001 /*
002 * Copyright 2005 Sun Microsystems, Inc. All Rights Reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation. Sun designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Sun in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022 * CA 95054 USA or visit www.sun.com if you need additional information or
023 * have any questions.
024 */
025
026 package com.sun.tools.javac.util;
027
028 import com.sun.tools.javac.code.Type;
029
030 import static com.sun.tools.javac.code.TypeTags.*;
031
032 /**
033 * Utilities for operating on constant values.
034 *
035 * <p><b>This is NOT part of any API supported by Sun Microsystems. If
036 * you write code that depends on this, you do so at your own risk.
037 * This code and its internal interfaces are subject to change or
038 * deletion without notice.</b>
039 */
040 public class Constants {
041
042 /**
043 * Converts a constant in internal representation (in which
044 * boolean, char, byte, short, and int are each represented by an
045 * Integer) into standard representation. Other values (including
046 * null) are returned unchanged.
047 */
048 public static Object decode(Object value, Type type) {
049 if (value instanceof Integer) {
050 int i = (Integer) value;
051 switch (type.tag) {
052 case BOOLEAN: return i != 0;
053 case CHAR: return (char) i;
054 case BYTE: return (byte) i;
055 case SHORT: return (short) i;
056 }
057 }
058 return value;
059 }
060
061 /**
062 * Returns a string representation of a constant value (given in
063 * internal representation), quoted and formatted as in Java source.
064 */
065 public static String format(Object value, Type type) {
066 value = decode(value, type);
067 switch (type.tag) {
068 case BYTE: return formatByte((Byte) value);
069 case LONG: return formatLong((Long) value);
070 case FLOAT: return formatFloat((Float) value);
071 case DOUBLE: return formatDouble((Double) value);
072 case CHAR: return formatChar((Character) value);
073 }
074 if (value instanceof String)
075 return formatString((String) value);
076 return value + "";
077 }
078
079 /**
080 * Returns a string representation of a constant value (given in
081 * standard wrapped representation), quoted and formatted as in
082 * Java source.
083 */
084 public static String format(Object value) {
085 if (value instanceof Byte) return formatByte((Byte) value);
086 if (value instanceof Long) return formatLong((Long) value);
087 if (value instanceof Float) return formatFloat((Float) value);
088 if (value instanceof Double) return formatDouble((Double) value);
089 if (value instanceof Character) return formatChar((Character) value);
090 if (value instanceof String) return formatString((String) value);
091 return value + "";
092 }
093
094 private static String formatByte(byte b) {
095 return String.format("0x%02x", b);
096 }
097
098 private static String formatLong(long lng) {
099 return lng + "L";
100 }
101
102 private static String formatFloat(float f) {
103 if (Float.isNaN(f))
104 return "0.0f/0.0f";
105 else if (Float.isInfinite(f))
106 return (f < 0) ? "-1.0f/0.0f" : "1.0f/0.0f";
107 else
108 return f + "f";
109 }
110
111 private static String formatDouble(double d) {
112 if (Double.isNaN(d))
113 return "0.0/0.0";
114 else if (Double.isInfinite(d))
115 return (d < 0) ? "-1.0/0.0" : "1.0/0.0";
116 else
117 return d + "";
118 }
119
120 private static String formatChar(char c) {
121 return '\'' + Convert.quote(c) + '\'';
122 }
123
124 private static String formatString(String s) {
125 return '"' + Convert.quote(s) + '"';
126 }
127 }