Chris@69: /*Copyright (c) 2003-2004, Mark Borgerding
Chris@69:   Lots of modifications by Jean-Marc Valin
Chris@69:   Copyright (c) 2005-2007, Xiph.Org Foundation
Chris@69:   Copyright (c) 2008,      Xiph.Org Foundation, CSIRO
Chris@69: 
Chris@69:   All rights reserved.
Chris@69: 
Chris@69:   Redistribution and use in source and binary forms, with or without
Chris@69:    modification, are permitted provided that the following conditions are met:
Chris@69: 
Chris@69:     * Redistributions of source code must retain the above copyright notice,
Chris@69:        this list of conditions and the following disclaimer.
Chris@69:     * Redistributions in binary form must reproduce the above copyright notice,
Chris@69:        this list of conditions and the following disclaimer in the
Chris@69:        documentation and/or other materials provided with the distribution.
Chris@69: 
Chris@69:   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
Chris@69:   AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
Chris@69:   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
Chris@69:   ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
Chris@69:   LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
Chris@69:   CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
Chris@69:   SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
Chris@69:   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
Chris@69:   CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
Chris@69:   ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
Chris@69:   POSSIBILITY OF SUCH DAMAGE.*/
Chris@69: 
Chris@69: /* This code is originally from Mark Borgerding's KISS-FFT but has been
Chris@69:    heavily modified to better suit Opus */
Chris@69: 
Chris@69: #ifndef SKIP_CONFIG_H
Chris@69: #  ifdef HAVE_CONFIG_H
Chris@69: #    include "config.h"
Chris@69: #  endif
Chris@69: #endif
Chris@69: 
Chris@69: #include "_kiss_fft_guts.h"
Chris@69: #include "arch.h"
Chris@69: #include "os_support.h"
Chris@69: #include "mathops.h"
Chris@69: #include "stack_alloc.h"
Chris@69: 
Chris@69: /* The guts header contains all the multiplication and addition macros that are defined for
Chris@69:    complex numbers.  It also delares the kf_ internal functions.
Chris@69: */
Chris@69: 
Chris@69: static void kf_bfly2(
Chris@69:                      kiss_fft_cpx * Fout,
Chris@69:                      int m,
Chris@69:                      int N
Chris@69:                     )
Chris@69: {
Chris@69:    kiss_fft_cpx * Fout2;
Chris@69:    int i;
Chris@69:    (void)m;
Chris@69: #ifdef CUSTOM_MODES
Chris@69:    if (m==1)
Chris@69:    {
Chris@69:       celt_assert(m==1);
Chris@69:       for (i=0;i<N;i++)
Chris@69:       {
Chris@69:          kiss_fft_cpx t;
Chris@69:          Fout2 = Fout + 1;
Chris@69:          t = *Fout2;
Chris@69:          C_SUB( *Fout2 ,  *Fout , t );
Chris@69:          C_ADDTO( *Fout ,  t );
Chris@69:          Fout += 2;
Chris@69:       }
Chris@69:    } else
Chris@69: #endif
Chris@69:    {
Chris@69:       opus_val16 tw;
Chris@69:       tw = QCONST16(0.7071067812f, 15);
Chris@69:       /* We know that m==4 here because the radix-2 is just after a radix-4 */
Chris@69:       celt_assert(m==4);
Chris@69:       for (i=0;i<N;i++)
Chris@69:       {
Chris@69:          kiss_fft_cpx t;
Chris@69:          Fout2 = Fout + 4;
Chris@69:          t = Fout2[0];
Chris@69:          C_SUB( Fout2[0] ,  Fout[0] , t );
Chris@69:          C_ADDTO( Fout[0] ,  t );
Chris@69: 
Chris@69:          t.r = S_MUL(ADD32_ovflw(Fout2[1].r, Fout2[1].i), tw);
Chris@69:          t.i = S_MUL(SUB32_ovflw(Fout2[1].i, Fout2[1].r), tw);
Chris@69:          C_SUB( Fout2[1] ,  Fout[1] , t );
Chris@69:          C_ADDTO( Fout[1] ,  t );
Chris@69: 
Chris@69:          t.r = Fout2[2].i;
Chris@69:          t.i = -Fout2[2].r;
Chris@69:          C_SUB( Fout2[2] ,  Fout[2] , t );
Chris@69:          C_ADDTO( Fout[2] ,  t );
Chris@69: 
Chris@69:          t.r = S_MUL(SUB32_ovflw(Fout2[3].i, Fout2[3].r), tw);
Chris@69:          t.i = S_MUL(NEG32_ovflw(ADD32_ovflw(Fout2[3].i, Fout2[3].r)), tw);
Chris@69:          C_SUB( Fout2[3] ,  Fout[3] , t );
Chris@69:          C_ADDTO( Fout[3] ,  t );
Chris@69:          Fout += 8;
Chris@69:       }
Chris@69:    }
Chris@69: }
Chris@69: 
Chris@69: static void kf_bfly4(
Chris@69:                      kiss_fft_cpx * Fout,
Chris@69:                      const size_t fstride,
Chris@69:                      const kiss_fft_state *st,
Chris@69:                      int m,
Chris@69:                      int N,
Chris@69:                      int mm
Chris@69:                     )
Chris@69: {
Chris@69:    int i;
Chris@69: 
Chris@69:    if (m==1)
Chris@69:    {
Chris@69:       /* Degenerate case where all the twiddles are 1. */
Chris@69:       for (i=0;i<N;i++)
Chris@69:       {
Chris@69:          kiss_fft_cpx scratch0, scratch1;
Chris@69: 
Chris@69:          C_SUB( scratch0 , *Fout, Fout[2] );
Chris@69:          C_ADDTO(*Fout, Fout[2]);
Chris@69:          C_ADD( scratch1 , Fout[1] , Fout[3] );
Chris@69:          C_SUB( Fout[2], *Fout, scratch1 );
Chris@69:          C_ADDTO( *Fout , scratch1 );
Chris@69:          C_SUB( scratch1 , Fout[1] , Fout[3] );
Chris@69: 
Chris@69:          Fout[1].r = ADD32_ovflw(scratch0.r, scratch1.i);
Chris@69:          Fout[1].i = SUB32_ovflw(scratch0.i, scratch1.r);
Chris@69:          Fout[3].r = SUB32_ovflw(scratch0.r, scratch1.i);
Chris@69:          Fout[3].i = ADD32_ovflw(scratch0.i, scratch1.r);
Chris@69:          Fout+=4;
Chris@69:       }
Chris@69:    } else {
Chris@69:       int j;
Chris@69:       kiss_fft_cpx scratch[6];
Chris@69:       const kiss_twiddle_cpx *tw1,*tw2,*tw3;
Chris@69:       const int m2=2*m;
Chris@69:       const int m3=3*m;
Chris@69:       kiss_fft_cpx * Fout_beg = Fout;
Chris@69:       for (i=0;i<N;i++)
Chris@69:       {
Chris@69:          Fout = Fout_beg + i*mm;
Chris@69:          tw3 = tw2 = tw1 = st->twiddles;
Chris@69:          /* m is guaranteed to be a multiple of 4. */
Chris@69:          for (j=0;j<m;j++)
Chris@69:          {
Chris@69:             C_MUL(scratch[0],Fout[m] , *tw1 );
Chris@69:             C_MUL(scratch[1],Fout[m2] , *tw2 );
Chris@69:             C_MUL(scratch[2],Fout[m3] , *tw3 );
Chris@69: 
Chris@69:             C_SUB( scratch[5] , *Fout, scratch[1] );
Chris@69:             C_ADDTO(*Fout, scratch[1]);
Chris@69:             C_ADD( scratch[3] , scratch[0] , scratch[2] );
Chris@69:             C_SUB( scratch[4] , scratch[0] , scratch[2] );
Chris@69:             C_SUB( Fout[m2], *Fout, scratch[3] );
Chris@69:             tw1 += fstride;
Chris@69:             tw2 += fstride*2;
Chris@69:             tw3 += fstride*3;
Chris@69:             C_ADDTO( *Fout , scratch[3] );
Chris@69: 
Chris@69:             Fout[m].r = ADD32_ovflw(scratch[5].r, scratch[4].i);
Chris@69:             Fout[m].i = SUB32_ovflw(scratch[5].i, scratch[4].r);
Chris@69:             Fout[m3].r = SUB32_ovflw(scratch[5].r, scratch[4].i);
Chris@69:             Fout[m3].i = ADD32_ovflw(scratch[5].i, scratch[4].r);
Chris@69:             ++Fout;
Chris@69:          }
Chris@69:       }
Chris@69:    }
Chris@69: }
Chris@69: 
Chris@69: 
Chris@69: #ifndef RADIX_TWO_ONLY
Chris@69: 
Chris@69: static void kf_bfly3(
Chris@69:                      kiss_fft_cpx * Fout,
Chris@69:                      const size_t fstride,
Chris@69:                      const kiss_fft_state *st,
Chris@69:                      int m,
Chris@69:                      int N,
Chris@69:                      int mm
Chris@69:                     )
Chris@69: {
Chris@69:    int i;
Chris@69:    size_t k;
Chris@69:    const size_t m2 = 2*m;
Chris@69:    const kiss_twiddle_cpx *tw1,*tw2;
Chris@69:    kiss_fft_cpx scratch[5];
Chris@69:    kiss_twiddle_cpx epi3;
Chris@69: 
Chris@69:    kiss_fft_cpx * Fout_beg = Fout;
Chris@69: #ifdef FIXED_POINT
Chris@69:    /*epi3.r = -16384;*/ /* Unused */
Chris@69:    epi3.i = -28378;
Chris@69: #else
Chris@69:    epi3 = st->twiddles[fstride*m];
Chris@69: #endif
Chris@69:    for (i=0;i<N;i++)
Chris@69:    {
Chris@69:       Fout = Fout_beg + i*mm;
Chris@69:       tw1=tw2=st->twiddles;
Chris@69:       /* For non-custom modes, m is guaranteed to be a multiple of 4. */
Chris@69:       k=m;
Chris@69:       do {
Chris@69: 
Chris@69:          C_MUL(scratch[1],Fout[m] , *tw1);
Chris@69:          C_MUL(scratch[2],Fout[m2] , *tw2);
Chris@69: 
Chris@69:          C_ADD(scratch[3],scratch[1],scratch[2]);
Chris@69:          C_SUB(scratch[0],scratch[1],scratch[2]);
Chris@69:          tw1 += fstride;
Chris@69:          tw2 += fstride*2;
Chris@69: 
Chris@69:          Fout[m].r = SUB32_ovflw(Fout->r, HALF_OF(scratch[3].r));
Chris@69:          Fout[m].i = SUB32_ovflw(Fout->i, HALF_OF(scratch[3].i));
Chris@69: 
Chris@69:          C_MULBYSCALAR( scratch[0] , epi3.i );
Chris@69: 
Chris@69:          C_ADDTO(*Fout,scratch[3]);
Chris@69: 
Chris@69:          Fout[m2].r = ADD32_ovflw(Fout[m].r, scratch[0].i);
Chris@69:          Fout[m2].i = SUB32_ovflw(Fout[m].i, scratch[0].r);
Chris@69: 
Chris@69:          Fout[m].r = SUB32_ovflw(Fout[m].r, scratch[0].i);
Chris@69:          Fout[m].i = ADD32_ovflw(Fout[m].i, scratch[0].r);
Chris@69: 
Chris@69:          ++Fout;
Chris@69:       } while(--k);
Chris@69:    }
Chris@69: }
Chris@69: 
Chris@69: 
Chris@69: #ifndef OVERRIDE_kf_bfly5
Chris@69: static void kf_bfly5(
Chris@69:                      kiss_fft_cpx * Fout,
Chris@69:                      const size_t fstride,
Chris@69:                      const kiss_fft_state *st,
Chris@69:                      int m,
Chris@69:                      int N,
Chris@69:                      int mm
Chris@69:                     )
Chris@69: {
Chris@69:    kiss_fft_cpx *Fout0,*Fout1,*Fout2,*Fout3,*Fout4;
Chris@69:    int i, u;
Chris@69:    kiss_fft_cpx scratch[13];
Chris@69:    const kiss_twiddle_cpx *tw;
Chris@69:    kiss_twiddle_cpx ya,yb;
Chris@69:    kiss_fft_cpx * Fout_beg = Fout;
Chris@69: 
Chris@69: #ifdef FIXED_POINT
Chris@69:    ya.r = 10126;
Chris@69:    ya.i = -31164;
Chris@69:    yb.r = -26510;
Chris@69:    yb.i = -19261;
Chris@69: #else
Chris@69:    ya = st->twiddles[fstride*m];
Chris@69:    yb = st->twiddles[fstride*2*m];
Chris@69: #endif
Chris@69:    tw=st->twiddles;
Chris@69: 
Chris@69:    for (i=0;i<N;i++)
Chris@69:    {
Chris@69:       Fout = Fout_beg + i*mm;
Chris@69:       Fout0=Fout;
Chris@69:       Fout1=Fout0+m;
Chris@69:       Fout2=Fout0+2*m;
Chris@69:       Fout3=Fout0+3*m;
Chris@69:       Fout4=Fout0+4*m;
Chris@69: 
Chris@69:       /* For non-custom modes, m is guaranteed to be a multiple of 4. */
Chris@69:       for ( u=0; u<m; ++u ) {
Chris@69:          scratch[0] = *Fout0;
Chris@69: 
Chris@69:          C_MUL(scratch[1] ,*Fout1, tw[u*fstride]);
Chris@69:          C_MUL(scratch[2] ,*Fout2, tw[2*u*fstride]);
Chris@69:          C_MUL(scratch[3] ,*Fout3, tw[3*u*fstride]);
Chris@69:          C_MUL(scratch[4] ,*Fout4, tw[4*u*fstride]);
Chris@69: 
Chris@69:          C_ADD( scratch[7],scratch[1],scratch[4]);
Chris@69:          C_SUB( scratch[10],scratch[1],scratch[4]);
Chris@69:          C_ADD( scratch[8],scratch[2],scratch[3]);
Chris@69:          C_SUB( scratch[9],scratch[2],scratch[3]);
Chris@69: 
Chris@69:          Fout0->r = ADD32_ovflw(Fout0->r, ADD32_ovflw(scratch[7].r, scratch[8].r));
Chris@69:          Fout0->i = ADD32_ovflw(Fout0->i, ADD32_ovflw(scratch[7].i, scratch[8].i));
Chris@69: 
Chris@69:          scratch[5].r = ADD32_ovflw(scratch[0].r, ADD32_ovflw(S_MUL(scratch[7].r,ya.r), S_MUL(scratch[8].r,yb.r)));
Chris@69:          scratch[5].i = ADD32_ovflw(scratch[0].i, ADD32_ovflw(S_MUL(scratch[7].i,ya.r), S_MUL(scratch[8].i,yb.r)));
Chris@69: 
Chris@69:          scratch[6].r =  ADD32_ovflw(S_MUL(scratch[10].i,ya.i), S_MUL(scratch[9].i,yb.i));
Chris@69:          scratch[6].i = NEG32_ovflw(ADD32_ovflw(S_MUL(scratch[10].r,ya.i), S_MUL(scratch[9].r,yb.i)));
Chris@69: 
Chris@69:          C_SUB(*Fout1,scratch[5],scratch[6]);
Chris@69:          C_ADD(*Fout4,scratch[5],scratch[6]);
Chris@69: 
Chris@69:          scratch[11].r = ADD32_ovflw(scratch[0].r, ADD32_ovflw(S_MUL(scratch[7].r,yb.r), S_MUL(scratch[8].r,ya.r)));
Chris@69:          scratch[11].i = ADD32_ovflw(scratch[0].i, ADD32_ovflw(S_MUL(scratch[7].i,yb.r), S_MUL(scratch[8].i,ya.r)));
Chris@69:          scratch[12].r = SUB32_ovflw(S_MUL(scratch[9].i,ya.i), S_MUL(scratch[10].i,yb.i));
Chris@69:          scratch[12].i = SUB32_ovflw(S_MUL(scratch[10].r,yb.i), S_MUL(scratch[9].r,ya.i));
Chris@69: 
Chris@69:          C_ADD(*Fout2,scratch[11],scratch[12]);
Chris@69:          C_SUB(*Fout3,scratch[11],scratch[12]);
Chris@69: 
Chris@69:          ++Fout0;++Fout1;++Fout2;++Fout3;++Fout4;
Chris@69:       }
Chris@69:    }
Chris@69: }
Chris@69: #endif /* OVERRIDE_kf_bfly5 */
Chris@69: 
Chris@69: 
Chris@69: #endif
Chris@69: 
Chris@69: 
Chris@69: #ifdef CUSTOM_MODES
Chris@69: 
Chris@69: static
Chris@69: void compute_bitrev_table(
Chris@69:          int Fout,
Chris@69:          opus_int16 *f,
Chris@69:          const size_t fstride,
Chris@69:          int in_stride,
Chris@69:          opus_int16 * factors,
Chris@69:          const kiss_fft_state *st
Chris@69:             )
Chris@69: {
Chris@69:    const int p=*factors++; /* the radix  */
Chris@69:    const int m=*factors++; /* stage's fft length/p */
Chris@69: 
Chris@69:     /*printf ("fft %d %d %d %d %d %d\n", p*m, m, p, s2, fstride*in_stride, N);*/
Chris@69:    if (m==1)
Chris@69:    {
Chris@69:       int j;
Chris@69:       for (j=0;j<p;j++)
Chris@69:       {
Chris@69:          *f = Fout+j;
Chris@69:          f += fstride*in_stride;
Chris@69:       }
Chris@69:    } else {
Chris@69:       int j;
Chris@69:       for (j=0;j<p;j++)
Chris@69:       {
Chris@69:          compute_bitrev_table( Fout , f, fstride*p, in_stride, factors,st);
Chris@69:          f += fstride*in_stride;
Chris@69:          Fout += m;
Chris@69:       }
Chris@69:    }
Chris@69: }
Chris@69: 
Chris@69: /*  facbuf is populated by p1,m1,p2,m2, ...
Chris@69:     where
Chris@69:     p[i] * m[i] = m[i-1]
Chris@69:     m0 = n                  */
Chris@69: static
Chris@69: int kf_factor(int n,opus_int16 * facbuf)
Chris@69: {
Chris@69:     int p=4;
Chris@69:     int i;
Chris@69:     int stages=0;
Chris@69:     int nbak = n;
Chris@69: 
Chris@69:     /*factor out powers of 4, powers of 2, then any remaining primes */
Chris@69:     do {
Chris@69:         while (n % p) {
Chris@69:             switch (p) {
Chris@69:                 case 4: p = 2; break;
Chris@69:                 case 2: p = 3; break;
Chris@69:                 default: p += 2; break;
Chris@69:             }
Chris@69:             if (p>32000 || (opus_int32)p*(opus_int32)p > n)
Chris@69:                 p = n;          /* no more factors, skip to end */
Chris@69:         }
Chris@69:         n /= p;
Chris@69: #ifdef RADIX_TWO_ONLY
Chris@69:         if (p!=2 && p != 4)
Chris@69: #else
Chris@69:         if (p>5)
Chris@69: #endif
Chris@69:         {
Chris@69:            return 0;
Chris@69:         }
Chris@69:         facbuf[2*stages] = p;
Chris@69:         if (p==2 && stages > 1)
Chris@69:         {
Chris@69:            facbuf[2*stages] = 4;
Chris@69:            facbuf[2] = 2;
Chris@69:         }
Chris@69:         stages++;
Chris@69:     } while (n > 1);
Chris@69:     n = nbak;
Chris@69:     /* Reverse the order to get the radix 4 at the end, so we can use the
Chris@69:        fast degenerate case. It turns out that reversing the order also
Chris@69:        improves the noise behaviour. */
Chris@69:     for (i=0;i<stages/2;i++)
Chris@69:     {
Chris@69:        int tmp;
Chris@69:        tmp = facbuf[2*i];
Chris@69:        facbuf[2*i] = facbuf[2*(stages-i-1)];
Chris@69:        facbuf[2*(stages-i-1)] = tmp;
Chris@69:     }
Chris@69:     for (i=0;i<stages;i++)
Chris@69:     {
Chris@69:         n /= facbuf[2*i];
Chris@69:         facbuf[2*i+1] = n;
Chris@69:     }
Chris@69:     return 1;
Chris@69: }
Chris@69: 
Chris@69: static void compute_twiddles(kiss_twiddle_cpx *twiddles, int nfft)
Chris@69: {
Chris@69:    int i;
Chris@69: #ifdef FIXED_POINT
Chris@69:    for (i=0;i<nfft;++i) {
Chris@69:       opus_val32 phase = -i;
Chris@69:       kf_cexp2(twiddles+i, DIV32(SHL32(phase,17),nfft));
Chris@69:    }
Chris@69: #else
Chris@69:    for (i=0;i<nfft;++i) {
Chris@69:       const double pi=3.14159265358979323846264338327;
Chris@69:       double phase = ( -2*pi /nfft ) * i;
Chris@69:       kf_cexp(twiddles+i, phase );
Chris@69:    }
Chris@69: #endif
Chris@69: }
Chris@69: 
Chris@69: int opus_fft_alloc_arch_c(kiss_fft_state *st) {
Chris@69:    (void)st;
Chris@69:    return 0;
Chris@69: }
Chris@69: 
Chris@69: /*
Chris@69:  *
Chris@69:  * Allocates all necessary storage space for the fft and ifft.
Chris@69:  * The return value is a contiguous block of memory.  As such,
Chris@69:  * It can be freed with free().
Chris@69:  * */
Chris@69: kiss_fft_state *opus_fft_alloc_twiddles(int nfft,void * mem,size_t * lenmem,
Chris@69:                                         const kiss_fft_state *base, int arch)
Chris@69: {
Chris@69:     kiss_fft_state *st=NULL;
Chris@69:     size_t memneeded = sizeof(struct kiss_fft_state); /* twiddle factors*/
Chris@69: 
Chris@69:     if ( lenmem==NULL ) {
Chris@69:         st = ( kiss_fft_state*)KISS_FFT_MALLOC( memneeded );
Chris@69:     }else{
Chris@69:         if (mem != NULL && *lenmem >= memneeded)
Chris@69:             st = (kiss_fft_state*)mem;
Chris@69:         *lenmem = memneeded;
Chris@69:     }
Chris@69:     if (st) {
Chris@69:         opus_int16 *bitrev;
Chris@69:         kiss_twiddle_cpx *twiddles;
Chris@69: 
Chris@69:         st->nfft=nfft;
Chris@69: #ifdef FIXED_POINT
Chris@69:         st->scale_shift = celt_ilog2(st->nfft);
Chris@69:         if (st->nfft == 1<<st->scale_shift)
Chris@69:            st->scale = Q15ONE;
Chris@69:         else
Chris@69:            st->scale = (1073741824+st->nfft/2)/st->nfft>>(15-st->scale_shift);
Chris@69: #else
Chris@69:         st->scale = 1.f/nfft;
Chris@69: #endif
Chris@69:         if (base != NULL)
Chris@69:         {
Chris@69:            st->twiddles = base->twiddles;
Chris@69:            st->shift = 0;
Chris@69:            while (st->shift < 32 && nfft<<st->shift != base->nfft)
Chris@69:               st->shift++;
Chris@69:            if (st->shift>=32)
Chris@69:               goto fail;
Chris@69:         } else {
Chris@69:            st->twiddles = twiddles = (kiss_twiddle_cpx*)KISS_FFT_MALLOC(sizeof(kiss_twiddle_cpx)*nfft);
Chris@69:            compute_twiddles(twiddles, nfft);
Chris@69:            st->shift = -1;
Chris@69:         }
Chris@69:         if (!kf_factor(nfft,st->factors))
Chris@69:         {
Chris@69:            goto fail;
Chris@69:         }
Chris@69: 
Chris@69:         /* bitrev */
Chris@69:         st->bitrev = bitrev = (opus_int16*)KISS_FFT_MALLOC(sizeof(opus_int16)*nfft);
Chris@69:         if (st->bitrev==NULL)
Chris@69:             goto fail;
Chris@69:         compute_bitrev_table(0, bitrev, 1,1, st->factors,st);
Chris@69: 
Chris@69:         /* Initialize architecture specific fft parameters */
Chris@69:         if (opus_fft_alloc_arch(st, arch))
Chris@69:             goto fail;
Chris@69:     }
Chris@69:     return st;
Chris@69: fail:
Chris@69:     opus_fft_free(st, arch);
Chris@69:     return NULL;
Chris@69: }
Chris@69: 
Chris@69: kiss_fft_state *opus_fft_alloc(int nfft,void * mem,size_t * lenmem, int arch)
Chris@69: {
Chris@69:    return opus_fft_alloc_twiddles(nfft, mem, lenmem, NULL, arch);
Chris@69: }
Chris@69: 
Chris@69: void opus_fft_free_arch_c(kiss_fft_state *st) {
Chris@69:    (void)st;
Chris@69: }
Chris@69: 
Chris@69: void opus_fft_free(const kiss_fft_state *cfg, int arch)
Chris@69: {
Chris@69:    if (cfg)
Chris@69:    {
Chris@69:       opus_fft_free_arch((kiss_fft_state *)cfg, arch);
Chris@69:       opus_free((opus_int16*)cfg->bitrev);
Chris@69:       if (cfg->shift < 0)
Chris@69:          opus_free((kiss_twiddle_cpx*)cfg->twiddles);
Chris@69:       opus_free((kiss_fft_state*)cfg);
Chris@69:    }
Chris@69: }
Chris@69: 
Chris@69: #endif /* CUSTOM_MODES */
Chris@69: 
Chris@69: void opus_fft_impl(const kiss_fft_state *st,kiss_fft_cpx *fout)
Chris@69: {
Chris@69:     int m2, m;
Chris@69:     int p;
Chris@69:     int L;
Chris@69:     int fstride[MAXFACTORS];
Chris@69:     int i;
Chris@69:     int shift;
Chris@69: 
Chris@69:     /* st->shift can be -1 */
Chris@69:     shift = st->shift>0 ? st->shift : 0;
Chris@69: 
Chris@69:     fstride[0] = 1;
Chris@69:     L=0;
Chris@69:     do {
Chris@69:        p = st->factors[2*L];
Chris@69:        m = st->factors[2*L+1];
Chris@69:        fstride[L+1] = fstride[L]*p;
Chris@69:        L++;
Chris@69:     } while(m!=1);
Chris@69:     m = st->factors[2*L-1];
Chris@69:     for (i=L-1;i>=0;i--)
Chris@69:     {
Chris@69:        if (i!=0)
Chris@69:           m2 = st->factors[2*i-1];
Chris@69:        else
Chris@69:           m2 = 1;
Chris@69:        switch (st->factors[2*i])
Chris@69:        {
Chris@69:        case 2:
Chris@69:           kf_bfly2(fout, m, fstride[i]);
Chris@69:           break;
Chris@69:        case 4:
Chris@69:           kf_bfly4(fout,fstride[i]<<shift,st,m, fstride[i], m2);
Chris@69:           break;
Chris@69:  #ifndef RADIX_TWO_ONLY
Chris@69:        case 3:
Chris@69:           kf_bfly3(fout,fstride[i]<<shift,st,m, fstride[i], m2);
Chris@69:           break;
Chris@69:        case 5:
Chris@69:           kf_bfly5(fout,fstride[i]<<shift,st,m, fstride[i], m2);
Chris@69:           break;
Chris@69:  #endif
Chris@69:        }
Chris@69:        m = m2;
Chris@69:     }
Chris@69: }
Chris@69: 
Chris@69: void opus_fft_c(const kiss_fft_state *st,const kiss_fft_cpx *fin,kiss_fft_cpx *fout)
Chris@69: {
Chris@69:    int i;
Chris@69:    opus_val16 scale;
Chris@69: #ifdef FIXED_POINT
Chris@69:    /* Allows us to scale with MULT16_32_Q16(), which is faster than
Chris@69:       MULT16_32_Q15() on ARM. */
Chris@69:    int scale_shift = st->scale_shift-1;
Chris@69: #endif
Chris@69:    scale = st->scale;
Chris@69: 
Chris@69:    celt_assert2 (fin != fout, "In-place FFT not supported");
Chris@69:    /* Bit-reverse the input */
Chris@69:    for (i=0;i<st->nfft;i++)
Chris@69:    {
Chris@69:       kiss_fft_cpx x = fin[i];
Chris@69:       fout[st->bitrev[i]].r = SHR32(MULT16_32_Q16(scale, x.r), scale_shift);
Chris@69:       fout[st->bitrev[i]].i = SHR32(MULT16_32_Q16(scale, x.i), scale_shift);
Chris@69:    }
Chris@69:    opus_fft_impl(st, fout);
Chris@69: }
Chris@69: 
Chris@69: 
Chris@69: void opus_ifft_c(const kiss_fft_state *st,const kiss_fft_cpx *fin,kiss_fft_cpx *fout)
Chris@69: {
Chris@69:    int i;
Chris@69:    celt_assert2 (fin != fout, "In-place FFT not supported");
Chris@69:    /* Bit-reverse the input */
Chris@69:    for (i=0;i<st->nfft;i++)
Chris@69:       fout[st->bitrev[i]] = fin[i];
Chris@69:    for (i=0;i<st->nfft;i++)
Chris@69:       fout[i].i = -fout[i].i;
Chris@69:    opus_fft_impl(st, fout);
Chris@69:    for (i=0;i<st->nfft;i++)
Chris@69:       fout[i].i = -fout[i].i;
Chris@69: }