mirror of git://gcc.gnu.org/git/gcc.git
2455 lines
71 KiB
Java
2455 lines
71 KiB
Java
/* Arrays.java -- Utility class with methods to operate on arrays
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Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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||
WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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||
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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||
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||
As a special exception, if you link this library with other files to
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produce an executable, this library does not by itself cause the
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resulting executable to be covered by the GNU General Public License.
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This exception does not however invalidate any other reasons why the
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executable file might be covered by the GNU General Public License. */
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package java.util;
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import java.io.Serializable;
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import java.lang.reflect.Array;
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/**
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* This class contains various static utility methods performing operations on
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* arrays, and a method to provide a List "view" of an array to facilitate
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* using arrays with Collection-based APIs. All methods throw a
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* {@link NullPointerException} if the parameter array is null.
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* <p>
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*
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* Implementations may use their own algorithms, but must obey the general
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* properties; for example, the sort must be stable and n*log(n) complexity.
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* Sun's implementation of sort, and therefore ours, is a tuned quicksort,
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* adapted from Jon L. Bentley and M. Douglas McIlroy's "Engineering a Sort
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* Function", Software-Practice and Experience, Vol. 23(11) P. 1249-1265
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* (November 1993). This algorithm offers n*log(n) performance on many data
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* sets that cause other quicksorts to degrade to quadratic performance.
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*
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* @author Original author unknown
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* @author Bryce McKinlay
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* @author Eric Blake <ebb9@email.byu.edu>
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* @see Comparable
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* @see Comparator
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* @since 1.2
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* @status updated to 1.4
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*/
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public class Arrays
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{
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/**
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* This class is non-instantiable.
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*/
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private Arrays()
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{
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}
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// binarySearch
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/**
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* Perform a binary search of a byte array for a key. The array must be
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* sorted (as by the sort() method) - if it is not, the behaviour of this
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* method is undefined, and may be an infinite loop. If the array contains
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* the key more than once, any one of them may be found. Note: although the
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* specification allows for an infinite loop if the array is unsorted, it
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* will not happen in this implementation.
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*
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* @param a the array to search (must be sorted)
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* @param key the value to search for
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* @return the index at which the key was found, or -n-1 if it was not
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* found, where n is the index of the first value higher than key or
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* a.length if there is no such value.
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*/
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public static int binarySearch(byte[] a, byte key)
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{
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int low = 0;
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int hi = a.length - 1;
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int mid = 0;
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while (low <= hi)
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{
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mid = (low + hi) >> 1;
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final byte d = a[mid];
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if (d == key)
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return mid;
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else if (d > key)
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hi = mid - 1;
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else
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// This gets the insertion point right on the last loop.
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low = ++mid;
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}
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return -mid - 1;
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}
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/**
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* Perform a binary search of a char array for a key. The array must be
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* sorted (as by the sort() method) - if it is not, the behaviour of this
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* method is undefined, and may be an infinite loop. If the array contains
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* the key more than once, any one of them may be found. Note: although the
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* specification allows for an infinite loop if the array is unsorted, it
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* will not happen in this implementation.
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*
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* @param a the array to search (must be sorted)
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* @param key the value to search for
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* @return the index at which the key was found, or -n-1 if it was not
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* found, where n is the index of the first value higher than key or
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* a.length if there is no such value.
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*/
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public static int binarySearch(char[] a, char key)
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{
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int low = 0;
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int hi = a.length - 1;
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int mid = 0;
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while (low <= hi)
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{
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mid = (low + hi) >> 1;
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final char d = a[mid];
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if (d == key)
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return mid;
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else if (d > key)
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hi = mid - 1;
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else
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// This gets the insertion point right on the last loop.
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low = ++mid;
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}
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return -mid - 1;
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}
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/**
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* Perform a binary search of a short array for a key. The array must be
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* sorted (as by the sort() method) - if it is not, the behaviour of this
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* method is undefined, and may be an infinite loop. If the array contains
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* the key more than once, any one of them may be found. Note: although the
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* specification allows for an infinite loop if the array is unsorted, it
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* will not happen in this implementation.
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*
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* @param a the array to search (must be sorted)
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* @param key the value to search for
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* @return the index at which the key was found, or -n-1 if it was not
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* found, where n is the index of the first value higher than key or
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* a.length if there is no such value.
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*/
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public static int binarySearch(short[] a, short key)
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{
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int low = 0;
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int hi = a.length - 1;
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int mid = 0;
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while (low <= hi)
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{
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mid = (low + hi) >> 1;
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final short d = a[mid];
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if (d == key)
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return mid;
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else if (d > key)
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hi = mid - 1;
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else
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// This gets the insertion point right on the last loop.
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low = ++mid;
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}
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return -mid - 1;
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}
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/**
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* Perform a binary search of an int array for a key. The array must be
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* sorted (as by the sort() method) - if it is not, the behaviour of this
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* method is undefined, and may be an infinite loop. If the array contains
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* the key more than once, any one of them may be found. Note: although the
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* specification allows for an infinite loop if the array is unsorted, it
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* will not happen in this implementation.
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*
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* @param a the array to search (must be sorted)
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* @param key the value to search for
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* @return the index at which the key was found, or -n-1 if it was not
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* found, where n is the index of the first value higher than key or
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* a.length if there is no such value.
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*/
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public static int binarySearch(int[] a, int key)
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{
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int low = 0;
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int hi = a.length - 1;
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int mid = 0;
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while (low <= hi)
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{
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mid = (low + hi) >> 1;
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final int d = a[mid];
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if (d == key)
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return mid;
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else if (d > key)
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hi = mid - 1;
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else
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// This gets the insertion point right on the last loop.
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low = ++mid;
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}
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return -mid - 1;
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}
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/**
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* Perform a binary search of a long array for a key. The array must be
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* sorted (as by the sort() method) - if it is not, the behaviour of this
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* method is undefined, and may be an infinite loop. If the array contains
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* the key more than once, any one of them may be found. Note: although the
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* specification allows for an infinite loop if the array is unsorted, it
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* will not happen in this implementation.
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*
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* @param a the array to search (must be sorted)
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* @param key the value to search for
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* @return the index at which the key was found, or -n-1 if it was not
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* found, where n is the index of the first value higher than key or
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* a.length if there is no such value.
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*/
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public static int binarySearch(long[] a, long key)
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{
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int low = 0;
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int hi = a.length - 1;
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int mid = 0;
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while (low <= hi)
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{
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mid = (low + hi) >> 1;
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final long d = a[mid];
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if (d == key)
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return mid;
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else if (d > key)
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hi = mid - 1;
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else
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// This gets the insertion point right on the last loop.
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low = ++mid;
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}
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return -mid - 1;
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}
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/**
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* Perform a binary search of a float array for a key. The array must be
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* sorted (as by the sort() method) - if it is not, the behaviour of this
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* method is undefined, and may be an infinite loop. If the array contains
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* the key more than once, any one of them may be found. Note: although the
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* specification allows for an infinite loop if the array is unsorted, it
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* will not happen in this implementation.
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*
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* @param a the array to search (must be sorted)
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* @param key the value to search for
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* @return the index at which the key was found, or -n-1 if it was not
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* found, where n is the index of the first value higher than key or
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* a.length if there is no such value.
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*/
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public static int binarySearch(float[] a, float key)
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{
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// Must use Float.compare to take into account NaN, +-0.
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int low = 0;
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int hi = a.length - 1;
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int mid = 0;
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while (low <= hi)
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{
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mid = (low + hi) >> 1;
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final int r = Float.compare(a[mid], key);
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if (r == 0)
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return mid;
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else if (r > 0)
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hi = mid - 1;
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else
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// This gets the insertion point right on the last loop
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low = ++mid;
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}
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return -mid - 1;
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||
}
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/**
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||
* Perform a binary search of a double array for a key. The array must be
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* sorted (as by the sort() method) - if it is not, the behaviour of this
|
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* method is undefined, and may be an infinite loop. If the array contains
|
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* the key more than once, any one of them may be found. Note: although the
|
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* specification allows for an infinite loop if the array is unsorted, it
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* will not happen in this implementation.
|
||
*
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||
* @param a the array to search (must be sorted)
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* @param key the value to search for
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||
* @return the index at which the key was found, or -n-1 if it was not
|
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* found, where n is the index of the first value higher than key or
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* a.length if there is no such value.
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*/
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public static int binarySearch(double[] a, double key)
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{
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// Must use Double.compare to take into account NaN, +-0.
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int low = 0;
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int hi = a.length - 1;
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int mid = 0;
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while (low <= hi)
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{
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mid = (low + hi) >> 1;
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final int r = Double.compare(a[mid], key);
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if (r == 0)
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return mid;
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else if (r > 0)
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hi = mid - 1;
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else
|
||
// This gets the insertion point right on the last loop
|
||
low = ++mid;
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||
}
|
||
return -mid - 1;
|
||
}
|
||
|
||
/**
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||
* Perform a binary search of an Object array for a key, using the natural
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* ordering of the elements. The array must be sorted (as by the sort()
|
||
* method) - if it is not, the behaviour of this method is undefined, and may
|
||
* be an infinite loop. Further, the key must be comparable with every item
|
||
* in the array. If the array contains the key more than once, any one of
|
||
* them may be found. Note: although the specification allows for an infinite
|
||
* loop if the array is unsorted, it will not happen in this (JCL)
|
||
* implementation.
|
||
*
|
||
* @param a the array to search (must be sorted)
|
||
* @param key the value to search for
|
||
* @return the index at which the key was found, or -n-1 if it was not
|
||
* found, where n is the index of the first value higher than key or
|
||
* a.length if there is no such value.
|
||
* @throws ClassCastException if key could not be compared with one of the
|
||
* elements of a
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||
* @throws NullPointerException if a null element in a is compared
|
||
*/
|
||
public static int binarySearch(Object[] a, Object key)
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||
{
|
||
return binarySearch(a, key, null);
|
||
}
|
||
|
||
/**
|
||
* Perform a binary search of an Object array for a key, using a supplied
|
||
* Comparator. The array must be sorted (as by the sort() method with the
|
||
* same Comparator) - if it is not, the behaviour of this method is
|
||
* undefined, and may be an infinite loop. Further, the key must be
|
||
* comparable with every item in the array. If the array contains the key
|
||
* more than once, any one of them may be found. Note: although the
|
||
* specification allows for an infinite loop if the array is unsorted, it
|
||
* will not happen in this (JCL) implementation.
|
||
*
|
||
* @param a the array to search (must be sorted)
|
||
* @param key the value to search for
|
||
* @param c the comparator by which the array is sorted; or null to
|
||
* use the elements' natural order
|
||
* @return the index at which the key was found, or -n-1 if it was not
|
||
* found, where n is the index of the first value higher than key or
|
||
* a.length if there is no such value.
|
||
* @throws ClassCastException if key could not be compared with one of the
|
||
* elements of a
|
||
* @throws NullPointerException if a null element is compared with natural
|
||
* ordering (only possible when c is null)
|
||
*/
|
||
public static int binarySearch(Object[] a, Object key, Comparator c)
|
||
{
|
||
int low = 0;
|
||
int hi = a.length - 1;
|
||
int mid = 0;
|
||
while (low <= hi)
|
||
{
|
||
mid = (low + hi) >> 1;
|
||
final int d = Collections.compare(key, a[mid], c);
|
||
if (d == 0)
|
||
return mid;
|
||
else if (d < 0)
|
||
hi = mid - 1;
|
||
else
|
||
// This gets the insertion point right on the last loop
|
||
low = ++mid;
|
||
}
|
||
return -mid - 1;
|
||
}
|
||
|
||
|
||
// equals
|
||
/**
|
||
* Compare two boolean arrays for equality.
|
||
*
|
||
* @param a1 the first array to compare
|
||
* @param a2 the second array to compare
|
||
* @return true if a1 and a2 are both null, or if a2 is of the same length
|
||
* as a1, and for each 0 <= i < a1.length, a1[i] == a2[i]
|
||
*/
|
||
public static boolean equals(boolean[] a1, boolean[] a2)
|
||
{
|
||
// Quick test which saves comparing elements of the same array, and also
|
||
// catches the case that both are null.
|
||
if (a1 == a2)
|
||
return true;
|
||
|
||
try
|
||
{
|
||
// If they're the same length, test each element
|
||
if (a1.length == a2.length)
|
||
{
|
||
int i = a1.length;
|
||
while (--i >= 0)
|
||
if (a1[i] != a2[i])
|
||
return false;
|
||
return true;
|
||
}
|
||
}
|
||
catch (NullPointerException e)
|
||
{
|
||
// If one is null, we get a harmless NullPointerException
|
||
}
|
||
|
||
return false;
|
||
}
|
||
|
||
/**
|
||
* Compare two byte arrays for equality.
|
||
*
|
||
* @param a1 the first array to compare
|
||
* @param a2 the second array to compare
|
||
* @return true if a1 and a2 are both null, or if a2 is of the same length
|
||
* as a1, and for each 0 <= i < a1.length, a1[i] == a2[i]
|
||
*/
|
||
public static boolean equals(byte[] a1, byte[] a2)
|
||
{
|
||
// Quick test which saves comparing elements of the same array, and also
|
||
// catches the case that both are null.
|
||
if (a1 == a2)
|
||
return true;
|
||
|
||
try
|
||
{
|
||
// If they're the same length, test each element
|
||
if (a1.length == a2.length)
|
||
{
|
||
int i = a1.length;
|
||
while (--i >= 0)
|
||
if (a1[i] != a2[i])
|
||
return false;
|
||
return true;
|
||
}
|
||
}
|
||
catch (NullPointerException e)
|
||
{
|
||
// If one is null, we get a harmless NullPointerException
|
||
}
|
||
return false;
|
||
}
|
||
|
||
/**
|
||
* Compare two char arrays for equality.
|
||
*
|
||
* @param a1 the first array to compare
|
||
* @param a2 the second array to compare
|
||
* @return true if a1 and a2 are both null, or if a2 is of the same length
|
||
* as a1, and for each 0 <= i < a1.length, a1[i] == a2[i]
|
||
*/
|
||
public static boolean equals(char[] a1, char[] a2)
|
||
{
|
||
// Quick test which saves comparing elements of the same array, and also
|
||
// catches the case that both are null.
|
||
if (a1 == a2)
|
||
return true;
|
||
|
||
try
|
||
{
|
||
// If they're the same length, test each element
|
||
if (a1.length == a2.length)
|
||
{
|
||
int i = a1.length;
|
||
while (--i >= 0)
|
||
if (a1[i] != a2[i])
|
||
return false;
|
||
return true;
|
||
}
|
||
}
|
||
catch (NullPointerException e)
|
||
{
|
||
// If one is null, we get a harmless NullPointerException
|
||
}
|
||
return false;
|
||
}
|
||
|
||
/**
|
||
* Compare two short arrays for equality.
|
||
*
|
||
* @param a1 the first array to compare
|
||
* @param a2 the second array to compare
|
||
* @return true if a1 and a2 are both null, or if a2 is of the same length
|
||
* as a1, and for each 0 <= i < a1.length, a1[i] == a2[i]
|
||
*/
|
||
public static boolean equals(short[] a1, short[] a2)
|
||
{
|
||
// Quick test which saves comparing elements of the same array, and also
|
||
// catches the case that both are null.
|
||
if (a1 == a2)
|
||
return true;
|
||
|
||
try
|
||
{
|
||
// If they're the same length, test each element
|
||
if (a1.length == a2.length)
|
||
{
|
||
int i = a1.length;
|
||
while (--i >= 0)
|
||
if (a1[i] != a2[i])
|
||
return false;
|
||
return true;
|
||
}
|
||
}
|
||
catch (NullPointerException e)
|
||
{
|
||
// If one is null, we get a harmless NullPointerException
|
||
}
|
||
return false;
|
||
}
|
||
|
||
/**
|
||
* Compare two int arrays for equality.
|
||
*
|
||
* @param a1 the first array to compare
|
||
* @param a2 the second array to compare
|
||
* @return true if a1 and a2 are both null, or if a2 is of the same length
|
||
* as a1, and for each 0 <= i < a1.length, a1[i] == a2[i]
|
||
*/
|
||
public static boolean equals(int[] a1, int[] a2)
|
||
{
|
||
// Quick test which saves comparing elements of the same array, and also
|
||
// catches the case that both are null.
|
||
if (a1 == a2)
|
||
return true;
|
||
|
||
try
|
||
{
|
||
// If they're the same length, test each element
|
||
if (a1.length == a2.length)
|
||
{
|
||
int i = a1.length;
|
||
while (--i >= 0)
|
||
if (a1[i] != a2[i])
|
||
return false;
|
||
return true;
|
||
}
|
||
}
|
||
catch (NullPointerException e)
|
||
{
|
||
// If one is null, we get a harmless NullPointerException
|
||
}
|
||
return false;
|
||
}
|
||
|
||
/**
|
||
* Compare two long arrays for equality.
|
||
*
|
||
* @param a1 the first array to compare
|
||
* @param a2 the second array to compare
|
||
* @return true if a1 and a2 are both null, or if a2 is of the same length
|
||
* as a1, and for each 0 <= i < a1.length, a1[i] == a2[i]
|
||
*/
|
||
public static boolean equals(long[] a1, long[] a2)
|
||
{
|
||
// Quick test which saves comparing elements of the same array, and also
|
||
// catches the case that both are null.
|
||
if (a1 == a2)
|
||
return true;
|
||
|
||
try
|
||
{
|
||
// If they're the same length, test each element
|
||
if (a1.length == a2.length)
|
||
{
|
||
int i = a1.length;
|
||
while (--i >= 0)
|
||
if (a1[i] != a2[i])
|
||
return false;
|
||
return true;
|
||
}
|
||
}
|
||
catch (NullPointerException e)
|
||
{
|
||
// If one is null, we get a harmless NullPointerException
|
||
}
|
||
return false;
|
||
}
|
||
|
||
/**
|
||
* Compare two float arrays for equality.
|
||
*
|
||
* @param a1 the first array to compare
|
||
* @param a2 the second array to compare
|
||
* @return true if a1 and a2 are both null, or if a2 is of the same length
|
||
* as a1, and for each 0 <= i < a1.length, a1[i] == a2[i]
|
||
*/
|
||
public static boolean equals(float[] a1, float[] a2)
|
||
{
|
||
// Quick test which saves comparing elements of the same array, and also
|
||
// catches the case that both are null.
|
||
if (a1 == a2)
|
||
return true;
|
||
|
||
// Must use Float.compare to take into account NaN, +-0.
|
||
try
|
||
{
|
||
// If they're the same length, test each element
|
||
if (a1.length == a2.length)
|
||
{
|
||
int i = a1.length;
|
||
while (--i >= 0)
|
||
if (Float.compare(a1[i], a2[i]) != 0)
|
||
return false;
|
||
return true;
|
||
}
|
||
}
|
||
catch (NullPointerException e)
|
||
{
|
||
// If one is null, we get a harmless NullPointerException
|
||
}
|
||
return false;
|
||
}
|
||
|
||
/**
|
||
* Compare two double arrays for equality.
|
||
*
|
||
* @param a1 the first array to compare
|
||
* @param a2 the second array to compare
|
||
* @return true if a1 and a2 are both null, or if a2 is of the same length
|
||
* as a1, and for each 0 <= i < a1.length, a1[i] == a2[i]
|
||
*/
|
||
public static boolean equals(double[] a1, double[] a2)
|
||
{
|
||
// Quick test which saves comparing elements of the same array, and also
|
||
// catches the case that both are null.
|
||
if (a1 == a2)
|
||
return true;
|
||
|
||
// Must use Double.compare to take into account NaN, +-0.
|
||
try
|
||
{
|
||
// If they're the same length, test each element
|
||
if (a1.length == a2.length)
|
||
{
|
||
int i = a1.length;
|
||
while (--i >= 0)
|
||
if (Double.compare(a1[i], a2[i]) != 0)
|
||
return false;
|
||
return true;
|
||
}
|
||
}
|
||
catch (NullPointerException e)
|
||
{
|
||
// If one is null, we get a harmless NullPointerException
|
||
}
|
||
return false;
|
||
}
|
||
|
||
/**
|
||
* Compare two Object arrays for equality.
|
||
*
|
||
* @param a1 the first array to compare
|
||
* @param a2 the second array to compare
|
||
* @return true if a1 and a2 are both null, or if a1 is of the same length
|
||
* as a2, and for each 0 <= i < a.length, a1[i] == null ?
|
||
* a2[i] == null : a1[i].equals(a2[i]).
|
||
*/
|
||
public static boolean equals(Object[] a1, Object[] a2)
|
||
{
|
||
// Quick test which saves comparing elements of the same array, and also
|
||
// catches the case that both are null.
|
||
if (a1 == a2)
|
||
return true;
|
||
|
||
try
|
||
{
|
||
// If they're the same length, test each element
|
||
if (a1.length == a2.length)
|
||
{
|
||
int i = a1.length;
|
||
while (--i >= 0)
|
||
if (! AbstractCollection.equals(a1[i], a2[i]))
|
||
return false;
|
||
return true;
|
||
}
|
||
}
|
||
catch (NullPointerException e)
|
||
{
|
||
// If one is null, we get a harmless NullPointerException
|
||
}
|
||
return false;
|
||
}
|
||
|
||
|
||
// fill
|
||
/**
|
||
* Fill an array with a boolean value.
|
||
*
|
||
* @param a the array to fill
|
||
* @param val the value to fill it with
|
||
*/
|
||
public static void fill(boolean[] a, boolean val)
|
||
{
|
||
fill(a, 0, a.length, val);
|
||
}
|
||
|
||
/**
|
||
* Fill a range of an array with a boolean value.
|
||
*
|
||
* @param a the array to fill
|
||
* @param fromIndex the index to fill from, inclusive
|
||
* @param toIndex the index to fill to, exclusive
|
||
* @param val the value to fill with
|
||
* @throws IllegalArgumentException if fromIndex > toIndex
|
||
* @throws ArrayIndexOutOfBoundsException if fromIndex < 0
|
||
* || toIndex > a.length
|
||
*/
|
||
public static void fill(boolean[] a, int fromIndex, int toIndex, boolean val)
|
||
{
|
||
if (fromIndex > toIndex)
|
||
throw new IllegalArgumentException();
|
||
for (int i = fromIndex; i < toIndex; i++)
|
||
a[i] = val;
|
||
}
|
||
|
||
/**
|
||
* Fill an array with a byte value.
|
||
*
|
||
* @param a the array to fill
|
||
* @param val the value to fill it with
|
||
*/
|
||
public static void fill(byte[] a, byte val)
|
||
{
|
||
fill(a, 0, a.length, val);
|
||
}
|
||
|
||
/**
|
||
* Fill a range of an array with a byte value.
|
||
*
|
||
* @param a the array to fill
|
||
* @param fromIndex the index to fill from, inclusive
|
||
* @param toIndex the index to fill to, exclusive
|
||
* @param val the value to fill with
|
||
* @throws IllegalArgumentException if fromIndex > toIndex
|
||
* @throws ArrayIndexOutOfBoundsException if fromIndex < 0
|
||
* || toIndex > a.length
|
||
*/
|
||
public static void fill(byte[] a, int fromIndex, int toIndex, byte val)
|
||
{
|
||
if (fromIndex > toIndex)
|
||
throw new IllegalArgumentException();
|
||
for (int i = fromIndex; i < toIndex; i++)
|
||
a[i] = val;
|
||
}
|
||
|
||
/**
|
||
* Fill an array with a char value.
|
||
*
|
||
* @param a the array to fill
|
||
* @param val the value to fill it with
|
||
*/
|
||
public static void fill(char[] a, char val)
|
||
{
|
||
fill(a, 0, a.length, val);
|
||
}
|
||
|
||
/**
|
||
* Fill a range of an array with a char value.
|
||
*
|
||
* @param a the array to fill
|
||
* @param fromIndex the index to fill from, inclusive
|
||
* @param toIndex the index to fill to, exclusive
|
||
* @param val the value to fill with
|
||
* @throws IllegalArgumentException if fromIndex > toIndex
|
||
* @throws ArrayIndexOutOfBoundsException if fromIndex < 0
|
||
* || toIndex > a.length
|
||
*/
|
||
public static void fill(char[] a, int fromIndex, int toIndex, char val)
|
||
{
|
||
if (fromIndex > toIndex)
|
||
throw new IllegalArgumentException();
|
||
for (int i = fromIndex; i < toIndex; i++)
|
||
a[i] = val;
|
||
}
|
||
|
||
/**
|
||
* Fill an array with a short value.
|
||
*
|
||
* @param a the array to fill
|
||
* @param val the value to fill it with
|
||
*/
|
||
public static void fill(short[] a, short val)
|
||
{
|
||
fill(a, 0, a.length, val);
|
||
}
|
||
|
||
/**
|
||
* Fill a range of an array with a short value.
|
||
*
|
||
* @param a the array to fill
|
||
* @param fromIndex the index to fill from, inclusive
|
||
* @param toIndex the index to fill to, exclusive
|
||
* @param val the value to fill with
|
||
* @throws IllegalArgumentException if fromIndex > toIndex
|
||
* @throws ArrayIndexOutOfBoundsException if fromIndex < 0
|
||
* || toIndex > a.length
|
||
*/
|
||
public static void fill(short[] a, int fromIndex, int toIndex, short val)
|
||
{
|
||
if (fromIndex > toIndex)
|
||
throw new IllegalArgumentException();
|
||
for (int i = fromIndex; i < toIndex; i++)
|
||
a[i] = val;
|
||
}
|
||
|
||
/**
|
||
* Fill an array with an int value.
|
||
*
|
||
* @param a the array to fill
|
||
* @param val the value to fill it with
|
||
*/
|
||
public static void fill(int[] a, int val)
|
||
{
|
||
fill(a, 0, a.length, val);
|
||
}
|
||
|
||
/**
|
||
* Fill a range of an array with an int value.
|
||
*
|
||
* @param a the array to fill
|
||
* @param fromIndex the index to fill from, inclusive
|
||
* @param toIndex the index to fill to, exclusive
|
||
* @param val the value to fill with
|
||
* @throws IllegalArgumentException if fromIndex > toIndex
|
||
* @throws ArrayIndexOutOfBoundsException if fromIndex < 0
|
||
* || toIndex > a.length
|
||
*/
|
||
public static void fill(int[] a, int fromIndex, int toIndex, int val)
|
||
{
|
||
if (fromIndex > toIndex)
|
||
throw new IllegalArgumentException();
|
||
for (int i = fromIndex; i < toIndex; i++)
|
||
a[i] = val;
|
||
}
|
||
|
||
/**
|
||
* Fill an array with a long value.
|
||
*
|
||
* @param a the array to fill
|
||
* @param val the value to fill it with
|
||
*/
|
||
public static void fill(long[] a, long val)
|
||
{
|
||
fill(a, 0, a.length, val);
|
||
}
|
||
|
||
/**
|
||
* Fill a range of an array with a long value.
|
||
*
|
||
* @param a the array to fill
|
||
* @param fromIndex the index to fill from, inclusive
|
||
* @param toIndex the index to fill to, exclusive
|
||
* @param val the value to fill with
|
||
* @throws IllegalArgumentException if fromIndex > toIndex
|
||
* @throws ArrayIndexOutOfBoundsException if fromIndex < 0
|
||
* || toIndex > a.length
|
||
*/
|
||
public static void fill(long[] a, int fromIndex, int toIndex, long val)
|
||
{
|
||
if (fromIndex > toIndex)
|
||
throw new IllegalArgumentException();
|
||
for (int i = fromIndex; i < toIndex; i++)
|
||
a[i] = val;
|
||
}
|
||
|
||
/**
|
||
* Fill an array with a float value.
|
||
*
|
||
* @param a the array to fill
|
||
* @param val the value to fill it with
|
||
*/
|
||
public static void fill(float[] a, float val)
|
||
{
|
||
fill(a, 0, a.length, val);
|
||
}
|
||
|
||
/**
|
||
* Fill a range of an array with a float value.
|
||
*
|
||
* @param a the array to fill
|
||
* @param fromIndex the index to fill from, inclusive
|
||
* @param toIndex the index to fill to, exclusive
|
||
* @param val the value to fill with
|
||
* @throws IllegalArgumentException if fromIndex > toIndex
|
||
* @throws ArrayIndexOutOfBoundsException if fromIndex < 0
|
||
* || toIndex > a.length
|
||
*/
|
||
public static void fill(float[] a, int fromIndex, int toIndex, float val)
|
||
{
|
||
if (fromIndex > toIndex)
|
||
throw new IllegalArgumentException();
|
||
for (int i = fromIndex; i < toIndex; i++)
|
||
a[i] = val;
|
||
}
|
||
|
||
/**
|
||
* Fill an array with a double value.
|
||
*
|
||
* @param a the array to fill
|
||
* @param val the value to fill it with
|
||
*/
|
||
public static void fill(double[] a, double val)
|
||
{
|
||
fill(a, 0, a.length, val);
|
||
}
|
||
|
||
/**
|
||
* Fill a range of an array with a double value.
|
||
*
|
||
* @param a the array to fill
|
||
* @param fromIndex the index to fill from, inclusive
|
||
* @param toIndex the index to fill to, exclusive
|
||
* @param val the value to fill with
|
||
* @throws IllegalArgumentException if fromIndex > toIndex
|
||
* @throws ArrayIndexOutOfBoundsException if fromIndex < 0
|
||
* || toIndex > a.length
|
||
*/
|
||
public static void fill(double[] a, int fromIndex, int toIndex, double val)
|
||
{
|
||
if (fromIndex > toIndex)
|
||
throw new IllegalArgumentException();
|
||
for (int i = fromIndex; i < toIndex; i++)
|
||
a[i] = val;
|
||
}
|
||
|
||
/**
|
||
* Fill an array with an Object value.
|
||
*
|
||
* @param a the array to fill
|
||
* @param val the value to fill it with
|
||
* @throws ClassCastException if val is not an instance of the element
|
||
* type of a.
|
||
*/
|
||
public static void fill(Object[] a, Object val)
|
||
{
|
||
fill(a, 0, a.length, val);
|
||
}
|
||
|
||
/**
|
||
* Fill a range of an array with an Object value.
|
||
*
|
||
* @param a the array to fill
|
||
* @param fromIndex the index to fill from, inclusive
|
||
* @param toIndex the index to fill to, exclusive
|
||
* @param val the value to fill with
|
||
* @throws ClassCastException if val is not an instance of the element
|
||
* type of a.
|
||
* @throws IllegalArgumentException if fromIndex > toIndex
|
||
* @throws ArrayIndexOutOfBoundsException if fromIndex < 0
|
||
* || toIndex > a.length
|
||
*/
|
||
public static void fill(Object[] a, int fromIndex, int toIndex, Object val)
|
||
{
|
||
if (fromIndex > toIndex)
|
||
throw new IllegalArgumentException();
|
||
for (int i = fromIndex; i < toIndex; i++)
|
||
a[i] = val;
|
||
}
|
||
|
||
|
||
// sort
|
||
// Thanks to Paul Fisher <rao@gnu.org> for finding this quicksort algorithm
|
||
// as specified by Sun and porting it to Java. The algorithm is an optimised
|
||
// quicksort, as described in Jon L. Bentley and M. Douglas McIlroy's
|
||
// "Engineering a Sort Function", Software-Practice and Experience, Vol.
|
||
// 23(11) P. 1249-1265 (November 1993). This algorithm gives n*log(n)
|
||
// performance on many arrays that would take quadratic time with a standard
|
||
// quicksort.
|
||
|
||
/**
|
||
* Performs a stable sort on the elements, arranging them according to their
|
||
* natural order.
|
||
*
|
||
* @param a the byte array to sort
|
||
*/
|
||
public static void sort(byte[] a)
|
||
{
|
||
qsort(a, 0, a.length);
|
||
}
|
||
|
||
/**
|
||
* Performs a stable sort on the elements, arranging them according to their
|
||
* natural order.
|
||
*
|
||
* @param a the byte array to sort
|
||
* @param fromIndex the first index to sort (inclusive)
|
||
* @param toIndex the last index to sort (exclusive)
|
||
* @throws IllegalArgumentException if fromIndex > toIndex
|
||
* @throws ArrayIndexOutOfBoundsException if fromIndex < 0
|
||
* || toIndex > a.length
|
||
*/
|
||
public static void sort(byte[] a, int fromIndex, int toIndex)
|
||
{
|
||
if (fromIndex > toIndex)
|
||
throw new IllegalArgumentException();
|
||
qsort(a, fromIndex, toIndex - fromIndex);
|
||
}
|
||
|
||
/**
|
||
* Finds the index of the median of three array elements.
|
||
*
|
||
* @param a the first index
|
||
* @param b the second index
|
||
* @param c the third index
|
||
* @param d the array
|
||
* @return the index (a, b, or c) which has the middle value of the three
|
||
*/
|
||
private static int med3(int a, int b, int c, byte[] d)
|
||
{
|
||
return (d[a] < d[b]
|
||
? (d[b] < d[c] ? b : d[a] < d[c] ? c : a)
|
||
: (d[b] > d[c] ? b : d[a] > d[c] ? c : a));
|
||
}
|
||
|
||
/**
|
||
* Swaps the elements at two locations of an array
|
||
*
|
||
* @param i the first index
|
||
* @param j the second index
|
||
* @param a the array
|
||
*/
|
||
private static void swap(int i, int j, byte[] a)
|
||
{
|
||
byte c = a[i];
|
||
a[i] = a[j];
|
||
a[j] = c;
|
||
}
|
||
|
||
/**
|
||
* Swaps two ranges of an array.
|
||
*
|
||
* @param i the first range start
|
||
* @param j the second range start
|
||
* @param n the element count
|
||
* @param a the array
|
||
*/
|
||
private static void vecswap(int i, int j, int n, byte[] a)
|
||
{
|
||
for ( ; n > 0; i++, j++, n--)
|
||
swap(i, j, a);
|
||
}
|
||
|
||
/**
|
||
* Performs a recursive modified quicksort.
|
||
*
|
||
* @param a the array to sort
|
||
* @param from the start index (inclusive)
|
||
* @param count the number of elements to sort
|
||
*/
|
||
private static void qsort(byte[] array, int from, int count)
|
||
{
|
||
// Use an insertion sort on small arrays.
|
||
if (count <= 7)
|
||
{
|
||
for (int i = from + 1; i < from + count; i++)
|
||
for (int j = i; j > 0 && array[j - 1] > array[j]; j--)
|
||
swap(j, j - 1, array);
|
||
return;
|
||
}
|
||
|
||
// Determine a good median element.
|
||
int mid = count / 2;
|
||
int lo = from;
|
||
int hi = from + count - 1;
|
||
|
||
if (count > 40)
|
||
{ // big arrays, pseudomedian of 9
|
||
int s = count / 8;
|
||
lo = med3(lo, lo + s, lo + s + s, array);
|
||
mid = med3(mid - s, mid, mid + s, array);
|
||
hi = med3(hi - s - s, hi - s, hi, array);
|
||
}
|
||
mid = med3(lo, mid, hi, array);
|
||
|
||
int a, b, c, d;
|
||
int comp;
|
||
|
||
// Pull the median element out of the fray, and use it as a pivot.
|
||
swap(from, mid, array);
|
||
a = b = from + 1;
|
||
c = d = hi;
|
||
|
||
// Repeatedly move b and c to each other, swapping elements so
|
||
// that all elements before index b are less than the pivot, and all
|
||
// elements after index c are greater than the pivot. a and b track
|
||
// the elements equal to the pivot.
|
||
while (true)
|
||
{
|
||
while (b <= c && (comp = array[b] - array[from]) <= 0)
|
||
{
|
||
if (comp == 0)
|
||
{
|
||
swap(a, b, array);
|
||
a++;
|
||
}
|
||
b++;
|
||
}
|
||
while (c >= b && (comp = array[c] - array[from]) >= 0)
|
||
{
|
||
if (comp == 0)
|
||
{
|
||
swap(c, d, array);
|
||
d--;
|
||
}
|
||
c--;
|
||
}
|
||
if (b > c)
|
||
break;
|
||
swap(b, c, array);
|
||
b++;
|
||
c--;
|
||
}
|
||
|
||
// Swap pivot(s) back in place, the recurse on left and right sections.
|
||
int span;
|
||
span = Math.min(a - from, b - a);
|
||
vecswap(from, b - span, span, array);
|
||
|
||
span = Math.min(d - c, hi - d - 1);
|
||
vecswap(b, hi - span + 1, span, array);
|
||
|
||
span = b - a;
|
||
if (span > 1)
|
||
qsort(array, from, span);
|
||
|
||
span = d - c;
|
||
if (span > 1)
|
||
qsort(array, hi - span + 1, span);
|
||
}
|
||
|
||
/**
|
||
* Performs a stable sort on the elements, arranging them according to their
|
||
* natural order.
|
||
*
|
||
* @param a the char array to sort
|
||
*/
|
||
public static void sort(char[] a)
|
||
{
|
||
qsort(a, 0, a.length);
|
||
}
|
||
|
||
/**
|
||
* Performs a stable sort on the elements, arranging them according to their
|
||
* natural order.
|
||
*
|
||
* @param a the char array to sort
|
||
* @param fromIndex the first index to sort (inclusive)
|
||
* @param toIndex the last index to sort (exclusive)
|
||
* @throws IllegalArgumentException if fromIndex > toIndex
|
||
* @throws ArrayIndexOutOfBoundsException if fromIndex < 0
|
||
* || toIndex > a.length
|
||
*/
|
||
public static void sort(char[] a, int fromIndex, int toIndex)
|
||
{
|
||
if (fromIndex > toIndex)
|
||
throw new IllegalArgumentException();
|
||
qsort(a, fromIndex, toIndex - fromIndex);
|
||
}
|
||
|
||
/**
|
||
* Finds the index of the median of three array elements.
|
||
*
|
||
* @param a the first index
|
||
* @param b the second index
|
||
* @param c the third index
|
||
* @param d the array
|
||
* @return the index (a, b, or c) which has the middle value of the three
|
||
*/
|
||
private static int med3(int a, int b, int c, char[] d)
|
||
{
|
||
return (d[a] < d[b]
|
||
? (d[b] < d[c] ? b : d[a] < d[c] ? c : a)
|
||
: (d[b] > d[c] ? b : d[a] > d[c] ? c : a));
|
||
}
|
||
|
||
/**
|
||
* Swaps the elements at two locations of an array
|
||
*
|
||
* @param i the first index
|
||
* @param j the second index
|
||
* @param a the array
|
||
*/
|
||
private static void swap(int i, int j, char[] a)
|
||
{
|
||
char c = a[i];
|
||
a[i] = a[j];
|
||
a[j] = c;
|
||
}
|
||
|
||
/**
|
||
* Swaps two ranges of an array.
|
||
*
|
||
* @param i the first range start
|
||
* @param j the second range start
|
||
* @param n the element count
|
||
* @param a the array
|
||
*/
|
||
private static void vecswap(int i, int j, int n, char[] a)
|
||
{
|
||
for ( ; n > 0; i++, j++, n--)
|
||
swap(i, j, a);
|
||
}
|
||
|
||
/**
|
||
* Performs a recursive modified quicksort.
|
||
*
|
||
* @param a the array to sort
|
||
* @param from the start index (inclusive)
|
||
* @param count the number of elements to sort
|
||
*/
|
||
private static void qsort(char[] array, int from, int count)
|
||
{
|
||
// Use an insertion sort on small arrays.
|
||
if (count <= 7)
|
||
{
|
||
for (int i = from + 1; i < from + count; i++)
|
||
for (int j = i; j > 0 && array[j - 1] > array[j]; j--)
|
||
swap(j, j - 1, array);
|
||
return;
|
||
}
|
||
|
||
// Determine a good median element.
|
||
int mid = count / 2;
|
||
int lo = from;
|
||
int hi = from + count - 1;
|
||
|
||
if (count > 40)
|
||
{ // big arrays, pseudomedian of 9
|
||
int s = count / 8;
|
||
lo = med3(lo, lo + s, lo + s + s, array);
|
||
mid = med3(mid - s, mid, mid + s, array);
|
||
hi = med3(hi - s - s, hi - s, hi, array);
|
||
}
|
||
mid = med3(lo, mid, hi, array);
|
||
|
||
int a, b, c, d;
|
||
int comp;
|
||
|
||
// Pull the median element out of the fray, and use it as a pivot.
|
||
swap(from, mid, array);
|
||
a = b = from + 1;
|
||
c = d = hi;
|
||
|
||
// Repeatedly move b and c to each other, swapping elements so
|
||
// that all elements before index b are less than the pivot, and all
|
||
// elements after index c are greater than the pivot. a and b track
|
||
// the elements equal to the pivot.
|
||
while (true)
|
||
{
|
||
while (b <= c && (comp = array[b] - array[from]) <= 0)
|
||
{
|
||
if (comp == 0)
|
||
{
|
||
swap(a, b, array);
|
||
a++;
|
||
}
|
||
b++;
|
||
}
|
||
while (c >= b && (comp = array[c] - array[from]) >= 0)
|
||
{
|
||
if (comp == 0)
|
||
{
|
||
swap(c, d, array);
|
||
d--;
|
||
}
|
||
c--;
|
||
}
|
||
if (b > c)
|
||
break;
|
||
swap(b, c, array);
|
||
b++;
|
||
c--;
|
||
}
|
||
|
||
// Swap pivot(s) back in place, the recurse on left and right sections.
|
||
int span;
|
||
span = Math.min(a - from, b - a);
|
||
vecswap(from, b - span, span, array);
|
||
|
||
span = Math.min(d - c, hi - d - 1);
|
||
vecswap(b, hi - span + 1, span, array);
|
||
|
||
span = b - a;
|
||
if (span > 1)
|
||
qsort(array, from, span);
|
||
|
||
span = d - c;
|
||
if (span > 1)
|
||
qsort(array, hi - span + 1, span);
|
||
}
|
||
|
||
/**
|
||
* Performs a stable sort on the elements, arranging them according to their
|
||
* natural order.
|
||
*
|
||
* @param a the short array to sort
|
||
*/
|
||
public static void sort(short[] a)
|
||
{
|
||
qsort(a, 0, a.length);
|
||
}
|
||
|
||
/**
|
||
* Performs a stable sort on the elements, arranging them according to their
|
||
* natural order.
|
||
*
|
||
* @param a the short array to sort
|
||
* @param fromIndex the first index to sort (inclusive)
|
||
* @param toIndex the last index to sort (exclusive)
|
||
* @throws IllegalArgumentException if fromIndex > toIndex
|
||
* @throws ArrayIndexOutOfBoundsException if fromIndex < 0
|
||
* || toIndex > a.length
|
||
*/
|
||
public static void sort(short[] a, int fromIndex, int toIndex)
|
||
{
|
||
if (fromIndex > toIndex)
|
||
throw new IllegalArgumentException();
|
||
qsort(a, fromIndex, toIndex - fromIndex);
|
||
}
|
||
|
||
/**
|
||
* Finds the index of the median of three array elements.
|
||
*
|
||
* @param a the first index
|
||
* @param b the second index
|
||
* @param c the third index
|
||
* @param d the array
|
||
* @return the index (a, b, or c) which has the middle value of the three
|
||
*/
|
||
private static int med3(int a, int b, int c, short[] d)
|
||
{
|
||
return (d[a] < d[b]
|
||
? (d[b] < d[c] ? b : d[a] < d[c] ? c : a)
|
||
: (d[b] > d[c] ? b : d[a] > d[c] ? c : a));
|
||
}
|
||
|
||
/**
|
||
* Swaps the elements at two locations of an array
|
||
*
|
||
* @param i the first index
|
||
* @param j the second index
|
||
* @param a the array
|
||
*/
|
||
private static void swap(int i, int j, short[] a)
|
||
{
|
||
short c = a[i];
|
||
a[i] = a[j];
|
||
a[j] = c;
|
||
}
|
||
|
||
/**
|
||
* Swaps two ranges of an array.
|
||
*
|
||
* @param i the first range start
|
||
* @param j the second range start
|
||
* @param n the element count
|
||
* @param a the array
|
||
*/
|
||
private static void vecswap(int i, int j, int n, short[] a)
|
||
{
|
||
for ( ; n > 0; i++, j++, n--)
|
||
swap(i, j, a);
|
||
}
|
||
|
||
/**
|
||
* Performs a recursive modified quicksort.
|
||
*
|
||
* @param a the array to sort
|
||
* @param from the start index (inclusive)
|
||
* @param count the number of elements to sort
|
||
*/
|
||
private static void qsort(short[] array, int from, int count)
|
||
{
|
||
// Use an insertion sort on small arrays.
|
||
if (count <= 7)
|
||
{
|
||
for (int i = from + 1; i < from + count; i++)
|
||
for (int j = i; j > 0 && array[j - 1] > array[j]; j--)
|
||
swap(j, j - 1, array);
|
||
return;
|
||
}
|
||
|
||
// Determine a good median element.
|
||
int mid = count / 2;
|
||
int lo = from;
|
||
int hi = from + count - 1;
|
||
|
||
if (count > 40)
|
||
{ // big arrays, pseudomedian of 9
|
||
int s = count / 8;
|
||
lo = med3(lo, lo + s, lo + s + s, array);
|
||
mid = med3(mid - s, mid, mid + s, array);
|
||
hi = med3(hi - s - s, hi - s, hi, array);
|
||
}
|
||
mid = med3(lo, mid, hi, array);
|
||
|
||
int a, b, c, d;
|
||
int comp;
|
||
|
||
// Pull the median element out of the fray, and use it as a pivot.
|
||
swap(from, mid, array);
|
||
a = b = from + 1;
|
||
c = d = hi;
|
||
|
||
// Repeatedly move b and c to each other, swapping elements so
|
||
// that all elements before index b are less than the pivot, and all
|
||
// elements after index c are greater than the pivot. a and b track
|
||
// the elements equal to the pivot.
|
||
while (true)
|
||
{
|
||
while (b <= c && (comp = array[b] - array[from]) <= 0)
|
||
{
|
||
if (comp == 0)
|
||
{
|
||
swap(a, b, array);
|
||
a++;
|
||
}
|
||
b++;
|
||
}
|
||
while (c >= b && (comp = array[c] - array[from]) >= 0)
|
||
{
|
||
if (comp == 0)
|
||
{
|
||
swap(c, d, array);
|
||
d--;
|
||
}
|
||
c--;
|
||
}
|
||
if (b > c)
|
||
break;
|
||
swap(b, c, array);
|
||
b++;
|
||
c--;
|
||
}
|
||
|
||
// Swap pivot(s) back in place, the recurse on left and right sections.
|
||
int span;
|
||
span = Math.min(a - from, b - a);
|
||
vecswap(from, b - span, span, array);
|
||
|
||
span = Math.min(d - c, hi - d - 1);
|
||
vecswap(b, hi - span + 1, span, array);
|
||
|
||
span = b - a;
|
||
if (span > 1)
|
||
qsort(array, from, span);
|
||
|
||
span = d - c;
|
||
if (span > 1)
|
||
qsort(array, hi - span + 1, span);
|
||
}
|
||
|
||
/**
|
||
* Performs a stable sort on the elements, arranging them according to their
|
||
* natural order.
|
||
*
|
||
* @param a the int array to sort
|
||
*/
|
||
public static void sort(int[] a)
|
||
{
|
||
qsort(a, 0, a.length);
|
||
}
|
||
|
||
/**
|
||
* Performs a stable sort on the elements, arranging them according to their
|
||
* natural order.
|
||
*
|
||
* @param a the int array to sort
|
||
* @param fromIndex the first index to sort (inclusive)
|
||
* @param toIndex the last index to sort (exclusive)
|
||
* @throws IllegalArgumentException if fromIndex > toIndex
|
||
* @throws ArrayIndexOutOfBoundsException if fromIndex < 0
|
||
* || toIndex > a.length
|
||
*/
|
||
public static void sort(int[] a, int fromIndex, int toIndex)
|
||
{
|
||
if (fromIndex > toIndex)
|
||
throw new IllegalArgumentException();
|
||
qsort(a, fromIndex, toIndex - fromIndex);
|
||
}
|
||
|
||
/**
|
||
* Finds the index of the median of three array elements.
|
||
*
|
||
* @param a the first index
|
||
* @param b the second index
|
||
* @param c the third index
|
||
* @param d the array
|
||
* @return the index (a, b, or c) which has the middle value of the three
|
||
*/
|
||
private static int med3(int a, int b, int c, int[] d)
|
||
{
|
||
return (d[a] < d[b]
|
||
? (d[b] < d[c] ? b : d[a] < d[c] ? c : a)
|
||
: (d[b] > d[c] ? b : d[a] > d[c] ? c : a));
|
||
}
|
||
|
||
/**
|
||
* Swaps the elements at two locations of an array
|
||
*
|
||
* @param i the first index
|
||
* @param j the second index
|
||
* @param a the array
|
||
*/
|
||
private static void swap(int i, int j, int[] a)
|
||
{
|
||
int c = a[i];
|
||
a[i] = a[j];
|
||
a[j] = c;
|
||
}
|
||
|
||
/**
|
||
* Swaps two ranges of an array.
|
||
*
|
||
* @param i the first range start
|
||
* @param j the second range start
|
||
* @param n the element count
|
||
* @param a the array
|
||
*/
|
||
private static void vecswap(int i, int j, int n, int[] a)
|
||
{
|
||
for ( ; n > 0; i++, j++, n--)
|
||
swap(i, j, a);
|
||
}
|
||
|
||
/**
|
||
* Compares two integers in natural order, since a - b is inadequate.
|
||
*
|
||
* @param a the first int
|
||
* @param b the second int
|
||
* @return < 0, 0, or > 0 accorting to the comparison
|
||
*/
|
||
private static int compare(int a, int b)
|
||
{
|
||
return a < b ? -1 : a == b ? 0 : 1;
|
||
}
|
||
|
||
/**
|
||
* Performs a recursive modified quicksort.
|
||
*
|
||
* @param a the array to sort
|
||
* @param from the start index (inclusive)
|
||
* @param count the number of elements to sort
|
||
*/
|
||
private static void qsort(int[] array, int from, int count)
|
||
{
|
||
// Use an insertion sort on small arrays.
|
||
if (count <= 7)
|
||
{
|
||
for (int i = from + 1; i < from + count; i++)
|
||
for (int j = i; j > 0 && array[j - 1] > array[j]; j--)
|
||
swap(j, j - 1, array);
|
||
return;
|
||
}
|
||
|
||
// Determine a good median element.
|
||
int mid = count / 2;
|
||
int lo = from;
|
||
int hi = from + count - 1;
|
||
|
||
if (count > 40)
|
||
{ // big arrays, pseudomedian of 9
|
||
int s = count / 8;
|
||
lo = med3(lo, lo + s, lo + s + s, array);
|
||
mid = med3(mid - s, mid, mid + s, array);
|
||
hi = med3(hi - s - s, hi - s, hi, array);
|
||
}
|
||
mid = med3(lo, mid, hi, array);
|
||
|
||
int a, b, c, d;
|
||
int comp;
|
||
|
||
// Pull the median element out of the fray, and use it as a pivot.
|
||
swap(from, mid, array);
|
||
a = b = from + 1;
|
||
c = d = hi;
|
||
|
||
// Repeatedly move b and c to each other, swapping elements so
|
||
// that all elements before index b are less than the pivot, and all
|
||
// elements after index c are greater than the pivot. a and b track
|
||
// the elements equal to the pivot.
|
||
while (true)
|
||
{
|
||
while (b <= c && (comp = compare(array[b], array[from])) <= 0)
|
||
{
|
||
if (comp == 0)
|
||
{
|
||
swap(a, b, array);
|
||
a++;
|
||
}
|
||
b++;
|
||
}
|
||
while (c >= b && (comp = compare(array[c], array[from])) >= 0)
|
||
{
|
||
if (comp == 0)
|
||
{
|
||
swap(c, d, array);
|
||
d--;
|
||
}
|
||
c--;
|
||
}
|
||
if (b > c)
|
||
break;
|
||
swap(b, c, array);
|
||
b++;
|
||
c--;
|
||
}
|
||
|
||
// Swap pivot(s) back in place, the recurse on left and right sections.
|
||
int span;
|
||
span = Math.min(a - from, b - a);
|
||
vecswap(from, b - span, span, array);
|
||
|
||
span = Math.min(d - c, hi - d - 1);
|
||
vecswap(b, hi - span + 1, span, array);
|
||
|
||
span = b - a;
|
||
if (span > 1)
|
||
qsort(array, from, span);
|
||
|
||
span = d - c;
|
||
if (span > 1)
|
||
qsort(array, hi - span + 1, span);
|
||
}
|
||
|
||
/**
|
||
* Performs a stable sort on the elements, arranging them according to their
|
||
* natural order.
|
||
*
|
||
* @param a the long array to sort
|
||
*/
|
||
public static void sort(long[] a)
|
||
{
|
||
qsort(a, 0, a.length);
|
||
}
|
||
|
||
/**
|
||
* Performs a stable sort on the elements, arranging them according to their
|
||
* natural order.
|
||
*
|
||
* @param a the long array to sort
|
||
* @param fromIndex the first index to sort (inclusive)
|
||
* @param toIndex the last index to sort (exclusive)
|
||
* @throws IllegalArgumentException if fromIndex > toIndex
|
||
* @throws ArrayIndexOutOfBoundsException if fromIndex < 0
|
||
* || toIndex > a.length
|
||
*/
|
||
public static void sort(long[] a, int fromIndex, int toIndex)
|
||
{
|
||
if (fromIndex > toIndex)
|
||
throw new IllegalArgumentException();
|
||
qsort(a, fromIndex, toIndex - fromIndex);
|
||
}
|
||
|
||
/**
|
||
* Finds the index of the median of three array elements.
|
||
*
|
||
* @param a the first index
|
||
* @param b the second index
|
||
* @param c the third index
|
||
* @param d the array
|
||
* @return the index (a, b, or c) which has the middle value of the three
|
||
*/
|
||
private static int med3(int a, int b, int c, long[] d)
|
||
{
|
||
return (d[a] < d[b]
|
||
? (d[b] < d[c] ? b : d[a] < d[c] ? c : a)
|
||
: (d[b] > d[c] ? b : d[a] > d[c] ? c : a));
|
||
}
|
||
|
||
/**
|
||
* Swaps the elements at two locations of an array
|
||
*
|
||
* @param i the first index
|
||
* @param j the second index
|
||
* @param a the array
|
||
*/
|
||
private static void swap(int i, int j, long[] a)
|
||
{
|
||
long c = a[i];
|
||
a[i] = a[j];
|
||
a[j] = c;
|
||
}
|
||
|
||
/**
|
||
* Swaps two ranges of an array.
|
||
*
|
||
* @param i the first range start
|
||
* @param j the second range start
|
||
* @param n the element count
|
||
* @param a the array
|
||
*/
|
||
private static void vecswap(int i, int j, int n, long[] a)
|
||
{
|
||
for ( ; n > 0; i++, j++, n--)
|
||
swap(i, j, a);
|
||
}
|
||
|
||
/**
|
||
* Compares two longs in natural order, since a - b is inadequate.
|
||
*
|
||
* @param a the first long
|
||
* @param b the second long
|
||
* @return < 0, 0, or > 0 accorting to the comparison
|
||
*/
|
||
private static int compare(long a, long b)
|
||
{
|
||
return a < b ? -1 : a == b ? 0 : 1;
|
||
}
|
||
|
||
/**
|
||
* Performs a recursive modified quicksort.
|
||
*
|
||
* @param a the array to sort
|
||
* @param from the start index (inclusive)
|
||
* @param count the number of elements to sort
|
||
*/
|
||
private static void qsort(long[] array, int from, int count)
|
||
{
|
||
// Use an insertion sort on small arrays.
|
||
if (count <= 7)
|
||
{
|
||
for (int i = from + 1; i < from + count; i++)
|
||
for (int j = i; j > 0 && array[j - 1] > array[j]; j--)
|
||
swap(j, j - 1, array);
|
||
return;
|
||
}
|
||
|
||
// Determine a good median element.
|
||
int mid = count / 2;
|
||
int lo = from;
|
||
int hi = from + count - 1;
|
||
|
||
if (count > 40)
|
||
{ // big arrays, pseudomedian of 9
|
||
int s = count / 8;
|
||
lo = med3(lo, lo + s, lo + s + s, array);
|
||
mid = med3(mid - s, mid, mid + s, array);
|
||
hi = med3(hi - s - s, hi - s, hi, array);
|
||
}
|
||
mid = med3(lo, mid, hi, array);
|
||
|
||
int a, b, c, d;
|
||
int comp;
|
||
|
||
// Pull the median element out of the fray, and use it as a pivot.
|
||
swap(from, mid, array);
|
||
a = b = from + 1;
|
||
c = d = hi;
|
||
|
||
// Repeatedly move b and c to each other, swapping elements so
|
||
// that all elements before index b are less than the pivot, and all
|
||
// elements after index c are greater than the pivot. a and b track
|
||
// the elements equal to the pivot.
|
||
while (true)
|
||
{
|
||
while (b <= c && (comp = compare(array[b], array[from])) <= 0)
|
||
{
|
||
if (comp == 0)
|
||
{
|
||
swap(a, b, array);
|
||
a++;
|
||
}
|
||
b++;
|
||
}
|
||
while (c >= b && (comp = compare(array[c], array[from])) >= 0)
|
||
{
|
||
if (comp == 0)
|
||
{
|
||
swap(c, d, array);
|
||
d--;
|
||
}
|
||
c--;
|
||
}
|
||
if (b > c)
|
||
break;
|
||
swap(b, c, array);
|
||
b++;
|
||
c--;
|
||
}
|
||
|
||
// Swap pivot(s) back in place, the recurse on left and right sections.
|
||
int span;
|
||
span = Math.min(a - from, b - a);
|
||
vecswap(from, b - span, span, array);
|
||
|
||
span = Math.min(d - c, hi - d - 1);
|
||
vecswap(b, hi - span + 1, span, array);
|
||
|
||
span = b - a;
|
||
if (span > 1)
|
||
qsort(array, from, span);
|
||
|
||
span = d - c;
|
||
if (span > 1)
|
||
qsort(array, hi - span + 1, span);
|
||
}
|
||
|
||
/**
|
||
* Performs a stable sort on the elements, arranging them according to their
|
||
* natural order.
|
||
*
|
||
* @param a the float array to sort
|
||
*/
|
||
public static void sort(float[] a)
|
||
{
|
||
qsort(a, 0, a.length);
|
||
}
|
||
|
||
/**
|
||
* Performs a stable sort on the elements, arranging them according to their
|
||
* natural order.
|
||
*
|
||
* @param a the float array to sort
|
||
* @param fromIndex the first index to sort (inclusive)
|
||
* @param toIndex the last index to sort (exclusive)
|
||
* @throws IllegalArgumentException if fromIndex > toIndex
|
||
* @throws ArrayIndexOutOfBoundsException if fromIndex < 0
|
||
* || toIndex > a.length
|
||
*/
|
||
public static void sort(float[] a, int fromIndex, int toIndex)
|
||
{
|
||
if (fromIndex > toIndex)
|
||
throw new IllegalArgumentException();
|
||
qsort(a, fromIndex, toIndex - fromIndex);
|
||
}
|
||
|
||
/**
|
||
* Finds the index of the median of three array elements.
|
||
*
|
||
* @param a the first index
|
||
* @param b the second index
|
||
* @param c the third index
|
||
* @param d the array
|
||
* @return the index (a, b, or c) which has the middle value of the three
|
||
*/
|
||
private static int med3(int a, int b, int c, float[] d)
|
||
{
|
||
return (Float.compare(d[a], d[b]) < 0
|
||
? (Float.compare(d[b], d[c]) < 0 ? b
|
||
: Float.compare(d[a], d[c]) < 0 ? c : a)
|
||
: (Float.compare(d[b], d[c]) > 0 ? b
|
||
: Float.compare(d[a], d[c]) > 0 ? c : a));
|
||
}
|
||
|
||
/**
|
||
* Swaps the elements at two locations of an array
|
||
*
|
||
* @param i the first index
|
||
* @param j the second index
|
||
* @param a the array
|
||
*/
|
||
private static void swap(int i, int j, float[] a)
|
||
{
|
||
float c = a[i];
|
||
a[i] = a[j];
|
||
a[j] = c;
|
||
}
|
||
|
||
/**
|
||
* Swaps two ranges of an array.
|
||
*
|
||
* @param i the first range start
|
||
* @param j the second range start
|
||
* @param n the element count
|
||
* @param a the array
|
||
*/
|
||
private static void vecswap(int i, int j, int n, float[] a)
|
||
{
|
||
for ( ; n > 0; i++, j++, n--)
|
||
swap(i, j, a);
|
||
}
|
||
|
||
/**
|
||
* Performs a recursive modified quicksort.
|
||
*
|
||
* @param a the array to sort
|
||
* @param from the start index (inclusive)
|
||
* @param count the number of elements to sort
|
||
*/
|
||
private static void qsort(float[] array, int from, int count)
|
||
{
|
||
// Use an insertion sort on small arrays.
|
||
if (count <= 7)
|
||
{
|
||
for (int i = from + 1; i < from + count; i++)
|
||
for (int j = i;
|
||
j > 0 && Float.compare(array[j - 1], array[j]) > 0;
|
||
j--)
|
||
{
|
||
swap(j, j - 1, array);
|
||
}
|
||
return;
|
||
}
|
||
|
||
// Determine a good median element.
|
||
int mid = count / 2;
|
||
int lo = from;
|
||
int hi = from + count - 1;
|
||
|
||
if (count > 40)
|
||
{ // big arrays, pseudomedian of 9
|
||
int s = count / 8;
|
||
lo = med3(lo, lo + s, lo + s + s, array);
|
||
mid = med3(mid - s, mid, mid + s, array);
|
||
hi = med3(hi - s - s, hi - s, hi, array);
|
||
}
|
||
mid = med3(lo, mid, hi, array);
|
||
|
||
int a, b, c, d;
|
||
int comp;
|
||
|
||
// Pull the median element out of the fray, and use it as a pivot.
|
||
swap(from, mid, array);
|
||
a = b = from + 1;
|
||
c = d = hi;
|
||
|
||
// Repeatedly move b and c to each other, swapping elements so
|
||
// that all elements before index b are less than the pivot, and all
|
||
// elements after index c are greater than the pivot. a and b track
|
||
// the elements equal to the pivot.
|
||
while (true)
|
||
{
|
||
while (b <= c && (comp = Float.compare(array[b], array[from])) <= 0)
|
||
{
|
||
if (comp == 0)
|
||
{
|
||
swap(a, b, array);
|
||
a++;
|
||
}
|
||
b++;
|
||
}
|
||
while (c >= b && (comp = Float.compare(array[c], array[from])) >= 0)
|
||
{
|
||
if (comp == 0)
|
||
{
|
||
swap(c, d, array);
|
||
d--;
|
||
}
|
||
c--;
|
||
}
|
||
if (b > c)
|
||
break;
|
||
swap(b, c, array);
|
||
b++;
|
||
c--;
|
||
}
|
||
|
||
// Swap pivot(s) back in place, the recurse on left and right sections.
|
||
int span;
|
||
span = Math.min(a - from, b - a);
|
||
vecswap(from, b - span, span, array);
|
||
|
||
span = Math.min(d - c, hi - d - 1);
|
||
vecswap(b, hi - span + 1, span, array);
|
||
|
||
span = b - a;
|
||
if (span > 1)
|
||
qsort(array, from, span);
|
||
|
||
span = d - c;
|
||
if (span > 1)
|
||
qsort(array, hi - span + 1, span);
|
||
}
|
||
|
||
/**
|
||
* Performs a stable sort on the elements, arranging them according to their
|
||
* natural order.
|
||
*
|
||
* @param a the double array to sort
|
||
*/
|
||
public static void sort(double[] a)
|
||
{
|
||
qsort(a, 0, a.length);
|
||
}
|
||
|
||
/**
|
||
* Performs a stable sort on the elements, arranging them according to their
|
||
* natural order.
|
||
*
|
||
* @param a the double array to sort
|
||
* @param fromIndex the first index to sort (inclusive)
|
||
* @param toIndex the last index to sort (exclusive)
|
||
* @throws IllegalArgumentException if fromIndex > toIndex
|
||
* @throws ArrayIndexOutOfBoundsException if fromIndex < 0
|
||
* || toIndex > a.length
|
||
*/
|
||
public static void sort(double[] a, int fromIndex, int toIndex)
|
||
{
|
||
if (fromIndex > toIndex)
|
||
throw new IllegalArgumentException();
|
||
qsort(a, fromIndex, toIndex - fromIndex);
|
||
}
|
||
|
||
/**
|
||
* Finds the index of the median of three array elements.
|
||
*
|
||
* @param a the first index
|
||
* @param b the second index
|
||
* @param c the third index
|
||
* @param d the array
|
||
* @return the index (a, b, or c) which has the middle value of the three
|
||
*/
|
||
private static int med3(int a, int b, int c, double[] d)
|
||
{
|
||
return (Double.compare(d[a], d[b]) < 0
|
||
? (Double.compare(d[b], d[c]) < 0 ? b
|
||
: Double.compare(d[a], d[c]) < 0 ? c : a)
|
||
: (Double.compare(d[b], d[c]) > 0 ? b
|
||
: Double.compare(d[a], d[c]) > 0 ? c : a));
|
||
}
|
||
|
||
/**
|
||
* Swaps the elements at two locations of an array
|
||
*
|
||
* @param i the first index
|
||
* @param j the second index
|
||
* @param a the array
|
||
*/
|
||
private static void swap(int i, int j, double[] a)
|
||
{
|
||
double c = a[i];
|
||
a[i] = a[j];
|
||
a[j] = c;
|
||
}
|
||
|
||
/**
|
||
* Swaps two ranges of an array.
|
||
*
|
||
* @param i the first range start
|
||
* @param j the second range start
|
||
* @param n the element count
|
||
* @param a the array
|
||
*/
|
||
private static void vecswap(int i, int j, int n, double[] a)
|
||
{
|
||
for ( ; n > 0; i++, j++, n--)
|
||
swap(i, j, a);
|
||
}
|
||
|
||
/**
|
||
* Performs a recursive modified quicksort.
|
||
*
|
||
* @param a the array to sort
|
||
* @param from the start index (inclusive)
|
||
* @param count the number of elements to sort
|
||
*/
|
||
private static void qsort(double[] array, int from, int count)
|
||
{
|
||
// Use an insertion sort on small arrays.
|
||
if (count <= 7)
|
||
{
|
||
for (int i = from + 1; i < from + count; i++)
|
||
for (int j = i;
|
||
j > 0 && Double.compare(array[j - 1], array[j]) > 0;
|
||
j--)
|
||
{
|
||
swap(j, j - 1, array);
|
||
}
|
||
return;
|
||
}
|
||
|
||
// Determine a good median element.
|
||
int mid = count / 2;
|
||
int lo = from;
|
||
int hi = from + count - 1;
|
||
|
||
if (count > 40)
|
||
{ // big arrays, pseudomedian of 9
|
||
int s = count / 8;
|
||
lo = med3(lo, lo + s, lo + s + s, array);
|
||
mid = med3(mid - s, mid, mid + s, array);
|
||
hi = med3(hi - s - s, hi - s, hi, array);
|
||
}
|
||
mid = med3(lo, mid, hi, array);
|
||
|
||
int a, b, c, d;
|
||
int comp;
|
||
|
||
// Pull the median element out of the fray, and use it as a pivot.
|
||
swap(from, mid, array);
|
||
a = b = from + 1;
|
||
c = d = hi;
|
||
|
||
// Repeatedly move b and c to each other, swapping elements so
|
||
// that all elements before index b are less than the pivot, and all
|
||
// elements after index c are greater than the pivot. a and b track
|
||
// the elements equal to the pivot.
|
||
while (true)
|
||
{
|
||
while (b <= c && (comp = Double.compare(array[b], array[from])) <= 0)
|
||
{
|
||
if (comp == 0)
|
||
{
|
||
swap(a, b, array);
|
||
a++;
|
||
}
|
||
b++;
|
||
}
|
||
while (c >= b && (comp = Double.compare(array[c], array[from])) >= 0)
|
||
{
|
||
if (comp == 0)
|
||
{
|
||
swap(c, d, array);
|
||
d--;
|
||
}
|
||
c--;
|
||
}
|
||
if (b > c)
|
||
break;
|
||
swap(b, c, array);
|
||
b++;
|
||
c--;
|
||
}
|
||
|
||
// Swap pivot(s) back in place, the recurse on left and right sections.
|
||
int span;
|
||
span = Math.min(a - from, b - a);
|
||
vecswap(from, b - span, span, array);
|
||
|
||
span = Math.min(d - c, hi - d - 1);
|
||
vecswap(b, hi - span + 1, span, array);
|
||
|
||
span = b - a;
|
||
if (span > 1)
|
||
qsort(array, from, span);
|
||
|
||
span = d - c;
|
||
if (span > 1)
|
||
qsort(array, hi - span + 1, span);
|
||
}
|
||
|
||
/**
|
||
* Sort an array of Objects according to their natural ordering. The sort is
|
||
* guaranteed to be stable, that is, equal elements will not be reordered.
|
||
* The sort algorithm is a mergesort with the merge omitted if the last
|
||
* element of one half comes before the first element of the other half. This
|
||
* algorithm gives guaranteed O(n*log(n)) time, at the expense of making a
|
||
* copy of the array.
|
||
*
|
||
* @param a the array to be sorted
|
||
* @throws ClassCastException if any two elements are not mutually
|
||
* comparable
|
||
* @throws NullPointerException if an element is null (since
|
||
* null.compareTo cannot work)
|
||
* @see Comparable
|
||
*/
|
||
public static void sort(Object[] a)
|
||
{
|
||
sort(a, 0, a.length, null);
|
||
}
|
||
|
||
/**
|
||
* Sort an array of Objects according to a Comparator. The sort is
|
||
* guaranteed to be stable, that is, equal elements will not be reordered.
|
||
* The sort algorithm is a mergesort with the merge omitted if the last
|
||
* element of one half comes before the first element of the other half. This
|
||
* algorithm gives guaranteed O(n*log(n)) time, at the expense of making a
|
||
* copy of the array.
|
||
*
|
||
* @param a the array to be sorted
|
||
* @param c a Comparator to use in sorting the array; or null to indicate
|
||
* the elements' natural order
|
||
* @throws ClassCastException if any two elements are not mutually
|
||
* comparable by the Comparator provided
|
||
* @throws NullPointerException if a null element is compared with natural
|
||
* ordering (only possible when c is null)
|
||
*/
|
||
public static void sort(Object[] a, Comparator c)
|
||
{
|
||
sort(a, 0, a.length, c);
|
||
}
|
||
|
||
/**
|
||
* Sort an array of Objects according to their natural ordering. The sort is
|
||
* guaranteed to be stable, that is, equal elements will not be reordered.
|
||
* The sort algorithm is a mergesort with the merge omitted if the last
|
||
* element of one half comes before the first element of the other half. This
|
||
* algorithm gives guaranteed O(n*log(n)) time, at the expense of making a
|
||
* copy of the array.
|
||
*
|
||
* @param a the array to be sorted
|
||
* @param fromIndex the index of the first element to be sorted
|
||
* @param toIndex the index of the last element to be sorted plus one
|
||
* @throws ClassCastException if any two elements are not mutually
|
||
* comparable
|
||
* @throws NullPointerException if an element is null (since
|
||
* null.compareTo cannot work)
|
||
* @throws ArrayIndexOutOfBoundsException, if fromIndex and toIndex
|
||
* are not in range.
|
||
* @throws IllegalArgumentException if fromIndex > toIndex
|
||
*/
|
||
public static void sort(Object[] a, int fromIndex, int toIndex)
|
||
{
|
||
sort(a, fromIndex, toIndex, null);
|
||
}
|
||
|
||
/**
|
||
* Sort an array of Objects according to a Comparator. The sort is
|
||
* guaranteed to be stable, that is, equal elements will not be reordered.
|
||
* The sort algorithm is a mergesort with the merge omitted if the last
|
||
* element of one half comes before the first element of the other half. This
|
||
* algorithm gives guaranteed O(n*log(n)) time, at the expense of making a
|
||
* copy of the array.
|
||
*
|
||
* @param a the array to be sorted
|
||
* @param fromIndex the index of the first element to be sorted
|
||
* @param toIndex the index of the last element to be sorted plus one
|
||
* @param c a Comparator to use in sorting the array; or null to indicate
|
||
* the elements' natural order
|
||
* @throws ClassCastException if any two elements are not mutually
|
||
* comparable by the Comparator provided
|
||
* @throws ArrayIndexOutOfBoundsException, if fromIndex and toIndex
|
||
* are not in range.
|
||
* @throws IllegalArgumentException if fromIndex > toIndex
|
||
* @throws NullPointerException if a null element is compared with natural
|
||
* ordering (only possible when c is null)
|
||
*/
|
||
public static void sort(Object[] a, int fromIndex, int toIndex, Comparator c)
|
||
{
|
||
if (fromIndex > toIndex)
|
||
throw new IllegalArgumentException("fromIndex " + fromIndex
|
||
+ " > toIndex " + toIndex);
|
||
|
||
// In general, the code attempts to be simple rather than fast, the
|
||
// idea being that a good optimising JIT will be able to optimise it
|
||
// better than I can, and if I try it will make it more confusing for
|
||
// the JIT. First presort the array in chunks of length 6 with insertion
|
||
// sort. A mergesort would give too much overhead for this length.
|
||
for (int chunk = fromIndex; chunk < toIndex; chunk += 6)
|
||
{
|
||
int end = Math.min(chunk + 6, toIndex);
|
||
for (int i = chunk + 1; i < end; i++)
|
||
{
|
||
if (Collections.compare(a[i - 1], a[i], c) > 0)
|
||
{
|
||
// not already sorted
|
||
int j = i;
|
||
Object elem = a[j];
|
||
do
|
||
{
|
||
a[j] = a[j - 1];
|
||
j--;
|
||
}
|
||
while (j > chunk
|
||
&& Collections.compare(a[j - 1], elem, c) > 0);
|
||
a[j] = elem;
|
||
}
|
||
}
|
||
}
|
||
|
||
int len = toIndex - fromIndex;
|
||
// If length is smaller or equal 6 we are done.
|
||
if (len <= 6)
|
||
return;
|
||
|
||
Object[] src = a;
|
||
Object[] dest = new Object[len];
|
||
Object[] t = null; // t is used for swapping src and dest
|
||
|
||
// The difference of the fromIndex of the src and dest array.
|
||
int srcDestDiff = -fromIndex;
|
||
|
||
// The merges are done in this loop
|
||
for (int size = 6; size < len; size <<= 1)
|
||
{
|
||
for (int start = fromIndex; start < toIndex; start += size << 1)
|
||
{
|
||
// mid is the start of the second sublist;
|
||
// end the start of the next sublist (or end of array).
|
||
int mid = start + size;
|
||
int end = Math.min(toIndex, mid + size);
|
||
|
||
// The second list is empty or the elements are already in
|
||
// order - no need to merge
|
||
if (mid >= end
|
||
|| Collections.compare(src[mid - 1], src[mid], c) <= 0)
|
||
{
|
||
System.arraycopy(src, start,
|
||
dest, start + srcDestDiff, end - start);
|
||
|
||
// The two halves just need swapping - no need to merge
|
||
}
|
||
else if (Collections.compare(src[start], src[end - 1], c) > 0)
|
||
{
|
||
System.arraycopy(src, start,
|
||
dest, end - size + srcDestDiff, size);
|
||
System.arraycopy(src, mid,
|
||
dest, start + srcDestDiff, end - mid);
|
||
|
||
}
|
||
else
|
||
{
|
||
// Declare a lot of variables to save repeating
|
||
// calculations. Hopefully a decent JIT will put these
|
||
// in registers and make this fast
|
||
int p1 = start;
|
||
int p2 = mid;
|
||
int i = start + srcDestDiff;
|
||
|
||
// The main merge loop; terminates as soon as either
|
||
// half is ended
|
||
while (p1 < mid && p2 < end)
|
||
{
|
||
dest[i++] =
|
||
src[(Collections.compare(src[p1], src[p2], c) <= 0
|
||
? p1++ : p2++)];
|
||
}
|
||
|
||
// Finish up by copying the remainder of whichever half
|
||
// wasn't finished.
|
||
if (p1 < mid)
|
||
System.arraycopy(src, p1, dest, i, mid - p1);
|
||
else
|
||
System.arraycopy(src, p2, dest, i, end - p2);
|
||
}
|
||
}
|
||
// swap src and dest ready for the next merge
|
||
t = src;
|
||
src = dest;
|
||
dest = t;
|
||
fromIndex += srcDestDiff;
|
||
toIndex += srcDestDiff;
|
||
srcDestDiff = -srcDestDiff;
|
||
}
|
||
|
||
// make sure the result ends up back in the right place. Note
|
||
// that src and dest may have been swapped above, so src
|
||
// contains the sorted array.
|
||
if (src != a)
|
||
{
|
||
// Note that fromIndex == 0.
|
||
System.arraycopy(src, 0, a, srcDestDiff, toIndex);
|
||
}
|
||
}
|
||
|
||
/**
|
||
* Returns a list "view" of the specified array. This method is intended to
|
||
* make it easy to use the Collections API with existing array-based APIs and
|
||
* programs. Changes in the list or the array show up in both places. The
|
||
* list does not support element addition or removal, but does permit
|
||
* value modification. The returned list implements both Serializable and
|
||
* RandomAccess.
|
||
*
|
||
* @param a the array to return a view of
|
||
* @return a fixed-size list, changes to which "write through" to the array
|
||
* @see Serializable
|
||
* @see RandomAccess
|
||
* @see Arrays.ArrayList
|
||
*/
|
||
public static List asList(final Object[] a)
|
||
{
|
||
return new Arrays.ArrayList(a);
|
||
}
|
||
|
||
/**
|
||
* Inner class used by {@link #asList(Object[])} to provide a list interface
|
||
* to an array. The name, though it clashes with java.util.ArrayList, is
|
||
* Sun's choice for Serialization purposes. Element addition and removal
|
||
* is prohibited, but values can be modified.
|
||
*
|
||
* @author Eric Blake <ebb9@email.byu.edu>
|
||
* @status updated to 1.4
|
||
*/
|
||
private static final class ArrayList extends AbstractList
|
||
implements Serializable, RandomAccess
|
||
{
|
||
// We override the necessary methods, plus others which will be much
|
||
// more efficient with direct iteration rather than relying on iterator().
|
||
|
||
/**
|
||
* Compatible with JDK 1.4.
|
||
*/
|
||
private static final long serialVersionUID = -2764017481108945198L;
|
||
|
||
/**
|
||
* The array we are viewing.
|
||
* @serial the array
|
||
*/
|
||
private final Object[] a;
|
||
|
||
/**
|
||
* Construct a list view of the array.
|
||
* @param a the array to view
|
||
* @throws NullPointerException if a is null
|
||
*/
|
||
ArrayList(Object[] a)
|
||
{
|
||
// We have to explicitly check.
|
||
if (a == null)
|
||
throw new NullPointerException();
|
||
this.a = a;
|
||
}
|
||
|
||
public Object get(int index)
|
||
{
|
||
return a[index];
|
||
}
|
||
|
||
public int size()
|
||
{
|
||
return a.length;
|
||
}
|
||
|
||
public Object set(int index, Object element)
|
||
{
|
||
Object old = a[index];
|
||
a[index] = element;
|
||
return old;
|
||
}
|
||
|
||
public boolean contains(Object o)
|
||
{
|
||
return lastIndexOf(o) >= 0;
|
||
}
|
||
|
||
public int indexOf(Object o)
|
||
{
|
||
int size = a.length;
|
||
for (int i = 0; i < size; i++)
|
||
if (equals(o, a[i]))
|
||
return i;
|
||
return -1;
|
||
}
|
||
|
||
public int lastIndexOf(Object o)
|
||
{
|
||
int i = a.length;
|
||
while (--i >= 0)
|
||
if (equals(o, a[i]))
|
||
return i;
|
||
return -1;
|
||
}
|
||
|
||
public Object[] toArray()
|
||
{
|
||
return (Object[]) a.clone();
|
||
}
|
||
|
||
public Object[] toArray(Object[] array)
|
||
{
|
||
int size = a.length;
|
||
if (array.length < size)
|
||
array = (Object[])
|
||
Array.newInstance(array.getClass().getComponentType(), size);
|
||
else if (array.length > size)
|
||
array[size] = null;
|
||
|
||
System.arraycopy(a, 0, array, 0, size);
|
||
return array;
|
||
}
|
||
}
|
||
}
|