Initial release

engine/vendor/vst3sdk/public.sdk/source/vst/utility/processdataslicer.h

@@ -0,0 +1,111 @@
+//-----------------------------------------------------------------------------
+// Flags       : clang-format SMTGSequencer
+// Project     : VST SDK
+//
+// Category    : Helpers
+// Filename    : public.sdk/source/vst/utility/processdataslicer.h
+// Created by  : Steinberg, 04/2021
+// Description : Process the process data in slices
+//
+//-----------------------------------------------------------------------------
+// This file is part of a Steinberg SDK. It is subject to the license terms
+// in the LICENSE file found in the top-level directory of this distribution
+// and at www.steinberg.net/sdklicenses.
+// No part of the SDK, including this file, may be copied, modified, propagated,
+// or distributed except according to the terms contained in the LICENSE file.
+//-----------------------------------------------------------------------------
+
+#pragma once
+
+#include "pluginterfaces/vst/ivstaudioprocessor.h"
+
+//------------------------------------------------------------------------
+namespace Steinberg {
+namespace Vst {
+
+//------------------------------------------------------------------------
+/** Process Data Slicer
+ *
+ *	Cuts the VST process data into slices to process
+ *
+ *	Example:
+ *	\code{.cpp}
+ *	tresult PLUGIN_API Processor::process (ProcessData& data)
+ *	{
+ *		ProcessDataSlicer slicer (32);
+ *		slicer.process<SymbolicSampleSizes::kSample32> (data, [&] (ProcessData& data) {
+ *			doSlicedProcessing (data); // data.numSamples <= 32
+ *		});
+ *	}
+ *	\endcode
+ */
+class ProcessDataSlicer
+{
+public:
+	/** Constructor
+	 *
+	 *	@param inSliceSice slice size in samples
+	 */
+	ProcessDataSlicer (int32 inSliceSize = 8) : sliceSize (inSliceSize) {}
+
+//------------------------------------------------------------------------
+	/** Process the data
+	 *
+	 *	@tparam SampleSize sample size 32 or 64 bit processing
+	 *	@tparam DoProcessCallback the callback proc
+	 *	@param data Process data
+	 *	@param doProcessing process callback
+	 */
+	template <SymbolicSampleSizes SampleSize, typename DoProcessCallback>
+	void process (ProcessData& data, DoProcessCallback doProcessing) noexcept
+	{
+		stopIt = false;
+		auto numSamples = data.numSamples;
+		auto samplesLeft = data.numSamples;
+		while (samplesLeft > 0 && !stopIt)
+		{
+			auto currentSliceSize = samplesLeft > sliceSize ? sliceSize : samplesLeft;
+
+			data.numSamples = currentSliceSize;
+			doProcessing (data);
+
+			advanceBuffers<SampleSize> (data.inputs, data.numInputs, currentSliceSize);
+			advanceBuffers<SampleSize> (data.outputs, data.numOutputs, currentSliceSize);
+			samplesLeft -= currentSliceSize;
+		}
+		// revert buffer pointers (otherwise some hosts may use these wrong pointers)
+		advanceBuffers<SampleSize> (data.inputs, data.numInputs, -(numSamples - samplesLeft));
+		advanceBuffers<SampleSize> (data.outputs, data.numOutputs, -(numSamples - samplesLeft));
+		data.numSamples = numSamples;
+	}
+
+	/** Stop the slice process
+	 *
+	 *	If you want to break the slice processing early, you have to capture the slicer in the
+	 *	DoProcessCallback and call the stop method.
+	 */
+	void stop () noexcept { stopIt = true; }
+
+private:
+	template <SymbolicSampleSizes SampleSize>
+	void advanceBuffers (AudioBusBuffers* buffers, int32 numBuffers, int32 numSamples) const
+	    noexcept
+	{
+		for (auto index = 0; index < numBuffers; ++index)
+		{
+			for (auto channelIndex = 0; channelIndex < buffers[index].numChannels; ++channelIndex)
+			{
+				if (SampleSize == SymbolicSampleSizes::kSample32)
+					buffers[index].channelBuffers32[channelIndex] += numSamples;
+				else
+					buffers[index].channelBuffers64[channelIndex] += numSamples;
+			}
+		}
+	}
+	int32 sliceSize;
+	bool stopIt {false};
+};
+
+//------------------------------------------------------------------------
+} // Vst
+} // Steinberg