/*

  * Licensed to the Apache Software Foundation (ASF) under one or more

  * contributor license agreements.  See the NOTICE file distributed with

  * this work for additional information regarding copyright ownership.

  * The ASF licenses this file to You under the Apache License, Version 2.0

  * (the "License"); you may not use this file except in compliance with

  * the License.  You may obtain a copy of the License at

  *

  *      http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.apache.commons.nabla.forward.instructions;

 import org.apache.commons.math3.analysis.differentiation.DerivativeStructure;

 import org.apache.commons.nabla.DifferentiationException;

 import org.apache.commons.nabla.forward.analysis.InstructionsTransformer;

 import org.apache.commons.nabla.forward.analysis.MethodDifferentiator;

 import org.objectweb.asm.Opcodes;

 import org.objectweb.asm.Type;

 import org.objectweb.asm.tree.AbstractInsnNode;

 import org.objectweb.asm.tree.InsnList;

 import org.objectweb.asm.tree.InsnNode;

 import org.objectweb.asm.tree.LdcInsnNode;

 import org.objectweb.asm.tree.MethodInsnNode;

 import org.objectweb.asm.tree.TypeInsnNode;

 import org.objectweb.asm.tree.VarInsnNode;

 /** Differentiation transformer for promoting a double on the stack

  * to a derivative structure.

  * @version $Id$

  */

 public class WideningTransformer implements InstructionsTransformer {

     /** Simple constructor.

      */

     public WideningTransformer() {

     }

     /** {@inheritDoc} */

     public InsnList getReplacement(final AbstractInsnNode insn,

                                    final MethodDifferentiator methodDifferentiator)

         throws DifferentiationException {

         final InsnList list = new InsnList();

         // copy the instruction creating the double (DCONST_0, DCONST_1, LDC, I2D, L2D or F2D)

         if (insn.getOpcode() == Opcodes.LDC) {

             list.add(new LdcInsnNode(((LdcInsnNode) insn).cst));

         } else {

             list.add(new InsnNode(insn.getOpcode()));

         }

         // operand stack initial state: d

         list.add(new TypeInsnNode(Opcodes.NEW,

                                   Type.getInternalName(DerivativeStructure.class)));      // => d y_ds

         list.add(new InsnNode(Opcodes.DUP_X2));                                           // => y_ds d y_ds

         list.add(new InsnNode(Opcodes.DUP_X2));                                           // => y_ds y_ds d y_ds

         list.add(new InsnNode(Opcodes.POP));                                              // => y_ds y_ds d

         list.add(new VarInsnNode(Opcodes.ALOAD, methodDifferentiator.getInputDSIndex())); // => y_ds y_ds d x_ds

         list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL,

                                     Type.getInternalName(DerivativeStructure.class),

                                     "getFreeParameters",

                                     Type.getMethodDescriptor(Type.INT_TYPE)));            // => y_ds y_ds d params

         list.add(new VarInsnNode(Opcodes.ALOAD, 1));                                      // => y_ds y_ds d params x_ds

         list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL,

                                     Type.getInternalName(DerivativeStructure.class),

                                     "getOrder",

                                     Type.getMethodDescriptor(Type.INT_TYPE)));            // => y_ds y_ds d params order

         list.add(new InsnNode(Opcodes.DUP2_X2));                                          // => y_ds y_ds params order d params order

         list.add(new InsnNode(Opcodes.POP2));                                             // => y_ds y_ds params order d

         list.add(new MethodInsnNode(Opcodes.INVOKESPECIAL,

                                     Type.getInternalName(DerivativeStructure.class),

                                     "<init>",

                                     Type.getMethodDescriptor(Type.VOID_TYPE,

                                                              Type.INT_TYPE,

                                                              Type.INT_TYPE,

                                                              Type.DOUBLE_TYPE)));         // => y_ds

         return list;

     }

 }