1/*
2Copyright (c) 2003-2004, Mark Borgerding
3
4All rights reserved.
5
6Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
7
8 * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
9 * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
10 * Neither the author nor the names of any contributors may be used to endorse or promote products derived from this software without specific prior written permission.
11
12THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 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.
13*/
14
15#include "kiss_fftr.h"
16#include "_kiss_fft_guts.h"
17
18struct kiss_fftr_state{
19 kiss_fft_cfg substate;
20 kiss_fft_cpx * tmpbuf;
21 kiss_fft_cpx * super_twiddles;
22#ifdef USE_SIMD
23 void * pad;
24#endif
25};
26
27kiss_fftr_cfg kiss_fftr_alloc(int nfft,int inverse_fft,void * mem,size_t * lenmem)
28{
29 int i;
30 kiss_fftr_cfg st = NULL;
31 size_t subsize, memneeded;
32
33 if (nfft & 1) {
34 fprintf(stderr,"Real FFT optimization must be even.\n");
35 return NULL;
36 }
37 nfft >>= 1;
38
39 kiss_fft_alloc (nfft, inverse_fft, NULL, &subsize);
40 memneeded = sizeof(struct kiss_fftr_state) + subsize + sizeof(kiss_fft_cpx) * ( nfft * 3 / 2);
41
42 if (lenmem == NULL) {
43 st = (kiss_fftr_cfg) KISS_FFT_MALLOC (memneeded);
44 } else {
45 if (*lenmem >= memneeded)
46 st = (kiss_fftr_cfg) mem;
47 *lenmem = memneeded;
48 }
49 if (!st)
50 return NULL;
51
52 st->substate = (kiss_fft_cfg) (st + 1); /*just beyond kiss_fftr_state struct */
53 st->tmpbuf = (kiss_fft_cpx *) (((char *) st->substate) + subsize);
54 st->super_twiddles = st->tmpbuf + nfft;
55 kiss_fft_alloc(nfft, inverse_fft, st->substate, &subsize);
56
57 for (i = 0; i < nfft/2; ++i) {
58 double phase =
59 -3.14159265358979323846264338327 * ((double) (i+1) / nfft + .5);
60 if (inverse_fft)
61 phase *= -1;
62 kf_cexp (st->super_twiddles+i,phase);
63 }
64 return st;
65}
66
67void kiss_fftr(kiss_fftr_cfg st,const kiss_fft_scalar *timedata,kiss_fft_cpx *freqdata)
68{
69 /* input buffer timedata is stored row-wise */
70 int k,ncfft;
71 kiss_fft_cpx fpnk,fpk,f1k,f2k,tw,tdc;
72
73 if ( st->substate->inverse) {
74 fprintf(stderr,"kiss fft usage error: improper alloc\n");
75 exit(1);
76 }
77
78 ncfft = st->substate->nfft;
79
80 /*perform the parallel fft of two real signals packed in real,imag*/
81 kiss_fft( st->substate , (const kiss_fft_cpx*)timedata, st->tmpbuf );
82 /* The real part of the DC element of the frequency spectrum in st->tmpbuf
83 * contains the sum of the even-numbered elements of the input time sequence
84 * The imag part is the sum of the odd-numbered elements
85 *
86 * The sum of tdc.r and tdc.i is the sum of the input time sequence.
87 * yielding DC of input time sequence
88 * The difference of tdc.r - tdc.i is the sum of the input (dot product) [1,-1,1,-1...
89 * yielding Nyquist bin of input time sequence
90 */
91
92 tdc.r = st->tmpbuf[0].r;
93 tdc.i = st->tmpbuf[0].i;
94 C_FIXDIV(tdc,2);
95 CHECK_OVERFLOW_OP(tdc.r ,+, tdc.i);
96 CHECK_OVERFLOW_OP(tdc.r ,-, tdc.i);
97 freqdata[0].r = tdc.r + tdc.i;
98 freqdata[ncfft].r = tdc.r - tdc.i;
99#ifdef USE_SIMD
100 freqdata[ncfft].i = freqdata[0].i = _mm_set1_ps(0);
101#else
102 freqdata[ncfft].i = freqdata[0].i = 0;
103#endif
104
105 for ( k=1;k <= ncfft/2 ; ++k ) {
106 fpk = st->tmpbuf[k];
107 fpnk.r = st->tmpbuf[ncfft-k].r;
108 fpnk.i = - st->tmpbuf[ncfft-k].i;
109 C_FIXDIV(fpk,2);
110 C_FIXDIV(fpnk,2);
111
112 C_ADD( f1k, fpk , fpnk );
113 C_SUB( f2k, fpk , fpnk );
114 C_MUL( tw , f2k , st->super_twiddles[k-1]);
115
116 freqdata[k].r = HALF_OF(f1k.r + tw.r);
117 freqdata[k].i = HALF_OF(f1k.i + tw.i);
118 freqdata[ncfft-k].r = HALF_OF(f1k.r - tw.r);
119 freqdata[ncfft-k].i = HALF_OF(tw.i - f1k.i);
120 }
121}
122
123void kiss_fftri(kiss_fftr_cfg st,const kiss_fft_cpx *freqdata,kiss_fft_scalar *timedata)
124{
125 /* input buffer timedata is stored row-wise */
126 int k, ncfft;
127
128 if (st->substate->inverse == 0) {
129 fprintf (stderr, "kiss fft usage error: improper alloc\n");
130 exit (1);
131 }
132
133 ncfft = st->substate->nfft;
134
135 st->tmpbuf[0].r = freqdata[0].r + freqdata[ncfft].r;
136 st->tmpbuf[0].i = freqdata[0].r - freqdata[ncfft].r;
137 C_FIXDIV(st->tmpbuf[0],2);
138
139 for (k = 1; k <= ncfft / 2; ++k) {
140 kiss_fft_cpx fk, fnkc, fek, fok, tmp;
141 fk = freqdata[k];
142 fnkc.r = freqdata[ncfft - k].r;
143 fnkc.i = -freqdata[ncfft - k].i;
144 C_FIXDIV( fk , 2 );
145 C_FIXDIV( fnkc , 2 );
146
147 C_ADD (fek, fk, fnkc);
148 C_SUB (tmp, fk, fnkc);
149 C_MUL (fok, tmp, st->super_twiddles[k-1]);
150 C_ADD (st->tmpbuf[k], fek, fok);
151 C_SUB (st->tmpbuf[ncfft - k], fek, fok);
152#ifdef USE_SIMD
153 st->tmpbuf[ncfft - k].i *= _mm_set1_ps(-1.0);
154#else
155 st->tmpbuf[ncfft - k].i *= -1;
156#endif
157 }
158 kiss_fft (st->substate, st->tmpbuf, (kiss_fft_cpx *) timedata);
159}