com.mchange.v1.util.ArrayUtils Maven / Gradle / Ivy
/*
* Distributed as part of mchange-commons-java v.0.2.3
*
* Copyright (C) 2012 Machinery For Change, Inc.
*
* Author: Steve Waldman
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License version 2.1, as
* published by the Free Software Foundation.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this software; see the file LICENSE. If not, write to the
* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307, USA.
*/
package com.mchange.v1.util;
import com.mchange.v2.lang.ObjectUtils;
public final class ArrayUtils
{
/**
* The array may contain nulls, but o
* must be non-null.
*/
public static int indexOf(Object[] array, Object o)
{
for (int i = 0, len = array.length; i < len; ++i)
if (o.equals(array[i])) return i;
return -1;
}
public static int identityIndexOf(Object[] array, Object o)
{
for (int i = 0, len = array.length; i < len; ++i)
if (o == array[i]) return i;
return -1;
}
public static boolean startsWith( byte[] checkMe, byte[] maybePrefix )
{
int cm_len = checkMe.length;
int mp_len = maybePrefix.length;
if (cm_len < mp_len)
return false;
for (int i = 0; i < mp_len; ++i)
if (checkMe[i] != maybePrefix[i])
return false;
return true;
}
/**
* returns a hash-code for an array consistent with Arrays.equals( ... )
*/
public static int hashArray(Object[] oo)
{
int len = oo.length;
int out = len;
for (int i = 0; i < len; ++i)
{
//we rotate the bits of the element hashes
//around so that the hash has some loaction
//dependency
int elem_hash = ObjectUtils.hashOrZero(oo[i]);
int rot = i % 32;
int rot_hash = elem_hash >>> rot;
rot_hash |= elem_hash << (32 - rot);
out ^= rot_hash;
}
return out;
}
/**
* returns a hash-code for an array consistent with Arrays.equals( ... )
*/
public static int hashArray(int[] ii)
{
int len = ii.length;
int out = len;
for (int i = 0; i < len; ++i)
{
//we rotate the bits of the element hashes
//around so that the hash has some loaction
//dependency
int elem_hash = ii[i];
int rot = i % 32;
int rot_hash = elem_hash >>> rot;
rot_hash |= elem_hash << (32 - rot);
out ^= rot_hash;
}
return out;
}
public static int hashOrZeroArray(Object[] oo)
{ return (oo == null ? 0 : hashArray(oo)); }
public static int hashOrZeroArray(int[] ii)
{ return (ii == null ? 0 : hashArray(ii)); }
/**
* @deprecated use the various toString(T[] methods)
*/
public static String stringifyContents(Object[] array)
{
StringBuffer sb = new StringBuffer();
sb.append("[ ");
for (int i = 0, len = array.length; i < len; ++i)
{
if (i != 0)
sb.append(", ");
sb.append( array[i].toString() );
}
sb.append(" ]");
return sb.toString();
}
//these methods are obsoleted by Arrays.toString() in jdk1.5, but
//for libs that support older VMs...
private static String toString(String[] strings, int guessed_len)
{
StringBuffer sb = new StringBuffer( guessed_len );
boolean first = true;
sb.append('[');
for (int i = 0, len = strings.length; i < len; ++i)
{
if (first)
first = false;
else
sb.append(',');
sb.append( strings[i] );
}
sb.append(']');
return sb.toString();
}
public static String toString(boolean[] arr)
{
String[] strings = new String[arr.length];
int chars = 0;
for(int i = 0, len = arr.length; i < len; ++i)
{
String str = String.valueOf(arr[i]);
chars += str.length();
strings[i] = str;
}
return toString(strings, chars + arr.length + 1);
}
public static String toString(byte[] arr)
{
String[] strings = new String[arr.length];
int chars = 0;
for(int i = 0, len = arr.length; i < len; ++i)
{
String str = String.valueOf(arr[i]);
chars += str.length();
strings[i] = str;
}
return toString(strings, chars + arr.length + 1);
}
public static String toString(char[] arr)
{
String[] strings = new String[arr.length];
int chars = 0;
for(int i = 0, len = arr.length; i < len; ++i)
{
String str = String.valueOf(arr[i]);
chars += str.length();
strings[i] = str;
}
return toString(strings, chars + arr.length + 1);
}
public static String toString(short[] arr)
{
String[] strings = new String[arr.length];
int chars = 0;
for(int i = 0, len = arr.length; i < len; ++i)
{
String str = String.valueOf(arr[i]);
chars += str.length();
strings[i] = str;
}
return toString(strings, chars + arr.length + 1);
}
public static String toString(int[] arr)
{
String[] strings = new String[arr.length];
int chars = 0;
for(int i = 0, len = arr.length; i < len; ++i)
{
String str = String.valueOf(arr[i]);
chars += str.length();
strings[i] = str;
}
return toString(strings, chars + arr.length + 1);
}
public static String toString(long[] arr)
{
String[] strings = new String[arr.length];
int chars = 0;
for(int i = 0, len = arr.length; i < len; ++i)
{
String str = String.valueOf(arr[i]);
chars += str.length();
strings[i] = str;
}
return toString(strings, chars + arr.length + 1);
}
public static String toString(float[] arr)
{
String[] strings = new String[arr.length];
int chars = 0;
for(int i = 0, len = arr.length; i < len; ++i)
{
String str = String.valueOf(arr[i]);
chars += str.length();
strings[i] = str;
}
return toString(strings, chars + arr.length + 1);
}
public static String toString(double[] arr)
{
String[] strings = new String[arr.length];
int chars = 0;
for(int i = 0, len = arr.length; i < len; ++i)
{
String str = String.valueOf(arr[i]);
chars += str.length();
strings[i] = str;
}
return toString(strings, chars + arr.length + 1);
}
public static String toString(Object[] arr)
{
String[] strings = new String[arr.length];
int chars = 0;
for(int i = 0, len = arr.length; i < len; ++i)
{
String str;
Object o = arr[i];
if (o instanceof Object[])
str = toString((Object[]) o);
else if (o instanceof double[])
str = toString((double[]) o);
else if (o instanceof float[])
str = toString((float[]) o);
else if (o instanceof long[])
str = toString((long[]) o);
else if (o instanceof int[])
str = toString((int[]) o);
else if (o instanceof short[])
str = toString((short[]) o);
else if (o instanceof char[])
str = toString((char[]) o);
else if (o instanceof byte[])
str = toString((byte[]) o);
else if (o instanceof boolean[])
str = toString((boolean[]) o);
else
str = String.valueOf(arr[i]);
chars += str.length();
strings[i] = str;
}
return toString(strings, chars + arr.length + 1);
}
private ArrayUtils()
{}
/*
public static void main(String[] argv)
{
int[] is = {1,2,3,4};
String[] ss = {"Hello", "There"};
Object[] os = {"Poop", is, ss, new Thread()};
System.out.println( toString(is) );
System.out.println( toString(ss) );
System.out.println( toString(os) );
}
*/
}
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