Differential D2716 Diff 9153 extern/audaspace/include/respec/JOSResampleReader.h

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extern/audaspace/include/respec/JOSResampleReader.h

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				/*******************************************************************************
				* Copyright 2009-2016 Jörg Müller
				*
				* Licensed under the Apache License, Version 2.0 (the "License");
				* you may not use this file except in compliance with the License.
				* You may obtain a copy of the License at
				*
				* http://www.apache.org/licenses/LICENSE-2.0
				*
				* Unless required by applicable law or agreed to in writing, software
				* distributed under the License is distributed on an "AS IS" BASIS,
				* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
				* See the License for the specific language governing permissions and
				* limitations under the License.
				******************************************************************************/

				#pragma once

				/**
				* @file JOSResampleReader.h
				* @ingroup respec
				* The JOSResampleReader class.
				*/

				#include "respec/ResampleReader.h"
				#include "util/Buffer.h"

				AUD_NAMESPACE_BEGIN

				/**
				* This resampling reader uses Julius O. Smith's resampling algorithm.
				*/
				class AUD_API JOSResampleReader : public ResampleReader
				{
				private:
				typedef void (JOSResampleReader::resample_f)(double target_factor, int length, sample_t buffer);

				/**
				* The half filter length.
				*/
				static const int m_len;

				/**
				* The sample step size for the filter.
				*/
				static const int m_L;

				/**
				* The filter coefficients.
				*/
				static const float m_coeff[];

				/**
				* The reader channels.
				*/
				Channels m_channels;

				/**
				* The sample position in the cache.
				*/
				unsigned int m_n;

				/**
				* The subsample position in the cache.
				*/
				double m_P;

				/**
				* The input data buffer.
				*/
				Buffer m_buffer;

				/**
				* Double buffer for the sums.
				*/
				Buffer m_sums;

				/**
				* How many samples in the cache are valid.
				*/
				int m_cache_valid;

				/**
				* Resample function.
				*/
				resample_f m_resample;

				/**
				* Last resampling factor.
				*/
				double m_last_factor;

				// delete copy constructor and operator=
				JOSResampleReader(const JOSResampleReader&) = delete;
				JOSResampleReader& operator=(const JOSResampleReader&) = delete;

				/**
				* Resets the resampler to its initial state.
				*/
				void AUD_LOCAL reset();

				/**
				* Updates the buffer to be as small as possible for the coming reading.
				* \param size The size of samples to be read.
				* \param factor The next resampling factor.
				* \param samplesize The size of a sample.
				*/
				void AUD_LOCAL updateBuffer(int size, double factor, int samplesize);

				void AUD_LOCAL resample(double target_factor, int length, sample_t* buffer);
				void AUD_LOCAL resample_mono(double target_factor, int length, sample_t* buffer);
				void AUD_LOCAL resample_stereo(double target_factor, int length, sample_t* buffer);

				public:
				/**
				* Creates a resampling reader.
				* \param reader The reader to mix.
				* \param rate The target sampling rate.
				*/
				JOSResampleReader(std::shared_ptr<IReader> reader, SampleRate rate);

				virtual void seek(int position);
				virtual int getLength() const;
				virtual int getPosition() const;
				virtual Specs getSpecs() const;
				virtual void read(int& length, bool& eos, sample_t* buffer);
				};

				AUD_NAMESPACE_END