/*

 * 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 com.sun.tools.javac.jvm;

import com.sun.tools.javac.code.Type;

import com.sun.tools.javac.code.Types;

import com.sun.tools.javac.code.Types.UniqueType;

import com.sun.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 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_InvokeDynamic = 18;

    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 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

        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 '.'.

     */

    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 '.'.

     */

    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 '/'.

     */

    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 '.'.

     */

    public static byte[] externalize(Name name) {

        return externalize(name.getByteArray(), name.getByteOffset(), name.getByteLength());

    }

/************************************************************************

 * Name-and-type

 ***********************************************************************/

    /** A class for the name-and-type signature of a method or field.

     */

    public static class NameAndType {

        Name name;

        UniqueType uniqueType;

        Types types;

        NameAndType(Name name, Type type, Types types) {

            this.name = name;

            this.uniqueType = new UniqueType(type, types);

            this.types = types;

        }

        void setType(Type type) {

            this.uniqueType = new UniqueType(type, types);

        }

        @Override

        public boolean equals(Object other) {

            return (other instanceof NameAndType &&

                    name == ((NameAndType) other).name &&

                        uniqueType.equals(((NameAndType) other).uniqueType));

        }

        @Override

        public int hashCode() {

            return name.hashCode() * uniqueType.hashCode();

        }

    }

}