/*
* @(#)Arrays.java 1.48 03/01/23
*
* Copyright 2003 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package instrumented.java.util;
import java.lang.reflect.*;
/**
* This class contains various methods for manipulating arrays (such as
* sorting and searching). This class also contains a static factory
* that allows arrays to be viewed as lists.
*
* <p>The methods in this class all throw a <tt>NullPointerException</tt> if
* the specified array reference is null.
*
* <p>The documentation for the methods contained in this class includes
* briefs description of the <i>implementations</i>. Such descriptions should
* be regarded as <i>implementation notes</i>, rather than parts of the
* <i>specification</i>. Implementors should feel free to substitute other
* algorithms, so long as the specification itself is adhered to. (For
* example, the algorithm used by <tt>sort(Object[])</tt> does not have to be
* a mergesort, but it does have to be <i>stable</i>.)
*
* <p>This class is a member of the
* <a href="{@docRoot}/../guide/collections/index.html">
* Java Collections Framework</a>.
*
* @author Josh Bloch
* @version 1.48, 01/23/03
* @see Comparable
* @see Comparator
* @since 1.2
*/
public class Arrays {
// Suppresses default constructor, ensuring non-instantiability.
private Arrays() {
}
// Sorting
/**
* Sorts the specified array of longs into ascending numerical order.
* The sorting algorithm is a tuned quicksort, adapted from 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 offers n*log(n) performance on many data sets
* that cause other quicksorts to degrade to quadratic performance.
*
* @param a the array to be sorted.
*/
public static void sort(long[] a) {
sort1(a, 0, a.length);
}
/**
* Sorts the specified range of the specified array of longs into
* ascending numerical order. 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.)
*
* <p>The sorting algorithm is a tuned quicksort, adapted from 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 offers n*log(n) performance on many data sets
* that cause other quicksorts to degrade to quadratic performance.
*
* @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>
*/
public static void sort(long[] a, int fromIndex, int toIndex) {
rangeCheck(a.length, fromIndex, toIndex);
sort1(a, fromIndex, toIndex-fromIndex);
}
/**
* Sorts the specified array of ints into ascending numerical order.
* The sorting algorithm is a tuned quicksort, adapted from 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 offers n*log(n) performance on many data sets
* that cause other quicksorts to degrade to quadratic performance.
*
* @param a the array to be sorted.
*/
public static void sort(int[] a) {
sort1(a, 0, a.length);
}
/**
* Sorts the specified range of the specified array of ints into
* ascending numerical order. 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.)<p>
*
* The sorting algorithm is a tuned quicksort, adapted from 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 offers n*log(n) performance on many data sets
* that cause other quicksorts to degrade to quadratic performance.
*
* @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>
*/
public static void sort(int[] a, int fromIndex, int toIndex) {
rangeCheck(a.length, fromIndex, toIndex);
sort1(a, fromIndex, toIndex-fromIndex);
}
/**
* Sorts the specified array of shorts into ascending numerical order.
* The sorting algorithm is a tuned quicksort, adapted from 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 offers n*log(n) performance on many data sets
* that cause other quicksorts to degrade to quadratic performance.
*
* @param a the array to be sorted.
*/
public static void sort(short[] a) {
sort1(a, 0, a.length);
}
/**
* Sorts the specified range of the specified array of shorts into
* ascending numerical order. 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.)<p>
*
* The sorting algorithm is a tuned quicksort, adapted from 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 offers n*log(n) performance on many data sets
* that cause other quicksorts to degrade to quadratic performance.
*
* @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>
*/
public static void sort(short[] a, int fromIndex, int toIndex) {
rangeCheck(a.length, fromIndex, toIndex);
sort1(a, fromIndex, toIndex-fromIndex);
}
/**
* Sorts the specified array of chars into ascending numerical order.
* The sorting algorithm is a tuned quicksort, adapted from 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 offers n*log(n) performance on many data sets
* that cause other quicksorts to degrade to quadratic performance.
*
* @param a the array to be sorted.
*/
public static void sort(char[] a) {
sort1(a, 0, a.length);
}
/**
* Sorts the specified range of the specified array of chars into
* ascending numerical order. 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.)<p>
*
* The sorting algorithm is a tuned quicksort, adapted from 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 offers n*log(n) performance on many data sets
* that cause other quicksorts to degrade to quadratic performance.
*
* @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>
*/
public static void sort(char[] a, int fromIndex, int toIndex) {
rangeCheck(a.length, fromIndex, toIndex);
sort1(a, fromIndex, toIndex-fromIndex);
}
/**
* Sorts the specified array of bytes into ascending numerical order.
* The sorting algorithm is a tuned quicksort, adapted from 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 offers n*log(n) performance on many data sets
* that cause other quicksorts to degrade to quadratic performance.
*
* @param a the array to be sorted.
*/
public static void sort(byte[] a) {
sort1(a, 0, a.length);
}
/**
* Sorts the specified range of the specified array of bytes into
* ascending numerical order. 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.)<p>
*
* The sorting algorithm is a tuned quicksort, adapted from 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 offers n*log(n) performance on many data sets
* that cause other quicksorts to degrade to quadratic performance.
*
* @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>
*/
public static void sort(byte[] a, int fromIndex, int toIndex) {
rangeCheck(a.length, fromIndex, toIndex);
sort1(a, fromIndex, toIndex-fromIndex);
}
/**
* Sorts the specified array of doubles into ascending numerical order.
* <p>
* The <code><</code> relation does not provide a total order on
* all floating-point values; although they are distinct numbers
* <code>-0.0 == 0.0</code> is <code>true</code> and a NaN value
* compares neither less than, greater than, nor equal to any
* floating-point value, even itself. To allow the sort to
* proceed, instead of using the <code><</code> relation to
* determine ascending numerical order, this method uses the total
* order imposed by {@link Double#compareTo}. This ordering
* differs from the <code><</code> relation in that
* <code>-0.0</code> is treated as less than <code>0.0</code> and
* NaN is considered greater than any other floating-point value.
* For the purposes of sorting, all NaN values are considered
* equivalent and equal.
* <p>
* The sorting algorithm is a tuned quicksort, adapted from 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 offers n*log(n) performance on many data sets
* that cause other quicksorts to degrade to quadratic performance.
*
* @param a the array to be sorted.
*/
public static void sort(double[] a) {
sort2(a, 0, a.length);
}
/**
* Sorts the specified range of the specified array of doubles into
* ascending numerical order. 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.)
* <p>
* The <code><</code> relation does not provide a total order on
* all floating-point values; although they are distinct numbers
* <code>-0.0 == 0.0</code> is <code>true</code> and a NaN value
* compares neither less than, greater than, nor equal to any
* floating-point value, even itself. To allow the sort to
* proceed, instead of using the <code><</code> relation to
* determine ascending numerical order, this method uses the total
* order imposed by {@link Double#compareTo}. This ordering
* differs from the <code><</code> relation in that
* <code>-0.0</code> is treated as less than <code>0.0</code> and
* NaN is considered greater than any other floating-point value.
* For the purposes of sorting, all NaN values are considered
* equivalent and equal.
* <p>
* The sorting algorithm is a tuned quicksort, adapted from 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 offers n*log(n) performance on many data sets
* that cause other quicksorts to degrade to quadratic performance.
*
* @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>
*/
public static void sort(double[] a, int fromIndex, int toIndex) {
rangeCheck(a.length, fromIndex, toIndex);
sort2(a, fromIndex, toIndex);
}
/**
* Sorts the specified array of floats into ascending numerical order.
* <p>
* The <code><</code> relation does not provide a total order on
* all floating-point values; although they are distinct numbers
* <code>-0.0f == 0.0f</code> is <code>true</code> and a NaN value
* compares neither less than, greater than, nor equal to any
* floating-point value, even itself. To allow the sort to
* proceed, instead of using the <code><</code> relation to
* determine ascending numerical order, this method uses the total
* order imposed by {@link Float#compareTo}. This ordering
* differs from the <code><</code> relation in that
* <code>-0.0f</code> is treated as less than <code>0.0f</code> and
* NaN is considered greater than any other floating-point value.
* For the purposes of sorting, all NaN values are considered
* equivalent and equal.
* <p>
* The sorting algorithm is a tuned quicksort, adapted from 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 offers n*log(n) performance on many data sets
* that cause other quicksorts to degrade to quadratic performance.
*
* @param a the array to be sorted.
*/
public static void sort(float[] a) {
sort2(a, 0, a.length);
}
/**
* Sorts the specified range of the specified array of floats into
* ascending numerical order. 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.)
* <p>
* The <code><</code> relation does not provide a total order on
* all floating-point values; although they are distinct numbers
* <code>-0.0f == 0.0f</code> is <code>true</code> and a NaN value
* compares neither less than, greater than, nor equal to any
* floating-point value, even itself. To allow the sort to
* proceed, instead of using the <code><</code> relation to
* determine ascending numerical order, this method uses the total
* order imposed by {@link Float#compareTo}. This ordering
* differs from the <code><</code> relation in that
* <code>-0.0f</code> is treated as less than <code>0.0f</code> and
* NaN is considered greater than any other floating-point value.
* For the purposes of sorting, all NaN values are considered
* equivalent and equal.
* <p>
* The sorting algorithm is a tuned quicksort, adapted from 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 offers n*log(n) performance on many data sets
* that cause other quicksorts to degrade to quadratic performance.
*
* @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>
*/
public static void sort(float[] a, int fromIndex, int toIndex) {
rangeCheck(a.length, fromIndex, toIndex);
sort2(a, fromIndex, toIndex);
}
private static void sort2(double a[], int fromIndex, int toIndex) {
final long NEG_ZERO_BITS = Double.doubleToLongBits(-0.0d);
/*
* The sort is done in three phases to avoid the expense of using
* NaN and -0.0 aware comparisons during the main sort.
*/
/*
* Preprocessing phase: Move any NaN's to end of array, count the
* number of -0.0's, and turn them into 0.0's.
*/
int numNegZeros = 0;
int i = fromIndex, n = toIndex;
while(i < n) {
if (a[i] != a[i]) {
double swap = a[i];
a[i] = a[--n];
a[n] = swap;
} else {
if (a[i]==0 && Double.doubleToLongBits(a[i])==NEG_ZERO_BITS) {
a[i] = 0.0d;
numNegZeros++;
}
i++;
}
}
// Main sort phase: quicksort everything but the NaN's
sort1(a, fromIndex, n-fromIndex);
// Postprocessing phase: change 0.0's to -0.0's as required
if (numNegZeros != 0) {
int j = binarySearch(a, 0.0d, fromIndex, n-1); // posn of ANY zero
do {
j--;
} while (j>=0 && a[j]==0.0d);
// j is now one less than the index of the FIRST zero
for (int k=0; k<numNegZeros; k++)
a[++j] = -0.0d;
}
}
private static void sort2(float a[], int fromIndex, int toIndex) {
final int NEG_ZERO_BITS = Float.floatToIntBits(-0.0f);
/*
* The sort is done in three phases to avoid the expense of using
* NaN and -0.0 aware comparisons during the main sort.
*/
/*
* Preprocessing phase: Move any NaN's to end of array, count the
* number of -0.0's, and turn them into 0.0's.
*/
int numNegZeros = 0;
int i = fromIndex, n = toIndex;
while(i < n) {
if (a[i] != a[i]) {
float swap = a[i];
a[i] = a[--n];
a[n] = swap;
} else {
if (a[i]==0 && Float.floatToIntBits(a[i])==NEG_ZERO_BITS) {
a[i] = 0.0f;
numNegZeros++;
}
i++;
}
}
// Main sort phase: quicksort everything but the NaN's
sort1(a, fromIndex, n-fromIndex);
// Postprocessing phase: change 0.0's to -0.0's as required
if (numNegZeros != 0) {
int j = binarySearch(a, 0.0f, fromIndex, n-1); // posn of ANY zero
do {
j--;
} while (j>=0 && a[j]==0.0f);
// j is now one less than the index of the FIRST zero
for (int k=0; k<numNegZeros; k++)
a[++j] = -0.0f;
}
}
/*
* The code for each of the seven primitive types is largely identical.
* C'est la vie.
*/
/**
* Sorts the specified sub-array of longs into ascending order.
*/
private static void sort1(long x[], int off, int len) {
// Insertion sort on smallest arrays
if (len < 7) {
for (int i=off; i<len+off; i++)
for (int j=i; j>off && x[j-1]>x[j]; j--)
swap(x, j, j-1);
return;
}
// Choose a partition element, v
int m = off + (len >> 1); // Small arrays, middle element
if (len > 7) {
int l = off;
int n = off + len - 1;
if (len > 40) { // Big arrays, pseudomedian of 9
int s = len/8;
l = med3(x, l, l+s, l+2*s);
m = med3(x, m-s, m, m+s);
n = med3(x, n-2*s, n-s, n);
}
m = med3(x, l, m, n); // Mid-size, med of 3
}
long v = x[m];
// Establish Invariant: v* (<v)* (>v)* v*
int a = off, b = a, c = off + len - 1, d = c;
while(true) {
while (b <= c && x[b] <= v) {
if (x[b] == v)
swap(x, a++, b);
b++;
}
while (c >= b && x[c] >= v) {
if (x[c] == v)
swap(x, c, d--);
c--;
}
if (b > c)
break;
swap(x, b++, c--);
}
// Swap partition elements back to middle
int s, n = off + len;
s = Math.min(a-off, b-a ); vecswap(x, off, b-s, s);
s = Math.min(d-c, n-d-1); vecswap(x, b, n-s, s);
// Recursively sort non-partition-elements
if ((s = b-a) > 1)
sort1(x, off, s);
if ((s = d-c) > 1)
sort1(x, n-s, s);
}
/**
* Swaps x[a] with x[b].
*/
private static void swap(long x[], int a, int b) {
long t = x[a];
x[a] = x[b];
x[b] = t;
}
/**
* Swaps x[a .. (a+n-1)] with x[b .. (b+n-1)].
*/
private static void vecswap(long x[], int a, int b, int n) {
for (int i=0; i<n; i++, a++, b++)
swap(x, a, b);
}
/**
* Returns the index of the median of the three indexed longs.
*/
private static int med3(long x[], int a, int b, int c) {
return (x[a] < x[b] ?
(x[b] < x[c] ? b : x[a] < x[c] ? c : a) :
(x[b] > x[c] ? b : x[a] > x[c] ? c : a));
}
/**
* Sorts the specified sub-array of integers into ascending order.
*/
private static void sort1(int x[], int off, int len) {
// Insertion sort on smallest arrays
if (len < 7) {
for (int i=off; i<len+off; i++)
for (int j=i; j>off && x[j-1]>x[j]; j--)
swap(x, j, j-1);
return;
}
// Choose a partition element, v
int m = off + (len >> 1); // Small arrays, middle element
if (len > 7) {
int l = off;
int n = off + len - 1;
if (len > 40) { // Big arrays, pseudomedian of 9
int s = len/8;
l = med3(x, l, l+s, l+2*s);
m = med3(x, m-s, m, m+s);
n = med3(x, n-2*s, n-s, n);
}
m = med3(x, l, m, n); // Mid-size, med of 3
}
int v = x[m];
// Establish Invariant: v* (<v)* (>v)* v*
int a = off, b = a, c = off + len - 1, d = c;
while(true) {
while (b <= c && x[b] <= v) {
if (x[b] == v)
swap(x, a++, b);
b++;
}
while (c >= b && x[c] >= v) {
if (x[c] == v)
swap(x, c, d--);
c--;
}
if (b > c)
break;
swap(x, b++, c--);
}
// Swap partition elements back to middle
int s, n = off + len;
s = Math.min(a-off, b-a ); vecswap(x, off, b-s, s);
s = Math.min(d-c, n-d-1); vecswap(x, b, n-s, s);
// Recursively sort non-partition-elements
if ((s = b-a) > 1)
sort1(x, off, s);
if ((s = d-c) > 1)
sort1(x, n-s, s);
}
/**
* Swaps x[a] with x[b].
*/
private static void swap(int x[], int a, int b) {
int t = x[a];
x[a] = x[b];
x[b] = t;
}
/**
* Swaps x[a .. (a+n-1)] with x[b .. (b+n-1)].
*/
private static void vecswap(int x[], int a, int b, int n) {
for (int i=0; i<n; i++, a++, b++)
swap(x, a, b);
}
/**
* Returns the index of the median of the three indexed integers.
*/
private static int med3(int x[], int a, int b, int c) {
return (x[a] < x[b] ?
(x[b] < x[c] ? b : x[a] < x[c] ? c : a) :
(x[b] > x[c] ? b : x[a] > x[c] ? c : a));
}
/**
* Sorts the specified sub-array of shorts into ascending order.
*/
private static void sort1(short x[], int off, int len) {
// Insertion sort on smallest arrays
if (len < 7) {
for (int i=off; i<len+off; i++)
for (int j=i; j>off && x[j-1]>x[j]; j--)
swap(x, j, j-1);
return;
}
// Choose a partition element, v
int m = off + (len >> 1); // Small arrays, middle element
if (len > 7) {
int l = off;
int n = off + len - 1;
if (len > 40) { // Big arrays, pseudomedian of 9
int s = len/8;
l = med3(x, l, l+s, l+2*s);
m = med3(x, m-s, m, m+s);
n = med3(x, n-2*s, n-s, n);
}
m = med3(x, l, m, n); // Mid-size, med of 3
}
short v = x[m];
// Establish Invariant: v* (<v)* (>v)* v*
int a = off, b = a, c = off + len - 1, d = c;
while(true) {
while (b <= c && x[b] <= v) {
if (x[b] == v)
swap(x, a++, b);
b++;
}
while (c >= b && x[c] >= v) {
if (x[c] == v)
swap(x, c, d--);
c--;
}
if (b > c)
break;
swap(x, b++, c--);
}
// Swap partition elements back to middle
int s, n = off + len;
s = Math.min(a-off, b-a ); vecswap(x, off, b-s, s);
s = Math.min(d-c, n-d-1); vecswap(x, b, n-s, s);
// Recursively sort non-partition-elements
if ((s = b-a) > 1)
sort1(x, off, s);
if ((s = d-c) > 1)
sort1(x, n-s, s);
}
/**
* Swaps x[a] with x[b].
*/
private static void swap(short x[], int a, int b) {
short t = x[a];
x[a] = x[b];
x[b] = t;
}
/**
* Swaps x[a .. (a+n-1)] with x[b .. (b+n-1)].
*/
private static void vecswap(short x[], int a, int b, int n) {
for (int i=0; i<n; i++, a++, b++)
swap(x, a, b);
}
/**
* Returns the index of the median of the three indexed shorts.
*/
private static int med3(short x[], int a, int b, int c) {
return (x[a] < x[b] ?
(x[b] < x[c] ? b : x[a] < x[c] ? c : a) :
(x[b] > x[c] ? b : x[a] > x[c] ? c : a));
}
/**
* Sorts the specified sub-array of chars into ascending order.
*/
private static void sort1(char x[], int off, int len) {
// Insertion sort on smallest arrays
if (len < 7) {
for (int i=off; i<len+off; i++)
for (int j=i; j>off && x[j-1]>x[j]; j--)
swap(x, j, j-1);
return;
}
// Choose a partition element, v
int m = off + (len >> 1); // Small arrays, middle element
if (len > 7) {
int l = off;
int n = off + len - 1;
if (len > 40) { // Big arrays, pseudomedian of 9
int s = len/8;
l = med3(x, l, l+s, l+2*s);
m = med3(x, m-s, m, m+s);
n = med3(x, n-2*s, n-s, n);
}
m = med3(x, l, m, n); // Mid-size, med of 3
}
char v = x[m];
// Establish Invariant: v* (<v)* (>v)* v*
int a = off, b = a, c = off + len - 1, d = c;
while(true) {
while (b <= c && x[b] <= v) {
if (x[b] == v)
swap(x, a++, b);
b++;
}
while (c >= b && x[c] >= v) {
if (x[c] == v)
swap(x, c, d--);
c--;
}
if (b > c)
break;
swap(x, b++, c--);
}
// Swap partition elements back to middle
int s, n = off + len;
s = Math.min(a-off, b-a ); vecswap(x, off, b-s, s);
s = Math.min(d-c, n-d-1); vecswap(x, b, n-s, s);
// Recursively sort non-partition-elements
if ((s = b-a) > 1)
sort1(x, off, s);
if ((s = d-c) > 1)
sort1(x, n-s, s);
}
/**
* Swaps x[a] with x[b].
*/
private static void swap(char x[], int a, int b) {
char t = x[a];
x[a] = x[b];
x[b] = t;
}
/**
* Swaps x[a .. (a+n-1)] with x[b .. (b+n-1)].
*/
private static void vecswap(char x[], int a, int b, int n) {
for (int i=0; i<n; i++, a++, b++)
swap(x, a, b);
}
/**
* Returns the index of the median of the three indexed chars.
*/
private static int med3(char x[], int a, int b, int c) {
return (x[a] < x[b] ?
(x[b] < x[c] ? b : x[a] < x[c] ? c : a) :
(x[b] > x[c] ? b : x[a] > x[c] ? c : a));
}
/**
* Sorts the specified sub-array of bytes into ascending order.
*/
private static void sort1(byte x[], int off, int len) {
// Insertion sort on smallest arrays
if (len < 7) {
for (int i=off; i<len+off; i++)
for (int j=i; j>off && x[j-1]>x[j]; j--)
swap(x, j, j-1);
return;
}
// Choose a partition element, v
int m = off + (len >> 1); // Small arrays, middle element
if (len > 7) {
int l = off;
int n = off + len - 1;
if (len > 40) { // Big arrays, pseudomedian of 9
int s = len/8;
l = med3(x, l, l+s, l+2*s);
m = med3(x, m-s, m, m+s);
n = med3(x, n-2*s, n-s, n);
}
m = med3(x, l, m, n); // Mid-size, med of 3
}
byte v = x[m];
// Establish Invariant: v* (<v)* (>v)* v*
int a = off, b = a, c = off + len - 1, d = c;
while(true) {
while (b <= c && x[b] <= v) {
if (x[b] == v)
swap(x, a++, b);
b++;
}
while (c >= b && x[c] >= v) {
if (x[c] == v)
swap(x, c, d--);
c--;
}
if (b > c)
break;
swap(x, b++, c--);
}
// Swap partition elements back to middle
int s, n = off + len;
s = Math.min(a-off, b-a ); vecswap(x, off, b-s, s);
s = Math.min(d-c, n-d-1); vecswap(x, b, n-s, s);
// Recursively sort non-partition-elements
if ((s = b-a) > 1)
sort1(x, off, s);
if ((s = d-c) > 1)
sort1(x, n-s, s);
}
/**
* Swaps x[a] with x[b].
*/
private static void swap(byte x[], int a, int b) {
byte t = x[a];
x[a] = x[b];
x[b] = t;
}
/**
* Swaps x[a .. (a+n-1)] with x[b .. (b+n-1)].
*/
private static void vecswap(byte x[], int a, int b, int n) {
for (int i=0; i<n; i++, a++, b++)
swap(x, a, b);
}
/**
* Returns the index of the median of the three indexed bytes.
*/
private static int med3(byte x[], int a, int b, int c) {
return (x[a] < x[b] ?
(x[b] < x[c] ? b : x[a] < x[c] ? c : a) :
(x[b] > x[c] ? b : x[a] > x[c] ? c : a));
}
/**
* Sorts the specified sub-array of doubles into ascending order.
*/
private static void sort1(double x[], int off, int len) {
// Insertion sort on smallest arrays
if (len < 7) {
for (int i=off; i<len+off; i++)
for (int j=i; j>off && x[j-1]>x[j]; j--)
swap(x, j, j-1);
return;
}
// Choose a partition element, v
int m = off + (len >> 1); // Small arrays, middle element
if (len > 7) {
int l = off;
int n = off + len - 1;
if (len > 40) { // Big arrays, pseudomedian of 9
int s = len/8;
l = med3(x, l, l+s, l+2*s);
m = med3(x, m-s, m, m+s);
n = med3(x, n-2*s, n-s, n);
}
m = med3(x, l, m, n); // Mid-size, med of 3
}
double v = x[m];
// Establish Invariant: v* (<v)* (>v)* v*
int a = off, b = a, c = off + len - 1, d = c;
while(true) {
while (b <= c && x[b] <= v) {
if (x[b] == v)
swap(x, a++, b);
b++;
}
while (c >= b && x[c] >= v) {
if (x[c] == v)
swap(x, c, d--);
c--;
}
if (b > c)
break;
swap(x, b++, c--);
}
// Swap partition elements back to middle
int s, n = off + len;
s = Math.min(a-off, b-a ); vecswap(x, off, b-s, s);
s = Math.min(d-c, n-d-1); vecswap(x, b, n-s, s);
// Recursively sort non-partition-elements
if ((s = b-a) > 1)
sort1(x, off, s);
if ((s = d-c) > 1)
sort1(x, n-s, s);
}
/**
* Swaps x[a] with x[b].
*/
private static void swap(double x[], int a, int b) {
double t = x[a];
x[a] = x[b];
x[b] = t;
}
/**
* Swaps x[a .. (a+n-1)] with x[b .. (b+n-1)].
*/
private static void vecswap(double x[], int a, int b, int n) {
for (int i=0; i<n; i++, a++, b++)
swap(x, a, b);
}
/**
* Returns the index of the median of the three indexed doubles.
*/
private static int med3(double x[], int a, int b, int c) {
return (x[a] < x[b] ?
(x[b] < x[c] ? b : x[a] < x[c] ? c : a) :
(x[b] > x[c] ? b : x[a] > x[c] ? c : a));
}
/**
* Sorts the specified sub-array of floats into ascending order.
*/
private static void sort1(float x[], int off, int len) {
// Insertion sort on smallest arrays
if (len < 7) {
for (int i=off; i<len+off; i++)
for (int j=i; j>off && x[j-1]>x[j]; j--)
swap(x, j, j-1);
return;
}
// Choose a partition element, v
int m = off + (len >> 1); // Small arrays, middle element
if (len > 7) {
int l = off;
int n = off + len - 1;
if (len > 40) { // Big arrays, pseudomedian of 9
int s = len/8;
l = med3(x, l, l+s, l+2*s);
m = med3(x, m-s, m, m+s);
n = med3(x, n-2*s, n-s, n);
}
m = med3(x, l, m, n); // Mid-size, med of 3
}
float v = x[m];
// Establish Invariant: v* (<v)* (>v)* v*
int a = off, b = a, c = off + len - 1, d = c;
while(true) {
while (b <= c && x[b] <= v) {
if (x[b] == v)
swap(x, a++, b);
b++;
}
while (c >= b && x[c] >= v) {
if (x[c] == v)
swap(x, c, d--);
c--;
}
if (b > c)
break;
swap(x, b++, c--);
}
// Swap partition elements back to middle
int s, n = off + len;
s = Math.min(a-off, b-a ); vecswap(x, off, b-s, s);
s = Math.min(d-c, n-d-1); vecswap(x, b, n-s, s);
// Recursively sort non-partition-elements
if ((s = b-a) > 1)
sort1(x, off, s);
if ((s = d-c) > 1)
sort1(x, n-s, s);
}
/**
* Swaps x[a] with x[b].
*/
private static void swap(float x[], int a, int b) {
float t = x[a];
x[a] = x[b];
x[b] = t;
}
/**
* Swaps x[a .. (a+n-1)] with x[b .. (b+n-1)].
*/
private static void vecswap(float x[], int a, int b, int n) {
for (int i=0; i<n; i++, a++, b++)
swap(x, a, b);
}
/**
* Returns the index of the median of the three indexed floats.
*/
private static int med3(float x[], int a, int b, int c) {
return (x[a] < x[b] ?
(x[b] < x[c] ? b : x[a] < x[c] ? c : a) :
(x[b] > x[c] ? b : x[a] > x[c] ? c : a));
}
/**
* Sorts the specified array of objects into ascending order, according to
* the <i>natural ordering</i> of its elements. All elements in the array
* must implement the <tt>Comparable</tt> 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>
*
* This sort is guaranteed to be <i>stable</i>: equal elements will
* not be reordered as a result of the sort.<p>
*
* 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.
*
* @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).
* @see Comparable
*/
public static void sort(Object[] a) {
Object aux[] = (Object[])a.clone();
mergeSort(aux, a, 0, a.length, 0);
}
/**
* Sorts the specified range of the specified array of objects into
* ascending order, according to the <i>natural ordering</i> 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
* elements in this range must implement the <tt>Comparable</tt>
* 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>
*
* This sort is guaranteed to be <i>stable</i>: equal elements will
* not be reordered as a result of the sort.<p>
*
* 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.
*
* @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).
* @see Comparable
*/
public static void sort(Object[] a, int fromIndex, int toIndex) {
rangeCheck(a.length, fromIndex, toIndex);
Object aux[] = (Object[])cloneSubarray(a, fromIndex, toIndex);
mergeSort(aux, a, fromIndex, toIndex, -fromIndex);
}
/**
* Tuning parameter: list size at or below which insertion sort will be
* used in preference to mergesort or quicksort.
*/
private static final int INSERTIONSORT_THRESHOLD = 7;
/**
* Clones an array within the specified bounds.
* This method assumes that a is an array.
*/
private static Object cloneSubarray(Object[] a, int from, int to) {
int n = to - from;
Object result = Array.newInstance(a.getClass().getComponentType(), n);
System.arraycopy(a, from, result, 0, n);
return result;
}
/**
* Src is the source array that starts at index 0
* Dest is the (possibly larger) array destination with a possible offset
* 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
*/
private static void mergeSort(Object src[], Object dest[],
int low, int high, int off) {
int length = high - low;
// Insertion sort on smallest arrays
if (length < INSERTIONSORT_THRESHOLD) {
for (int i=low; i<high; i++)
for (int j=i; j>low &&
((Comparable)dest[j-1]).compareTo((Comparable)dest[j])>0; j--)
swap(dest, j, j-1);
return;
}
// Recursively sort halves of dest into src
int destLow = low;
int destHigh = high;
low += off;
high += off;
int mid = (low + high) >> 1;
mergeSort(dest, src, low, mid, -off);
mergeSort(dest, src, mid, high, -off);
// If list is already sorted, just copy from src to dest. This is an
// optimization that results in faster sorts for nearly ordered lists.
if (((Comparable)src[mid-1]).compareTo((Comparable)src[mid]) <= 0) {
System.arraycopy(src, low, dest, destLow, length);
return;
}
// Merge sorted halves (now in src) into dest
for(int i = destLow, p = low, q = mid; i < destHigh; i++) {
if (q >= high || p < mid && ((Comparable)src[p]).compareTo(src[q])<=0)
dest[i] = src[p++];
else
dest[i] = src[q++];
}
}
/**
* Swaps x[a] with x[b].
*/
private static void swap(Object x[], int a, int b) {
Object t = x[a];
x[a] = x[b];
x[b] = t;
}
/**
* 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>
*
* This sort is guaranteed to be <i>stable</i>: equal elements will
* not be reordered as a result of the sort.<p>
*
* 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.
*
* @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' <i>natural
* ordering</i> should be used.
* @throws ClassCastException if the array contains elements that are
* not <i>mutually comparable</i> using the specified comparator.
* @see Comparator
*/
public static void sort(Object[] a, Comparator c) {
Object aux[] = (Object[])a.clone();
if (c==null)
mergeSort(aux, a, 0, a.length, 0);
else
mergeSort(aux, a, 0, a.length, 0, c);
}
/**
* 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
* 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>
*
* This sort is guaranteed to be <i>stable</i>: equal elements will
* not be reordered as a result of the sort.<p>
*
* 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.
*
* @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' <i>natural
* ordering</i> 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>
* @see Comparator
*/
public static void sort(Object[] a, int fromIndex, int toIndex,
Comparator c) {
rangeCheck(a.length, fromIndex, toIndex);
Object aux[] = (Object[])cloneSubarray(a, fromIndex, toIndex);
if (c==null)
mergeSort(aux, a, fromIndex, toIndex, -fromIndex);
else
mergeSort(aux, a, fromIndex, toIndex, -fromIndex, c);
}
/**
* Src is the source array that starts at index 0
* Dest is the (possibly larger) array destination with a possible offset
* 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
*/
private static void mergeSort(Object src[], Object dest[],
int low, int high, int off, Comparator c) {
int length = high - low;
// Insertion sort on smallest arrays
if (length < INSERTIONSORT_THRESHOLD) {
for (int i=low; i<high; i++)
for (int j=i; j>low && c.compare(dest[j-1], dest[j])>0; j--)
swap(dest, j, j-1);
return;
}
// Recursively sort halves of dest into src
int destLow = low;
int destHigh = high;
low += off;
high += off;
int mid = (low + high) >> 1;
mergeSort(dest, src, low, mid, -off, c);
mergeSort(dest, src, mid, high, -off, c);
// If list is already sorted, just copy from src to dest. This is an
// optimization that results in faster sorts for nearly ordered lists.
if (c.compare(src[mid-1], src[mid]) <= 0) {
System.arraycopy(src, low, dest, destLow, length);
return;
}
// Merge sorted halves (now in src) into dest
for(int i = destLow, p = low, q = mid; i < destHigh; i++) {
if (q >= high || p < mid && c.compare(src[p], src[q]) <= 0)
dest[i] = src[p++];
else
dest[i] = src[q++];
}
}
/**
* Check that fromIndex and toIndex are in range, and throw an
* appropriate exception if they aren't.
*/
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);
}
// Searching
/**
* Searches the specified array of longs for the specified value using the
* binary search algorithm. The array <strong>must</strong> be sorted (as
* by the <tt>sort</tt> method, above) prior to making this call. If it
* is not sorted, the results are undefined. If the array contains
* multiple elements with the specified value, there is no guarantee which
* one will be found.
*
* @param a the array to be searched.
* @param key the value to be searched for.
* @return index of the search key, if it is contained in the list;
* otherwise, <tt>(-(<i>insertion point</i>) - 1)</tt>. The
* <i>insertion point</i> is defined as the point at which the
* key would be inserted into the list: the index of the first
* element greater than the key, or <tt>list.size()</tt>, if all
* elements in the list are less than the specified key. Note
* that this guarantees that the return value will be >= 0 if
* and only if the key is found.
* @see #sort(long[])
*/
public static int binarySearch(long[] a, long key) {
int low = 0;
int high = a.length-1;
while (low <= high) {
int mid = (low + high) >> 1;
long midVal = a[mid];
if (midVal < key)
low = mid + 1;
else if (midVal > key)
high = mid - 1;
else
return mid; // key found
}
return -(low + 1); // key not found.
}
/**
* Searches the specified array of ints for the specified value using the
* binary search algorithm. The array <strong>must</strong> be sorted (as
* by the <tt>sort</tt> method, above) prior to making this call. If it
* is not sorted, the results are undefined. If the array contains
* multiple elements with the specified value, there is no guarantee which
* one will be found.
*
* @param a the array to be searched.
* @param key the value to be searched for.
* @return index of the search key, if it is contained in the list;
* otherwise, <tt>(-(<i>insertion point</i>) - 1)</tt>. The
* <i>insertion point</i> is defined as the point at which the
* key would be inserted into the list: the index of the first
* element greater than the key, or <tt>list.size()</tt>, if all
* elements in the list are less than the specified key. Note
* that this guarantees that the return value will be >= 0 if
* and only if the key is found.
* @see #sort(int[])
*/
public static int binarySearch(int[] a, int key) {
int low = 0;
int high = a.length-1;
while (low <= high) {
int mid = (low + high) >> 1;
int midVal = a[mid];
if (midVal < key)
low = mid + 1;
else if (midVal > key)
high = mid - 1;
else
return mid; // key found
}
return -(low + 1); // key not found.
}
/**
* Searches the specified array of shorts for the specified value using
* the binary search algorithm. The array <strong>must</strong> be sorted
* (as by the <tt>sort</tt> method, above) prior to making this call. If
* it is not sorted, the results are undefined. If the array contains
* multiple elements with the specified value, there is no guarantee which
* one will be found.
*
* @param a the array to be searched.
* @param key the value to be searched for.
* @return index of the search key, if it is contained in the list;
* otherwise, <tt>(-(<i>insertion point</i>) - 1)</tt>. The
* <i>insertion point</i> is defined as the point at which the
* key would be inserted into the list: the index of the first
* element greater than the key, or <tt>list.size()</tt>, if all
* elements in the list are less than the specified key. Note
* that this guarantees that the return value will be >= 0 if
* and only if the key is found.
* @see #sort(short[])
*/
public static int binarySearch(short[] a, short key) {
int low = 0;
int high = a.length-1;
while (low <= high) {
int mid = (low + high) >> 1;
short midVal = a[mid];
if (midVal < key)
low = mid + 1;
else if (midVal > key)
high = mid - 1;
else
return mid; // key found
}
return -(low + 1); // key not found.
}
/**
* Searches the specified array of chars for the specified value using the
* binary search algorithm. The array <strong>must</strong> be sorted (as
* by the <tt>sort</tt> method, above) prior to making this call. If it
* is not sorted, the results are undefined. If the array contains
* multiple elements with the specified value, there is no guarantee which
* one will be found.
*
* @param a the array to be searched.
* @param key the value to be searched for.
* @return index of the search key, if it is contained in the list;
* otherwise, <tt>(-(<i>insertion point</i>) - 1)</tt>. The
* <i>insertion point</i> is defined as the point at which the
* key would be inserted into the list: the index of the first
* element greater than the key, or <tt>list.size()</tt>, if all
* elements in the list are less than the specified key. Note
* that this guarantees that the return value will be >= 0 if
* and only if the key is found.
* @see #sort(char[])
*/
public static int binarySearch(char[] a, char key) {
int low = 0;
int high = a.length-1;
while (low <= high) {
int mid = (low + high) >> 1;
char midVal = a[mid];
if (midVal < key)
low = mid + 1;
else if (midVal > key)
high = mid - 1;
else
return mid; // key found
}
return -(low + 1); // key not found.
}
/**
* Searches the specified array of bytes for the specified value using the
* binary search algorithm. The array <strong>must</strong> be sorted (as
* by the <tt>sort</tt> method, above) prior to making this call. If it
* is not sorted, the results are undefined. If the array contains
* multiple elements with the specified value, there is no guarantee which
* one will be found.
*
* @param a the array to be searched.
* @param key the value to be searched for.
* @return index of the search key, if it is contained in the list;
* otherwise, <tt>(-(<i>insertion point</i>) - 1)</tt>. The
* <i>insertion point</i> is defined as the point at which the
* key would be inserted into the list: the index of the first
* element greater than the key, or <tt>list.size()</tt>, if all
* elements in the list are less than the specified key. Note
* that this guarantees that the return value will be >= 0 if
* and only if the key is found.
* @see #sort(byte[])
*/
public static int binarySearch(byte[] a, byte key) {
int low = 0;
int high = a.length-1;
while (low <= high) {
int mid = (low + high) >> 1;
byte midVal = a[mid];
if (midVal < key)
low = mid + 1;
else if (midVal > key)
high = mid - 1;
else
return mid; // key found
}
return -(low + 1); // key not found.
}
/**
* Searches the specified array of doubles for the specified value using
* the binary search algorithm. The array <strong>must</strong> be sorted
* (as by the <tt>sort</tt> method, above) prior to making this call. If
* it is not sorted, the results are undefined. If the array contains
* multiple elements with the specified value, there is no guarantee which
* one will be found. This method considers all NaN values to be
* equivalent and equal.
*
* @param a the array to be searched.
* @param key the value to be searched for.
* @return index of the search key, if it is contained in the list;
* otherwise, <tt>(-(<i>insertion point</i>) - 1)</tt>. The
* <i>insertion point</i> is defined as the point at which the
* key would be inserted into the list: the index of the first
* element greater than the key, or <tt>list.size()</tt>, if all
* elements in the list are less than the specified key. Note
* that this guarantees that the return value will be >= 0 if
* and only if the key is found.
* @see #sort(double[])
*/
public static int binarySearch(double[] a, double key) {
return binarySearch(a, key, 0, a.length-1);
}
private static int binarySearch(double[] a, double key, int low,int high) {
while (low <= high) {
int mid = (low + high) >> 1;
double midVal = a[mid];
int cmp;
if (midVal < key) {
cmp = -1; // Neither val is NaN, thisVal is smaller
} else if (midVal > key) {
cmp = 1; // Neither val is NaN, thisVal is larger
} else {
long midBits = Double.doubleToLongBits(midVal);
long keyBits = Double.doubleToLongBits(key);
cmp = (midBits == keyBits ? 0 : // Values are equal
(midBits < keyBits ? -1 : // (-0.0, 0.0) or (!NaN, NaN)
1)); // (0.0, -0.0) or (NaN, !NaN)
}
if (cmp < 0)
low = mid + 1;
else if (cmp > 0)
high = mid - 1;
else
return mid; // key found
}
return -(low + 1); // key not found.
}
/**
* Searches the specified array of floats for the specified value using
* the binary search algorithm. The array <strong>must</strong> be sorted
* (as by the <tt>sort</tt> method, above) prior to making this call. If
* it is not sorted, the results are undefined. If the array contains
* multiple elements with the specified value, there is no guarantee which
* one will be found. This method considers all NaN values to be
* equivalent and equal.
*
* @param a the array to be searched.
* @param key the value to be searched for.
* @return index of the search key, if it is contained in the list;
* otherwise, <tt>(-(<i>insertion point</i>) - 1)</tt>. The
* <i>insertion point</i> is defined as the point at which the
* key would be inserted into the list: the index of the first
* element greater than the key, or <tt>list.size()</tt>, if all
* elements in the list are less than the specified key. Note
* that this guarantees that the return value will be >= 0 if
* and only if the key is found.
* @see #sort(float[])
*/
public static int binarySearch(float[] a, float key) {
return binarySearch(a, key, 0, a.length-1);
}
private static int binarySearch(float[] a, float key, int low,int high) {
while (low <= high) {
int mid = (low + high) >> 1;
float midVal = a[mid];
int cmp;
if (midVal < key) {
cmp = -1; // Neither val is NaN, thisVal is smaller
} else if (midVal > key) {
cmp = 1; // Neither val is NaN, thisVal is larger
} else {
int midBits = Float.floatToIntBits(midVal);
int keyBits = Float.floatToIntBits(key);
cmp = (midBits == keyBits ? 0 : // Values are equal
(midBits < keyBits ? -1 : // (-0.0, 0.0) or (!NaN, NaN)
1)); // (0.0, -0.0) or (NaN, !NaN)
}
if (cmp < 0)
low = mid + 1;
else if (cmp > 0)
high = mid - 1;
else
return mid; // key found
}
return -(low + 1); // key not found.
}
/**
* Searches the specified array for the specified object using the binary
* search algorithm. The array must be sorted into ascending order
* according to the <i>natural ordering</i> of its elements (as by
* <tt>Sort(Object[]</tt>), above) prior to making this call. If it is
* not sorted, the results are undefined.
* (If the array contains elements that are not mutually comparable (for
* example,strings and integers), it <i>cannot</i> be sorted according
* to the natural order of its elements, hence results are undefined.)
* If the array contains multiple
* elements equal to the specified object, there is no guarantee which
* one will be found.
*
* @param a the array to be searched.
* @param key the value to be searched for.
* @return index of the search key, if it is contained in the list;
* otherwise, <tt>(-(<i>insertion point</i>) - 1)</tt>. The
* <i>insertion point</i> is defined as the point at which the
* key would be inserted into the list: the index of the first
* element greater than the key, or <tt>list.size()</tt>, if all
* elements in the list are less than the specified key. Note
* that this guarantees that the return value will be >= 0 if
* and only if the key is found.
* @throws ClassCastException if the search key in not comparable to the
* elements of the array.
* @see Comparable
* @see #sort(Object[])
*/
public static int binarySearch(Object[] a, Object key) {
int low = 0;
int high = a.length-1;
while (low <= high) {
int mid = (low + high) >> 1;
Object midVal = a[mid];
int cmp = ((Comparable)midVal).compareTo(key);
if (cmp < 0)
low = mid + 1;
else if (cmp > 0)
high = mid - 1;
else
return mid; // key found
}
return -(low + 1); // key not found.
}
/**
* Searches the specified array for the specified object using the binary
* search algorithm. The array must be sorted into ascending order
* according to the specified comparator (as by the <tt>Sort(Object[],
* Comparator)</tt> method, above), prior to making this call. If it is
* not sorted, the results are undefined.
* If the array contains multiple
* elements equal to the specified object, there is no guarantee which one
* will be found.
*
* @param a the array to be searched.
* @param key the value to be searched for.
* @param c the comparator by which the array is ordered. A
* <tt>null</tt> value indicates that the elements' <i>natural
* ordering</i> should be used.
* @return index of the search key, if it is contained in the list;
* otherwise, <tt>(-(<i>insertion point</i>) - 1)</tt>. The
* <i>insertion point</i> is defined as the point at which the
* key would be inserted into the list: the index of the first
* element greater than the key, or <tt>list.size()</tt>, if all
* elements in the list are less than the specified key. Note
* that this guarantees that the return value will be >= 0 if
* and only if the key is found.
* @throws ClassCastException if the array contains elements that are not
* <i>mutually comparable</i> using the specified comparator,
* or the search key in not mutually comparable with the
* elements of the array using this comparator.
* @see Comparable
* @see #sort(Object[], Comparator)
*/
public static int binarySearch(Object[] a, Object key, Comparator c) {
if (c==null)
return binarySearch(a, key);
int low = 0;
int high = a.length-1;
while (low <= high) {
int mid = (low + high) >> 1;
Object midVal = a[mid];
int cmp = c.compare(midVal, key);
if (cmp < 0)
low = mid + 1;
else if (cmp > 0)
high = mid - 1;
else
return mid; // key found
}
return -(low + 1); // key not found.
}
// Equality Testing
/**
* Returns <tt>true</tt> if the two specified arrays of longs are
* <i>equal</i> to one another. Two arrays are considered equal if both
* arrays contain the same number of elements, and all corresponding pairs
* of elements in the two arrays are equal. In other words, two arrays
* are equal if they contain the same elements in the same order. Also,
* two array references are considered equal if both are <tt>null</tt>.<p>
*
* @param a one array to be tested for equality.
* @param a2 the other array to be tested for equality.
* @return <tt>true</tt> if the two arrays are equal.
*/
public static boolean equals(long[] a, long[] a2) {
if (a==a2)
return true;
if (a==null || a2==null)
return false;
int length = a.length;
if (a2.length != length)
return false;
for (int i=0; i<length; i++)
if (a[i] != a2[i])
return false;
return true;
}
/**
* Returns <tt>true</tt> if the two specified arrays of ints are
* <i>equal</i> to one another. Two arrays are considered equal if both
* arrays contain the same number of elements, and all corresponding pairs
* of elements in the two arrays are equal. In other words, two arrays
* are equal if they contain the same elements in the same order. Also,
* two array references are considered equal if both are <tt>null</tt>.<p>
*
* @param a one array to be tested for equality.
* @param a2 the other array to be tested for equality.
* @return <tt>true</tt> if the two arrays are equal.
*/
public static boolean equals(int[] a, int[] a2) {
if (a==a2)
return true;
if (a==null || a2==null)
return false;
int length = a.length;
if (a2.length != length)
return false;
for (int i=0; i<length; i++)
if (a[i] != a2[i])
return false;
return true;
}
/**
* Returns <tt>true</tt> if the two specified arrays of shorts are
* <i>equal</i> to one another. Two arrays are considered equal if both
* arrays contain the same number of elements, and all corresponding pairs
* of elements in the two arrays are equal. In other words, two arrays
* are equal if they contain the same elements in the same order. Also,
* two array references are considered equal if both are <tt>null</tt>.<p>
*
* @param a one array to be tested for equality.
* @param a2 the other array to be tested for equality.
* @return <tt>true</tt> if the two arrays are equal.
*/
public static boolean equals(short[] a, short a2[]) {
if (a==a2)
return true;
if (a==null || a2==null)
return false;
int length = a.length;
if (a2.length != length)
return false;
for (int i=0; i<length; i++)
if (a[i] != a2[i])
return false;
return true;
}
/**
* Returns <tt>true</tt> if the two specified arrays of chars are
* <i>equal</i> to one another. Two arrays are considered equal if both
* arrays contain the same number of elements, and all corresponding pairs
* of elements in the two arrays are equal. In other words, two arrays
* are equal if they contain the same elements in the same order. Also,
* two array references are considered equal if both are <tt>null</tt>.<p>
*
* @param a one array to be tested for equality.
* @param a2 the other array to be tested for equality.
* @return <tt>true</tt> if the two arrays are equal.
*/
public static boolean equals(char[] a, char[] a2) {
if (a==a2)
return true;
if (a==null || a2==null)
return false;
int length = a.length;
if (a2.length != length)
return false;
for (int i=0; i<length; i++)
if (a[i] != a2[i])
return false;
return true;
}
/**
* Returns <tt>true</tt> if the two specified arrays of bytes are
* <i>equal</i> to one another. Two arrays are considered equal if both
* arrays contain the same number of elements, and all corresponding pairs
* of elements in the two arrays are equal. In other words, two arrays
* are equal if they contain the same elements in the same order. Also,
* two array references are considered equal if both are <tt>null</tt>.<p>
*
* @param a one array to be tested for equality.
* @param a2 the other array to be tested for equality.
* @return <tt>true</tt> if the two arrays are equal.
*/
public static boolean equals(byte[] a, byte[] a2) {
if (a==a2)
return true;
if (a==null || a2==null)
return false;
int length = a.length;
if (a2.length != length)
return false;
for (int i=0; i<length; i++)
if (a[i] != a2[i])
return false;
return true;
}
/**
* Returns <tt>true</tt> if the two specified arrays of booleans are
* <i>equal</i> to one another. Two arrays are considered equal if both
* arrays contain the same number of elements, and all corresponding pairs
* of elements in the two arrays are equal. In other words, two arrays
* are equal if they contain the same elements in the same order. Also,
* two array references are considered equal if both are <tt>null</tt>.<p>
*
* @param a one array to be tested for equality.
* @param a2 the other array to be tested for equality.
* @return <tt>true</tt> if the two arrays are equal.
*/
public static boolean equals(boolean[] a, boolean[] a2) {
if (a==a2)
return true;
if (a==null || a2==null)
return false;
int length = a.length;
if (a2.length != length)
return false;
for (int i=0; i<length; i++)
if (a[i] != a2[i])
return false;
return true;
}
/**
* Returns <tt>true</tt> if the two specified arrays of doubles are
* <i>equal</i> to one another. Two arrays are considered equal if both
* arrays contain the same number of elements, and all corresponding pairs
* of elements in the two arrays are equal. In other words, two arrays
* are equal if they contain the same elements in the same order. Also,
* two array references are considered equal if both are <tt>null</tt>.<p>
*
* Two doubles <tt>d1</tt> and <tt>d2</tt> are considered equal if:
* <pre> <tt>new Double(d1).equals(new Double(d2))</tt></pre>
* (Unlike the <tt>==</tt> operator, this method considers
* <tt>NaN</tt> equals to itself, and 0.0d unequal to -0.0d.)
*
* @param a one array to be tested for equality.
* @param a2 the other array to be tested for equality.
* @return <tt>true</tt> if the two arrays are equal.
* @see Double#equals(Object)
*/
public static boolean equals(double[] a, double[] a2) {
if (a==a2)
return true;
if (a==null || a2==null)
return false;
int length = a.length;
if (a2.length != length)
return false;
for (int i=0; i<length; i++)
if (Double.doubleToLongBits(a[i])!=Double.doubleToLongBits(a2[i]))
return false;
return true;
}
/**
* Returns <tt>true</tt> if the two specified arrays of floats are
* <i>equal</i> to one another. Two arrays are considered equal if both
* arrays contain the same number of elements, and all corresponding pairs
* of elements in the two arrays are equal. In other words, two arrays
* are equal if they contain the same elements in the same order. Also,
* two array references are considered equal if both are <tt>null</tt>.<p>
*
* Two floats <tt>f1</tt> and <tt>f2</tt> are considered equal if:
* <pre> <tt>new Float(f1).equals(new Float(f2))</tt></pre>
* (Unlike the <tt>==</tt> operator, this method considers
* <tt>NaN</tt> equals to itself, and 0.0f unequal to -0.0f.)
*
* @param a one array to be tested for equality.
* @param a2 the other array to be tested for equality.
* @return <tt>true</tt> if the two arrays are equal.
* @see Float#equals(Object)
*/
public static boolean equals(float[] a, float[] a2) {
if (a==a2)
return true;
if (a==null || a2==null)
return false;
int length = a.length;
if (a2.length != length)
return false;
for (int i=0; i<length; i++)
if (Float.floatToIntBits(a[i])!=Float.floatToIntBits(a2[i]))
return false;
return true;
}
/**
* Returns <tt>true</tt> if the two specified arrays of Objects are
* <i>equal</i> to one another. The two arrays are considered equal if
* both arrays contain the same number of elements, and all corresponding
* pairs of elements in the two arrays are equal. Two objects <tt>e1</tt>
* and <tt>e2</tt> are considered <i>equal</i> if <tt>(e1==null ? e2==null
* : e1.equals(e2))</tt>. In other words, the two arrays are equal if
* they contain the same elements in the same order. Also, two array
* references are considered equal if both are <tt>null</tt>.<p>
*
* @param a one array to be tested for equality.
* @param a2 the other array to be tested for equality.
* @return <tt>true</tt> if the two arrays are equal.
*/
public static boolean equals(Object[] a, Object[] a2) {
if (a==a2)
return true;
if (a==null || a2==null)
return false;
int length = a.length;
if (a2.length != length)
return false;
for (int i=0; i<length; i++) {
Object o1 = a[i];
Object o2 = a2[i];
if (!(o1==null ? o2==null : o1.equals(o2)))
return false;
}
return true;
}
// Filling
/**
* Assigns the specified long value to each element of the specified array
* of longs.
*
* @param a the array to be filled.
* @param val the value to be stored in all elements of the array.
*/
public static void fill(long[] a, long val) {
fill(a, 0, a.length, val);
}
/**
* Assigns the specified long value to each element of the specified
* range of the specified array of longs. The range to be filled
* extends from index <tt>fromIndex</tt>, inclusive, to index
* <tt>toIndex</tt>, exclusive. (If <tt>fromIndex==toIndex</tt>, the
* range to be filled is empty.)
*
* @param a the array to be filled.
* @param fromIndex the index of the first element (inclusive) to be
* filled with the specified value.
* @param toIndex the index of the last element (exclusive) to be
* filled with the specified value.
* @param val the value to be stored in all elements of the array.
* @throws IllegalArgumentException if <tt>fromIndex > toIndex</tt>
* @throws ArrayIndexOutOfBoundsException if <tt>fromIndex < 0</tt> or
* <tt>toIndex > a.length</tt>
*/
public static void fill(long[] a, int fromIndex, int toIndex, long val) {
rangeCheck(a.length, fromIndex, toIndex);
for (int i=fromIndex; i<toIndex; i++)
a[i] = val;
}
/**
* Assigns the specified int value to each element of the specified array
* of ints.
*
* @param a the array to be filled.
* @param val the value to be stored in all elements of the array.
*/
public static void fill(int[] a, int val) {
fill(a, 0, a.length, val);
}
/**
* Assigns the specified int value to each element of the specified
* range of the specified array of ints. The range to be filled
* extends from index <tt>fromIndex</tt>, inclusive, to index
* <tt>toIndex</tt>, exclusive. (If <tt>fromIndex==toIndex</tt>, the
* range to be filled is empty.)
*
* @param a the array to be filled.
* @param fromIndex the index of the first element (inclusive) to be
* filled with the specified value.
* @param toIndex the index of the last element (exclusive) to be
* filled with the specified value.
* @param val the value to be stored in all elements of the array.
* @throws IllegalArgumentException if <tt>fromIndex > toIndex</tt>
* @throws ArrayIndexOutOfBoundsException if <tt>fromIndex < 0</tt> or
* <tt>toIndex > a.length</tt>
*/
public static void fill(int[] a, int fromIndex, int toIndex, int val) {
rangeCheck(a.length, fromIndex, toIndex);
for (int i=fromIndex; i<toIndex; i++)
a[i] = val;
}
/**
* Assigns the specified short value to each element of the specified array
* of shorts.
*
* @param a the array to be filled.
* @param val the value to be stored in all elements of the array.
*/
public static void fill(short[] a, short val) {
fill(a, 0, a.length, val);
}
/**
* Assigns the specified short value to each element of the specified
* range of the specified array of shorts. The range to be filled
* extends from index <tt>fromIndex</tt>, inclusive, to index
* <tt>toIndex</tt>, exclusive. (If <tt>fromIndex==toIndex</tt>, the
* range to be filled is empty.)
*
* @param a the array to be filled.
* @param fromIndex the index of the first element (inclusive) to be
* filled with the specified value.
* @param toIndex the index of the last element (exclusive) to be
* filled with the specified value.
* @param val the value to be stored in all elements of the array.
* @throws IllegalArgumentException if <tt>fromIndex > toIndex</tt>
* @throws ArrayIndexOutOfBoundsException if <tt>fromIndex < 0</tt> or
* <tt>toIndex > a.length</tt>
*/
public static void fill(short[] a, int fromIndex, int toIndex, short val) {
rangeCheck(a.length, fromIndex, toIndex);
for (int i=fromIndex; i<toIndex; i++)
a[i] = val;
}
/**
* Assigns the specified char value to each element of the specified array
* of chars.
*
* @param a the array to be filled.
* @param val the value to be stored in all elements of the array.
*/
public static void fill(char[] a, char val) {
fill(a, 0, a.length, val);
}
/**
* Assigns the specified char value to each element of the specified
* range of the specified array of chars. The range to be filled
* extends from index <tt>fromIndex</tt>, inclusive, to index
* <tt>toIndex</tt>, exclusive. (If <tt>fromIndex==toIndex</tt>, the
* range to be filled is empty.)
*
* @param a the array to be filled.
* @param fromIndex the index of the first element (inclusive) to be
* filled with the specified value.
* @param toIndex the index of the last element (exclusive) to be
* filled with the specified value.
* @param val the value to be stored in all elements of the array.
* @throws IllegalArgumentException if <tt>fromIndex > toIndex</tt>
* @throws ArrayIndexOutOfBoundsException if <tt>fromIndex < 0</tt> or
* <tt>toIndex > a.length</tt>
*/
public static void fill(char[] a, int fromIndex, int toIndex, char val) {
rangeCheck(a.length, fromIndex, toIndex);
for (int i=fromIndex; i<toIndex; i++)
a[i] = val;
}
/**
* Assigns the specified byte value to each element of the specified array
* of bytes.
*
* @param a the array to be filled.
* @param val the value to be stored in all elements of the array.
*/
public static void fill(byte[] a, byte val) {
fill(a, 0, a.length, val);
}
/**
* Assigns the specified byte value to each element of the specified
* range of the specified array of bytes. The range to be filled
* extends from index <tt>fromIndex</tt>, inclusive, to index
* <tt>toIndex</tt>, exclusive. (If <tt>fromIndex==toIndex</tt>, the
* range to be filled is empty.)
*
* @param a the array to be filled.
* @param fromIndex the index of the first element (inclusive) to be
* filled with the specified value.
* @param toIndex the index of the last element (exclusive) to be
* filled with the specified value.
* @param val the value to be stored in all elements of the array.
* @throws IllegalArgumentException if <tt>fromIndex > toIndex</tt>
* @throws ArrayIndexOutOfBoundsException if <tt>fromIndex < 0</tt> or
* <tt>toIndex > a.length</tt>
*/
public static void fill(byte[] a, int fromIndex, int toIndex, byte val) {
rangeCheck(a.length, fromIndex, toIndex);
for (int i=fromIndex; i<toIndex; i++)
a[i] = val;
}
/**
* Assigns the specified boolean value to each element of the specified
* array of booleans.
*
* @param a the array to be filled.
* @param val the value to be stored in all elements of the array.
*/
public static void fill(boolean[] a, boolean val) {
fill(a, 0, a.length, val);
}
/**
* Assigns the specified boolean value to each element of the specified
* range of the specified array of booleans. The range to be filled
* extends from index <tt>fromIndex</tt>, inclusive, to index
* <tt>toIndex</tt>, exclusive. (If <tt>fromIndex==toIndex</tt>, the
* range to be filled is empty.)
*
* @param a the array to be filled.
* @param fromIndex the index of the first element (inclusive) to be
* filled with the specified value.
* @param toIndex the index of the last element (exclusive) to be
* filled with the specified value.
* @param val the value to be stored in all elements of the array.
* @throws IllegalArgumentException if <tt>fromIndex > toIndex</tt>
* @throws ArrayIndexOutOfBoundsException if <tt>fromIndex < 0</tt> or
* <tt>toIndex > a.length</tt>
*/
public static void fill(boolean[] a, int fromIndex, int toIndex,
boolean val) {
rangeCheck(a.length, fromIndex, toIndex);
for (int i=fromIndex; i<toIndex; i++)
a[i] = val;
}
/**
* Assigns the specified double value to each element of the specified
* array of doubles.
*
* @param a the array to be filled.
* @param val the value to be stored in all elements of the array.
*/
public static void fill(double[] a, double val) {
fill(a, 0, a.length, val);
}
/**
* Assigns the specified double value to each element of the specified
* range of the specified array of doubles. The range to be filled
* extends from index <tt>fromIndex</tt>, inclusive, to index
* <tt>toIndex</tt>, exclusive. (If <tt>fromIndex==toIndex</tt>, the
* range to be filled is empty.)
*
* @param a the array to be filled.
* @param fromIndex the index of the first element (inclusive) to be
* filled with the specified value.
* @param toIndex the index of the last element (exclusive) to be
* filled with the specified value.
* @param val the value to be stored in all elements of the array.
* @throws IllegalArgumentException if <tt>fromIndex > toIndex</tt>
* @throws ArrayIndexOutOfBoundsException if <tt>fromIndex < 0</tt> or
* <tt>toIndex > a.length</tt>
*/
public static void fill(double[] a, int fromIndex, int toIndex,double val){
rangeCheck(a.length, fromIndex, toIndex);
for (int i=fromIndex; i<toIndex; i++)
a[i] = val;
}
/**
* Assigns the specified float value to each element of the specified array
* of floats.
*
* @param a the array to be filled.
* @param val the value to be stored in all elements of the array.
*/
public static void fill(float[] a, float val) {
fill(a, 0, a.length, val);
}
/**
* Assigns the specified float value to each element of the specified
* range of the specified array of floats. The range to be filled
* extends from index <tt>fromIndex</tt>, inclusive, to index
* <tt>toIndex</tt>, exclusive. (If <tt>fromIndex==toIndex</tt>, the
* range to be filled is empty.)
*
* @param a the array to be filled.
* @param fromIndex the index of the first element (inclusive) to be
* filled with the specified value.
* @param toIndex the index of the last element (exclusive) to be
* filled with the specified value.
* @param val the value to be stored in all elements of the array.
* @throws IllegalArgumentException if <tt>fromIndex > toIndex</tt>
* @throws ArrayIndexOutOfBoundsException if <tt>fromIndex < 0</tt> or
* <tt>toIndex > a.length</tt>
*/
public static void fill(float[] a, int fromIndex, int toIndex, float val) {
rangeCheck(a.length, fromIndex, toIndex);
for (int i=fromIndex; i<toIndex; i++)
a[i] = val;
}
/**
* Assigns the specified Object reference to each element of the specified
* array of Objects.
*
* @param a the array to be filled.
* @param val the value to be stored in all elements of the array.
*/
public static void fill(Object[] a, Object val) {
fill(a, 0, a.length, val);
}
/**
* Assigns the specified Object reference to each element of the specified
* range of the specified array of Objects. The range to be filled
* extends from index <tt>fromIndex</tt>, inclusive, to index
* <tt>toIndex</tt>, exclusive. (If <tt>fromIndex==toIndex</tt>, the
* range to be filled is empty.)
*
* @param a the array to be filled.
* @param fromIndex the index of the first element (inclusive) to be
* filled with the specified value.
* @param toIndex the index of the last element (exclusive) to be
* filled with the specified value.
* @param val the value to be stored in all elements of the array.
* @throws IllegalArgumentException if <tt>fromIndex > toIndex</tt>
* @throws ArrayIndexOutOfBoundsException if <tt>fromIndex < 0</tt> or
* <tt>toIndex > a.length</tt>
*/
public static void fill(Object[] a, int fromIndex, int toIndex,Object val){
rangeCheck(a.length, fromIndex, toIndex);
for (int i=fromIndex; i<toIndex; i++)
a[i] = val;
}
// Misc
/**
* Returns a fixed-size list backed by the specified array. (Changes to
* the returned list "write through" to the array.) This method acts
* as bridge between array-based and collection-based APIs, in
* combination with <tt>Collection.toArray</tt>. The returned list is
* serializable and implements {@link RandomAccess}.
*
* @param a the array by which the list will be backed.
* @return a list view of the specified array.
* @see Collection#toArray()
*/
public static List asList(Object[] a) {
return new ArrayList(a);
}
/**
* @serial include
*/
private static class ArrayList extends AbstractList
implements RandomAccess, java.io.Serializable
{
private static final long serialVersionUID = -2764017481108945198L;
private Object[] a;
ArrayList(Object[] array) {
if (array==null)
throw new NullPointerException();
a = array;
}
public int size() {
return a.length;
}
public Object[] toArray() {
return (Object[]) a.clone();
}
public Object get(int index) {
return a[index];
}
public Object set(int index, Object element) {
Object oldValue = a[index];
a[index] = element;
return oldValue;
}
public int indexOf(Object o) {
if (o==null) {
for (int i=0; i<a.length; i++)
if (a[i]==null)
return i;
} else {
for (int i=0; i<a.length; i++)
if (o.equals(a[i]))
return i;
}
return -1;
}
public boolean contains(Object o) {
return indexOf(o) != -1;
}
}
}