1 /*
   2  * Copyright 2005 Sun Microsystems, Inc.  All Rights Reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Sun designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Sun in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  22  * CA 95054 USA or visit www.sun.com if you need additional information or
  23  * have any questions.
  24  */
  25 
  26 package com.sun.tools.javac.util;
  27 
  28 import com.sun.tools.javac.code.Type;
  29 
  30 import static com.sun.tools.javac.code.TypeTags.*;
  31 
  32 /**
  33  * Utilities for operating on constant values.
  34  *
  35  * <p><b>This is NOT part of any API supported by Sun Microsystems.  If
  36  * you write code that depends on this, you do so at your own risk.
  37  * This code and its internal interfaces are subject to change or
  38  * deletion without notice.</b>
  39  */
  40 public class Constants {
  41 
  42     /**
  43      * Converts a constant in internal representation (in which
  44      * boolean, char, byte, short, and int are each represented by an
  45      * Integer) into standard representation.  Other values (including
  46      * null) are returned unchanged.
  47      */
  48     public static Object decode(Object value, Type type) {
  49         if (value instanceof Integer) {
  50             int i = (Integer) value;
  51             switch (type.tag) {
  52             case BOOLEAN:  return i != 0;
  53             case CHAR:     return (char) i;
  54             case BYTE:     return (byte) i;
  55             case SHORT:    return (short) i;
  56             }
  57         }
  58         return value;
  59     }
  60 
  61     /**
  62      * Returns a string representation of a constant value (given in
  63      * internal representation), quoted and formatted as in Java source.
  64      */
  65     public static String format(Object value, Type type) {
  66         value = decode(value, type);
  67         switch (type.tag) {
  68         case BYTE:      return formatByte((Byte) value);
  69         case LONG:      return formatLong((Long) value);
  70         case FLOAT:     return formatFloat((Float) value);
  71         case DOUBLE:    return formatDouble((Double) value);
  72         case CHAR:      return formatChar((Character) value);
  73         }
  74         if (value instanceof String)
  75             return formatString((String) value);
  76         return value + "";
  77     }
  78 
  79     /**
  80      * Returns a string representation of a constant value (given in
  81      * standard wrapped representation), quoted and formatted as in
  82      * Java source.
  83      */
  84     public static String format(Object value) {
  85         if (value instanceof Byte)      return formatByte((Byte) value);
  86         if (value instanceof Long)      return formatLong((Long) value);
  87         if (value instanceof Float)     return formatFloat((Float) value);
  88         if (value instanceof Double)    return formatDouble((Double) value);
  89         if (value instanceof Character) return formatChar((Character) value);
  90         if (value instanceof String)    return formatString((String) value);
  91         return value + "";
  92     }
  93 
  94     private static String formatByte(byte b) {
  95         return String.format("0x%02x", b);
  96     }
  97 
  98     private static String formatLong(long lng) {
  99         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 }