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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
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