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/*******************************************************************************
* Copyright 2015-2016 Juan Francisco Crespo Galán
*
* 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 FFTPlan.h
* @ingroup util
* The FFTPlan class.
*/
#include <complex>
#include <fftw3.h>
#include "Audaspace.h"
#include <memory>
#include <vector>
/**Default FFT size.*/
#define DEFAULT_N 4096
AUD_NAMESPACE_BEGIN
/**
* Thas class represents an plan object that allows to calculate FFTs and IFFTs.
*/
class AUD_API FFTPlan
{
private:
/**
* The size of the FFT plan.
*/
int m_N;
/**
* The plan to transform the input to the frequency domain.
*/
fftwf_plan m_fftPlanR2C;
/**
* The plan to transform the input to the time domain again.
*/
fftwf_plan m_fftPlanC2R;
/**
* The size of a buffer for its use with the FFT plan (in bytes).
*/
unsigned int m_bufferSize;
// delete copy constructor and operator=
FFTPlan(const FFTPlan&) = delete;
FFTPlan& operator=(const FFTPlan&) = delete;
public:
/**
* Creates a new FFTPlan object with DEFAULT_N size (4096).
* \param measureTime The aproximate amount of seconds that FFTW will spend searching for the optimal plan,
* which means faster FFTs and IFFTs while using this plan. If measureTime is negative, it will take all the time it needs.
*/
FFTPlan(double measureTime = 0);
/**
* Creates a new FFTPlan object with a custom size.
* \param n The size of the FFT plan. Values that are a power of two are faster.
* The useful range usually is between 2048 and 8192, but bigger values can be useful
* in certain situations (when using the StreamBuffer class per example).
* Generally, low values use more CPU power and are a bit faster than large ones,
* there is also a huge decrease in efficiency when n is lower than 2048.
* \param measureTime The aproximate amount of seconds that FFTW will spend searching for the optimal plan,
* which means faster FFTs while using this plan. If measureTime is negative, it will take all the time it needs.
*/
FFTPlan(int n, double measureTime = 0);
~FFTPlan();
/**
* Retrieves the size of the FFT plan.
* \return The size of the plan.
*/
int getSize();
/**
* Calculates the FFT of an input buffer with the current plan.
* \param[in,out] buffer A buffer with the input data an in which the output data will be written.
*/
void FFT(void* buffer);
/**
* Calculates the IFFT of an input buffer with the current plan.
* \param[in,out] buffer A buffer with the input data an in which the output data will be written.
*/
void IFFT(void* buffer);
/**
* Reserves memory for a buffer that can be used for inplace transformations with this plan.
* \return A pointer to a buffer of size ((N/2)+1)*2*sizeof(fftwf_complex).
* \warning The returned buffer must be freed with the freeBuffer method of this class.
*/
void* getBuffer();
/**
* Frees one of the buffers reserved with the getRealOnlyBuffer(), getComplexOnlyBuffer() or getInplaceBuffer() method.
* \param buffer A pointer to the buufer taht must be freed.
*/
void freeBuffer(void* buffer);
};
AUD_NAMESPACE_END
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