1 /*
2 Copyright (c) 2003-2004, Mark Borgerding
3
4 All rights reserved.
5
6 Redistribution 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
12 THIS 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 #ifdef HAVE_CONFIG_H
16 #include "config.h"
17 #endif
18
19 #ifdef _WIN32
20 #pragma warning(disable:4244)
21 #pragma warning(disable:4127)
22 #endif
23
24 #include "kiss_fftr.h"
25 #include "_kiss_fft_guts.h"
26
27 struct kiss_fftr_state{
28 kiss_fft_cfg substate;
29 kiss_fft_cpx * tmpbuf;
30 kiss_fft_cpx * super_twiddles;
31 #ifdef USE_SIMD
32 long pad;
33 #endif
34 };
35
kiss_fftr_alloc(int nfft,int inverse_fft,void * mem,size_t * lenmem)36 kiss_fftr_cfg kiss_fftr_alloc(int nfft,int inverse_fft,void * mem,size_t * lenmem)
37 {
38 int i;
39 kiss_fftr_cfg st = NULL;
40 size_t subsize, memneeded;
41
42 if (nfft & 1) {
43 fprintf(stderr,"Real FFT optimization must be even.\n");
44 return NULL;
45 }
46 nfft >>= 1;
47
48 kiss_fft_alloc (nfft, inverse_fft, NULL, &subsize);
49 memneeded = sizeof(struct kiss_fftr_state) + subsize + sizeof(kiss_fft_cpx) * ( nfft * 2);
50
51 if (lenmem == NULL) {
52 st = (kiss_fftr_cfg) KISS_FFT_MALLOC (memneeded);
53 } else {
54 if (*lenmem >= memneeded)
55 st = (kiss_fftr_cfg) mem;
56 *lenmem = memneeded;
57 }
58 if (!st)
59 return NULL;
60
61 st->substate = (kiss_fft_cfg) (st + 1); /*just beyond kiss_fftr_state struct */
62 st->tmpbuf = (kiss_fft_cpx *) (((char *) st->substate) + subsize);
63 st->super_twiddles = st->tmpbuf + nfft;
64 kiss_fft_alloc(nfft, inverse_fft, st->substate, &subsize);
65
66 for (i = 0; i < nfft; ++i) {
67 double phase =
68 -3.14159265358979323846264338327 * ((double) i / nfft + .5);
69 if (inverse_fft)
70 phase *= -1;
71 kf_cexp (st->super_twiddles+i,phase);
72 }
73 return st;
74 }
75
kiss_fftr(kiss_fftr_cfg st,const kiss_fft_scalar * timedata,kiss_fft_cpx * freqdata)76 void kiss_fftr(kiss_fftr_cfg st,const kiss_fft_scalar *timedata,kiss_fft_cpx *freqdata)
77 {
78 /* input buffer timedata is stored row-wise */
79 int k,ncfft;
80 kiss_fft_cpx fpnk,fpk,f1k,f2k,tw,tdc;
81
82 if ( st->substate->inverse) {
83 fprintf(stderr,"kiss fft usage error: improper alloc\n");
84 exit(1);
85 }
86
87 ncfft = st->substate->nfft;
88
89 /*perform the parallel fft of two real signals packed in real,imag*/
90 kiss_fft( st->substate , (const kiss_fft_cpx*)timedata, st->tmpbuf );
91 /* The real part of the DC element of the frequency spectrum in st->tmpbuf
92 * contains the sum of the even-numbered elements of the input time sequence
93 * The imag part is the sum of the odd-numbered elements
94 *
95 * The sum of tdc.r and tdc.i is the sum of the input time sequence.
96 * yielding DC of input time sequence
97 * The difference of tdc.r - tdc.i is the sum of the input (dot product) [1,-1,1,-1...
98 * yielding Nyquist bin of input time sequence
99 */
100
101 tdc.r = st->tmpbuf[0].r;
102 tdc.i = st->tmpbuf[0].i;
103 C_FIXDIV(tdc,2);
104 CHECK_OVERFLOW_OP(tdc.r ,+, tdc.i);
105 CHECK_OVERFLOW_OP(tdc.r ,-, tdc.i);
106 freqdata[0].r = tdc.r + tdc.i;
107 freqdata[ncfft].r = tdc.r - tdc.i;
108 #ifdef USE_SIMD
109 freqdata[ncfft].i = freqdata[0].i = _mm_set1_ps(0);
110 #else
111 freqdata[ncfft].i = freqdata[0].i = 0;
112 #endif
113
114 for ( k=1;k <= ncfft/2 ; ++k ) {
115 fpk = st->tmpbuf[k];
116 fpnk.r = st->tmpbuf[ncfft-k].r;
117 fpnk.i = - st->tmpbuf[ncfft-k].i;
118 C_FIXDIV(fpk,2);
119 C_FIXDIV(fpnk,2);
120
121 C_ADD( f1k, fpk , fpnk );
122 C_SUB( f2k, fpk , fpnk );
123 C_MUL( tw , f2k , st->super_twiddles[k]);
124
125 freqdata[k].r = HALF_OF(f1k.r + tw.r);
126 freqdata[k].i = HALF_OF(f1k.i + tw.i);
127 freqdata[ncfft-k].r = HALF_OF(f1k.r - tw.r);
128 freqdata[ncfft-k].i = HALF_OF(tw.i - f1k.i);
129 }
130 }
131
kiss_fftri(kiss_fftr_cfg st,const kiss_fft_cpx * freqdata,kiss_fft_scalar * timedata)132 void kiss_fftri(kiss_fftr_cfg st,const kiss_fft_cpx *freqdata,kiss_fft_scalar *timedata)
133 {
134 /* input buffer timedata is stored row-wise */
135 int k, ncfft;
136
137 if (st->substate->inverse == 0) {
138 fprintf (stderr, "kiss fft usage error: improper alloc\n");
139 exit (1);
140 }
141
142 ncfft = st->substate->nfft;
143
144 st->tmpbuf[0].r = freqdata[0].r + freqdata[ncfft].r;
145 st->tmpbuf[0].i = freqdata[0].r - freqdata[ncfft].r;
146 /*C_FIXDIV(st->tmpbuf[0],2);*/
147
148 for (k = 1; k <= ncfft / 2; ++k) {
149 kiss_fft_cpx fk, fnkc, fek, fok, tmp;
150 fk = freqdata[k];
151 fnkc.r = freqdata[ncfft - k].r;
152 fnkc.i = -freqdata[ncfft - k].i;
153 /*C_FIXDIV( fk , 2 );
154 C_FIXDIV( fnkc , 2 );*/
155
156 C_ADD (fek, fk, fnkc);
157 C_SUB (tmp, fk, fnkc);
158 C_MUL (fok, tmp, st->super_twiddles[k]);
159 C_ADD (st->tmpbuf[k], fek, fok);
160 C_SUB (st->tmpbuf[ncfft - k], fek, fok);
161 #ifdef USE_SIMD
162 st->tmpbuf[ncfft - k].i *= _mm_set1_ps(-1.0);
163 #else
164 st->tmpbuf[ncfft - k].i *= -1;
165 #endif
166 }
167 kiss_fft (st->substate, st->tmpbuf, (kiss_fft_cpx *) timedata);
168 }
169