ref: 42667b0a5f4fde51f211e50b5eb78a1d5c98b1d0
parent: 4508ebd58562e23980157a3e954085bf31640870
author: Jean-Marc Valin <[email protected]>
date: Mon Feb 25 04:47:25 EST 2008
real fft no longer needs an internal buffer.
--- a/libcelt/kiss_fft.c
+++ b/libcelt/kiss_fft.c
@@ -478,8 +478,8 @@
static
void compute_bitrev_table(
- int * Fout,
- int f,
+ int Fout,
+ int *f,
const size_t fstride,
int in_stride,
int * factors,
@@ -495,7 +495,7 @@
int j;
for (j=0;j<p;j++)
{- Fout[j] = f;
+ *f = Fout+j;
f += fstride*in_stride;
}
} else {@@ -539,18 +539,18 @@
}
}
-static
- void ki_work(
- kiss_fft_cpx * Fout,
- const kiss_fft_cpx * f,
- const size_t fstride,
- int in_stride,
- int * factors,
- const kiss_fft_cfg st,
- int N,
- int s2,
- int m2
- )
+
+void ki_work(
+ kiss_fft_cpx * Fout,
+ const kiss_fft_cpx * f,
+ const size_t fstride,
+ int in_stride,
+ int * factors,
+ const kiss_fft_cfg st,
+ int N,
+ int s2,
+ int m2
+ )
{int i;
kiss_fft_cpx * Fout_beg=Fout;
@@ -636,7 +636,7 @@
/* bitrev */
st->bitrev = (int*)((char*)st + memneeded - sizeof(int)*nfft);
- compute_bitrev_table(st->bitrev, 0, 1,1, st->factors,st);
+ compute_bitrev_table(0, st->bitrev, 1,1, st->factors,st);
}
return st;
}
@@ -654,10 +654,10 @@
int i;
for (i=0;i<st->nfft;i++)
{- fout[i] = fin[st->bitrev[i]];
+ fout[st->bitrev[i]] = fin[i];
#ifndef FIXED_POINT
- fout[i].r *= st->scale;
- fout[i].i *= st->scale;
+ fout[st->bitrev[i]].r *= st->scale;
+ fout[st->bitrev[i]].i *= st->scale;
#endif
}
kf_work( fout, fin, 1,in_stride, st->factors,st, 1, in_stride, 1);
@@ -678,7 +678,7 @@
/* Bit-reverse the input */
int i;
for (i=0;i<st->nfft;i++)
- fout[i] = fin[st->bitrev[i]];
+ fout[st->bitrev[i]] = fin[i];
ki_work( fout, fin, 1,in_stride, st->factors,st, 1, in_stride, 1);
}
}
--- a/libcelt/kiss_fft.h
+++ b/libcelt/kiss_fft.h
@@ -85,6 +85,10 @@
kiss_fft_cfg kiss_fft_alloc(int nfft,void * mem,size_t * lenmem);
+/** Internal function. Can be useful when you want to do the bit-reversing yourself */
+void ki_work(kiss_fft_cpx * Fout, const kiss_fft_cpx * f, const size_t fstride,
+ int in_stride,int * factors,const kiss_fft_cfg st,int N,int s2,int m2);
+
/**
* kiss_fft(cfg,in_out_buf)
*
--- a/libcelt/kiss_fftr.c
+++ b/libcelt/kiss_fftr.c
@@ -26,7 +26,6 @@
struct kiss_fftr_state{kiss_fft_cfg substate;
- kiss_fft_cpx * tmpbuf;
kiss_twiddle_cpx * super_twiddles;
#ifdef USE_SIMD
long pad;
@@ -46,7 +45,7 @@
nfft >>= 1;
kiss_fft_alloc (nfft, NULL, &subsize);
- memneeded = sizeof(struct kiss_fftr_state) + subsize + sizeof(kiss_fft_cpx) * ( nfft) + sizeof(kiss_twiddle_cpx)*nfft;
+ memneeded = sizeof(struct kiss_fftr_state) + subsize + sizeof(kiss_twiddle_cpx)*nfft;
if (lenmem == NULL) {st = (kiss_fftr_cfg) KISS_FFT_MALLOC (memneeded);
@@ -59,8 +58,7 @@
return NULL;
st->substate = (kiss_fft_cfg) (st + 1); /*just beyond kiss_fftr_state struct */
- st->tmpbuf = (kiss_fft_cpx *) (((char *) st->substate) + subsize);
- st->super_twiddles = (kiss_twiddle_cpx*)(st->tmpbuf + nfft);
+ st->super_twiddles = (kiss_twiddle_cpx*) (((char *) st->substate) + subsize);
kiss_fft_alloc(nfft, st->substate, &subsize);
#ifndef FIXED_POINT
st->substate->scale *= .5;
@@ -135,26 +133,25 @@
ncfft = st->substate->nfft;
- st->tmpbuf[0].r = freqdata[0] + freqdata[1];
- st->tmpbuf[0].i = freqdata[0] - freqdata[1];
-
+ timedata[2*st->substate->bitrev[0]] = freqdata[0] + freqdata[1];
+ timedata[2*st->substate->bitrev[0]+1] = freqdata[0] - freqdata[1];
for (k = 1; k <= ncfft / 2; ++k) {kiss_fft_cpx fk, fnkc, fek, fok, tmp;
+ int k1, k2;
+ k1 = st->substate->bitrev[k];
+ k2 = st->substate->bitrev[ncfft-k];
fk.r = freqdata[2*k];
fk.i = freqdata[2*k+1];
- fnkc.r = freqdata[2*(ncfft - k)];
- fnkc.i = -freqdata[2*(ncfft - k)+1];
+ fnkc.r = freqdata[2*(ncfft-k)];
+ fnkc.i = -freqdata[2*(ncfft-k)+1];
C_ADD (fek, fk, fnkc);
C_SUB (tmp, fk, fnkc);
C_MUL (fok, tmp, st->super_twiddles[k]);
- C_ADD (st->tmpbuf[k], fek, fok);
- C_SUB (st->tmpbuf[ncfft - k], fek, fok);
-#ifdef USE_SIMD
- st->tmpbuf[ncfft - k].i *= _mm_set1_ps(-1.0);
-#else
- st->tmpbuf[ncfft - k].i *= -1;
-#endif
+ timedata[2*k1] = fek.r + fok.r;
+ timedata[2*k1+1] = fek.i + fok.i;
+ timedata[2*k2] = fek.r - fok.r;
+ timedata[2*k2+1] = fok.i - fek.i;
}
- kiss_ifft (st->substate, st->tmpbuf, (kiss_fft_cpx *) timedata);
+ ki_work((kiss_fft_cpx*)timedata, NULL, 1,1, st->substate->factors,st->substate, 1, 1, 1);
}