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/*
* ====================================================================
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* ====================================================================
*/
package org.apache.poi.hwpf.converter;
import org.apache.poi.util.Beta;
/**
* Utility class to translate numbers in letters, usually for lists.
*
* @author Sergey Vladimirov (vlsergey {at} gmail {dot} com)
*/
@Beta
public final class NumberFormatter
{
private static final String[] ENGLISH_LETTERS = new String[] { "a", "b",
"c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o",
"p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z" };
private static final String[] ROMAN_LETTERS = { "m", "cm", "d", "cd", "c",
"xc", "l", "xl", "x", "ix", "v", "iv", "i" };
private static final int[] ROMAN_VALUES = { 1000, 900, 500, 400, 100, 90,
50, 40, 10, 9, 5, 4, 1 };
private static final int T_ARABIC = 0;
private static final int T_LOWER_LETTER = 4;
private static final int T_LOWER_ROMAN = 2;
private static final int T_ORDINAL = 5;
private static final int T_UPPER_LETTER = 3;
private static final int T_UPPER_ROMAN = 1;
public static String getNumber( int num, int style )
{
switch ( style )
{
case T_UPPER_ROMAN:
return toRoman( num ).toUpperCase();
case T_LOWER_ROMAN:
return toRoman( num );
case T_UPPER_LETTER:
return toLetters( num ).toUpperCase();
case T_LOWER_LETTER:
return toLetters( num );
case T_ARABIC:
case T_ORDINAL:
default:
return String.valueOf( num );
}
}
private static String toLetters( int number )
{
final int base = 26;
if ( number <= 0 )
throw new IllegalArgumentException( "Unsupported number: " + number );
if ( number < base + 1 )
return ENGLISH_LETTERS[number - 1];
long toProcess = number;
StringBuilder stringBuilder = new StringBuilder();
int maxPower = 0;
{
int boundary = 0;
while ( toProcess > boundary )
{
maxPower++;
boundary = boundary * base + base;
if ( boundary > Integer.MAX_VALUE )
throw new IllegalArgumentException( "Unsupported number: "
+ toProcess );
}
}
maxPower--;
for ( int p = maxPower; p > 0; p-- )
{
long boundary = 0;
long shift = 1;
for ( int i = 0; i < p; i++ )
{
shift *= base;
boundary = boundary * base + base;
}
int count = 0;
while ( toProcess > boundary )
{
count++;
toProcess -= shift;
}
stringBuilder.append( ENGLISH_LETTERS[count - 1] );
}
stringBuilder.append( ENGLISH_LETTERS[(int) toProcess - 1] );
return stringBuilder.toString();
}
private static String toRoman( int number )
{
if ( number <= 0 )
throw new IllegalArgumentException( "Unsupported number: " + number );
StringBuilder result = new StringBuilder();
for ( int i = 0; i < ROMAN_LETTERS.length; i++ )
{
String letter = ROMAN_LETTERS[i];
int value = ROMAN_VALUES[i];
while ( number >= value )
{
number -= value;
result.append( letter );
}
}
return result.toString();
}
}