BufferedWaveProvider configurable Read behaviour

ReadFully defaults to true and ensures bytes requested from count is always returned

NAudio/Wave/WaveProviders/BufferedWaveProvider.cs

@@ -1,6 +1,7 @@
 using System;
 using NAudio.Utils;
 
+// ReSharper disable once CheckNamespace
 namespace NAudio.Wave
 {
     /// <summary>
@@ -20,9 +21,16 @@ public class BufferedWaveProvider : IWaveProvider
         public BufferedWaveProvider(WaveFormat waveFormat)
         {
             this.waveFormat = waveFormat;
-            this.BufferLength = waveFormat.AverageBytesPerSecond * 5;
+            BufferLength = waveFormat.AverageBytesPerSecond * 5;
+            ReadFully = true;
         }
 
+        /// <summary>
+        /// If true, always read the amount of data requested, padding with zeroes if necessary
+        /// By default is set to true
+        /// </summary>
+        public bool ReadFully { get; set; }
+
         /// <summary>
         /// Buffer length in bytes
         /// </summary>
@@ -84,7 +92,7 @@ public void AddSamples(byte[] buffer, int offset, int count)
             // create buffer here to allow user to customise buffer length
             if (circularBuffer == null)
             { 
-                circularBuffer = new CircularBuffer(this.BufferLength);
+                circularBuffer = new CircularBuffer(BufferLength);
             }
 
             var written = circularBuffer.Write(buffer, offset, count);
@@ -103,14 +111,15 @@ public int Read(byte[] buffer, int offset, int count)
             int read = 0;
             if (circularBuffer != null) // not yet created
             { 
-                read = this.circularBuffer.Read(buffer, offset, count);
+                read = circularBuffer.Read(buffer, offset, count);
             }
-            if (read < count)
+            if (ReadFully && read < count)
             {
                 // zero the end of the buffer
                 Array.Clear(buffer, offset + read, count - read);
+                read = count;
             }
-            return count;
+            return read;
         }
 
         /// <summary>

NAudioTests/WaveStreams/BufferedWaveProviderTests.cs

@@ -1,6 +1,4 @@
-using System;
-using System.ComponentModel;
-using System.Linq;
+using System.Linq;
 using NAudio.Wave;
 using NUnit.Framework;
 
@@ -31,5 +29,50 @@ public void BufferedBytesAreReturned()
             Assert.AreEqual(readBuffer,data);
             Assert.AreEqual(0, bwp.BufferedBytes);
         }
+
+        [Test]
+        public void EmptyBufferCanReturnZeroFromRead()
+        {
+            var bwp = new BufferedWaveProvider(new WaveFormat());
+            bwp.ReadFully = false;
+            var buffer = new byte[44100];
+            var read = bwp.Read(buffer, 0, buffer.Length);
+            Assert.AreEqual(0, read);
+        }
+
+        [Test]
+        public void PartialReadsPossibleWithReadFullyFalse()
+        {
+            var bwp = new BufferedWaveProvider(new WaveFormat());
+            bwp.ReadFully = false;
+            var buffer = new byte[44100];
+            bwp.AddSamples(buffer, 0, 2000);
+            var read = bwp.Read(buffer, 0, buffer.Length);
+            Assert.AreEqual(2000, read);
+            Assert.AreEqual(0, bwp.BufferedBytes);
+        }
+
+        [Test]
+        public void FullReadsByDefault()
+        {
+            var bwp = new BufferedWaveProvider(new WaveFormat());
+            var buffer = new byte[44100];
+            bwp.AddSamples(buffer, 0, 2000);
+            var read = bwp.Read(buffer, 0, buffer.Length);
+            Assert.AreEqual(buffer.Length, read);
+            Assert.AreEqual(0, bwp.BufferedBytes);
+        }
+
+        [Test]
+        public void WhenBufferHasMoreThanNeededReadFully()
+        {
+            var bwp = new BufferedWaveProvider(new WaveFormat());
+            var buffer = new byte[44100];
+            bwp.AddSamples(buffer, 0, 5000);
+            var read = bwp.Read(buffer, 0, 2000);
+            Assert.AreEqual(2000, read);
+            Assert.AreEqual(3000, bwp.BufferedBytes);
+        }
+
     }
 }

RELEASE_NOTES.md

@@ -20,6 +20,10 @@
   * RawSourceStream handles end of stream better
   * PropVariant supports VT_BOOL
   * Better handling of exceptions in WaveFileReader constructor
+  * WasapiOut default constructor (uses default device, shared mode)
+  * WasapiCapture and WasapiLoopbackCapture can report capture state
+  * BufferedWaveProvider can be configured to not fully read if no data is available
+  * WasapiOut can report the default mix format for shared mode
 
 #### 1.7.3 5 Mar 2015