/*
    * 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.bcel.generic;
  
  import java.util.Objects;
  
  import org.apache.bcel.Const;
  
  /**
   * Wrapper class for push operations, which are implemented either as BIPUSH, LDC or xCONST_n instructions.
   */
  public final class PUSH implements CompoundInstruction, VariableLengthInstruction, InstructionConstants {
  
      private final Instruction instruction;
  
      /**
       * Pushes an array type constant, for example {@code int[].class}, {@code String[].class}, and so on.
       *
       * @param cp generated constant pool.
       * @param value to be pushed.
       * @since 6.7.0
       */
      public PUSH(final ConstantPoolGen cp, final ArrayType value) {
          if (value == null) {
              instruction = InstructionConst.ACONST_NULL;
          } else {
              instruction = new LDC(cp.addArrayClass(value));
          }
      }
  
     /**
       * @param cp Constant pool
       * @param value to be pushed
       */
      public PUSH(final ConstantPoolGen cp, final boolean value) {
          Objects.requireNonNull(cp, "cp");
          instruction = InstructionConst.getInstruction(Const.ICONST_0 + (value ? 1 : 0));
      }
  
      /**
       * @param cp Constant pool
       * @param value to be pushed
       */
      public PUSH(final ConstantPoolGen cp, final Boolean value) {
          this(cp, value.booleanValue());
      }
  
      /**
       * creates a push object from a Character value. Warning: Make sure not to attempt to allow autoboxing to create this
       * value parameter, as an alternative constructor will be called
       *
       * @param cp Constant pool
       * @param value to be pushed
       */
      public PUSH(final ConstantPoolGen cp, final Character value) {
          this(cp, value.charValue());
      }
  
      /**
       * @param cp Constant pool
       * @param value to be pushed
       */
      public PUSH(final ConstantPoolGen cp, final double value) {
          if (value == 0.0) {
              instruction = InstructionConst.DCONST_0;
          } else if (value == 1.0) {
              instruction = InstructionConst.DCONST_1;
          } else {
              instruction = new LDC2_W(cp.addDouble(value));
          }
      }
  
      /**
       * @param cp Constant pool
       * @param value to be pushed
       */
      public PUSH(final ConstantPoolGen cp, final float value) {
          if (value == 0.0) {
              instruction = InstructionConst.FCONST_0;
          } else if (value == 1.0) {
              instruction = InstructionConst.FCONST_1;
          } else if (value == 2.0) {
              instruction = InstructionConst.FCONST_2;
          } else {
              instruction = new LDC(cp.addFloat(value));
         }
     }
 
     /**
      * This constructor also applies for values of type short, char, byte
      *
      * @param cp Constant pool
      * @param value to be pushed
      */
     public PUSH(final ConstantPoolGen cp, final int value) {
         if (value >= -1 && value <= 5) {
             instruction = InstructionConst.getInstruction(Const.ICONST_0 + value);
         } else if (Instruction.isValidByte(value)) {
             instruction = new BIPUSH((byte) value);
         } else if (Instruction.isValidShort(value)) {
             instruction = new SIPUSH((short) value);
         } else {
             instruction = new LDC(cp.addInteger(value));
         }
     }
 
     /**
      * @param cp Constant pool
      * @param value to be pushed
      */
     public PUSH(final ConstantPoolGen cp, final long value) {
         if (value == 0) {
             instruction = InstructionConst.LCONST_0;
         } else if (value == 1) {
             instruction = InstructionConst.LCONST_1;
         } else {
             instruction = new LDC2_W(cp.addLong(value));
         }
     }
 
     /**
      * @param cp Constant pool
      * @param value to be pushed
      */
     public PUSH(final ConstantPoolGen cp, final Number value) {
         if (value instanceof Integer || value instanceof Short || value instanceof Byte) {
             instruction = new PUSH(cp, value.intValue()).instruction;
         } else if (value instanceof Double) {
             instruction = new PUSH(cp, value.doubleValue()).instruction;
         } else if (value instanceof Float) {
             instruction = new PUSH(cp, value.floatValue()).instruction;
         } else if (value instanceof Long) {
             instruction = new PUSH(cp, value.longValue()).instruction;
         } else {
             throw new ClassGenException("What's this: " + value);
         }
     }
 
     /**
      *
      * @param cp
      * @param value
      * @since 6.0
      */
     public PUSH(final ConstantPoolGen cp, final ObjectType value) {
         if (value == null) {
             instruction = InstructionConst.ACONST_NULL;
         } else {
             instruction = new LDC(cp.addClass(value));
         }
     }
 
     /**
      * @param cp Constant pool
      * @param value to be pushed
      */
     public PUSH(final ConstantPoolGen cp, final String value) {
         if (value == null) {
             instruction = InstructionConst.ACONST_NULL;
         } else {
             instruction = new LDC(cp.addString(value));
         }
     }
 
     public Instruction getInstruction() {
         return instruction;
     }
 
     @Override
     public InstructionList getInstructionList() {
         return new InstructionList(instruction);
     }
 
     /**
      * @return mnemonic for instruction
      */
     @Override
     public String toString() {
         return instruction + " (PUSH)";
     }
 }