lubomir@221: /*
lubomir@221:  * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
lubomir@221:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
lubomir@221:  *
lubomir@221:  * This code is free software; you can redistribute it and/or modify it
lubomir@221:  * under the terms of the GNU General Public License version 2 only, as
lubomir@221:  * published by the Free Software Foundation.  Oracle designates this
lubomir@221:  * particular file as subject to the "Classpath" exception as provided
lubomir@221:  * by Oracle in the LICENSE file that accompanied this code.
lubomir@221:  *
lubomir@221:  * This code is distributed in the hope that it will be useful, but WITHOUT
lubomir@221:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
lubomir@221:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
lubomir@221:  * version 2 for more details (a copy is included in the LICENSE file that
lubomir@221:  * accompanied this code).
lubomir@221:  *
lubomir@221:  * You should have received a copy of the GNU General Public License version
lubomir@221:  * 2 along with this work; if not, write to the Free Software Foundation,
lubomir@221:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
lubomir@221:  *
lubomir@221:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
lubomir@221:  * or visit www.oracle.com if you need additional information or have any
lubomir@221:  * questions.
lubomir@221:  */
lubomir@221: 
lubomir@221: package org.apidesign.javap;
lubomir@221: 
lubomir@221: public final class StackMapIterator {
lubomir@221:     private static final StackMapTableData INITIAL_FRAME =
lubomir@221:             new StackMapTableData(-1) {
lubomir@221:                 @Override
lubomir@221:                 int getStackItemsCount() {
lubomir@221:                     return 0;
lubomir@221:                 }
lubomir@221: 
lubomir@221:                 @Override
lubomir@221:                 public String toString() {
lubomir@221:                     return "INITIAL(0)";
lubomir@221:                 }
lubomir@221:             };
lubomir@221: 
lubomir@221:     private final StackMapTableData[] stackMapTable;
lubomir@221: 
lubomir@221:     private int nextFrameIndex;
lubomir@221:     private int lastFrameByteCodeOffset;
lubomir@221: 
lubomir@221:     private int byteCodeOffset;
lubomir@221: 
lubomir@221:     StackMapIterator(final StackMapTableData[] stackMapTable) {
lubomir@221:         this.stackMapTable = (stackMapTable != null)
lubomir@221:                                  ? stackMapTable
lubomir@221:                                  : new StackMapTableData[0];
lubomir@221:         this.lastFrameByteCodeOffset = -1;
lubomir@221:         advanceBy(0);
lubomir@221:     }
lubomir@221: 
lubomir@221:     public String getFrameAsString() {
lubomir@221:         return getCurrentFrame().toString();
lubomir@221:     }
lubomir@221: 
lubomir@221:     public int getFrameIndex() {
lubomir@221:         return nextFrameIndex;
lubomir@221:     }
lubomir@221: 
lubomir@221:     public int getFrameStackItemsCount() {
lubomir@221:         return getCurrentFrame().getStackItemsCount();
lubomir@221:     }
lubomir@221: 
lubomir@221:     public void advanceBy(final int numByteCodes) {
lubomir@221:         if (numByteCodes < 0) {
lubomir@221:             throw new IllegalStateException("Forward only iterator");
lubomir@221:         }
lubomir@221: 
lubomir@221:         byteCodeOffset += numByteCodes;
lubomir@221:         while ((nextFrameIndex < stackMapTable.length)
lubomir@221:                     && ((byteCodeOffset - lastFrameByteCodeOffset)
lubomir@221:                             >= (stackMapTable[nextFrameIndex].offsetDelta
lubomir@221:                                     + 1))) {
lubomir@221:             lastFrameByteCodeOffset +=
lubomir@221:                     stackMapTable[nextFrameIndex].offsetDelta + 1;
lubomir@221:             ++nextFrameIndex;
lubomir@221:         }
lubomir@221:     }
lubomir@221: 
lubomir@221:     public void advanceTo(final int nextByteCodeOffset) {
lubomir@221:         advanceBy(nextByteCodeOffset - byteCodeOffset);
lubomir@221:     }
lubomir@221: 
lubomir@221:     private StackMapTableData getCurrentFrame() {
lubomir@221:         return (nextFrameIndex == 0)
lubomir@221:                 ? INITIAL_FRAME
lubomir@221:                 : stackMapTable[nextFrameIndex - 1];
lubomir@221:     }
lubomir@221: }