an exact power of 2, return MIN_MERGE/2.
+ * Else return an int k, MIN_MERGE/2 <= k <= MIN_MERGE, such that n/k
+ * is close to, but strictly less than, an exact power of 2.
+ *
+ * For the rationale, see listsort.txt.
+ *
+ * @param n the length of the array to be sorted
+ * @return the length of the minimum run to be merged
+ */
+ private static int minRunLength(int n) {
+ assert n >= 0;
+ int r = 0; // Becomes 1 if any 1 bits are shifted off
+ while (n >= MIN_MERGE) {
+ r |= (n & 1);
+ n >>= 1;
+ }
+ return n + r;
+ }
+
+ /**
+ * Pushes the specified run onto the pending-run stack.
+ *
+ * @param runBase index of the first element in the run
+ * @param runLen the number of elements in the run
+ */
+ private void pushRun(int runBase, int runLen) {
+ this.runBase[stackSize] = runBase;
+ this.runLen[stackSize] = runLen;
+ stackSize++;
+ }
+
+ /**
+ * Examines the stack of runs waiting to be merged and merges adjacent runs
+ * until the stack invariants are reestablished:
+ *
+ * 1. runLen[i - 3] > runLen[i - 2] + runLen[i - 1]
+ * 2. runLen[i - 2] > runLen[i - 1]
+ *
+ * This method is called each time a new run is pushed onto the stack,
+ * so the invariants are guaranteed to hold for i < stackSize upon
+ * entry to the method.
+ */
+ private void mergeCollapse() {
+ while (stackSize > 1) {
+ int n = stackSize - 2;
+ if (n > 0 && runLen[n-1] <= runLen[n] + runLen[n+1]) {
+ if (runLen[n - 1] < runLen[n + 1])
+ n--;
+ mergeAt(n);
+ } else if (runLen[n] <= runLen[n + 1]) {
+ mergeAt(n);
+ } else {
+ break; // Invariant is established
+ }
+ }
+ }
+
+ /**
+ * Merges all runs on the stack until only one remains. This method is
+ * called once, to complete the sort.
+ */
+ private void mergeForceCollapse() {
+ while (stackSize > 1) {
+ int n = stackSize - 2;
+ if (n > 0 && runLen[n - 1] < runLen[n + 1])
+ n--;
+ mergeAt(n);
+ }
+ }
+
+ /**
+ * Merges the two runs at stack indices i and i+1. Run i must be
+ * the penultimate or antepenultimate run on the stack. In other words,
+ * i must be equal to stackSize-2 or stackSize-3.
+ *
+ * @param i stack index of the first of the two runs to merge
+ */
+ @SuppressWarnings("unchecked")
+ private void mergeAt(int i) {
+ assert stackSize >= 2;
+ assert i >= 0;
+ assert i == stackSize - 2 || i == stackSize - 3;
+
+ int base1 = runBase[i];
+ int len1 = runLen[i];
+ int base2 = runBase[i + 1];
+ int len2 = runLen[i + 1];
+ assert len1 > 0 && len2 > 0;
+ assert base1 + len1 == base2;
+
+ /*
+ * Record the length of the combined runs; if i is the 3rd-last
+ * run now, also slide over the last run (which isn't involved
+ * in this merge). The current run (i+1) goes away in any case.
+ */
+ runLen[i] = len1 + len2;
+ if (i == stackSize - 3) {
+ runBase[i + 1] = runBase[i + 2];
+ runLen[i + 1] = runLen[i + 2];
+ }
+ stackSize--;
+
+ /*
+ * Find where the first element of run2 goes in run1. Prior elements
+ * in run1 can be ignored (because they're already in place).
+ */
+ int k = gallopRight((Comparable<Object>) a[base2], a, base1, len1, 0);
+ assert k >= 0;
+ base1 += k;
+ len1 -= k;
+ if (len1 == 0)
+ return;
+
+ /*
+ * Find where the last element of run1 goes in run2. Subsequent elements
+ * in run2 can be ignored (because they're already in place).
+ */
+ len2 = gallopLeft((Comparable<Object>) a[base1 + len1 - 1], a,
+ base2, len2, len2 - 1);
+ assert len2 >= 0;
+ if (len2 == 0)
+ return;
+
+ // Merge remaining runs, using tmp array with min(len1, len2) elements
+ if (len1 <= len2)
+ mergeLo(base1, len1, base2, len2);
+ else
+ mergeHi(base1, len1, base2, len2);
+ }
+
+ /**
+ * Locates the position at which to insert the specified key into the
+ * specified sorted range; if the range contains an element equal to key,
+ * returns the index of the leftmost equal element.
+ *
+ * @param key the key whose insertion point to search for
+ * @param a the array in which to search
+ * @param base the index of the first element in the range
+ * @param len the length of the range; must be > 0
+ * @param hint the index at which to begin the search, 0 <= hint < n.
+ * The closer hint is to the result, the faster this method will run.
+ * @return the int k, 0 <= k <= n such that a[b + k - 1] < key <= a[b + k],
+ * pretending that a[b - 1] is minus infinity and a[b + n] is infinity.
+ * In other words, key belongs at index b + k; or in other words,
+ * the first k elements of a should precede key, and the last n - k
+ * should follow it.
+ */
+ private static int gallopLeft(Comparable<Object> key, Object[] a,
+ int base, int len, int hint) {
+ assert len > 0 && hint >= 0 && hint < len;
+
+ int lastOfs = 0;
+ int ofs = 1;
+ if (key.compareTo(a[base + hint]) > 0) {
+ // Gallop right until a[base+hint+lastOfs] < key <= a[base+hint+ofs]
+ int maxOfs = len - hint;
+ while (ofs < maxOfs && key.compareTo(a[base + hint + ofs]) > 0) {
+ lastOfs = ofs;
+ ofs = (ofs << 1) + 1;
+ if (ofs <= 0) // int overflow
+ ofs = maxOfs;
+ }
+ if (ofs > maxOfs)
+ ofs = maxOfs;
+
+ // Make offsets relative to base
+ lastOfs += hint;
+ ofs += hint;
+ } else { // key <= a[base + hint]
+ // Gallop left until a[base+hint-ofs] < key <= a[base+hint-lastOfs]
+ final int maxOfs = hint + 1;
+ while (ofs < maxOfs && key.compareTo(a[base + hint - ofs]) <= 0) {
+ lastOfs = ofs;
+ ofs = (ofs << 1) + 1;
+ if (ofs <= 0) // int overflow
+ ofs = maxOfs;
+ }
+ if (ofs > maxOfs)
+ ofs = maxOfs;
+
+ // Make offsets relative to base
+ int tmp = lastOfs;
+ lastOfs = hint - ofs;
+ ofs = hint - tmp;
+ }
+ assert -1 <= lastOfs && lastOfs < ofs && ofs <= len;
+
+ /*
+ * Now a[base+lastOfs] < key <= a[base+ofs], so key belongs somewhere
+ * to the right of lastOfs but no farther right than ofs. Do a binary
+ * search, with invariant a[base + lastOfs - 1] < key <= a[base + ofs].
+ */
+ lastOfs++;
+ while (lastOfs < ofs) {
+ int m = lastOfs + ((ofs - lastOfs) >>> 1);
+
+ if (key.compareTo(a[base + m]) > 0)
+ lastOfs = m + 1; // a[base + m] < key
+ else
+ ofs = m; // key <= a[base + m]
+ }
+ assert lastOfs == ofs; // so a[base + ofs - 1] < key <= a[base + ofs]
+ return ofs;
+ }
+
+ /**
+ * Like gallopLeft, except that if the range contains an element equal to
+ * key, gallopRight returns the index after the rightmost equal element.
+ *
+ * @param key the key whose insertion point to search for
+ * @param a the array in which to search
+ * @param base the index of the first element in the range
+ * @param len the length of the range; must be > 0
+ * @param hint the index at which to begin the search, 0 <= hint < n.
+ * The closer hint is to the result, the faster this method will run.
+ * @return the int k, 0 <= k <= n such that a[b + k - 1] <= key < a[b + k]
+ */
+ private static int gallopRight(Comparable<Object> key, Object[] a,
+ int base, int len, int hint) {
+ assert len > 0 && hint >= 0 && hint < len;
+
+ int ofs = 1;
+ int lastOfs = 0;
+ if (key.compareTo(a[base + hint]) < 0) {
+ // Gallop left until a[b+hint - ofs] <= key < a[b+hint - lastOfs]
+ int maxOfs = hint + 1;
+ while (ofs < maxOfs && key.compareTo(a[base + hint - ofs]) < 0) {
+ lastOfs = ofs;
+ ofs = (ofs << 1) + 1;
+ if (ofs <= 0) // int overflow
+ ofs = maxOfs;
+ }
+ if (ofs > maxOfs)
+ ofs = maxOfs;
+
+ // Make offsets relative to b
+ int tmp = lastOfs;
+ lastOfs = hint - ofs;
+ ofs = hint - tmp;
+ } else { // a[b + hint] <= key
+ // Gallop right until a[b+hint + lastOfs] <= key < a[b+hint + ofs]
+ int maxOfs = len - hint;
+ while (ofs < maxOfs && key.compareTo(a[base + hint + ofs]) >= 0) {
+ lastOfs = ofs;
+ ofs = (ofs << 1) + 1;
+ if (ofs <= 0) // int overflow
+ ofs = maxOfs;
+ }
+ if (ofs > maxOfs)
+ ofs = maxOfs;
+
+ // Make offsets relative to b
+ lastOfs += hint;
+ ofs += hint;
+ }
+ assert -1 <= lastOfs && lastOfs < ofs && ofs <= len;
+
+ /*
+ * Now a[b + lastOfs] <= key < a[b + ofs], so key belongs somewhere to
+ * the right of lastOfs but no farther right than ofs. Do a binary
+ * search, with invariant a[b + lastOfs - 1] <= key < a[b + ofs].
+ */
+ lastOfs++;
+ while (lastOfs < ofs) {
+ int m = lastOfs + ((ofs - lastOfs) >>> 1);
+
+ if (key.compareTo(a[base + m]) < 0)
+ ofs = m; // key < a[b + m]
+ else
+ lastOfs = m + 1; // a[b + m] <= key
+ }
+ assert lastOfs == ofs; // so a[b + ofs - 1] <= key < a[b + ofs]
+ return ofs;
+ }
+
+ /**
+ * Merges two adjacent runs in place, in a stable fashion. The first
+ * element of the first run must be greater than the first element of the
+ * second run (a[base1] > a[base2]), and the last element of the first run
+ * (a[base1 + len1-1]) must be greater than all elements of the second run.
+ *
+ * For performance, this method should be called only when len1 <= len2;
+ * its twin, mergeHi should be called if len1 >= len2. (Either method
+ * may be called if len1 == len2.)
+ *
+ * @param base1 index of first element in first run to be merged
+ * @param len1 length of first run to be merged (must be > 0)
+ * @param base2 index of first element in second run to be merged
+ * (must be aBase + aLen)
+ * @param len2 length of second run to be merged (must be > 0)
+ */
+ @SuppressWarnings("unchecked")
+ private void mergeLo(int base1, int len1, int base2, int len2) {
+ assert len1 > 0 && len2 > 0 && base1 + len1 == base2;
+
+ // Copy first run into temp array
+ Object[] a = this.a; // For performance
+ Object[] tmp = ensureCapacity(len1);
+ System.arraycopy(a, base1, tmp, 0, len1);
+
+ int cursor1 = 0; // Indexes into tmp array
+ int cursor2 = base2; // Indexes int a
+ int dest = base1; // Indexes int a
+
+ // Move first element of second run and deal with degenerate cases
+ a[dest++] = a[cursor2++];
+ if (--len2 == 0) {
+ System.arraycopy(tmp, cursor1, a, dest, len1);
+ return;
+ }
+ if (len1 == 1) {
+ System.arraycopy(a, cursor2, a, dest, len2);
+ a[dest + len2] = tmp[cursor1]; // Last elt of run 1 to end of merge
+ return;
+ }
+
+ int minGallop = this.minGallop; // Use local variable for performance
+ outer:
+ while (true) {
+ int count1 = 0; // Number of times in a row that first run won
+ int count2 = 0; // Number of times in a row that second run won
+
+ /*
+ * Do the straightforward thing until (if ever) one run starts
+ * winning consistently.
+ */
+ do {
+ assert len1 > 1 && len2 > 0;
+ if (((Comparable) a[cursor2]).compareTo(tmp[cursor1]) < 0) {
+ a[dest++] = a[cursor2++];
+ count2++;
+ count1 = 0;
+ if (--len2 == 0)
+ break outer;
+ } else {
+ a[dest++] = tmp[cursor1++];
+ count1++;
+ count2 = 0;
+ if (--len1 == 1)
+ break outer;
+ }
+ } while ((count1 | count2) < minGallop);
+
+ /*
+ * One run is winning so consistently that galloping may be a
+ * huge win. So try that, and continue galloping until (if ever)
+ * neither run appears to be winning consistently anymore.
+ */
+ do {
+ assert len1 > 1 && len2 > 0;
+ count1 = gallopRight((Comparable) a[cursor2], tmp, cursor1, len1, 0);
+ if (count1 != 0) {
+ System.arraycopy(tmp, cursor1, a, dest, count1);
+ dest += count1;
+ cursor1 += count1;
+ len1 -= count1;
+ if (len1 <= 1) // len1 == 1 || len1 == 0
+ break outer;
+ }
+ a[dest++] = a[cursor2++];
+ if (--len2 == 0)
+ break outer;
+
+ count2 = gallopLeft((Comparable) tmp[cursor1], a, cursor2, len2, 0);
+ if (count2 != 0) {
+ System.arraycopy(a, cursor2, a, dest, count2);
+ dest += count2;
+ cursor2 += count2;
+ len2 -= count2;
+ if (len2 == 0)
+ break outer;
+ }
+ a[dest++] = tmp[cursor1++];
+ if (--len1 == 1)
+ break outer;
+ minGallop--;
+ } while (count1 >= MIN_GALLOP | count2 >= MIN_GALLOP);
+ if (minGallop < 0)
+ minGallop = 0;
+ minGallop += 2; // Penalize for leaving gallop mode
+ } // End of "outer" loop
+ this.minGallop = minGallop < 1 ? 1 : minGallop; // Write back to field
+
+ if (len1 == 1) {
+ assert len2 > 0;
+ System.arraycopy(a, cursor2, a, dest, len2);
+ a[dest + len2] = tmp[cursor1]; // Last elt of run 1 to end of merge
+ } else if (len1 == 0) {
+ throw new IllegalArgumentException(
+ "Comparison method violates its general contract!");
+ } else {
+ assert len2 == 0;
+ assert len1 > 1;
+ System.arraycopy(tmp, cursor1, a, dest, len1);
+ }
+ }
+
+ /**
+ * Like mergeLo, except that this method should be called only if
+ * len1 >= len2; mergeLo should be called if len1 <= len2. (Either method
+ * may be called if len1 == len2.)
+ *
+ * @param base1 index of first element in first run to be merged
+ * @param len1 length of first run to be merged (must be > 0)
+ * @param base2 index of first element in second run to be merged
+ * (must be aBase + aLen)
+ * @param len2 length of second run to be merged (must be > 0)
+ */
+ @SuppressWarnings("unchecked")
+ private void mergeHi(int base1, int len1, int base2, int len2) {
+ assert len1 > 0 && len2 > 0 && base1 + len1 == base2;
+
+ // Copy second run into temp array
+ Object[] a = this.a; // For performance
+ Object[] tmp = ensureCapacity(len2);
+ System.arraycopy(a, base2, tmp, 0, len2);
+
+ int cursor1 = base1 + len1 - 1; // Indexes into a
+ int cursor2 = len2 - 1; // Indexes into tmp array
+ int dest = base2 + len2 - 1; // Indexes into a
+
+ // Move last element of first run and deal with degenerate cases
+ a[dest--] = a[cursor1--];
+ if (--len1 == 0) {
+ System.arraycopy(tmp, 0, a, dest - (len2 - 1), len2);
+ return;
+ }
+ if (len2 == 1) {
+ dest -= len1;
+ cursor1 -= len1;
+ System.arraycopy(a, cursor1 + 1, a, dest + 1, len1);
+ a[dest] = tmp[cursor2];
+ return;
+ }
+
+ int minGallop = this.minGallop; // Use local variable for performance
+ outer:
+ while (true) {
+ int count1 = 0; // Number of times in a row that first run won
+ int count2 = 0; // Number of times in a row that second run won
+
+ /*
+ * Do the straightforward thing until (if ever) one run
+ * appears to win consistently.
+ */
+ do {
+ assert len1 > 0 && len2 > 1;
+ if (((Comparable) tmp[cursor2]).compareTo(a[cursor1]) < 0) {
+ a[dest--] = a[cursor1--];
+ count1++;
+ count2 = 0;
+ if (--len1 == 0)
+ break outer;
+ } else {
+ a[dest--] = tmp[cursor2--];
+ count2++;
+ count1 = 0;
+ if (--len2 == 1)
+ break outer;
+ }
+ } while ((count1 | count2) < minGallop);
+
+ /*
+ * One run is winning so consistently that galloping may be a
+ * huge win. So try that, and continue galloping until (if ever)
+ * neither run appears to be winning consistently anymore.
+ */
+ do {
+ assert len1 > 0 && len2 > 1;
+ count1 = len1 - gallopRight((Comparable) tmp[cursor2], a, base1, len1, len1 - 1);
+ if (count1 != 0) {
+ dest -= count1;
+ cursor1 -= count1;
+ len1 -= count1;
+ System.arraycopy(a, cursor1 + 1, a, dest + 1, count1);
+ if (len1 == 0)
+ break outer;
+ }
+ a[dest--] = tmp[cursor2--];
+ if (--len2 == 1)
+ break outer;
+
+ count2 = len2 - gallopLeft((Comparable) a[cursor1], tmp, 0, len2, len2 - 1);
+ if (count2 != 0) {
+ dest -= count2;
+ cursor2 -= count2;
+ len2 -= count2;
+ System.arraycopy(tmp, cursor2 + 1, a, dest + 1, count2);
+ if (len2 <= 1)
+ break outer; // len2 == 1 || len2 == 0
+ }
+ a[dest--] = a[cursor1--];
+ if (--len1 == 0)
+ break outer;
+ minGallop--;
+ } while (count1 >= MIN_GALLOP | count2 >= MIN_GALLOP);
+ if (minGallop < 0)
+ minGallop = 0;
+ minGallop += 2; // Penalize for leaving gallop mode
+ } // End of "outer" loop
+ this.minGallop = minGallop < 1 ? 1 : minGallop; // Write back to field
+
+ if (len2 == 1) {
+ assert len1 > 0;
+ dest -= len1;
+ cursor1 -= len1;
+ System.arraycopy(a, cursor1 + 1, a, dest + 1, len1);
+ a[dest] = tmp[cursor2]; // Move first elt of run2 to front of merge
+ } else if (len2 == 0) {
+ throw new IllegalArgumentException(
+ "Comparison method violates its general contract!");
+ } else {
+ assert len1 == 0;
+ assert len2 > 0;
+ System.arraycopy(tmp, 0, a, dest - (len2 - 1), len2);
+ }
+ }
+
+ /**
+ * Ensures that the external array tmp has at least the specified
+ * number of elements, increasing its size if necessary. The size
+ * increases exponentially to ensure amortized linear time complexity.
+ *
+ * @param minCapacity the minimum required capacity of the tmp array
+ * @return tmp, whether or not it grew
+ */
+ private Object[] ensureCapacity(int minCapacity) {
+ if (tmp.length < minCapacity) {
+ // Compute smallest power of 2 > minCapacity
+ int newSize = minCapacity;
+ newSize |= newSize >> 1;
+ newSize |= newSize >> 2;
+ newSize |= newSize >> 4;
+ newSize |= newSize >> 8;
+ newSize |= newSize >> 16;
+ newSize++;
+
+ if (newSize < 0) // Not bloody likely!
+ newSize = minCapacity;
+ else
+ newSize = Math.min(newSize, a.length >>> 1);
+
+ @SuppressWarnings({"unchecked", "UnnecessaryLocalVariable"})
+ Object[] newArray = new Object[newSize];
+ tmp = newArray;
+ }
+ return tmp;
+ }
+
+ /**
+ * Checks that fromIndex and toIndex are in range, and throws an
+ * appropriate exception if they aren't.
+ *
+ * @param arrayLen the length of the array
+ * @param fromIndex the index of the first element of the range
+ * @param toIndex the index after the last element of the range
+ * @throws IllegalArgumentException if fromIndex > toIndex
+ * @throws ArrayIndexOutOfBoundsException if fromIndex < 0
+ * or toIndex > arrayLen
+ */
+ private static void rangeCheck(int arrayLen, int fromIndex, int toIndex) {
+ if (fromIndex > toIndex)
+ throw new IllegalArgumentException("fromIndex(" + fromIndex +
+ ") > toIndex(" + toIndex+")");
+ if (fromIndex < 0)
+ throw new ArrayIndexOutOfBoundsException(fromIndex);
+ if (toIndex > arrayLen)
+ throw new ArrayIndexOutOfBoundsException(toIndex);
+ }
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/util/TimSort.java Wed Jul 29 14:24:19 2009 -0700
@@ -0,0 +1,928 @@
+/*
+ * Copyright 2009 Google Inc. 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. Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package java.util;
+
+/**
+ * A stable, adaptive, iterative mergesort that requires far fewer than
+ * n lg(n) comparisons when running on partially sorted arrays, while
+ * offering performance comparable to a traditional mergesort when run
+ * on random arrays. Like all proper mergesorts, this sort is stable and
+ * runs O(n log n) time (worst case). In the worst case, this sort requires
+ * temporary storage space for n/2 object references; in the best case,
+ * it requires only a small constant amount of space.
+ *
+ * This implementation was adapted from Tim Peters's list sort for
+ * Python, which is described in detail here:
+ *
+ * http://svn.python.org/projects/python/trunk/Objects/listsort.txt
+ *
+ * Tim's C code may be found here:
+ *
+ * http://svn.python.org/projects/python/trunk/Objects/listobject.c
+ *
+ * The underlying techniques are described in this paper (and may have
+ * even earlier origins):
+ *
+ * "Optimistic Sorting and Information Theoretic Complexity"
+ * Peter McIlroy
+ * SODA (Fourth Annual ACM-SIAM Symposium on Discrete Algorithms),
+ * pp 467-474, Austin, Texas, 25-27 January 1993.
+ *
+ * While the API to this class consists solely of static methods, it is
+ * (privately) instantiable; a TimSort instance holds the state of an ongoing
+ * sort, assuming the input array is large enough to warrant the full-blown
+ * TimSort. Small arrays are sorted in place, using a binary insertion sort.
+ *
+ * @author Josh Bloch
+ */
+class TimSort<T> {
+ /**
+ * This is the minimum sized sequence that will be merged. Shorter
+ * sequences will be lengthened by calling binarySort. If the entire
+ * array is less than this length, no merges will be performed.
+ *
+ * This constant should be a power of two. It was 64 in Tim Peter's C
+ * implementation, but 32 was empirically determined to work better in
+ * this implementation. In the unlikely event that you set this constant
+ * to be a number that's not a power of two, you'll need to change the
+ * {@link #minRunLength} computation.
+ *
+ * If you decrease this constant, you must change the stackLen
+ * computation in the TimSort constructor, or you risk an
+ * ArrayOutOfBounds exception. See listsort.txt for a discussion
+ * of the minimum stack length required as a function of the length
+ * of the array being sorted and the minimum merge sequence length.
+ */
+ private static final int MIN_MERGE = 32;
+
+ /**
+ * The array being sorted.
+ */
+ private final T[] a;
+
+ /**
+ * The comparator for this sort.
+ */
+ private final Comparator<? super T> c;
+
+ /**
+ * When we get into galloping mode, we stay there until both runs win less
+ * often than MIN_GALLOP consecutive times.
+ */
+ private static final int MIN_GALLOP = 7;
+
+ /**
+ * This controls when we get *into* galloping mode. It is initialized
+ * to MIN_GALLOP. The mergeLo and mergeHi methods nudge it higher for
+ * random data, and lower for highly structured data.
+ */
+ private int minGallop = MIN_GALLOP;
+
+ /**
+ * Maximum initial size of tmp array, which is used for merging. The array
+ * can grow to accommodate demand.
+ *
+ * Unlike Tim's original C version, we do not allocate this much storage
+ * when sorting smaller arrays. This change was required for performance.
+ */
+ private static final int INITIAL_TMP_STORAGE_LENGTH = 256;
+
+ /**
+ * Temp storage for merges.
+ */
+ private T[] tmp; // Actual runtime type will be Object[], regardless of T
+
+ /**
+ * A stack of pending runs yet to be merged. Run i starts at
+ * address base[i] and extends for len[i] elements. It's always
+ * true (so long as the indices are in bounds) that:
+ *
+ * runBase[i] + runLen[i] == runBase[i + 1]
+ *
+ * so we could cut the storage for this, but it's a minor amount,
+ * and keeping all the info explicit simplifies the code.
+ */
+ private int stackSize = 0; // Number of pending runs on stack
+ private final int[] runBase;
+ private final int[] runLen;
+
+ /**
+ * Creates a TimSort instance to maintain the state of an ongoing sort.
+ *
+ * @param a the array to be sorted
+ * @param c the comparator to determine the order of the sort
+ */
+ private TimSort(T[] a, Comparator<? super T> c) {
+ this.a = a;
+ this.c = c;
+
+ // Allocate temp storage (which may be increased later if necessary)
+ int len = a.length;
+ @SuppressWarnings({"unchecked", "UnnecessaryLocalVariable"})
+ T[] newArray = (T[]) new Object[len < 2 * INITIAL_TMP_STORAGE_LENGTH ?
+ len >>> 1 : INITIAL_TMP_STORAGE_LENGTH];
+ tmp = newArray;
+
+ /*
+ * Allocate runs-to-be-merged stack (which cannot be expanded). The
+ * stack length requirements are described in listsort.txt. The C
+ * version always uses the same stack length (85), but this was
+ * measured to be too expensive when sorting "mid-sized" arrays (e.g.,
+ * 100 elements) in Java. Therefore, we use smaller (but sufficiently
+ * large) stack lengths for smaller arrays. The "magic numbers" in the
+ * computation below must be changed if MIN_MERGE is decreased. See
+ * the MIN_MERGE declaration above for more information.
+ */
+ int stackLen = (len < 120 ? 5 :
+ len < 1542 ? 10 :
+ len < 119151 ? 19 : 40);
+ runBase = new int[stackLen];
+ runLen = new int[stackLen];
+ }
+
+ /*
+ * The next two methods (which are package private and static) constitute
+ * the entire API of this class. Each of these methods obeys the contract
+ * of the public method with the same signature in java.util.Arrays.
+ */
+
+ static <T> void sort(T[] a, Comparator<? super T> c) {
+ sort(a, 0, a.length, c);
+ }
+
+ static <T> void sort(T[] a, int lo, int hi, Comparator<? super T> c) {
+ if (c == null) {
+ Arrays.sort(a, lo, hi);
+ return;
+ }
+
+ rangeCheck(a.length, lo, hi);
+ int nRemaining = hi - lo;
+ if (nRemaining < 2)
+ return; // Arrays of size 0 and 1 are always sorted
+
+ // If array is small, do a "mini-TimSort" with no merges
+ if (nRemaining < MIN_MERGE) {
+ int initRunLen = countRunAndMakeAscending(a, lo, hi, c);
+ binarySort(a, lo, hi, lo + initRunLen, c);
+ return;
+ }
+
+ /**
+ * March over the array once, left to right, finding natural runs,
+ * extending short natural runs to minRun elements, and merging runs
+ * to maintain stack invariant.
+ */
+ TimSort<T> ts = new TimSort<T>(a, c);
+ int minRun = minRunLength(nRemaining);
+ do {
+ // Identify next run
+ int runLen = countRunAndMakeAscending(a, lo, hi, c);
+
+ // If run is short, extend to min(minRun, nRemaining)
+ if (runLen < minRun) {
+ int force = nRemaining <= minRun ? nRemaining : minRun;
+ binarySort(a, lo, lo + force, lo + runLen, c);
+ runLen = force;
+ }
+
+ // Push run onto pending-run stack, and maybe merge
+ ts.pushRun(lo, runLen);
+ ts.mergeCollapse();
+
+ // Advance to find next run
+ lo += runLen;
+ nRemaining -= runLen;
+ } while (nRemaining != 0);
+
+ // Merge all remaining runs to complete sort
+ assert lo == hi;
+ ts.mergeForceCollapse();
+ assert ts.stackSize == 1;
+ }
+
+ /**
+ * Sorts the specified portion of the specified array using a binary
+ * insertion sort. This is the best method for sorting small numbers
+ * of elements. It requires O(n log n) compares, but O(n^2) data
+ * movement (worst case).
+ *
+ * If the initial part of the specified range is already sorted,
+ * this method can take advantage of it: the method assumes that the
+ * elements from index {@code lo}, inclusive, to {@code start},
+ * exclusive are already sorted.
+ *
+ * @param a the array in which a range is to be sorted
+ * @param lo the index of the first element in the range to be sorted
+ * @param hi the index after the last element in the range to be sorted
+ * @param start the index of the first element in the range that is
+ * not already known to be sorted (@code lo <= start <= hi}
+ * @param c comparator to used for the sort
+ */
+ @SuppressWarnings("fallthrough")
+ private static <T> void binarySort(T[] a, int lo, int hi, int start,
+ Comparator<? super T> c) {
+ assert lo <= start && start <= hi;
+ if (start == lo)
+ start++;
+ for ( ; start < hi; start++) {
+ T pivot = a[start];
+
+ // Set left (and right) to the index where a[start] (pivot) belongs
+ int left = lo;
+ int right = start;
+ assert left <= right;
+ /*
+ * Invariants:
+ * pivot >= all in [lo, left).
+ * pivot < all in [right, start).
+ */
+ while (left < right) {
+ int mid = (left + right) >>> 1;
+ if (c.compare(pivot, a[mid]) < 0)
+ right = mid;
+ else
+ left = mid + 1;
+ }
+ assert left == right;
+
+ /*
+ * The invariants still hold: pivot >= all in [lo, left) and
+ * pivot < all in [left, start), so pivot belongs at left. Note
+ * that if there are elements equal to pivot, left points to the
+ * first slot after them -- that's why this sort is stable.
+ * Slide elements over to make room to make room for pivot.
+ */
+ int n = start - left; // The number of elements to move
+ // Switch is just an optimization for arraycopy in default case
+ switch(n) {
+ case 2: a[left + 2] = a[left + 1];
+ case 1: a[left + 1] = a[left];
+ break;
+ default: System.arraycopy(a, left, a, left + 1, n);
+ }
+ a[left] = pivot;
+ }
+ }
+
+ /**
+ * Returns the length of the run beginning at the specified position in
+ * the specified array and reverses the run if it is descending (ensuring
+ * that the run will always be ascending when the method returns).
+ *
+ * A run is the longest ascending sequence with:
+ *
+ * a[lo] <= a[lo + 1] <= a[lo + 2] <= ...
+ *
+ * or the longest descending sequence with:
+ *
+ * a[lo] > a[lo + 1] > a[lo + 2] > ...
+ *
+ * For its intended use in a stable mergesort, the strictness of the
+ * definition of "descending" is needed so that the call can safely
+ * reverse a descending sequence without violating stability.
+ *
+ * @param a the array in which a run is to be counted and possibly reversed
+ * @param lo index of the first element in the run
+ * @param hi index after the last element that may be contained in the run.
+ It is required that @code{lo < hi}.
+ * @param c the comparator to used for the sort
+ * @return the length of the run beginning at the specified position in
+ * the specified array
+ */
+ private static <T> int countRunAndMakeAscending(T[] a, int lo, int hi,
+ Comparator<? super T> c) {
+ assert lo < hi;
+ int runHi = lo + 1;
+ if (runHi == hi)
+ return 1;
+
+ // Find end of run, and reverse range if descending
+ if (c.compare(a[runHi++], a[lo]) < 0) { // Descending
+ while(runHi < hi && c.compare(a[runHi], a[runHi - 1]) < 0)
+ runHi++;
+ reverseRange(a, lo, runHi);
+ } else { // Ascending
+ while (runHi < hi && c.compare(a[runHi], a[runHi - 1]) >= 0)
+ runHi++;
+ }
+
+ return runHi - lo;
+ }
+
+ /**
+ * Reverse the specified range of the specified array.
+ *
+ * @param a the array in which a range is to be reversed
+ * @param lo the index of the first element in the range to be reversed
+ * @param hi the index after the last element in the range to be reversed
+ */
+ private static void reverseRange(Object[] a, int lo, int hi) {
+ hi--;
+ while (lo < hi) {
+ Object t = a[lo];
+ a[lo++] = a[hi];
+ a[hi--] = t;
+ }
+ }
+
+ /**
+ * Returns the minimum acceptable run length for an array of the specified
+ * length. Natural runs shorter than this will be extended with
+ * {@link #binarySort}.
+ *
+ * Roughly speaking, the computation is:
+ *
+ * If n < MIN_MERGE, return n (it's too small to bother with fancy stuff).
+ * Else if n is an exact power of 2, return MIN_MERGE/2.
+ * Else return an int k, MIN_MERGE/2 <= k <= MIN_MERGE, such that n/k
+ * is close to, but strictly less than, an exact power of 2.
+ *
+ * For the rationale, see listsort.txt.
+ *
+ * @param n the length of the array to be sorted
+ * @return the length of the minimum run to be merged
+ */
+ private static int minRunLength(int n) {
+ assert n >= 0;
+ int r = 0; // Becomes 1 if any 1 bits are shifted off
+ while (n >= MIN_MERGE) {
+ r |= (n & 1);
+ n >>= 1;
+ }
+ return n + r;
+ }
+
+ /**
+ * Pushes the specified run onto the pending-run stack.
+ *
+ * @param runBase index of the first element in the run
+ * @param runLen the number of elements in the run
+ */
+ private void pushRun(int runBase, int runLen) {
+ this.runBase[stackSize] = runBase;
+ this.runLen[stackSize] = runLen;
+ stackSize++;
+ }
+
+ /**
+ * Examines the stack of runs waiting to be merged and merges adjacent runs
+ * until the stack invariants are reestablished:
+ *
+ * 1. runLen[i - 3] > runLen[i - 2] + runLen[i - 1]
+ * 2. runLen[i - 2] > runLen[i - 1]
+ *
+ * This method is called each time a new run is pushed onto the stack,
+ * so the invariants are guaranteed to hold for i < stackSize upon
+ * entry to the method.
+ */
+ private void mergeCollapse() {
+ while (stackSize > 1) {
+ int n = stackSize - 2;
+ if (n > 0 && runLen[n-1] <= runLen[n] + runLen[n+1]) {
+ if (runLen[n - 1] < runLen[n + 1])
+ n--;
+ mergeAt(n);
+ } else if (runLen[n] <= runLen[n + 1]) {
+ mergeAt(n);
+ } else {
+ break; // Invariant is established
+ }
+ }
+ }
+
+ /**
+ * Merges all runs on the stack until only one remains. This method is
+ * called once, to complete the sort.
+ */
+ private void mergeForceCollapse() {
+ while (stackSize > 1) {
+ int n = stackSize - 2;
+ if (n > 0 && runLen[n - 1] < runLen[n + 1])
+ n--;
+ mergeAt(n);
+ }
+ }
+
+ /**
+ * Merges the two runs at stack indices i and i+1. Run i must be
+ * the penultimate or antepenultimate run on the stack. In other words,
+ * i must be equal to stackSize-2 or stackSize-3.
+ *
+ * @param i stack index of the first of the two runs to merge
+ */
+ private void mergeAt(int i) {
+ assert stackSize >= 2;
+ assert i >= 0;
+ assert i == stackSize - 2 || i == stackSize - 3;
+
+ int base1 = runBase[i];
+ int len1 = runLen[i];
+ int base2 = runBase[i + 1];
+ int len2 = runLen[i + 1];
+ assert len1 > 0 && len2 > 0;
+ assert base1 + len1 == base2;
+
+ /*
+ * Record the length of the combined runs; if i is the 3rd-last
+ * run now, also slide over the last run (which isn't involved
+ * in this merge). The current run (i+1) goes away in any case.
+ */
+ runLen[i] = len1 + len2;
+ if (i == stackSize - 3) {
+ runBase[i + 1] = runBase[i + 2];
+ runLen[i + 1] = runLen[i + 2];
+ }
+ stackSize--;
+
+ /*
+ * Find where the first element of run2 goes in run1. Prior elements
+ * in run1 can be ignored (because they're already in place).
+ */
+ int k = gallopRight(a[base2], a, base1, len1, 0, c);
+ assert k >= 0;
+ base1 += k;
+ len1 -= k;
+ if (len1 == 0)
+ return;
+
+ /*
+ * Find where the last element of run1 goes in run2. Subsequent elements
+ * in run2 can be ignored (because they're already in place).
+ */
+ len2 = gallopLeft(a[base1 + len1 - 1], a, base2, len2, len2 - 1, c);
+ assert len2 >= 0;
+ if (len2 == 0)
+ return;
+
+ // Merge remaining runs, using tmp array with min(len1, len2) elements
+ if (len1 <= len2)
+ mergeLo(base1, len1, base2, len2);
+ else
+ mergeHi(base1, len1, base2, len2);
+ }
+
+ /**
+ * Locates the position at which to insert the specified key into the
+ * specified sorted range; if the range contains an element equal to key,
+ * returns the index of the leftmost equal element.
+ *
+ * @param key the key whose insertion point to search for
+ * @param a the array in which to search
+ * @param base the index of the first element in the range
+ * @param len the length of the range; must be > 0
+ * @param hint the index at which to begin the search, 0 <= hint < n.
+ * The closer hint is to the result, the faster this method will run.
+ * @param c the comparator used to order the range, and to search
+ * @return the int k, 0 <= k <= n such that a[b + k - 1] < key <= a[b + k],
+ * pretending that a[b - 1] is minus infinity and a[b + n] is infinity.
+ * In other words, key belongs at index b + k; or in other words,
+ * the first k elements of a should precede key, and the last n - k
+ * should follow it.
+ */
+ private static <T> int gallopLeft(T key, T[] a, int base, int len, int hint,
+ Comparator<? super T> c) {
+ assert len > 0 && hint >= 0 && hint < len;
+ int lastOfs = 0;
+ int ofs = 1;
+ if (c.compare(key, a[base + hint]) > 0) {
+ // Gallop right until a[base+hint+lastOfs] < key <= a[base+hint+ofs]
+ int maxOfs = len - hint;
+ while (ofs < maxOfs && c.compare(key, a[base + hint + ofs]) > 0) {
+ lastOfs = ofs;
+ ofs = (ofs << 1) + 1;
+ if (ofs <= 0) // int overflow
+ ofs = maxOfs;
+ }
+ if (ofs > maxOfs)
+ ofs = maxOfs;
+
+ // Make offsets relative to base
+ lastOfs += hint;
+ ofs += hint;
+ } else { // key <= a[base + hint]
+ // Gallop left until a[base+hint-ofs] < key <= a[base+hint-lastOfs]
+ final int maxOfs = hint + 1;
+ while (ofs < maxOfs && c.compare(key, a[base + hint - ofs]) <= 0) {
+ lastOfs = ofs;
+ ofs = (ofs << 1) + 1;
+ if (ofs <= 0) // int overflow
+ ofs = maxOfs;
+ }
+ if (ofs > maxOfs)
+ ofs = maxOfs;
+
+ // Make offsets relative to base
+ int tmp = lastOfs;
+ lastOfs = hint - ofs;
+ ofs = hint - tmp;
+ }
+ assert -1 <= lastOfs && lastOfs < ofs && ofs <= len;
+
+ /*
+ * Now a[base+lastOfs] < key <= a[base+ofs], so key belongs somewhere
+ * to the right of lastOfs but no farther right than ofs. Do a binary
+ * search, with invariant a[base + lastOfs - 1] < key <= a[base + ofs].
+ */
+ lastOfs++;
+ while (lastOfs < ofs) {
+ int m = lastOfs + ((ofs - lastOfs) >>> 1);
+
+ if (c.compare(key, a[base + m]) > 0)
+ lastOfs = m + 1; // a[base + m] < key
+ else
+ ofs = m; // key <= a[base + m]
+ }
+ assert lastOfs == ofs; // so a[base + ofs - 1] < key <= a[base + ofs]
+ return ofs;
+ }
+
+ /**
+ * Like gallopLeft, except that if the range contains an element equal to
+ * key, gallopRight returns the index after the rightmost equal element.
+ *
+ * @param key the key whose insertion point to search for
+ * @param a the array in which to search
+ * @param base the index of the first element in the range
+ * @param len the length of the range; must be > 0
+ * @param hint the index at which to begin the search, 0 <= hint < n.
+ * The closer hint is to the result, the faster this method will run.
+ * @param c the comparator used to order the range, and to search
+ * @return the int k, 0 <= k <= n such that a[b + k - 1] <= key < a[b + k]
+ */
+ private static <T> int gallopRight(T key, T[] a, int base, int len,
+ int hint, Comparator<? super T> c) {
+ assert len > 0 && hint >= 0 && hint < len;
+
+ int ofs = 1;
+ int lastOfs = 0;
+ if (c.compare(key, a[base + hint]) < 0) {
+ // Gallop left until a[b+hint - ofs] <= key < a[b+hint - lastOfs]
+ int maxOfs = hint + 1;
+ while (ofs < maxOfs && c.compare(key, a[base + hint - ofs]) < 0) {
+ lastOfs = ofs;
+ ofs = (ofs << 1) + 1;
+ if (ofs <= 0) // int overflow
+ ofs = maxOfs;
+ }
+ if (ofs > maxOfs)
+ ofs = maxOfs;
+
+ // Make offsets relative to b
+ int tmp = lastOfs;
+ lastOfs = hint - ofs;
+ ofs = hint - tmp;
+ } else { // a[b + hint] <= key
+ // Gallop right until a[b+hint + lastOfs] <= key < a[b+hint + ofs]
+ int maxOfs = len - hint;
+ while (ofs < maxOfs && c.compare(key, a[base + hint + ofs]) >= 0) {
+ lastOfs = ofs;
+ ofs = (ofs << 1) + 1;
+ if (ofs <= 0) // int overflow
+ ofs = maxOfs;
+ }
+ if (ofs > maxOfs)
+ ofs = maxOfs;
+
+ // Make offsets relative to b
+ lastOfs += hint;
+ ofs += hint;
+ }
+ assert -1 <= lastOfs && lastOfs < ofs && ofs <= len;
+
+ /*
+ * Now a[b + lastOfs] <= key < a[b + ofs], so key belongs somewhere to
+ * the right of lastOfs but no farther right than ofs. Do a binary
+ * search, with invariant a[b + lastOfs - 1] <= key < a[b + ofs].
+ */
+ lastOfs++;
+ while (lastOfs < ofs) {
+ int m = lastOfs + ((ofs - lastOfs) >>> 1);
+
+ if (c.compare(key, a[base + m]) < 0)
+ ofs = m; // key < a[b + m]
+ else
+ lastOfs = m + 1; // a[b + m] <= key
+ }
+ assert lastOfs == ofs; // so a[b + ofs - 1] <= key < a[b + ofs]
+ return ofs;
+ }
+
+ /**
+ * Merges two adjacent runs in place, in a stable fashion. The first
+ * element of the first run must be greater than the first element of the
+ * second run (a[base1] > a[base2]), and the last element of the first run
+ * (a[base1 + len1-1]) must be greater than all elements of the second run.
+ *
+ * For performance, this method should be called only when len1 <= len2;
+ * its twin, mergeHi should be called if len1 >= len2. (Either method
+ * may be called if len1 == len2.)
+ *
+ * @param base1 index of first element in first run to be merged
+ * @param len1 length of first run to be merged (must be > 0)
+ * @param base2 index of first element in second run to be merged
+ * (must be aBase + aLen)
+ * @param len2 length of second run to be merged (must be > 0)
+ */
+ private void mergeLo(int base1, int len1, int base2, int len2) {
+ assert len1 > 0 && len2 > 0 && base1 + len1 == base2;
+
+ // Copy first run into temp array
+ T[] a = this.a; // For performance
+ T[] tmp = ensureCapacity(len1);
+ System.arraycopy(a, base1, tmp, 0, len1);
+
+ int cursor1 = 0; // Indexes into tmp array
+ int cursor2 = base2; // Indexes int a
+ int dest = base1; // Indexes int a
+
+ // Move first element of second run and deal with degenerate cases
+ a[dest++] = a[cursor2++];
+ if (--len2 == 0) {
+ System.arraycopy(tmp, cursor1, a, dest, len1);
+ return;
+ }
+ if (len1 == 1) {
+ System.arraycopy(a, cursor2, a, dest, len2);
+ a[dest + len2] = tmp[cursor1]; // Last elt of run 1 to end of merge
+ return;
+ }
+
+ Comparator<? super T> c = this.c; // Use local variable for performance
+ int minGallop = this.minGallop; // " " " " "
+ outer:
+ while (true) {
+ int count1 = 0; // Number of times in a row that first run won
+ int count2 = 0; // Number of times in a row that second run won
+
+ /*
+ * Do the straightforward thing until (if ever) one run starts
+ * winning consistently.
+ */
+ do {
+ assert len1 > 1 && len2 > 0;
+ if (c.compare(a[cursor2], tmp[cursor1]) < 0) {
+ a[dest++] = a[cursor2++];
+ count2++;
+ count1 = 0;
+ if (--len2 == 0)
+ break outer;
+ } else {
+ a[dest++] = tmp[cursor1++];
+ count1++;
+ count2 = 0;
+ if (--len1 == 1)
+ break outer;
+ }
+ } while ((count1 | count2) < minGallop);
+
+ /*
+ * One run is winning so consistently that galloping may be a
+ * huge win. So try that, and continue galloping until (if ever)
+ * neither run appears to be winning consistently anymore.
+ */
+ do {
+ assert len1 > 1 && len2 > 0;
+ count1 = gallopRight(a[cursor2], tmp, cursor1, len1, 0, c);
+ if (count1 != 0) {
+ System.arraycopy(tmp, cursor1, a, dest, count1);
+ dest += count1;
+ cursor1 += count1;
+ len1 -= count1;
+ if (len1 <= 1) // len1 == 1 || len1 == 0
+ break outer;
+ }
+ a[dest++] = a[cursor2++];
+ if (--len2 == 0)
+ break outer;
+
+ count2 = gallopLeft(tmp[cursor1], a, cursor2, len2, 0, c);
+ if (count2 != 0) {
+ System.arraycopy(a, cursor2, a, dest, count2);
+ dest += count2;
+ cursor2 += count2;
+ len2 -= count2;
+ if (len2 == 0)
+ break outer;
+ }
+ a[dest++] = tmp[cursor1++];
+ if (--len1 == 1)
+ break outer;
+ minGallop--;
+ } while (count1 >= MIN_GALLOP | count2 >= MIN_GALLOP);
+ if (minGallop < 0)
+ minGallop = 0;
+ minGallop += 2; // Penalize for leaving gallop mode
+ } // End of "outer" loop
+ this.minGallop = minGallop < 1 ? 1 : minGallop; // Write back to field
+
+ if (len1 == 1) {
+ assert len2 > 0;
+ System.arraycopy(a, cursor2, a, dest, len2);
+ a[dest + len2] = tmp[cursor1]; // Last elt of run 1 to end of merge
+ } else if (len1 == 0) {
+ throw new IllegalArgumentException(
+ "Comparison method violates its general contract!");
+ } else {
+ assert len2 == 0;
+ assert len1 > 1;
+ System.arraycopy(tmp, cursor1, a, dest, len1);
+ }
+ }
+
+ /**
+ * Like mergeLo, except that this method should be called only if
+ * len1 >= len2; mergeLo should be called if len1 <= len2. (Either method
+ * may be called if len1 == len2.)
+ *
+ * @param base1 index of first element in first run to be merged
+ * @param len1 length of first run to be merged (must be > 0)
+ * @param base2 index of first element in second run to be merged
+ * (must be aBase + aLen)
+ * @param len2 length of second run to be merged (must be > 0)
+ */
+ private void mergeHi(int base1, int len1, int base2, int len2) {
+ assert len1 > 0 && len2 > 0 && base1 + len1 == base2;
+
+ // Copy second run into temp array
+ T[] a = this.a; // For performance
+ T[] tmp = ensureCapacity(len2);
+ System.arraycopy(a, base2, tmp, 0, len2);
+
+ int cursor1 = base1 + len1 - 1; // Indexes into a
+ int cursor2 = len2 - 1; // Indexes into tmp array
+ int dest = base2 + len2 - 1; // Indexes into a
+
+ // Move last element of first run and deal with degenerate cases
+ a[dest--] = a[cursor1--];
+ if (--len1 == 0) {
+ System.arraycopy(tmp, 0, a, dest - (len2 - 1), len2);
+ return;
+ }
+ if (len2 == 1) {
+ dest -= len1;
+ cursor1 -= len1;
+ System.arraycopy(a, cursor1 + 1, a, dest + 1, len1);
+ a[dest] = tmp[cursor2];
+ return;
+ }
+
+ Comparator<? super T> c = this.c; // Use local variable for performance
+ int minGallop = this.minGallop; // " " " " "
+ outer:
+ while (true) {
+ int count1 = 0; // Number of times in a row that first run won
+ int count2 = 0; // Number of times in a row that second run won
+
+ /*
+ * Do the straightforward thing until (if ever) one run
+ * appears to win consistently.
+ */
+ do {
+ assert len1 > 0 && len2 > 1;
+ if (c.compare(tmp[cursor2], a[cursor1]) < 0) {
+ a[dest--] = a[cursor1--];
+ count1++;
+ count2 = 0;
+ if (--len1 == 0)
+ break outer;
+ } else {
+ a[dest--] = tmp[cursor2--];
+ count2++;
+ count1 = 0;
+ if (--len2 == 1)
+ break outer;
+ }
+ } while ((count1 | count2) < minGallop);
+
+ /*
+ * One run is winning so consistently that galloping may be a
+ * huge win. So try that, and continue galloping until (if ever)
+ * neither run appears to be winning consistently anymore.
+ */
+ do {
+ assert len1 > 0 && len2 > 1;
+ count1 = len1 - gallopRight(tmp[cursor2], a, base1, len1, len1 - 1, c);
+ if (count1 != 0) {
+ dest -= count1;
+ cursor1 -= count1;
+ len1 -= count1;
+ System.arraycopy(a, cursor1 + 1, a, dest + 1, count1);
+ if (len1 == 0)
+ break outer;
+ }
+ a[dest--] = tmp[cursor2--];
+ if (--len2 == 1)
+ break outer;
+
+ count2 = len2 - gallopLeft(a[cursor1], tmp, 0, len2, len2 - 1, c);
+ if (count2 != 0) {
+ dest -= count2;
+ cursor2 -= count2;
+ len2 -= count2;
+ System.arraycopy(tmp, cursor2 + 1, a, dest + 1, count2);
+ if (len2 <= 1) // len2 == 1 || len2 == 0
+ break outer;
+ }
+ a[dest--] = a[cursor1--];
+ if (--len1 == 0)
+ break outer;
+ minGallop--;
+ } while (count1 >= MIN_GALLOP | count2 >= MIN_GALLOP);
+ if (minGallop < 0)
+ minGallop = 0;
+ minGallop += 2; // Penalize for leaving gallop mode
+ } // End of "outer" loop
+ this.minGallop = minGallop < 1 ? 1 : minGallop; // Write back to field
+
+ if (len2 == 1) {
+ assert len1 > 0;
+ dest -= len1;
+ cursor1 -= len1;
+ System.arraycopy(a, cursor1 + 1, a, dest + 1, len1);
+ a[dest] = tmp[cursor2]; // Move first elt of run2 to front of merge
+ } else if (len2 == 0) {
+ throw new IllegalArgumentException(
+ "Comparison method violates its general contract!");
+ } else {
+ assert len1 == 0;
+ assert len2 > 0;
+ System.arraycopy(tmp, 0, a, dest - (len2 - 1), len2);
+ }
+ }
+
+ /**
+ * Ensures that the external array tmp has at least the specified
+ * number of elements, increasing its size if necessary. The size
+ * increases exponentially to ensure amortized linear time complexity.
+ *
+ * @param minCapacity the minimum required capacity of the tmp array
+ * @return tmp, whether or not it grew
+ */
+ private T[] ensureCapacity(int minCapacity) {
+ if (tmp.length < minCapacity) {
+ // Compute smallest power of 2 > minCapacity
+ int newSize = minCapacity;
+ newSize |= newSize >> 1;
+ newSize |= newSize >> 2;
+ newSize |= newSize >> 4;
+ newSize |= newSize >> 8;
+ newSize |= newSize >> 16;
+ newSize++;
+
+ if (newSize < 0) // Not bloody likely!
+ newSize = minCapacity;
+ else
+ newSize = Math.min(newSize, a.length >>> 1);
+
+ @SuppressWarnings({"unchecked", "UnnecessaryLocalVariable"})
+ T[] newArray = (T[]) new Object[newSize];
+ tmp = newArray;
+ }
+ return tmp;
+ }
+
+ /**
+ * Checks that fromIndex and toIndex are in range, and throws an
+ * appropriate exception if they aren't.
+ *
+ * @param arrayLen the length of the array
+ * @param fromIndex the index of the first element of the range
+ * @param toIndex the index after the last element of the range
+ * @throws IllegalArgumentException if fromIndex > toIndex
+ * @throws ArrayIndexOutOfBoundsException if fromIndex < 0
+ * or toIndex > arrayLen
+ */
+ private static void rangeCheck(int arrayLen, int fromIndex, int toIndex) {
+ if (fromIndex > toIndex)
+ throw new IllegalArgumentException("fromIndex(" + fromIndex +
+ ") > toIndex(" + toIndex+")");
+ if (fromIndex < 0)
+ throw new ArrayIndexOutOfBoundsException(fromIndex);
+ if (toIndex > arrayLen)
+ throw new ArrayIndexOutOfBoundsException(toIndex);
+ }
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/util/TimSort/ArrayBuilder.java Wed Jul 29 14:24:19 2009 -0700
@@ -0,0 +1,142 @@
+/*
+ * Copyright 2009 Google Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+import java.util.Random;
+import java.math.BigInteger;
+
+public enum ArrayBuilder {
+
+ // These seven are from Tim's paper (listsort.txt)
+
+ RANDOM_INT {
+ public Object[] build(int len) {
+ Integer[] result = new Integer[len];
+ for (int i = 0; i < len; i++)
+ result[i] = rnd.nextInt();
+ return result;
+ }
+ },
+
+ DESCENDING_INT {
+ public Object[] build(int len) {
+ Integer[] result = new Integer[len];
+ for (int i = 0; i < len; i++)
+ result[i] = len - i;
+ return result;
+ }
+ },
+
+ ASCENDING_INT {
+ public Object[] build(int len) {
+ Integer[] result = new Integer[len];
+ for (int i = 0; i < len; i++)
+ result[i] = i;
+ return result;
+ }
+ },
+
+ ASCENDING_3_RND_EXCH_INT {
+ public Object[] build(int len) {
+ Integer[] result = new Integer[len];
+ for (int i = 0; i < len; i++)
+ result[i] = i;
+ for (int i = 0; i < 3; i++)
+ swap(result, rnd.nextInt(result.length),
+ rnd.nextInt(result.length));
+ return result;
+ }
+ },
+
+ ASCENDING_10_RND_AT_END_INT {
+ public Object[] build(int len) {
+ Integer[] result = new Integer[len];
+ int endStart = len - 10;
+ for (int i = 0; i < endStart; i++)
+ result[i] = i;
+ for (int i = endStart; i < len; i++)
+ result[i] = rnd.nextInt(endStart + 10);
+ return result;
+ }
+ },
+
+ ALL_EQUAL_INT {
+ public Object[] build(int len) {
+ Integer[] result = new Integer[len];
+ for (int i = 0; i < len; i++)
+ result[i] = 666;
+ return result;
+ }
+ },
+
+ DUPS_GALORE_INT {
+ public Object[] build(int len) {
+ Integer[] result = new Integer[len];
+ for (int i = 0; i < len; i++)
+ result[i] = rnd.nextInt(4);
+ return result;
+ }
+ },
+
+ RANDOM_WITH_DUPS_INT {
+ public Object[] build(int len) {
+ Integer[] result = new Integer[len];
+ for (int i = 0; i < len; i++)
+ result[i] = rnd.nextInt(len);
+ return result;
+ }
+ },
+
+ PSEUDO_ASCENDING_STRING {
+ public String[] build(int len) {
+ String[] result = new String[len];
+ for (int i = 0; i < len; i++)
+ result[i] = Integer.toString(i);
+ return result;
+ }
+ },
+
+ RANDOM_BIGINT {
+ public BigInteger[] build(int len) {
+ BigInteger[] result = new BigInteger[len];
+ for (int i = 0; i < len; i++)
+ result[i] = HUGE.add(BigInteger.valueOf(rnd.nextInt(len)));
+ return result;
+ }
+ };
+
+ public abstract Object[] build(int len);
+
+ public void resetRandom() {
+ rnd = new Random(666);
+ }
+
+ private static Random rnd = new Random(666);
+
+ private static void swap(Object[] a, int i, int j) {
+ Object t = a[i];
+ a[i] = a[j];
+ a[j] = t;
+ }
+
+ private static BigInteger HUGE = BigInteger.ONE.shiftLeft(100);
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/util/TimSort/README Wed Jul 29 14:24:19 2009 -0700
@@ -0,0 +1,4 @@
+This directory contains benchmark programs used to compare the
+performance of the TimSort algorithm against the historic 1997
+implementation of Arrays.sort. Any future benchmarking will require
+minor modifications.
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/util/TimSort/SortPerf.java Wed Jul 29 14:24:19 2009 -0700
@@ -0,0 +1,66 @@
+/*
+ * Copyright 2009 Google Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+import java.util.Arrays;
+
+public class SortPerf {
+ private static final int NUM_SETS = 5;
+ private static final int[] lengths = { 10, 100, 1000, 10000, 1000000 };
+
+ // Returns the number of repetitions as a function of the list length
+ private static int reps(int n) {
+ return (int) (12000000 / (n * Math.log10(n)));
+ }
+
+ public static void main(String[] args) {
+ Sorter.warmup();
+
+ System.out.print("Strategy,Length");
+ for (Sorter sorter : Sorter.values())
+ System.out.print("," + sorter);
+ System.out.println();
+
+ for (ArrayBuilder ab : ArrayBuilder.values()) {
+ for (int n : lengths) {
+ System.out.printf("%s,%d", ab, n);
+ int reps = reps(n);
+ Object[] proto = ab.build(n);
+ for (Sorter sorter : Sorter.values()) {
+ double minTime = Double.POSITIVE_INFINITY;
+ for (int set = 0; set < NUM_SETS; set++) {
+ long startTime = System.nanoTime();
+ for (int k = 0; k < reps; k++) {
+ Object[] a = proto.clone();
+ sorter.sort(a);
+ }
+ long endTime = System.nanoTime();
+ double time = (endTime - startTime) / (1000000. * reps);
+ minTime = Math.min(minTime, time);
+ }
+ System.out.printf(",%5f", minTime);
+ }
+ System.out.println();
+ }
+ }
+ }
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/util/TimSort/Sorter.java Wed Jul 29 14:24:19 2009 -0700
@@ -0,0 +1,55 @@
+/*
+ * Copyright 2009 Google Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+import java.util.*;
+
+public enum Sorter {
+ TIMSORT {
+ public void sort(Object[] array) {
+ ComparableTimSort.sort(array);
+ }
+ },
+ MERGESORT {
+ public void sort(Object[] array) {
+ Arrays.sort(array);
+ }
+ };
+
+ public abstract void sort(Object[] array);
+
+ public static void warmup() {
+ System.out.println("start warm up");
+ Integer[] gold = new Integer[10000];
+ Random random = new java.util.Random();
+ for (int i=0; i < gold.length; i++)
+ gold[i] = random.nextInt();
+
+ for (int i=0; i < 10000; i++) {
+ for (Sorter s : values()) {
+ Integer[] test= gold.clone();
+ s.sort(test);
+ }
+ }
+ System.out.println(" end warm up");
+ }
+}