package org.sim0mq.message;
   
   import org.djunits.unit.Unit;
   import org.sim0mq.Sim0MQException;
   import org.sim0mq.message.types.Sim0MQDisplayType;
   import org.sim0mq.message.types.Sim0MQUnitType;
   import org.sim0mq.message.types.TypesUtil;
   import org.sim0mq.message.util.EndianUtil;
   
  /**
   * Container for decoding a message to allow for easy buffer manipulation including the pointer.
   * <p>
   * Copyright (c) 2013-2017 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
   * BSD-style license. See <a href="http://sim0mq.org/docs/current/license.html">Sim0MQ License</a>.
   * </p>
   * $LastChangedDate: 2015-07-24 02:58:59 +0200 (Fri, 24 Jul 2015) $, @version $Revision: 1147 $, by $Author: averbraeck $,
   * initial version Aug 11, 2018 <br>
   * @author <a href="http://www.tbm.tudelft.nl/averbraeck">Alexander Verbraeck</a>
   */
  class MessageBuffer
  {
      /** the message content. */
      private byte[] message;
  
      /** the pointer into the message content. */
      private int pointer;
  
      /**
       * Create a message buffer for decoding.
       * @param message the message
       */
      MessageBuffer(final byte[] message)
      {
          this.message = message;
          this.pointer = 0;
      }
  
      /**
       * @return the pointer into the message buffer
       */
      public int getPointer()
      {
          return this.pointer;
      }
  
      /**
       * @return whether the buffer has more bytes to process
       */
      public boolean hasMore()
      {
          return this.pointer < this.message.length;
      }
  
      /**
       * @return the next byte in the buffer
       */
      public byte getByte()
      {
          return this.message[this.pointer++];
      }
  
      /**
       * @return the next short in the buffer
       */
      public short getShort()
      {
          short value = EndianUtil.decodeShort(this.message, this.pointer);
          this.pointer += 2;
          return value;
      }
  
      /**
       * @return the next int in the buffer
       */
      public int getInt()
      {
          int value = EndianUtil.decodeInt(this.message, this.pointer);
          this.pointer += 4;
          return value;
      }
  
      /**
       * @return the next long in the buffer
       */
      public long getLong()
      {
          long value = EndianUtil.decodeLong(this.message, this.pointer);
          this.pointer += 8;
          return value;
      }
  
      /**
       * @return the next float in the buffer
       */
      public float getFloat()
      {
          float value = EndianUtil.decodeFloat(this.message, this.pointer);
          this.pointer += 4;
          return value;
     }
 
     /**
      * @return the next double in the buffer
      */
     public double getDouble()
     {
         double value = EndianUtil.decodeDouble(this.message, this.pointer);
         this.pointer += 8;
         return value;
     }
 
     /**
      * @return the next boolean in the buffer
      */
     public boolean getBoolean()
     {
         return getByte() == 0 ? false : true;
     }
 
     /**
      * @return the next char with UTF8 in the buffer
      */
     public char getCharUTF8()
     {
         return (char) getByte();
     }
 
     /**
      * @return the next char with UTF16 in the buffer
      */
     public char getCharUTF16()
     {
         char value = EndianUtil.decodeChar(this.message, this.pointer);
         this.pointer += 2;
         return value;
     }
 
     /**
      * @return the next String with UTF8 in the buffer
      */
     public String getStringUTF8()
     {
         String s = EndianUtil.decodeUTF8String(this.message, this.pointer);
         this.pointer += 4 + s.length();
         return s;
     }
 
     /**
      * @return the next String with UTF16 in the buffer
      */
     public String getStringUTF16()
     {
         String s = EndianUtil.decodeUTF16String(this.message, this.pointer);
         this.pointer += 4 + 2 * s.length();
         return s;
     }
 
     /**
      * @return the next 1, 2, or 3 byte Unit in the buffer
      */
     public Unit<? extends Unit<?>> getUnit()
     {
         Unit<? extends Unit<?>> unit;
         Sim0MQUnitType unitType = Sim0MQUnitType.getUnitType(getByte());
         if (unitType.getCode() == 100) // money
         {
             unit = decodeMoneyUnit();
         }
         else if (unitType.getCode() >= 101 && unitType.getCode() <= 106)
         {
             unit = decodeMoneyPerUnit(unitType);
         }
         else
         {
             Sim0MQDisplayType displayType = Sim0MQDisplayType.getDisplayType(unitType, getByte());
             unit = displayType.getDjunitsType();
         }
         return unit;
     }
 
     /**
      * Decode the 2-byte Money unit in the message (code 100).
      * @return decoded money unit
      */
     private Unit<? extends Unit<?>> decodeMoneyUnit()
     {
         short moneyCode = getShort();
         Sim0MQDisplayType displayType = Sim0MQDisplayType.getDisplayType(Sim0MQUnitType.MONEY, moneyCode);
         return displayType.getDjunitsType();
     }
 
     /**
      * Decode the 2-byte MoneyPerUnit unit in the message (code 101 - 106).
      * @param unitType the unit type (e.g., MoneyPerArea)
      * @return decoded MoneyPerUnit unit
      */
     @SuppressWarnings("checkstyle:needbraces")
     private Unit<? extends Unit<?>> decodeMoneyPerUnit(final Sim0MQUnitType unitType)
     {
         short moneyCode = getShort();
         Sim0MQDisplayType moneyDisplayType = Sim0MQDisplayType.getDisplayType(Sim0MQUnitType.MONEY, moneyCode);
         byte perCode = getByte();
         Sim0MQDisplayType perDisplayType;
         if (unitType.getCode() == 101)
             perDisplayType = Sim0MQDisplayType.getDisplayType(Sim0MQUnitType.AREA, perCode);
         else if (unitType.getCode() == 102)
             perDisplayType = Sim0MQDisplayType.getDisplayType(Sim0MQUnitType.ENERGY, perCode);
         else if (unitType.getCode() == 103)
             perDisplayType = Sim0MQDisplayType.getDisplayType(Sim0MQUnitType.LENGTH, perCode);
         else if (unitType.getCode() == 104)
             perDisplayType = Sim0MQDisplayType.getDisplayType(Sim0MQUnitType.MASS, perCode);
         else if (unitType.getCode() == 105)
             perDisplayType = Sim0MQDisplayType.getDisplayType(Sim0MQUnitType.DURATION, perCode);
         else if (unitType.getCode() == 106)
             perDisplayType = Sim0MQDisplayType.getDisplayType(Sim0MQUnitType.VOLUME, perCode);
         else
             throw new RuntimeException(new Sim0MQException("Unknown MoneyPerUnit type with code " + unitType.getCode()));
         return TypesUtil.moneyPerUnitType(moneyDisplayType, perDisplayType);
     }
 
 }