content: /*
   * 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
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  package openjdk.tools.javac.jvm;
  
  import openjdk.tools.javac.util.Name;
  
  
  /** 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 static final int JAVA_MAGIC = 0xCAFEBABE;
  
      // see Target
      public static final int CONSTANT_Utf8 = 1;
      public static final int CONSTANT_Unicode = 2;
      public static final int CONSTANT_Integer = 3;
      public static final int CONSTANT_Float = 4;
      public static final int CONSTANT_Long = 5;
      public static final int CONSTANT_Double = 6;
      public static final int CONSTANT_Class = 7;
      public static final int CONSTANT_String = 8;
      public static final int CONSTANT_Fieldref = 9;
      public static final int CONSTANT_Methodref = 10;
      public static final int CONSTANT_InterfaceMethodref = 11;
      public static final int CONSTANT_NameandType = 12;
      public static final int CONSTANT_MethodHandle = 15;
      public static final int CONSTANT_MethodType = 16;
      public static final int CONSTANT_Dynamic = 17;
      public static final int CONSTANT_InvokeDynamic = 18;
      public static final int CONSTANT_Module = 19;
      public static final int CONSTANT_Package = 20;
  
      public static final int REF_getField = 1;
      public static final int REF_getStatic = 2;
      public static final int REF_putField = 3;
      public static final int REF_putStatic = 4;
      public static final int REF_invokeVirtual = 5;
      public static final int REF_invokeStatic = 6;
      public static final int REF_invokeSpecial = 7;
      public static final int REF_newInvokeSpecial = 8;
      public static final int REF_invokeInterface = 9;
  
      public static final int MAX_PARAMETERS = 0xff;
      public static final int MAX_DIMENSIONS = 0xff;
      public static final int MAX_CODE = 0xffff;
      public static final int MAX_LOCALS = 0xffff;
      public static final int MAX_STACK = 0xffff;
  
      public static final 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 */
          public static Version MIN() { return MIN; }
  
          private static final Version MAX = values()[values().length-1];
          /** 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 "."
       */
      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 "."
       */
      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 "."
       */
      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 "."
       */
      public static byte[] externalize(Name name) {
          return externalize(name.getByteArray(), name.getByteOffset(), name.getByteLength());
      }
  }
  