/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2011 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 org.objectweb.asm.tree;

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

import org.objectweb.asm.MethodVisitor;
import org.objectweb.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 Opcodes#V1_6 V1_6}.
 * 
 * @author Eric Bruneton
 */
public class FrameNode extends AbstractInsnNode {

  /**
   * The type of this frame. Must be {@link Opcodes#F_NEW} for expanded frames,
   * or {@link Opcodes#F_FULL}, {@link Opcodes#F_APPEND}, {@link Opcodes#F_CHOP}
   * , {@link Opcodes#F_SAME} or {@link Opcodes#F_APPEND},
   * {@link 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 MethodVisitor}).
   */
  public List<Object> 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 MethodVisitor}
   * ).
   */
  public List<Object> stack;

  public FrameNode() {
    super(-1);
    local = new ArrayList<>();
    stack = new ArrayList<>();

  }

  /**
   * Constructs a new {@link FrameNode}.
   * 
   * @param type
   *          the type of this frame. Must be {@link Opcodes#F_NEW} for expanded
   *          frames, or {@link Opcodes#F_FULL}, {@link Opcodes#F_APPEND},
   *          {@link Opcodes#F_CHOP}, {@link Opcodes#F_SAME} or
   *          {@link Opcodes#F_APPEND}, {@link 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 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 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 = new ArrayList<Object>(Arrays.asList(new Object[nLocal]));
      break;
    case Opcodes.F_SAME:
      break;
    case Opcodes.F_SAME1:
      this.stack = asList(1, stack);
      break;
    }
  }

  @Override
  public int getType() {
    return FRAME;
  }

  /**
   * Makes the given visitor visit this stack map frame.
   * 
   * @param mv
   *          a method visitor.
   */
  @Override
  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;
    }
  }

  @Override
  public AbstractInsnNode clone(final Map<LabelNode, LabelNode> labels) {
    FrameNode clone = new FrameNode();
    clone.type = type;
    if (local != null) {
      clone.local = new ArrayList<Object>();
      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<Object>();
      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 ArrayList<Object> asList(final int n, final Object[] o) {
    return new ArrayList<Object>(Arrays.asList(o).subList(0, n));
  }

  private static Object[] asArray(final List<Object> 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;
  }
}