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

   1 /*
   2  * Sonitus - SampleOutputStream.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 is aware of channels and samples and can
  26  * process samples before forwarding them to the wrapped output stream.
  27  *
  28  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  29  */
  30 public abstract class ProcessingOutputStream extends FilterOutputStream {
  31
  32         /** The number of channels. */
  33         private final int channels;
  34
  35         /** The current sample’s channel values. */
  36         private int[] currentSamples;
  37
  38         /** The index of the current channel. */
  39         private int currentSampleIndex;
  40
  41         /** The byte ofset of the current sample’s current channel. */
  42         private int currentOffset;
  43
  44         /** The current sample’s channel value. */
  45         private int currentSample;
  46
  47         /**
  48          * Creates a new processing output stream. Sample values are always assumed to
  49          * be 16 bits wide little-ending signed integers.
  50          *
  51          * @param outputStream
  52          *              The output stream to wrap
  53          * @param channels
  54          *              The number of channels
  55          */
  56         public ProcessingOutputStream(OutputStream outputStream, int channels) {
  57                 super(outputStream);
  58                 this.channels = channels;
  59                 currentSamples = new int[channels];
  60         }
  61
  62         //
  63         // OUTPUTSTREAM METHODS
  64         //
  65
  66         @Override
  67         public void write(int data) throws IOException {
  68                 currentSample = ((currentSample >> 8) & 0xff) | (data << 8);
  69                 if (++currentOffset == 2) {
  70                         currentOffset = 0;
  71                         currentSamples[currentSampleIndex++] = currentSample;
  72                         currentSample = 0;
  73                         if (currentSampleIndex == channels) {
  74                                 currentSampleIndex = 0;
  75                                 int[] newSamples = processSamples(currentSamples);
  76                                 for (int sampleIndex = 0; sampleIndex < newSamples.length; ++sampleIndex) {
  77                                         super.write(newSamples[sampleIndex] & 0xff);
  78                                         super.write(newSamples[sampleIndex] >> 8);
  79                                 }
  80                         }
  81                 }
  82         }
  83
  84         @Override
  85         public void write(byte[] buffer) throws IOException {
  86                 write(buffer, 0, buffer.length);
  87         }
  88
  89         @Override
  90         public void write(byte[] buffer, int offset, int length) throws IOException {
  91                 for (int index = 0; index < length; ++index) {
  92                         write(buffer[offset + index]);
  93                 }
  94         }
  95
  96         //
  97         // SUBCLASS METHODS
  98         //
  99
 100         /**
 101          * Processes the given sample.
 102          *
 103          * @param samples
 104          *              The channel values for a single sample
 105          * @return The processed sample’s channel values
 106          */
 107         protected abstract int[] processSamples(int[] samples);
 108
 109 }