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162 lines
5.3 KiB
C
162 lines
5.3 KiB
C
#ifndef KISS_FFT_H
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#define KISS_FFT_H
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#include <stdio.h>
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#include <math.h>
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/*
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Copyright (c) 2003-2004, Mark Borgerding
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All rights reserved.
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Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentatio
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n and/or other materials provided with the distribution.
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* Neither the author nor the names of any contributors may be used to endorse or promote products derived from this software without specific prior
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written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IM
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PLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
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FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR S
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ERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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ATTENTION!
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If you would like a :
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-- a utility that will handle the caching of fft objects
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-- real-only FFT
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-- a multi-dimensional FFT
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-- a command-line utility to perform ffts
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-- a command-line utility to perform fast-convolution filtering
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then see tools/
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*/
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#ifdef FIXED_POINT
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# define kiss_fft_scalar short
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#else
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# ifndef kiss_fft_scalar
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/* default is float */
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# define kiss_fft_scalar float
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# endif
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#endif
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typedef struct _kiss_fft_cpx
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{
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kiss_fft_scalar r;
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kiss_fft_scalar i;
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} kiss_fft_cpx;
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#define MAXFACTORS 32
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/* e.g. an fft of length 128 has 4 factors
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as far as kissfft is concerned
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4*4*4*2
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*/
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typedef struct _kiss_fft_state
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{
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int nfft;
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int inverse;
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int factors[2*MAXFACTORS];
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kiss_fft_cpx twiddles[1];
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} kiss_fft_state, *kiss_fft_cfg;
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/*
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* kiss_fft_alloc
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*
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* Initialize a FFT (or IFFT) algorithm's cfg/state buffer.
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*
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* typical usage: kiss_fft_cfg mycfg=kiss_fft_alloc(1024,0,NULL,NULL);
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*
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* The return value from fft_alloc is a cfg buffer used internally
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* by the fft routine or NULL.
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*
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* If lenmem is NULL, then kiss_fft_alloc will allocate a cfg buffer using malloc.
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* The returned value should be free()d when done to avoid memory leaks.
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*
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* The state can be placed in a user supplied buffer 'mem':
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* If lenmem is not NULL and mem is not NULL and *lenmem is large enough,
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* then the function places the cfg in mem and the size used in *lenmem
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* and returns mem.
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*
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* If lenmem is not NULL and ( mem is NULL or *lenmem is not large enough),
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* then the function returns NULL and places the minimum cfg
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* buffer size in *lenmem.
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* */
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kiss_fft_cfg kiss_fft_alloc(int nfft,int inverse_fft,void * mem,size_t * lenmem);
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/*
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* kiss_fft(cfg,in_out_buf)
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*
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* Perform an FFT on a complex input buffer.
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* for a forward FFT,
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* fin should be f[0] , f[1] , ... ,f[nfft-1]
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* fout will be F[0] , F[1] , ... ,F[nfft-1]
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* Note that each element is complex and can be accessed like
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f[k].r and f[k].i
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* */
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void kiss_fft(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout);
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void kiss_fft_stride(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout,int fin_stride);
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/* If kiss_fft_alloc allocated a buffer, it is one contiguous
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buffer and can be simply free()d when no longer needed*/
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#define kiss_fft_free free
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/*
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Explanation of macros dealing with complex math:
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C_MUL(m,a,b) : m = a*b
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C_FIXDIV( c , div ) : if a fixed point impl., c /= div. noop otherwise
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C_SUB( res, a,b) : res = a - b
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C_SUBFROM( res , a) : res -= a
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C_ADDTO( res , a) : res += a
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* */
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#ifdef FIXED_POINT
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# define smul(a,b) ( (long)(a)*(b) )
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# define sround( x ) (short)( ( (x) + (1<<14) ) >>15 )
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# define S_MUL(a,b) sround( smul(a,b) )
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# define C_MUL(m,a,b) \
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do{ (m).r = sround( smul((a).r,(b).r) - smul((a).i,(b).i) ); \
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(m).i = sround( smul((a).r,(b).i) + smul((a).i,(b).r) ); }while(0)
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# define C_FIXDIV(c,div) \
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do{ (c).r /= div; (c).i /=div; }while(0)
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# define C_MULBYSCALAR( c, s ) \
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do{ (c).r = sround( smul( (c).r , s ) ) ;\
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(c).i = sround( smul( (c).i , s ) ) ; }while(0)
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#else /* not FIXED_POINT*/
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# define S_MUL(a,b) ( (a)*(b) )
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#define C_MUL(m,a,b) \
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do{ (m).r = (a).r*(b).r - (a).i*(b).i;\
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(m).i = (a).r*(b).i + (a).i*(b).r; }while(0)
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# define C_FIXDIV(c,div) /* NOOP */
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# define C_MULBYSCALAR( c, s ) \
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do{ (c).r *= (s);\
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(c).i *= (s); }while(0)
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#endif
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#define C_ADD( res, a,b)\
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do { (res).r=(a).r+(b).r; (res).i=(a).i+(b).i; }while(0)
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#define C_SUB( res, a,b)\
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do { (res).r=(a).r-(b).r; (res).i=(a).i-(b).i; }while(0)
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#define C_ADDTO( res , a)\
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do { (res).r += (a).r; (res).i += (a).i; }while(0)
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#define C_SUBFROM( res , a)\
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do { (res).r -= (a).r; (res).i -= (a).i; }while(0)
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#endif
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