media/kiss_fft/kiss_fftr.c

   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 #include "kiss_fftr.h"
  16 #include "_kiss_fft_guts.h"
  17
  18 struct 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
  27 kiss_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
  67 void 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
 123 void 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 }