/*
    * Copyright (C) 2007 The Guava Authors
    *
    * Licensed 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 com.google.common.io;
  
  import com.google.common.annotations.Beta;
  import com.google.common.base.Preconditions;
  import com.google.common.primitives.Longs;
  
  import java.io.DataOutput;
  import java.io.DataOutputStream;
  import java.io.FilterOutputStream;
  import java.io.IOException;
  import java.io.OutputStream;
  
  /**
   * An implementation of {@link DataOutput} that uses little-endian byte ordering
   * for writing {@code char}, {@code short}, {@code int}, {@code float}, {@code
   * double}, and {@code long} values.
   * <p>
   * <b>Note:</b> This class intentionally violates the specification of its
   * supertype {@code DataOutput}, which explicitly requires big-endian byte
   * order.
   *
   * @author Chris Nokleberg
   * @author Keith Bottner
   * @since 8.0
   */
  @Beta
  public class LittleEndianDataOutputStream extends FilterOutputStream
      implements DataOutput {
  
    /**
     * Creates a {@code LittleEndianDataOutputStream} that wraps the given stream.
     *
     * @param out the stream to delegate to
     */
    public LittleEndianDataOutputStream(OutputStream out) {
      super(new DataOutputStream(Preconditions.checkNotNull(out)));
    }
  
    @Override public void write(byte[] b, int off, int len) throws IOException {
      // Override slow FilterOutputStream impl
      out.write(b, off, len);
    }
  
    @Override public void writeBoolean(boolean v) throws IOException {
      ((DataOutputStream) out).writeBoolean(v);
    }
  
    @Override public void writeByte(int v) throws IOException {
      ((DataOutputStream) out).writeByte(v);
    }
  
    /**
     * @deprecated The semantics of {@code writeBytes(String s)} are considered
     *             dangerous. Please use {@link #writeUTF(String s)},
     *             {@link #writeChars(String s)} or another write method instead.
     */
    @Deprecated
    @Override public void writeBytes(String s) throws IOException {
      ((DataOutputStream) out).writeBytes(s);
    }
  
    /**
     * Writes a char as specified by {@link DataOutputStream#writeChar(int)},
     * except using little-endian byte order.
     *
     * @throws IOException if an I/O error occurs
     */
    @Override public void writeChar(int v) throws IOException {
      writeShort(v);
    }
  
    /**
     * Writes a {@code String} as specified by
     * {@link DataOutputStream#writeChars(String)}, except each character is
     * written using little-endian byte order.
     *
     * @throws IOException if an I/O error occurs
     */
    @Override public void writeChars(String s) throws IOException {
      for (int i = 0; i < s.length(); i++) {
        writeChar(s.charAt(i));
      }
    }
 
   /**
    * Writes a {@code double} as specified by
    * {@link DataOutputStream#writeDouble(double)}, except using little-endian
    * byte order.
    *
    * @throws IOException if an I/O error occurs
    */
   @Override public void writeDouble(double v) throws IOException {
     writeLong(Double.doubleToLongBits(v));
   }
 
   /**
    * Writes a {@code float} as specified by
    * {@link DataOutputStream#writeFloat(float)}, except using little-endian byte
    * order.
    *
    * @throws IOException if an I/O error occurs
    */
   @Override public void writeFloat(float v) throws IOException {
     writeInt(Float.floatToIntBits(v));
   }
 
   /**
    * Writes an {@code int} as specified by
    * {@link DataOutputStream#writeInt(int)}, except using little-endian byte
    * order.
    *
    * @throws IOException if an I/O error occurs
    */
   @Override public void writeInt(int v) throws IOException {
     out.write(0xFF & v);
     out.write(0xFF & (v >> 8));
     out.write(0xFF & (v >> 16));
     out.write(0xFF & (v >> 24));
   }
 
   /**
    * Writes a {@code long} as specified by
    * {@link DataOutputStream#writeLong(long)}, except using little-endian byte
    * order.
    *
    * @throws IOException if an I/O error occurs
    */
   @Override public void writeLong(long v) throws IOException {
     byte[] bytes = Longs.toByteArray(Long.reverseBytes(v));
     write(bytes, 0, bytes.length);
   }
 
   /**
    * Writes a {@code short} as specified by
    * {@link DataOutputStream#writeShort(int)}, except using little-endian byte
    * order.
    *
    * @throws IOException if an I/O error occurs
    */
   @Override public void writeShort(int v) throws IOException {
     out.write(0xFF & v);
     out.write(0xFF & (v >> 8));
   }
 
   @Override public void writeUTF(String str) throws IOException {
     ((DataOutputStream) out).writeUTF(str);
   }
 
   // Overriding close() because FilterOutputStream's close() method pre-JDK8 has bad behavior:
   // it silently ignores any exception thrown by flush(). Instead, just close the delegate stream.
   // It should flush itself if necessary.
   @Override public void close() throws IOException {
     out.close();
   }
 }