src/main/java/net/pterodactylus/sonitus/io/IntegralWriteOutputStream.java

   1 /*
   2  * Sonitus - IntegralWriteOutputStream.java - Copyright © 2013 David Roden
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 package net.pterodactylus.sonitus.io;
  19
  20 import java.io.FilterOutputStream;
  21 import java.io.IOException;
  22 import java.io.OutputStream;
  23
  24 /**
  25  * {@link OutputStream} wrapper that always writes a multiple of a fixed amount
  26  * of bytes at once.
  27  *
  28  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  29  */
  30 public class IntegralWriteOutputStream extends FilterOutputStream {
  31
  32         /** The current in-process values. */
  33         private final byte[] buffer;
  34
  35         /** The next position of the buffer that will be written to. */
  36         private int bufferPosition;
  37
  38         /**
  39          * Creates a new integral write output stream.
  40          *
  41          * @param outputStream
  42          *              The output stream to wrap
  43          * @param integralSize
  44          *              The number of bytes to write at once
  45          */
  46         public IntegralWriteOutputStream(OutputStream outputStream, int integralSize) {
  47                 super(outputStream);
  48                 buffer = new byte[integralSize];
  49         }
  50
  51         //
  52         // OUTPUTSTREAM METHODS
  53         //
  54
  55         @Override
  56         public void write(int data) throws IOException {
  57                 buffer[bufferPosition++] = (byte) data;
  58                 if (bufferPosition == buffer.length) {
  59                         bufferPosition = 0;
  60                         out.write(buffer);
  61                 }
  62         }
  63
  64         @Override
  65         public void write(byte[] buffer) throws IOException {
  66                 write(buffer, 0, buffer.length);
  67         }
  68
  69         @Override
  70         public void write(byte[] buffer, int offset, int length) throws IOException {
  71                 /* are the some bytes in the current buffer? */
  72                 int sourceOffset = 0;
  73                 if (bufferPosition != 0) {
  74                         int bytesToCopy = Math.min(length, this.buffer.length - bufferPosition);
  75                         System.arraycopy(buffer, offset, this.buffer, bufferPosition, bytesToCopy);
  76                         sourceOffset += bytesToCopy;
  77                         bufferPosition += bytesToCopy;
  78                         if (bufferPosition == this.buffer.length) {
  79                                 bufferPosition = 0;
  80                                 out.write(this.buffer);
  81                         }
  82                 }
  83
  84                 /* write the largest possible chunk at once. */
  85                 int integralBytesLeft = (int) ((length - sourceOffset) / this.buffer.length) * this.buffer.length;
  86                 if (integralBytesLeft != 0) {
  87                         out.write(buffer, offset + sourceOffset, integralBytesLeft);
  88                 }
  89
  90                 /* are there some bytes left? */
  91                 sourceOffset += integralBytesLeft;
  92                 if (sourceOffset < length) {
  93                         System.arraycopy(buffer, offset + sourceOffset, this.buffer, 0, length - sourceOffset);
  94                         bufferPosition = length - sourceOffset;
  95                 }
  96         }
  97
  98 }