1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache license, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the license for the specific language governing permissions and 15 * limitations under the license. 16 */ 17 package org.apache.logging.log4j.util; 18 19 /** 20 * <em>Consider this class private.</em> 21 */ 22 public final class Chars { 23 24 /** Carriage Return. */ 25 public static final char CR = '\r'; 26 27 /** Double Quote. */ 28 public static final char DQUOTE = '\"'; 29 30 /** Equals '='. */ 31 public static final char EQ = '='; 32 33 /** Line Feed. */ 34 public static final char LF = '\n'; 35 36 /** Single Quote [']. */ 37 public static final char QUOTE = '\''; 38 39 /** Space. */ 40 public static final char SPACE = ' '; 41 42 /** Tab. */ 43 public static final char TAB = '\t'; 44 45 /** 46 * Converts a digit into an uppercase hexadecimal character or the null character if invalid. 47 * 48 * @param digit a number 0 - 15 49 * @return the hex character for that digit or '\0' if invalid 50 */ 51 public static char getUpperCaseHex(final int digit) { 52 if (digit < 0 || digit >= 16) { 53 return '\0'; 54 } 55 return digit < 10 ? getNumericalDigit(digit) : getUpperCaseAlphaDigit(digit); 56 } 57 58 /** 59 * Converts a digit into an lowercase hexadecimal character or the null character if invalid. 60 * 61 * @param digit a number 0 - 15 62 * @return the hex character for that digit or '\0' if invalid 63 */ 64 public static char getLowerCaseHex(final int digit) { 65 if (digit < 0 || digit >= 16) { 66 return '\0'; 67 } 68 return digit < 10 ? getNumericalDigit(digit) : getLowerCaseAlphaDigit(digit); 69 } 70 71 private static char getNumericalDigit(final int digit) { 72 return (char) ('0' + digit); 73 } 74 75 private static char getUpperCaseAlphaDigit(final int digit) { 76 return (char) ('A' + digit - 10); 77 } 78 79 private static char getLowerCaseAlphaDigit(final int digit) { 80 return (char) ('a' + digit - 10); 81 } 82 83 private Chars() { 84 } 85 }