Add support for .ogg files.

OpenRA.Mods.Common/AudioLoaders/OggLoader.cs

@@ -0,0 +1,133 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2021 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System;
+using System.IO;
+using NVorbis;
+using OpenRA.Primitives;
+
+namespace OpenRA.Mods.Common.AudioLoaders
+{
+	public class OggLoader : ISoundLoader
+	{
+		bool ISoundLoader.TryParseSound(Stream stream, out ISoundFormat sound)
+		{
+			try
+			{
+				sound = new OggFormat(stream);
+				return true;
+			}
+			catch
+			{
+				// Unsupported file
+			}
+
+			sound = null;
+			return false;
+		}
+	}
+
+	public sealed class OggFormat : ISoundFormat
+	{
+		public int SampleBits => 16;
+		public int Channels => reader.Channels;
+		public int SampleRate => reader.SampleRate;
+		public float LengthInSeconds => (float)reader.TotalTime.TotalSeconds;
+		public Stream GetPCMInputStream() { return new OggStream(new OggFormat(this)); }
+		public void Dispose() { reader.Dispose(); }
+
+		readonly VorbisReader reader;
+		readonly Stream stream;
+
+		public OggFormat(Stream stream)
+		{
+			this.stream = stream;
+			reader = new VorbisReader(stream);
+		}
+
+		OggFormat(OggFormat cloneFrom)
+		{
+			stream = SegmentStream.CreateWithoutOwningStream(cloneFrom.stream, 0, (int)cloneFrom.stream.Length);
+			reader = new VorbisReader(stream)
+			{
+				// Tell NVorbis to clip samples so we don't have to range-check during reading.
+				ClipSamples = true
+			};
+		}
+
+		public class OggStream : Stream
+		{
+			readonly OggFormat format;
+
+			// This buffer can be static because it can only be used by 1 instance per thread.
+			[ThreadStatic]
+			static float[] conversionBuffer = null;
+
+			public OggStream(OggFormat format)
+			{
+				this.format = format;
+			}
+
+			public override bool CanRead => true;
+			public override bool CanSeek => false;
+			public override bool CanWrite => false;
+
+			public override long Length => format.reader.TotalSamples;
+
+			public override long Position
+			{
+				get => format.reader.SamplePosition;
+				set => throw new NotImplementedException();
+			}
+
+			public override int Read(byte[] buffer, int offset, int count)
+			{
+				// Adjust count so it is in 16-bit samples instead of bytes.
+				count /= 2;
+
+				// Make sure we don't have an odd count.
+				count -= count % format.reader.Channels;
+
+				// Get the buffer, creating a new one if none exists or the existing one is too small.
+				var floatBuffer = conversionBuffer ?? (conversionBuffer = new float[count]);
+				if (floatBuffer.Length < count)
+					floatBuffer = conversionBuffer = new float[count];
+
+				// Let NVorbis do the actual reading.
+				var samples = format.reader.ReadSamples(floatBuffer, offset, count);
+
+				// Move the data back to the request buffer and convert to 16-bit signed samples for OpenAL.
+				for (var i = 0; i < samples; i++)
+				{
+					var conversion = (short)(floatBuffer[i] * 32767);
+					buffer[offset++] = (byte)(conversion & 255);
+					buffer[offset++] = (byte)(conversion >> 8);
+				}
+
+				// Adjust count back to bytes.
+				return samples * 2;
+			}
+
+			public override void Flush() { throw new NotImplementedException(); }
+			public override long Seek(long offset, SeekOrigin origin) { throw new NotImplementedException(); }
+			public override void SetLength(long value) { throw new NotImplementedException(); }
+			public override void Write(byte[] buffer, int offset, int count) { throw new NotImplementedException(); }
+
+			protected override void Dispose(bool disposing)
+			{
+				if (disposing)
+					format.reader.Dispose();
+
+				base.Dispose(disposing);
+			}
+		}
+	}
+}