+++ /dev/null
-/*
- * FFT/IFFT transforms
- * Copyright (c) 2002 Fabrice Bellard.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library 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
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- */
-
-/**
- * @file fft.c
- * FFT/IFFT transforms.
- */
-
-#include "dsputil.h"
-
-/**
- * The size of the FFT is 2^nbits. If inverse is TRUE, inverse FFT is
- * done
- */
-int fft_init(FFTContext *s, int nbits, int inverse)
-{
- int i, j, m, n;
- float alpha, c1, s1, s2;
-
- s->nbits = nbits;
- n = 1 << nbits;
-
- s->exptab = av_malloc((n / 2) * sizeof(FFTComplex));
- if (!s->exptab)
- goto fail;
- s->revtab = av_malloc(n * sizeof(uint16_t));
- if (!s->revtab)
- goto fail;
- s->inverse = inverse;
-
- s2 = inverse ? 1.0 : -1.0;
-
- for(i=0;i<(n/2);i++) {
- alpha = 2 * M_PI * (float)i / (float)n;
- c1 = cos(alpha);
- s1 = sin(alpha) * s2;
- s->exptab[i].re = c1;
- s->exptab[i].im = s1;
- }
- s->fft_calc = fft_calc_c;
- s->exptab1 = NULL;
-
- /* compute constant table for HAVE_SSE version */
-#if (defined(HAVE_MMX) && defined(HAVE_BUILTIN_VECTOR)) || defined(HAVE_ALTIVEC)
- {
- int has_vectors = 0;
-
-#if defined(HAVE_MMX)
- has_vectors = mm_support() & MM_SSE;
-#endif
-#if defined(HAVE_ALTIVEC) && !defined(ALTIVEC_USE_REFERENCE_C_CODE)
- has_vectors = mm_support() & MM_ALTIVEC;
-#endif
- if (has_vectors) {
- int np, nblocks, np2, l;
- FFTComplex *q;
-
- np = 1 << nbits;
- nblocks = np >> 3;
- np2 = np >> 1;
- s->exptab1 = av_malloc(np * 2 * sizeof(FFTComplex));
- if (!s->exptab1)
- goto fail;
- q = s->exptab1;
- do {
- for(l = 0; l < np2; l += 2 * nblocks) {
- *q++ = s->exptab[l];
- *q++ = s->exptab[l + nblocks];
-
- q->re = -s->exptab[l].im;
- q->im = s->exptab[l].re;
- q++;
- q->re = -s->exptab[l + nblocks].im;
- q->im = s->exptab[l + nblocks].re;
- q++;
- }
- nblocks = nblocks >> 1;
- } while (nblocks != 0);
- av_freep(&s->exptab);
-#if defined(HAVE_MMX)
- s->fft_calc = fft_calc_sse;
-#else
- s->fft_calc = fft_calc_altivec;
-#endif
- }
- }
-#endif
-
- /* compute bit reverse table */
-
- for(i=0;i<n;i++) {
- m=0;
- for(j=0;j<nbits;j++) {
- m |= ((i >> j) & 1) << (nbits-j-1);
- }
- s->revtab[i]=m;
- }
- return 0;
- fail:
- av_freep(&s->revtab);
- av_freep(&s->exptab);
- av_freep(&s->exptab1);
- return -1;
-}
-
-/* butter fly op */
-#define BF(pre, pim, qre, qim, pre1, pim1, qre1, qim1) \
-{\
- FFTSample ax, ay, bx, by;\
- bx=pre1;\
- by=pim1;\
- ax=qre1;\
- ay=qim1;\
- pre = (bx + ax);\
- pim = (by + ay);\
- qre = (bx - ax);\
- qim = (by - ay);\
-}
-
-#define MUL16(a,b) ((a) * (b))
-
-#define CMUL(pre, pim, are, aim, bre, bim) \
-{\
- pre = (MUL16(are, bre) - MUL16(aim, bim));\
- pim = (MUL16(are, bim) + MUL16(bre, aim));\
-}
-
-/**
- * Do a complex FFT with the parameters defined in fft_init(). The
- * input data must be permuted before with s->revtab table. No
- * 1.0/sqrt(n) normalization is done.
- */
-void fft_calc_c(FFTContext *s, FFTComplex *z)
-{
- int ln = s->nbits;
- int j, np, np2;
- int nblocks, nloops;
- register FFTComplex *p, *q;
- FFTComplex *exptab = s->exptab;
- int l;
- FFTSample tmp_re, tmp_im;
-
- np = 1 << ln;
-
- /* pass 0 */
-
- p=&z[0];
- j=(np >> 1);
- do {
- BF(p[0].re, p[0].im, p[1].re, p[1].im,
- p[0].re, p[0].im, p[1].re, p[1].im);
- p+=2;
- } while (--j != 0);
-
- /* pass 1 */
-
-
- p=&z[0];
- j=np >> 2;
- if (s->inverse) {
- do {
- BF(p[0].re, p[0].im, p[2].re, p[2].im,
- p[0].re, p[0].im, p[2].re, p[2].im);
- BF(p[1].re, p[1].im, p[3].re, p[3].im,
- p[1].re, p[1].im, -p[3].im, p[3].re);
- p+=4;
- } while (--j != 0);
- } else {
- do {
- BF(p[0].re, p[0].im, p[2].re, p[2].im,
- p[0].re, p[0].im, p[2].re, p[2].im);
- BF(p[1].re, p[1].im, p[3].re, p[3].im,
- p[1].re, p[1].im, p[3].im, -p[3].re);
- p+=4;
- } while (--j != 0);
- }
- /* pass 2 .. ln-1 */
-
- nblocks = np >> 3;
- nloops = 1 << 2;
- np2 = np >> 1;
- do {
- p = z;
- q = z + nloops;
- for (j = 0; j < nblocks; ++j) {
- BF(p->re, p->im, q->re, q->im,
- p->re, p->im, q->re, q->im);
-
- p++;
- q++;
- for(l = nblocks; l < np2; l += nblocks) {
- CMUL(tmp_re, tmp_im, exptab[l].re, exptab[l].im, q->re, q->im);
- BF(p->re, p->im, q->re, q->im,
- p->re, p->im, tmp_re, tmp_im);
- p++;
- q++;
- }
-
- p += nloops;
- q += nloops;
- }
- nblocks = nblocks >> 1;
- nloops = nloops << 1;
- } while (nblocks != 0);
-}
-
-/**
- * Do the permutation needed BEFORE calling fft_calc()
- */
-void fft_permute(FFTContext *s, FFTComplex *z)
-{
- int j, k, np;
- FFTComplex tmp;
- const uint16_t *revtab = s->revtab;
-
- /* reverse */
- np = 1 << s->nbits;
- for(j=0;j<np;j++) {
- k = revtab[j];
- if (k < j) {
- tmp = z[k];
- z[k] = z[j];
- z[j] = tmp;
- }
- }
-}
-
-void fft_end(FFTContext *s)
-{
- av_freep(&s->revtab);
- av_freep(&s->exptab);
- av_freep(&s->exptab1);
-}
-
projects / synfig.git / blobdiff