/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2007 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package alterrs.asm.tree;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;

import alterrs.asm.MethodVisitor;
import alterrs.asm.Opcodes;

/**
 * A node that represents a stack map frame. These nodes are pseudo instruction
 * nodes in order to be inserted in an instruction list. In fact these nodes
 * must(*) be inserted <i>just before</i> any instruction node <b>i</b> that
 * follows an unconditionnal branch instruction such as GOTO or THROW, that is
 * the target of a jump instruction, or that starts an exception handler block.
 * The stack map frame types must describe the values of the local variables and
 * of the operand stack elements <i>just before</i> <b>i</b> is executed. <br>
 * <br>
 * (*) this is mandatory only for classes whose version is greater than or equal
 * to {@link alterrs.asm.Opcodes#V1_6 V1_6}.
 * 
 * @author Eric Bruneton
 */
public class FrameNode extends AbstractInsnNode {

	/**
	 * The type of this frame. Must be {@link alterrs.asm.Opcodes#F_NEW} for
	 * expanded frames, or {@link alterrs.asm.Opcodes#F_FULL},
	 * {@link alterrs.asm.Opcodes#F_APPEND}, {@link alterrs.asm.Opcodes#F_CHOP},
	 * {@link alterrs.asm.Opcodes#F_SAME} or
	 * {@link alterrs.asm.Opcodes#F_APPEND}, {@link alterrs.asm.Opcodes#F_SAME1}
	 * for compressed frames.
	 */
	public int type;

	/**
	 * The types of the local variables of this stack map frame. Elements of
	 * this list can be Integer, String or LabelNode objects (for primitive,
	 * reference and uninitialized types respectively - see
	 * {@link alterrs.asm.MethodVisitor}).
	 */
	public List local;

	/**
	 * The types of the operand stack elements of this stack map frame. Elements
	 * of this list can be Integer, String or LabelNode objects (for primitive,
	 * reference and uninitialized types respectively - see
	 * {@link alterrs.asm.MethodVisitor}).
	 */
	public List stack;

	private FrameNode() {
		super(-1);
	}

	/**
	 * Constructs a new {@link FrameNode}.
	 * 
	 * @param type
	 *            the type of this frame. Must be
	 *            {@link alterrs.asm.Opcodes#F_NEW} for expanded frames, or
	 *            {@link alterrs.asm.Opcodes#F_FULL},
	 *            {@link alterrs.asm.Opcodes#F_APPEND},
	 *            {@link alterrs.asm.Opcodes#F_CHOP},
	 *            {@link alterrs.asm.Opcodes#F_SAME} or
	 *            {@link alterrs.asm.Opcodes#F_APPEND},
	 *            {@link alterrs.asm.Opcodes#F_SAME1} for compressed frames.
	 * @param nLocal
	 *            number of local variables of this stack map frame.
	 * @param local
	 *            the types of the local variables of this stack map frame.
	 *            Elements of this list can be Integer, String or LabelNode
	 *            objects (for primitive, reference and uninitialized types
	 *            respectively - see {@link alterrs.asm.MethodVisitor}).
	 * @param nStack
	 *            number of operand stack elements of this stack map frame.
	 * @param stack
	 *            the types of the operand stack elements of this stack map
	 *            frame. Elements of this list can be Integer, String or
	 *            LabelNode objects (for primitive, reference and uninitialized
	 *            types respectively - see {@link alterrs.asm.MethodVisitor}).
	 */
	public FrameNode(final int type, final int nLocal, final Object[] local,
			final int nStack, final Object[] stack) {
		super(-1);
		this.type = type;
		switch (type) {
		case Opcodes.F_NEW:
		case Opcodes.F_FULL:
			this.local = asList(nLocal, local);
			this.stack = asList(nStack, stack);
			break;
		case Opcodes.F_APPEND:
			this.local = asList(nLocal, local);
			break;
		case Opcodes.F_CHOP:
			this.local = Arrays.asList(new Object[nLocal]);
			break;
		case Opcodes.F_SAME:
			break;
		case Opcodes.F_SAME1:
			this.stack = asList(1, stack);
			break;
		}
	}

	public int getType() {
		return FRAME;
	}

	/**
	 * Makes the given visitor visit this stack map frame.
	 * 
	 * @param mv
	 *            a method visitor.
	 */
	public void accept(final MethodVisitor mv) {
		switch (type) {
		case Opcodes.F_NEW:
		case Opcodes.F_FULL:
			mv.visitFrame(type, local.size(), asArray(local), stack.size(),
					asArray(stack));
			break;
		case Opcodes.F_APPEND:
			mv.visitFrame(type, local.size(), asArray(local), 0, null);
			break;
		case Opcodes.F_CHOP:
			mv.visitFrame(type, local.size(), null, 0, null);
			break;
		case Opcodes.F_SAME:
			mv.visitFrame(type, 0, null, 0, null);
			break;
		case Opcodes.F_SAME1:
			mv.visitFrame(type, 0, null, 1, asArray(stack));
			break;
		}
	}

	public AbstractInsnNode clone(final Map labels) {
		FrameNode clone = new FrameNode();
		clone.type = type;
		if (local != null) {
			clone.local = new ArrayList();
			for (int i = 0; i < local.size(); ++i) {
				Object l = local.get(i);
				if (l instanceof LabelNode) {
					l = labels.get(l);
				}
				clone.local.add(l);
			}
		}
		if (stack != null) {
			clone.stack = new ArrayList();
			for (int i = 0; i < stack.size(); ++i) {
				Object s = stack.get(i);
				if (s instanceof LabelNode) {
					s = labels.get(s);
				}
				clone.stack.add(s);
			}
		}
		return clone;
	}

	// ------------------------------------------------------------------------

	private static List asList(final int n, final Object[] o) {
		return Arrays.asList(o).subList(0, n);
	}

	private static Object[] asArray(final List l) {
		Object[] objs = new Object[l.size()];
		for (int i = 0; i < objs.length; ++i) {
			Object o = l.get(i);
			if (o instanceof LabelNode) {
				o = ((LabelNode) o).getLabel();
			}
			objs[i] = o;
		}
		return objs;
	}
}
