/*

 * Copyright (c) 2007, 2009, 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 com.sun.tools.classfile;

import java.io.IOException;

/**

 * See JVMS, section 4.8.4.

 *

 *  <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 StackMapTable_attribute extends Attribute {

    static class InvalidStackMap extends AttributeException {

        private static final long serialVersionUID = -5659038410855089780L;

        InvalidStackMap(String msg) {

            super(msg);

        }

    }

    StackMapTable_attribute(ClassReader cr, int name_index, int length)

            throws IOException, InvalidStackMap {

        super(name_index, length);

        number_of_entries = cr.readUnsignedShort();

        entries = new stack_map_frame[number_of_entries];

        for (int i = 0; i < number_of_entries; i++)

            entries[i] = stack_map_frame.read(cr);

    }

    public StackMapTable_attribute(ConstantPool constant_pool, stack_map_frame[] entries)

            throws ConstantPoolException {

        this(constant_pool.getUTF8Index(Attribute.StackMapTable), entries);

    }

    public StackMapTable_attribute(int name_index, stack_map_frame[] entries) {

        super(name_index, length(entries));

        this.number_of_entries = entries.length;

        this.entries = entries;

    }

    public <R, D> R accept(Visitor<R, D> visitor, D data) {

        return visitor.visitStackMapTable(this, data);

    }

    static int length(stack_map_frame[] entries) {

        int n = 2;

        for (stack_map_frame entry: entries)

            n += entry.length();

        return n;

    }

    public final int number_of_entries;

    public final stack_map_frame entries[];

    public static abstract class stack_map_frame {

        static stack_map_frame read(ClassReader cr)

                throws IOException, InvalidStackMap {

            int frame_type = cr.readUnsignedByte();

            if (frame_type <= 63)

                return new same_frame(frame_type);

            else if (frame_type <= 127)

                return new same_locals_1_stack_item_frame(frame_type, cr);

            else if (frame_type <= 246)

                throw new Error("unknown frame_type " + frame_type);

            else if (frame_type == 247)

                return new same_locals_1_stack_item_frame_extended(frame_type, cr);

            else if (frame_type <= 250)

                return new chop_frame(frame_type, cr);

            else if (frame_type == 251)

                return new same_frame_extended(frame_type, cr);

            else if (frame_type <= 254)

                return new append_frame(frame_type, cr);

            else

                return new full_frame(frame_type, cr);

        }

        protected stack_map_frame(int frame_type) {

            this.frame_type = frame_type;

        }

        public int length() {

            return 1;

        }

        public abstract int getOffsetDelta();

        public abstract <R,D> R accept(Visitor<R,D> visitor, D data);

        public final int frame_type;

        public static interface Visitor<R,P> {

            R visit_same_frame(same_frame frame, P p);

            R visit_same_locals_1_stack_item_frame(same_locals_1_stack_item_frame frame, P p);

            R visit_same_locals_1_stack_item_frame_extended(same_locals_1_stack_item_frame_extended frame, P p);

            R visit_chop_frame(chop_frame frame, P p);

            R visit_same_frame_extended(same_frame_extended frame, P p);

            R visit_append_frame(append_frame frame, P p);

            R visit_full_frame(full_frame frame, P p);

        }

    }

    public static class same_frame extends stack_map_frame {

        same_frame(int frame_type) {

            super(frame_type);

        }

        public <R, D> R accept(Visitor<R, D> visitor, D data) {

            return visitor.visit_same_frame(this, data);

        }

        public int getOffsetDelta() {

            return frame_type;

        }

    }

    public static class same_locals_1_stack_item_frame extends stack_map_frame {

        same_locals_1_stack_item_frame(int frame_type, ClassReader cr)

                throws IOException, InvalidStackMap {

            super(frame_type);

            stack = new verification_type_info[1];

            stack[0] = verification_type_info.read(cr);

        }

        @Override

        public int length() {

            return super.length() + stack[0].length();

        }

        public <R, D> R accept(Visitor<R, D> visitor, D data) {

            return visitor.visit_same_locals_1_stack_item_frame(this, data);

        }

        public int getOffsetDelta() {

            return frame_type - 64;

        }

        public final verification_type_info[] stack;

    }

    public static class same_locals_1_stack_item_frame_extended extends stack_map_frame {

        same_locals_1_stack_item_frame_extended(int frame_type, ClassReader cr)

                throws IOException, InvalidStackMap {

            super(frame_type);

            offset_delta = cr.readUnsignedShort();

            stack = new verification_type_info[1];

            stack[0] = verification_type_info.read(cr);

        }

        @Override

        public int length() {

            return super.length() + 2 + stack[0].length();

        }

        public <R, D> R accept(Visitor<R, D> visitor, D data) {

            return visitor.visit_same_locals_1_stack_item_frame_extended(this, data);

        }

        public int getOffsetDelta() {

            return offset_delta;

        }

        public final int offset_delta;

        public final verification_type_info[] stack;

    }

    public static class chop_frame extends stack_map_frame {

        chop_frame(int frame_type, ClassReader cr) throws IOException {

            super(frame_type);

            offset_delta = cr.readUnsignedShort();

        }

        @Override

        public int length() {

            return super.length() + 2;

        }

        public <R, D> R accept(Visitor<R, D> visitor, D data) {

            return visitor.visit_chop_frame(this, data);

        }

        public int getOffsetDelta() {

            return offset_delta;

        }

        public final int offset_delta;

    }

    public static class same_frame_extended extends stack_map_frame {

        same_frame_extended(int frame_type, ClassReader cr) throws IOException {

            super(frame_type);

            offset_delta = cr.readUnsignedShort();

        }

        @Override

        public int length() {

            return super.length() + 2;

        }

        public <R, D> R accept(Visitor<R, D> visitor, D data) {

            return visitor.visit_same_frame_extended(this, data);

        }

        public int getOffsetDelta() {

            return offset_delta;

        }

        public final int offset_delta;

    }

    public static class append_frame extends stack_map_frame {

        append_frame(int frame_type, ClassReader cr)

                throws IOException, InvalidStackMap {

            super(frame_type);

            offset_delta = cr.readUnsignedShort();

            locals = new verification_type_info[frame_type - 251];

            for (int i = 0; i < locals.length; i++)

                locals[i] = verification_type_info.read(cr);

        }

        @Override

        public int length() {

            int n = super.length() + 2;

            for (verification_type_info local: locals)

                n += local.length();

            return n;

        }

        public <R, D> R accept(Visitor<R, D> visitor, D data) {

            return visitor.visit_append_frame(this, data);

        }

        public int getOffsetDelta() {

            return offset_delta;

        }

        public final int offset_delta;

        public final verification_type_info[] locals;

    }

    public static class full_frame extends stack_map_frame {

        full_frame(int frame_type, ClassReader cr)

                throws IOException, InvalidStackMap {

            super(frame_type);

            offset_delta = cr.readUnsignedShort();

            number_of_locals = cr.readUnsignedShort();

            locals = new verification_type_info[number_of_locals];

            for (int i = 0; i < locals.length; i++)

                locals[i] = verification_type_info.read(cr);

            number_of_stack_items = cr.readUnsignedShort();

            stack = new verification_type_info[number_of_stack_items];

            for (int i = 0; i < stack.length; i++)

                stack[i] = verification_type_info.read(cr);

        }

        @Override

        public int length() {

            int n = super.length() + 2;

            for (verification_type_info local: locals)

                n += local.length();

            n += 2;

            for (verification_type_info item: stack)

                n += item.length();

            return n;

        }

        public <R, D> R accept(Visitor<R, D> visitor, D data) {

            return visitor.visit_full_frame(this, data);

        }

        public int getOffsetDelta() {

            return offset_delta;

        }

        public final int offset_delta;

        public final int number_of_locals;

        public final verification_type_info[] locals;

        public final int number_of_stack_items;

        public final verification_type_info[] stack;

    }

    public static class verification_type_info {

        public static final int ITEM_Top = 0;

        public static final int ITEM_Integer = 1;

        public static final int ITEM_Float = 2;

        public static final int ITEM_Long = 4;

        public static final int ITEM_Double = 3;

        public static final int ITEM_Null = 5;

        public static final int ITEM_UninitializedThis = 6;

        public static final int ITEM_Object = 7;

        public static final int ITEM_Uninitialized = 8;

        static verification_type_info read(ClassReader cr)

                throws IOException, InvalidStackMap {

            int tag = cr.readUnsignedByte();

            switch (tag) {

            case ITEM_Top:

            case ITEM_Integer:

            case ITEM_Float:

            case ITEM_Long:

            case ITEM_Double:

            case ITEM_Null:

            case ITEM_UninitializedThis:

                return new verification_type_info(tag);

            case ITEM_Object:

                return new Object_variable_info(cr);

            case ITEM_Uninitialized:

                return new Uninitialized_variable_info(cr);

            default:

                throw new InvalidStackMap("unrecognized verification_type_info tag");

            }

        }

        protected verification_type_info(int tag) {

            this.tag = tag;

        }

        public int length() {

            return 1;

        }

        public final int tag;

    }

    public static class Object_variable_info extends verification_type_info {

        Object_variable_info(ClassReader cr) throws IOException {

            super(ITEM_Object);

            cpool_index = cr.readUnsignedShort();

        }

        @Override

        public int length() {

            return super.length() + 2;

        }

        public final int cpool_index;

    }

    public static class Uninitialized_variable_info extends verification_type_info {

        Uninitialized_variable_info(ClassReader cr) throws IOException {

            super(ITEM_Uninitialized);

            offset = cr.readUnsignedShort();

        }

        @Override

        public int length() {

            return super.length() + 2;

        }

        public final int offset;

    }

}