pcm/Resampler: add method Reset()

src/pcm/GlueResampler.cxx

@@ -65,6 +65,12 @@ GluePcmResampler::Close()
 	resampler->Close();
 }
 
+void
+GluePcmResampler::Reset()
+{
+	resampler->Reset();
+}
+
 ConstBuffer<void>
 GluePcmResampler::Resample(ConstBuffer<void> src)
 {

src/pcm/GlueResampler.hxx

@@ -55,6 +55,11 @@ public:
 		return output_sample_format;
 	}
 
+	/**
+	 * @see PcmResampler::Reset()
+	 */
+	void Reset();
+
 	ConstBuffer<void> Resample(ConstBuffer<void> src);
 };
 

src/pcm/LibsamplerateResampler.cxx

@@ -114,6 +114,12 @@ LibsampleratePcmResampler::Close()
 	state = src_delete(state);
 }
 
+void
+LibsampleratePcmResampler::Reset()
+{
+	src_reset(state);
+}
+
 inline ConstBuffer<float>
 LibsampleratePcmResampler::Resample2(ConstBuffer<float> src)
 {

src/pcm/LibsamplerateResampler.hxx

@@ -44,6 +44,7 @@ class LibsampleratePcmResampler final : public PcmResampler {
 public:
 	AudioFormat Open(AudioFormat &af, unsigned new_sample_rate) override;
 	void Close() override;
+	void Reset() override;
 	ConstBuffer<void> Resample(ConstBuffer<void> src) override;
 
 private:

src/pcm/Resampler.hxx

@@ -55,6 +55,12 @@ public:
 	virtual void Close() = 0;
 
 	/**
+	 * Reset the filter's state, e.g. drop/flush buffers.
+	 */
+	virtual void Reset() {
+	}
+
+	/**
 	 * Resamples a block of PCM data.
 	 *
 	 * @param src the input buffer