package nl.tudelft.simulation.dsol.animation.gis.io;
   
   import java.io.DataInput;
   import java.io.DataInputStream;
   import java.io.IOException;
   import java.io.InputStream;
   
   /**
    * This class enables the object inputstream to be switched from big endian (default in Java) to little endian. The class works
   * exactly like an ObjectInputStream.
   * <p>
   * Copyright (c) 2020-2023 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See
   * for project information <a href="https://simulation.tudelft.nl/dsol/manual/" target="_blank">DSOL Manual</a>. The DSOL
   * project is distributed under a three-clause BSD-style license, which can be found at
   * <a href="https://https://simulation.tudelft.nl/dsol/docs/latest/license.html" target="_blank">DSOL License</a>.
   * </p>
   * @author <a href="https://www.tudelft.nl/averbraeck">Alexander Verbraeck</a>
   */
  public class ObjectEndianInputStream implements DataInput
  {
      /** the datainput stream. */
      private DataInputStream dataInputStream;
  
      /** the inputStream. */
      private InputStream inputStream;
  
      /** an 8byte buffer. */
      private byte[] buffer = new byte[8];
  
      /** the code. */
      private Endianness endianness = Endianness.BIG_ENDIAN;
  
      /**
       * constructs a new ObjectEndianInputStream.
       * @param inputStream InputStream; the inputStream to use
       */
      public ObjectEndianInputStream(final InputStream inputStream)
      {
          this.inputStream = inputStream;
          this.dataInputStream = new DataInputStream(inputStream);
      }
  
      /** {@inheritDoc} */
      @Override
      public short readShort() throws IOException
      {
          if (this.endianness.equals(Endianness.BIG_ENDIAN))
          {
              return this.dataInputStream.readShort();
          }
          this.dataInputStream.readFully(this.buffer, 0, 2);
          return (short) ((this.buffer[1] & 0xff) << 8 | (this.buffer[0] & 0xff));
      }
  
      /** {@inheritDoc} */
      @Override
      public int readUnsignedShort() throws IOException
      {
          if (this.endianness.equals(Endianness.BIG_ENDIAN))
          {
              return this.dataInputStream.readUnsignedShort();
          }
          this.dataInputStream.readFully(this.buffer, 0, 2);
          return ((this.buffer[1] & 0xff) << 8 | (this.buffer[0] & 0xff));
      }
  
      /** {@inheritDoc} */
      @Override
      public char readChar() throws IOException
      {
          if (this.endianness.equals(Endianness.BIG_ENDIAN))
          {
              return this.dataInputStream.readChar();
          }
          this.dataInputStream.readFully(this.buffer, 0, 2);
          return (char) ((this.buffer[1] & 0xff) << 8 | (this.buffer[0] & 0xff));
      }
  
      /** {@inheritDoc} */
      @Override
      public int readInt() throws IOException
      {
          if (this.endianness.equals(Endianness.BIG_ENDIAN))
          {
              return this.dataInputStream.readInt();
          }
          this.dataInputStream.readFully(this.buffer, 0, 4);
          return (this.buffer[3]) << 24 | (this.buffer[2] & 0xff) << 16 | (this.buffer[1] & 0xff) << 8 | (this.buffer[0] & 0xff);
      }
  
      /** {@inheritDoc} */
      @Override
      public long readLong() throws IOException
      {
          if (this.endianness.equals(Endianness.BIG_ENDIAN))
          {
              return this.dataInputStream.readLong();
          }
          this.dataInputStream.readFully(this.buffer, 0, 8);
         return (long) (this.buffer[7]) << 56 | (long) (this.buffer[6] & 0xff) << 48 | (long) (this.buffer[5] & 0xff) << 40
                 | (long) (this.buffer[4] & 0xff) << 32 | (long) (this.buffer[3] & 0xff) << 24
                 | (long) (this.buffer[2] & 0xff) << 16 | (long) (this.buffer[1] & 0xff) << 8 | (this.buffer[0] & 0xff);
     }
 
     /** {@inheritDoc} */
     @Override
     public float readFloat() throws IOException
     {
         if (this.endianness.equals(Endianness.BIG_ENDIAN))
         {
             return this.dataInputStream.readFloat();
         }
         return Float.intBitsToFloat(readInt());
     }
 
     /** {@inheritDoc} */
     @Override
     public double readDouble() throws IOException
     {
         if (this.endianness.equals(Endianness.BIG_ENDIAN))
         {
             return this.dataInputStream.readDouble();
         }
         return Double.longBitsToDouble(readLong());
     }
 
     /**
      * reads b from the stream.
      * @param b byte[]; byte
      * @return in the value
      * @throws IOException on failure
      */
     public int read(final byte[] b) throws IOException
     {
         return this.inputStream.read(b);
     }
 
     /**
      * reads b from the stream.
      * @param b byte[]; byte
      * @param off int; offset
      * @param len int; length
      * @return in the value
      * @throws IOException on failure
      */
     public int read(final byte[] b, final int off, final int len) throws IOException
     {
         return this.inputStream.read(b, off, len);
     }
 
     /** {@inheritDoc} */
     @Override
     public void readFully(final byte[] b) throws IOException
     {
         this.dataInputStream.readFully(b, 0, b.length);
     }
 
     /** {@inheritDoc} */
     @Override
     public void readFully(final byte[] b, final int off, final int len) throws IOException
     {
         this.dataInputStream.readFully(b, off, len);
     }
 
     /** {@inheritDoc} */
     @Override
     public int skipBytes(final int n) throws IOException
     {
         return this.dataInputStream.skipBytes(n);
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean readBoolean() throws IOException
     {
         return this.dataInputStream.readBoolean();
     }
 
     /** {@inheritDoc} */
     @Override
     public byte readByte() throws IOException
     {
         return this.dataInputStream.readByte();
     }
 
     /** {@inheritDoc} */
     @Override
     public int readUnsignedByte() throws IOException
     {
         return this.dataInputStream.readUnsignedByte();
     }
 
     /** {@inheritDoc} */
     @Override
     public String readUTF() throws IOException
     {
         return this.dataInputStream.readUTF();
     }
 
     /** {@inheritDoc} */
     @Override
     public String readLine()
     {
         throw new UnsupportedOperationException("Binary reading does not support readLine method");
     }
 
     /**
      * reads UTF from the stream.
      * @param dataInput DataInput; data input
      * @return String the value
      * @throws IOException on read failure
      */
     public static final String readUTF(final DataInput dataInput) throws IOException
     {
         return DataInputStream.readUTF(dataInput);
     }
 
     /**
      * @throws IOException on close failure
      */
     public void close() throws IOException
     {
         this.dataInputStream.close();
     }
 
     /**
      * Return the Endianness, i.e., big endian or little endian encoding.
      * @return Endianness; big endian or little endian encoding
      */
     public Endianness getEndianness()
     {
         return this.endianness;
     }
 
     /**
      * Set the Endianness, i.e., big endian or little endian encoding.
      * @param endianness Endianness; big endian or little endian encoding
      */
     public void setEndianness(final Endianness endianness)
     {
         this.endianness = endianness;
     }
 
 }