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/*****************************************************************************
* fft.h: Headers for iterative implementation of a FFT
*****************************************************************************
* $Id: 942fd5d1af270167dc97fc10482cfedb3f1f4af4 $
*
* Mainly taken from XMMS's code
*
* Authors: Richard Boulton <richard@tartarus.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
*****************************************************************************/
#ifndef _FFT_H_
#define _FFT_H_
#define FFT_BUFFER_SIZE_LOG 9
#define FFT_BUFFER_SIZE (1 << FFT_BUFFER_SIZE_LOG)
/* sound sample - should be an signed 16 bit value */
typedef short int sound_sample;
struct _struct_fft_state {
/* Temporary data stores to perform FFT in. */
float real[FFT_BUFFER_SIZE];
float imag[FFT_BUFFER_SIZE];
/* */
unsigned int bitReverse[FFT_BUFFER_SIZE];
/* The next two tables could be made to use less space in memory, since they
* overlap hugely, but hey. */
float sintable[FFT_BUFFER_SIZE / 2];
float costable[FFT_BUFFER_SIZE / 2];
};
/* FFT prototypes */
typedef struct _struct_fft_state fft_state;
fft_state *visual_fft_init (void);
void fft_perform (const sound_sample *input, float *output, fft_state *state);
void fft_close (fft_state *state);
#endif /* _FFT_H_ */
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