/*
* This file is part of Applied Energistics 2.
* Copyright (c) 2013 - 2015, AlgorithmX2, All rights reserved.
*
* Applied Energistics 2 is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Applied Energistics 2 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 Applied Energistics 2. If not, see <http://www.gnu.org/licenses/lgpl>.
*/
package appeng.util;
import java.math.RoundingMode;
import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;
import java.text.Format;
/**
* Converter class to convert a large number into a SI system.
*
* @author thatsIch
* @version rv2
* @since rv2
*/
public enum ReadableNumberConverter implements ISlimReadableNumberConverter, IWideReadableNumberConverter
{
INSTANCE;
/**
* Defines the base for a division, non-si standard could be 1024 for kilobytes
*/
private static final int DIVISION_BASE = 1000;
/**
* String representation of the sorted postfixes
*/
private static final char[] ENCODED_POSTFIXES = "KMGTPE".toCharArray();
private final Format format;
/**
* Initializes the specific decimal format with special format for negative and positive numbers
*/
ReadableNumberConverter()
{
final DecimalFormatSymbols symbols = new DecimalFormatSymbols();
symbols.setDecimalSeparator( '.' );
final DecimalFormat format = new DecimalFormat( ".#;0.#" );
format.setDecimalFormatSymbols( symbols );
format.setRoundingMode( RoundingMode.DOWN );
this.format = format;
}
@Override
public String toSlimReadableForm( final long number )
{
return this.toReadableFormRestrictedByWidth( number, 3 );
}
/**
* restricts a string representation of a number to a specific width
*
* @param number to be formatted number
* @param width width limitation of the resulting number
*
* @return formatted number restricted by the width limitation
*/
private String toReadableFormRestrictedByWidth( final long number, final int width )
{
assert number >= 0;
// handles low numbers more efficiently since no format is needed
final String numberString = Long.toString( number );
int numberSize = numberString.length();
if( numberSize <= width )
{
return numberString;
}
long base = number;
double last = base * 1000;
int exponent = -1;
String postFix = "";
while( numberSize > width )
{
last = base;
base /= DIVISION_BASE;
exponent++;
// adds +1 due to the postfix
numberSize = Long.toString( base ).length() + 1;
postFix = String.valueOf( ENCODED_POSTFIXES[exponent] );
}
final String withPrecision = this.format.format( last / DIVISION_BASE ) + postFix;
final String withoutPrecision = Long.toString( base ) + postFix;
final String slimResult = ( withPrecision.length() <= width ) ? withPrecision : withoutPrecision;
// post condition
assert slimResult.length() <= width;
return slimResult;
}
@Override
public String toWideReadableForm( final long number )
{
return this.toReadableFormRestrictedByWidth( number, 4 );
}
}