/***
 * 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.List;
import java.util.Map;

import alterrs.asm.MethodVisitor;

/**
 * A node that represents a bytecode instruction. <i>An instruction can appear
 * at most once in at most one {@link InsnList} at a time</i>.
 * 
 * @author Eric Bruneton
 */
public abstract class AbstractInsnNode {

	/**
	 * The type of {@link InsnNode} instructions.
	 */
	public static final int INSN = 0;

	/**
	 * The type of {@link IntInsnNode} instructions.
	 */
	public static final int INT_INSN = 1;

	/**
	 * The type of {@link VarInsnNode} instructions.
	 */
	public static final int VAR_INSN = 2;

	/**
	 * The type of {@link TypeInsnNode} instructions.
	 */
	public static final int TYPE_INSN = 3;

	/**
	 * The type of {@link FieldInsnNode} instructions.
	 */
	public static final int FIELD_INSN = 4;

	/**
	 * The type of {@link MethodInsnNode} instructions.
	 */
	public static final int METHOD_INSN = 5;

	/**
	 * The type of {@link JumpInsnNode} instructions.
	 */
	public static final int JUMP_INSN = 6;

	/**
	 * The type of {@link LabelNode} "instructions".
	 */
	public static final int LABEL = 7;

	/**
	 * The type of {@link LdcInsnNode} instructions.
	 */
	public static final int LDC_INSN = 8;

	/**
	 * The type of {@link IincInsnNode} instructions.
	 */
	public static final int IINC_INSN = 9;

	/**
	 * The type of {@link TableSwitchInsnNode} instructions.
	 */
	public static final int TABLESWITCH_INSN = 10;

	/**
	 * The type of {@link LookupSwitchInsnNode} instructions.
	 */
	public static final int LOOKUPSWITCH_INSN = 11;

	/**
	 * The type of {@link MultiANewArrayInsnNode} instructions.
	 */
	public static final int MULTIANEWARRAY_INSN = 12;

	/**
	 * The type of {@link FrameNode} "instructions".
	 */
	public static final int FRAME = 13;

	/**
	 * The type of {@link LineNumberNode} "instructions".
	 */
	public static final int LINE = 14;

	/**
	 * The opcode of this instruction.
	 */
	protected int opcode;

	/**
	 * Previous instruction in the list to which this instruction belongs.
	 */
	AbstractInsnNode prev;

	/**
	 * Next instruction in the list to which this instruction belongs.
	 */
	AbstractInsnNode next;

	/**
	 * Index of this instruction in the list to which it belongs. The value of
	 * this field is correct only when {@link InsnList#cache} is not null. A
	 * value of -1 indicates that this instruction does not belong to any
	 * {@link InsnList}.
	 */
	int index;

	/**
	 * Constructs a new {@link AbstractInsnNode}.
	 * 
	 * @param opcode
	 *            the opcode of the instruction to be constructed.
	 */
	protected AbstractInsnNode(final int opcode) {
		this.opcode = opcode;
		this.index = -1;
	}

	/**
	 * Returns the opcode of this instruction.
	 * 
	 * @return the opcode of this instruction.
	 */
	public int getOpcode() {
		return opcode;
	}

	/**
	 * Returns the type of this instruction.
	 * 
	 * @return the type of this instruction, i.e. one the constants defined in
	 *         this class.
	 */
	public abstract int getType();

	/**
	 * Returns the previous instruction in the list to which this instruction
	 * belongs, if any.
	 * 
	 * @return the previous instruction in the list to which this instruction
	 *         belongs, if any. May be <tt>null</tt>.
	 */
	public AbstractInsnNode getPrevious() {
		return prev;
	}

	/**
	 * Returns the next instruction in the list to which this instruction
	 * belongs, if any.
	 * 
	 * @return the next instruction in the list to which this instruction
	 *         belongs, if any. May be <tt>null</tt>.
	 */
	public AbstractInsnNode getNext() {
		return next;
	}

	/**
	 * Makes the given code visitor visit this instruction.
	 * 
	 * @param cv
	 *            a code visitor.
	 */
	public abstract void accept(final MethodVisitor cv);

	/**
	 * Returns a copy of this instruction.
	 * 
	 * @param labels
	 *            a map from LabelNodes to cloned LabelNodes.
	 * @return a copy of this instruction. The returned instruction does not
	 *         belong to any {@link InsnList}.
	 */
	public abstract AbstractInsnNode clone(final Map labels);

	/**
	 * Returns the clone of the given label.
	 * 
	 * @param label
	 *            a label.
	 * @param map
	 *            a map from LabelNodes to cloned LabelNodes.
	 * @return the clone of the given label.
	 */
	static LabelNode clone(final LabelNode label, final Map map) {
		return (LabelNode) map.get(label);
	}

	/**
	 * Returns the clones of the given labels.
	 * 
	 * @param labels
	 *            a list of labels.
	 * @param map
	 *            a map from LabelNodes to cloned LabelNodes.
	 * @return the clones of the given labels.
	 */
	static LabelNode[] clone(final List labels, final Map map) {
		LabelNode[] clones = new LabelNode[labels.size()];
		for (int i = 0; i < clones.length; ++i) {
			clones[i] = (LabelNode) map.get(labels.get(i));
		}
		return clones;
	}
}
