80 lines
2.8 KiB
C
80 lines
2.8 KiB
C
/*
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ESP32 FFT
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=========
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This provides a vanilla radix-2 FFT implementation and a test example.
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Author
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------
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This code was written by [Robin Scheibler](http://www.robinscheibler.org) during rainy days in October 2017.
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License
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-------
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Copyright (c) 2017 Robin Scheibler
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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*/
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#ifndef __FFT_H__
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#define __FFT_H__
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typedef enum
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{
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FFT_REAL,
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FFT_COMPLEX
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} fft_type_t;
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typedef enum
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{
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FFT_FORWARD,
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FFT_BACKWARD
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} fft_direction_t;
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#define FFT_OWN_INPUT_MEM 1
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#define FFT_OWN_OUTPUT_MEM 2
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typedef struct
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{
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int size; // FFT size
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float *input; // pointer to input buffer
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float *output; // pointer to output buffer
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float *twiddle_factors; // pointer to buffer holding twiddle factors
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fft_type_t type; // real or complex
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fft_direction_t direction; // forward or backward
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unsigned int flags; // FFT flags
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} fft_config_t;
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fft_config_t *fft_init(int size, fft_type_t type, fft_direction_t direction, float *input, float *output);
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void fft_destroy(fft_config_t *config);
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void fft_execute(fft_config_t *config);
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void fft(float *input, float *output, float *twiddle_factors, int n);
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void ifft(float *input, float *output, float *twiddle_factors, int n);
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void rfft(float *x, float *y, float *twiddle_factors, int n);
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void irfft(float *x, float *y, float *twiddle_factors, int n);
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void fft_primitive(float *x, float *y, int n, int stride, float *twiddle_factors, int tw_stride);
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void split_radix_fft(float *x, float *y, int n, int stride, float *twiddle_factors, int tw_stride);
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void ifft_primitive(float *input, float *output, int n, int stride, float *twiddle_factors, int tw_stride);
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void fft8(float *input, int stride_in, float *output, int stride_out);
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void fft4(float *input, int stride_in, float *output, int stride_out);
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#endif // __FFT_H__
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