static
void compute_bitrev_table(
int Fout,
opus_int16 *f,
const size_t fstride,
int in_stride,
opus_int16 * factors,
const kiss_fft_state *st
)
{
const int p=*factors++; /* the radix */
const int m=*factors++; /* stage's fft length/p */
/*printf ("fft %d %d %d %d %d %d\n", p*m, m, p, s2, fstride*in_stride, N);*/
if (m==1)
{
int j;
for (j=0;j<p;j++)
{
*f = Fout+j;
f += fstride*in_stride;
}
} else {
int j;
for (j=0;j<p;j++)
{
compute_bitrev_table( Fout , f, fstride*p, in_stride, factors,st);
f += fstride*in_stride;
Fout += m;
}
}
}
/*
*
* Allocates all necessary storage space for the fft and ifft.
* The return value is a contiguous block of memory. As such,
* It can be freed with free().
* */
kiss_fft_state *opus_fft_alloc_twiddles(int nfft,void * mem,size_t * lenmem,
const kiss_fft_state *base, int arch)
{
kiss_fft_state *st=NULL;
size_t memneeded = sizeof(struct kiss_fft_state); /* twiddle factors*/
if ( lenmem==NULL ) {
st = ( kiss_fft_state*)KISS_FFT_MALLOC( memneeded );
}else{
if (mem != NULL && *lenmem >= memneeded)
st = (kiss_fft_state*)mem;
*lenmem = memneeded;
}
if (st) {
opus_int16 *bitrev;
kiss_twiddle_cpx *twiddles;
st->nfft=nfft;
#ifdef FIXED_POINT
st->scale_shift = celt_ilog2(st->nfft);
if (st->nfft == 1<<st->scale_shift)
st->scale = Q15ONE;
else
st->scale = (1073741824+st->nfft/2)/st->nfft>>(15-st->scale_shift);
#else
st->scale = 1.f/nfft;
#endif
if (base != NULL)
{
st->twiddles = base->twiddles;
st->shift = 0;
while (st->shift < 32 && nfft<<st->shift != base->nfft)
st->shift++;
if (st->shift>=32)
goto fail;
} else {
st->twiddles = twiddles = (kiss_twiddle_cpx*)KISS_FFT_MALLOC(sizeof(kiss_twiddle_cpx)*nfft);
compute_twiddles(twiddles, nfft);
st->shift = -1;
}
if (!kf_factor(nfft,st->factors))
{
goto fail;
}
/* bitrev */
st->bitrev = bitrev = (opus_int16*)KISS_FFT_MALLOC(sizeof(opus_int16)*nfft);
if (st->bitrev==NULL)
goto fail;
compute_bitrev_table(0, bitrev, 1,1, st->factors,st);
/* Initialize architecture specific fft parameters */
if (opus_fft_alloc_arch(st, arch))
goto fail;
}
return st;
fail:
opus_fft_free(st, arch);
return NULL;
}
/*
*
* Allocates all necessary storage space for the fft and ifft.
* The return value is a contiguous block of memory. As such,
* It can be freed with free().
* */
kiss_fft_state *opus_fft_alloc_twiddles(int nfft,void * mem,size_t * lenmem, const kiss_fft_state *base)
{
kiss_fft_state *st=NULL;
size_t memneeded = sizeof(struct kiss_fft_state); /* twiddle factors*/
if ( lenmem==NULL ) {
st = ( kiss_fft_state*)KISS_FFT_MALLOC( memneeded );
}else{
if (mem != NULL && *lenmem >= memneeded)
st = (kiss_fft_state*)mem;
*lenmem = memneeded;
}
if (st) {
opus_int16 *bitrev;
kiss_twiddle_cpx *twiddles;
st->nfft=nfft;
#ifndef FIXED_POINT
st->scale = 1.f/nfft;
#endif
if (base != NULL)
{
st->twiddles = base->twiddles;
st->shift = 0;
while (nfft<<st->shift != base->nfft && st->shift < 32)
st->shift++;
if (st->shift>=32)
goto fail;
} else {
st->twiddles = twiddles = (kiss_twiddle_cpx*)KISS_FFT_MALLOC(sizeof(kiss_twiddle_cpx)*nfft);
compute_twiddles(twiddles, nfft);
st->shift = -1;
}
if (!kf_factor(nfft,st->factors))
{
goto fail;
}
/* bitrev */
st->bitrev = bitrev = (opus_int16*)KISS_FFT_MALLOC(sizeof(opus_int16)*nfft);
if (st->bitrev==NULL)
goto fail;
compute_bitrev_table(0, bitrev, 1,1, st->factors,st);
}
return st;
fail:
opus_fft_free(st);
return NULL;
}
