Differential D2716 Diff 9122 extern/audaspace/include/util/FFTPlan.h

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extern/audaspace/include/util/FFTPlan.h

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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)2sizeof(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