/*

  * Copyright (c) 2005, 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 org.apidesign.javap;

 import java.io.*;

 import static org.apidesign.javap.RuntimeConstants.*;

 /* represents one entry of StackMapTable attribute

  */

 abstract class StackMapTableData {

     final int frameType;

     int offsetDelta;

     StackMapTableData(int frameType) {

         this.frameType = frameType;

     }

     abstract int getStackItemsCount();

     static class SameFrame extends StackMapTableData {

         SameFrame(int frameType, int offsetDelta) {

             super(frameType);

             this.offsetDelta = offsetDelta;

         }

         @Override

         int getStackItemsCount() {

             return 0;

         }

         @Override

         public String toString() {

             return "SAME"

                        + ((frameType == SAME_FRAME_EXTENDED)

                               ? "_FRAME_EXTENDED" : "")

                        + "(" + offsetDelta + ")";

         }

     }

     static class SameLocals1StackItem extends StackMapTableData {

         final int[] stack;

         SameLocals1StackItem(int frameType, int offsetDelta, int[] stack) {

             super(frameType);

             this.offsetDelta = offsetDelta;

             this.stack = stack;

         }

         @Override

         int getStackItemsCount() {

             return 1;

         }

         @Override

         public String toString() {

             return "SAME_LOCALS_1_STACK_ITEM"

                        + ((frameType == SAME_LOCALS_1_STACK_ITEM_EXTENDED)

                               ? "_EXTENDED" : "")

                        + "(" + offsetDelta + ")";

         }

     }

     static class ChopFrame extends StackMapTableData {

         ChopFrame(int frameType, int offsetDelta) {

             super(frameType);

             this.offsetDelta = offsetDelta;

         }

         @Override

         int getStackItemsCount() {

             return 0;

         }

         @Override

         public String toString() {

             return "CHOP(" + offsetDelta + ")";

         }

     }

     static class AppendFrame extends StackMapTableData {

         final int[] locals;

         AppendFrame(int frameType, int offsetDelta, int[] locals) {

             super(frameType);

             this.offsetDelta = offsetDelta;

             this.locals = locals;

         }

         @Override

         int getStackItemsCount() {

             return 0;

         }

         @Override

         public String toString() {

             return "APPEND(" + offsetDelta + ")";

         }

     }

     static class FullFrame extends StackMapTableData {

         final int[] locals;

         final int[] stack;

         FullFrame(int offsetDelta, int[] locals, int[] stack) {

             super(FULL_FRAME);

             this.offsetDelta = offsetDelta;

             this.locals = locals;

             this.stack = stack;

         }

         @Override

         int getStackItemsCount() {

             return stack.length;

         }

         @Override

         public String toString() {

             return "FULL(" + offsetDelta + ")";

         }

     }

     static StackMapTableData getInstance(DataInputStream in, MethodData method)

                   throws IOException {

         int frameType = in.readUnsignedByte();

         if (frameType < SAME_FRAME_BOUND) {

             // same_frame

             return new SameFrame(frameType, frameType);

         } else if (SAME_FRAME_BOUND <= frameType && frameType < SAME_LOCALS_1_STACK_ITEM_BOUND) {

             // same_locals_1_stack_item_frame

             // read additional single stack element

             return new SameLocals1StackItem(frameType,

                                             (frameType - SAME_FRAME_BOUND),

                                             StackMapData.readTypeArray(in, 1, method));

         } else if (frameType == SAME_LOCALS_1_STACK_ITEM_EXTENDED) {

             // same_locals_1_stack_item_extended

             return new SameLocals1StackItem(frameType,

                                             in.readUnsignedShort(),

                                             StackMapData.readTypeArray(in, 1, method));

         } else if (SAME_LOCALS_1_STACK_ITEM_EXTENDED < frameType  && frameType < SAME_FRAME_EXTENDED) {

             // chop_frame or same_frame_extended

             return new ChopFrame(frameType, in.readUnsignedShort());

         } else if (frameType == SAME_FRAME_EXTENDED) {

             // chop_frame or same_frame_extended

             return new SameFrame(frameType, in.readUnsignedShort());

         } else if (SAME_FRAME_EXTENDED < frameType  && frameType < FULL_FRAME) {

             // append_frame

             return new AppendFrame(frameType, in.readUnsignedShort(),

                                    StackMapData.readTypeArray(in, frameType - SAME_FRAME_EXTENDED, method));

         } else if (frameType == FULL_FRAME) {

             // full_frame

             int offsetDelta = in.readUnsignedShort();

             int locals_size = in.readUnsignedShort();

             int[] locals = StackMapData.readTypeArray(in, locals_size, method);

             int stack_size = in.readUnsignedShort();

             int[] stack = StackMapData.readTypeArray(in, stack_size, method);

             return new FullFrame(offsetDelta, locals, stack);

         } else {

             throw new ClassFormatError("unrecognized frame_type in StackMapTable");

         }

     }

 }