/*
 * Copyright (c) 1999, 2020, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 */

package com.sun.tools.javac.jvm;

import com.sun.tools.javac.util.Name;


A JVM class file.
 
Generic Java classfiles have one additional attribute for classes,
 methods and fields:
 
  "Signature" (u4 attr-length, u2 signature-index)
 
 
A signature gives the full Java type of a method or field. When
 used as a class attribute, it indicates type parameters, followed
 by supertype, followed by all interfaces.
 
    methodOrFieldSignature ::= type
    classSignature         ::= [ typeparams ] supertype { interfacetype }
 
 
The type syntax in signatures is extended as follows:
 
    type       ::= ... | classtype | methodtype | typevar
    classtype  ::= classsig { '.' classsig }
    classig    ::= 'L' name [typeargs] ';'
    methodtype ::= [ typeparams ] '(' { type } ')' type
    typevar    ::= 'T' name ';'
    typeargs   ::= '<' type { type } '>'
    typeparams ::= '<' typeparam { typeparam } '>'
    typeparam  ::= name ':' type
 
 
This class defines constants used in class files as well
 as routines to convert between internal ``.'' and external ``/''
 separators in class names.
 
This is NOT part of any supported API.
 If you write code that depends on this, you do so at your own risk.
 This code and its internal interfaces are subject to change or
 deletion without notice. /** A JVM class file.
 *
 *  <p>Generic Java classfiles have one additional attribute for classes,
 *  methods and fields:
 *  <pre>
 *   "Signature" (u4 attr-length, u2 signature-index)
 *  </pre>
 *
 *  <p>A signature gives the full Java type of a method or field. When
 *  used as a class attribute, it indicates type parameters, followed
 *  by supertype, followed by all interfaces.
 *  <pre>
 *     methodOrFieldSignature ::= type
 *     classSignature         ::= [ typeparams ] supertype { interfacetype }
 *  </pre>
 *  <p>The type syntax in signatures is extended as follows:
 *  <pre>{@literal
 *     type       ::= ... | classtype | methodtype | typevar
 *     classtype  ::= classsig { '.' classsig }
 *     classig    ::= 'L' name [typeargs] ';'
 *     methodtype ::= [ typeparams ] '(' { type } ')' type
 *     typevar    ::= 'T' name ';'
 *     typeargs   ::= '<' type { type } '>'
 *     typeparams ::= '<' typeparam { typeparam } '>'
 *     typeparam  ::= name ':' type
 *  }</pre>
 *  <p>This class defines constants used in class files as well
 *  as routines to convert between internal ``.'' and external ``/''
 *  separators in class names.
 *
 *  <p><b>This is NOT part of any supported API.
 *  If you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b> */
public class ClassFile {

    public final static int JAVA_MAGIC = 0xCAFEBABE;

    // see Target
    public final static int CONSTANT_Utf8 = 1;
    public final static int CONSTANT_Unicode = 2;
    public final static int CONSTANT_Integer = 3;
    public final static int CONSTANT_Float = 4;
    public final static int CONSTANT_Long = 5;
    public final static int CONSTANT_Double = 6;
    public final static int CONSTANT_Class = 7;
    public final static int CONSTANT_String = 8;
    public final static int CONSTANT_Fieldref = 9;
    public final static int CONSTANT_Methodref = 10;
    public final static int CONSTANT_InterfaceMethodref = 11;
    public final static int CONSTANT_NameandType = 12;
    public final static int CONSTANT_MethodHandle = 15;
    public final static int CONSTANT_MethodType = 16;
    public final static int CONSTANT_Dynamic = 17;
    public final static int CONSTANT_InvokeDynamic = 18;
    public final static int CONSTANT_Module = 19;
    public final static int CONSTANT_Package = 20;

    public final static int REF_getField = 1;
    public final static int REF_getStatic = 2;
    public final static int REF_putField = 3;
    public final static int REF_putStatic = 4;
    public final static int REF_invokeVirtual = 5;
    public final static int REF_invokeStatic = 6;
    public final static int REF_invokeSpecial = 7;
    public final static int REF_newInvokeSpecial = 8;
    public final static int REF_invokeInterface = 9;

    public final static int MAX_PARAMETERS = 0xff;
    public final static int MAX_DIMENSIONS = 0xff;
    public final static int MAX_CODE = 0xffff;
    public final static int MAX_LOCALS = 0xffff;
    public final static int MAX_STACK = 0xffff;

    public final static int PREVIEW_MINOR_VERSION = 0xffff;

    public enum Version {
        V45_3(45, 3), // base level for all attributes
        V49(49, 0),   // JDK 1.5: enum, generics, annotations
        V50(50, 0),   // JDK 1.6: stackmaps
        V51(51, 0),   // JDK 1.7
        V52(52, 0),   // JDK 1.8: lambda, type annos, param names
        V53(53, 0),   // JDK 1.9: modules, indy string concat
        V54(54, 0),   // JDK 10
        V55(55, 0),   // JDK 11: constant dynamic, nest mates
        V56(56, 0),   // JDK 12
        V57(57, 0),   // JDK 13
        V58(58, 0),   // JDK 14
        V59(59, 0),   // JDK 15
        V60(60, 0),   // JDK 16
        V61(61, 0);   // JDK 17
        Version(int major, int minor) {
            this.major = major;
            this.minor = minor;
        }
        public final int major, minor;

        private static final Version MIN = values()[0];
        
Return the least version supported, MIN /** Return the least version supported, MIN */
        public static Version MIN() { return MIN; }

        private static final Version MAX = values()[values().length-1];
        
Return the largest version supported, MAX /** Return the largest version supported, MAX */
        public static Version MAX() { return MAX; }
    }


/************************************************************************
 * String Translation Routines
 ***********************************************************************/

    
Return internal representation of buf[offset..offset+len-1], converting '/' to '.'.
Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
which defines "internal name" to be the form using "/" instead of "."
/**
     * Return internal representation of buf[offset..offset+len-1], converting '/' to '.'.
     *
     * Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
     * which defines "internal name" to be the form using "/" instead of "."
     */
    public static byte[] internalize(byte[] buf, int offset, int len) {
        byte[] translated = new byte[len];
        for (int j = 0; j < len; j++) {
            byte b = buf[offset + j];
            if (b == '/') translated[j] = (byte) '.';
            else translated[j] = b;
        }
        return translated;
    }

    
Return internal representation of given name, converting '/' to '.'.
Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
which defines "internal name" to be the form using "/" instead of "."
/**
     * Return internal representation of given name, converting '/' to '.'.
     *
     * Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
     * which defines "internal name" to be the form using "/" instead of "."
     */
    public static byte[] internalize(Name name) {
        return internalize(name.getByteArray(), name.getByteOffset(), name.getByteLength());
    }

    
Return external representation of buf[offset..offset+len-1], converting '.' to '/'.
Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
which defines "internal name" to be the form using "/" instead of "."
/**
     * Return external representation of buf[offset..offset+len-1], converting '.' to '/'.
     *
     * Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
     * which defines "internal name" to be the form using "/" instead of "."
     */
    public static byte[] externalize(byte[] buf, int offset, int len) {
        byte[] translated = new byte[len];
        for (int j = 0; j < len; j++) {
            byte b = buf[offset + j];
            if (b == '.') translated[j] = (byte) '/';
            else translated[j] = b;
        }
        return translated;
    }

    
Return external representation of given name, converting '/' to '.'.
Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
which defines "internal name" to be the form using "/" instead of "."
/**
     * Return external representation of given name, converting '/' to '.'.
     *
     * Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
     * which defines "internal name" to be the form using "/" instead of "."
     */
    public static byte[] externalize(Name name) {
        return externalize(name.getByteArray(), name.getByteOffset(), name.getByteLength());
    }
}