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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 java.util.Arrays;
import java.util.Locale;
import org.apache.poi.util.Beta;
/**
* Utility class to translate numbers in letters, usually for lists.
*/
@Beta
public final class NumberFormatter {
// use char[] instead of String to speed up StringBuilder.append(), especially in JDK 11+
// where StringBuilder internally switched from char[] to byte[]
private static final char[][] ROMAN_LETTERS = Arrays.stream(
new String[] { "m", "cm", "d", "cd", "c", "xc", "l", "xl", "x", "ix", "v", "iv", "i" }).
map(String::toCharArray).
toArray(char[][]::new);
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(Locale.ROOT);
case T_LOWER_ROMAN:
return toRoman( num );
case T_UPPER_LETTER:
return toLetters( num ).toUpperCase(Locale.ROOT);
case T_LOWER_LETTER:
return toLetters( num );
case T_ARABIC:
case T_ORDINAL:
default:
return String.valueOf( num );
}
}
private static String toLetters(int number) {
if ( number <= 0 ) {
throw new IllegalArgumentException( "Unsupported number: " + number );
}
int num = number;
final int radix = 26;
char[] buf = new char[33];
int charPos = buf.length;
while (num > 0) {
num--; // 1 => a, not 0 => a
int remainder = num % radix;
buf[--charPos] = (char)('a'+remainder);
num = (num - remainder) / radix;
}
return new String(buf, charPos, (buf.length - charPos));
}
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++ ) {
char[] letter = ROMAN_LETTERS[i];
int value = ROMAN_VALUES[i];
while ( number >= value ) {
number -= value;
result.append( letter );
}
}
return result.toString();
}
}
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