1 /*
   2  * Copyright (c) 1999, 2018, Oracle and/or its affiliates. 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.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package com.sun.tools.javac.jvm;
  27 
  28 import com.sun.tools.javac.util.Name;
  29 
  30 
  31 /** A JVM class file.
  32  *
  33  *  <p>Generic Java classfiles have one additional attribute for classes,
  34  *  methods and fields:
  35  *  <pre>
  36  *   "Signature" (u4 attr-length, u2 signature-index)
  37  *  </pre>
  38  *
  39  *  <p>A signature gives the full Java type of a method or field. When
  40  *  used as a class attribute, it indicates type parameters, followed
  41  *  by supertype, followed by all interfaces.
  42  *  <pre>
  43  *     methodOrFieldSignature ::= type
  44  *     classSignature         ::= [ typeparams ] supertype { interfacetype }
  45  *  </pre>
  46  *  <p>The type syntax in signatures is extended as follows:
  47  *  <pre>{@literal
  48  *     type       ::= ... | classtype | methodtype | typevar
  49  *     classtype  ::= classsig { '.' classsig }
  50  *     classig    ::= 'L' name [typeargs] ';'
  51  *     methodtype ::= [ typeparams ] '(' { type } ')' type
  52  *     typevar    ::= 'T' name ';'
  53  *     typeargs   ::= '<' type { type } '>'
  54  *     typeparams ::= '<' typeparam { typeparam } '>'
  55  *     typeparam  ::= name ':' type
  56  *  }</pre>
  57  *  <p>This class defines constants used in class files as well
  58  *  as routines to convert between internal ``.'' and external ``/''
  59  *  separators in class names.
  60  *
  61  *  <p><b>This is NOT part of any supported API.
  62  *  If you write code that depends on this, you do so at your own risk.
  63  *  This code and its internal interfaces are subject to change or
  64  *  deletion without notice.</b> */
  65 public class ClassFile {
  66 
  67     public final static int JAVA_MAGIC = 0xCAFEBABE;
  68 
  69     // see Target
  70     public final static int CONSTANT_Utf8 = 1;
  71     public final static int CONSTANT_Unicode = 2;
  72     public final static int CONSTANT_Integer = 3;
  73     public final static int CONSTANT_Float = 4;
  74     public final static int CONSTANT_Long = 5;
  75     public final static int CONSTANT_Double = 6;
  76     public final static int CONSTANT_Class = 7;
  77     public final static int CONSTANT_String = 8;
  78     public final static int CONSTANT_Fieldref = 9;
  79     public final static int CONSTANT_Methodref = 10;
  80     public final static int CONSTANT_InterfaceMethodref = 11;
  81     public final static int CONSTANT_NameandType = 12;
  82     public final static int CONSTANT_MethodHandle = 15;
  83     public final static int CONSTANT_MethodType = 16;
  84     public final static int CONSTANT_Dynamic = 17;
  85     public final static int CONSTANT_InvokeDynamic = 18;
  86     public final static int CONSTANT_Module = 19;
  87     public final static int CONSTANT_Package = 20;
  88 
  89     public final static int REF_getField = 1;
  90     public final static int REF_getStatic = 2;
  91     public final static int REF_putField = 3;
  92     public final static int REF_putStatic = 4;
  93     public final static int REF_invokeVirtual = 5;
  94     public final static int REF_invokeStatic = 6;
  95     public final static int REF_invokeSpecial = 7;
  96     public final static int REF_newInvokeSpecial = 8;
  97     public final static int REF_invokeInterface = 9;
  98 
  99     public final static int MAX_PARAMETERS = 0xff;
 100     public final static int MAX_DIMENSIONS = 0xff;
 101     public final static int MAX_CODE = 0xffff;
 102     public final static int MAX_LOCALS = 0xffff;
 103     public final static int MAX_STACK = 0xffff;
 104 
 105     public final static int PREVIEW_MINOR_VERSION = 0xffff;
 106 
 107     public enum Version {
 108         V45_3(45, 3), // base level for all attributes
 109         V49(49, 0),   // JDK 1.5: enum, generics, annotations
 110         V50(50, 0),   // JDK 1.6: stackmaps
 111         V51(51, 0),   // JDK 1.7
 112         V52(52, 0),   // JDK 1.8: lambda, type annos, param names
 113         V53(53, 0),   // JDK 1.9: modules, indy string concat
 114         V54(54, 0),   // JDK 10
 115         V55(55, 0),   // JDK 11: constant dynamic, nest mates
 116         V56(56, 0),   // JDK 12
 117         V57(57, 0);   // JDK 13
 118         Version(int major, int minor) {
 119             this.major = major;
 120             this.minor = minor;
 121         }
 122         public final int major, minor;
 123 
 124         private static final Version MIN = values()[0];
 125         /** Return the least version supported, MIN */
 126         public static Version MIN() { return MIN; }
 127 
 128         private static final Version MAX = values()[values().length-1];
 129         /** Return the largest version supported, MAX */
 130         public static Version MAX() { return MAX; }
 131     }
 132 
 133 
 134 /************************************************************************
 135  * String Translation Routines
 136  ***********************************************************************/
 137 
 138     /**
 139      * Return internal representation of buf[offset..offset+len-1], converting '/' to '.'.
 140      *
 141      * Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
 142      * which defines "internal name" to be the form using "/" instead of "."
 143      */
 144     public static byte[] internalize(byte[] buf, int offset, int len) {
 145         byte[] translated = new byte[len];
 146         for (int j = 0; j < len; j++) {
 147             byte b = buf[offset + j];
 148             if (b == '/') translated[j] = (byte) '.';
 149             else translated[j] = b;
 150         }
 151         return translated;
 152     }
 153 
 154     /**
 155      * Return internal representation of given name, converting '/' to '.'.
 156      *
 157      * Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
 158      * which defines "internal name" to be the form using "/" instead of "."
 159      */
 160     public static byte[] internalize(Name name) {
 161         return internalize(name.getByteArray(), name.getByteOffset(), name.getByteLength());
 162     }
 163 
 164     /**
 165      * Return external representation of buf[offset..offset+len-1], converting '.' to '/'.
 166      *
 167      * Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
 168      * which defines "internal name" to be the form using "/" instead of "."
 169      */
 170     public static byte[] externalize(byte[] buf, int offset, int len) {
 171         byte[] translated = new byte[len];
 172         for (int j = 0; j < len; j++) {
 173             byte b = buf[offset + j];
 174             if (b == '.') translated[j] = (byte) '/';
 175             else translated[j] = b;
 176         }
 177         return translated;
 178     }
 179 
 180     /**
 181      * Return external representation of given name, converting '/' to '.'.
 182      *
 183      * Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
 184      * which defines "internal name" to be the form using "/" instead of "."
 185      */
 186     public static byte[] externalize(Name name) {
 187         return externalize(name.getByteArray(), name.getByteOffset(), name.getByteLength());
 188     }
 189 }