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-rw-r--r--libs/qm-dsp/ext/kissfft/kissfft.hh300
1 files changed, 300 insertions, 0 deletions
diff --git a/libs/qm-dsp/ext/kissfft/kissfft.hh b/libs/qm-dsp/ext/kissfft/kissfft.hh
new file mode 100644
index 0000000000..4f6ac92f3b
--- /dev/null
+++ b/libs/qm-dsp/ext/kissfft/kissfft.hh
@@ -0,0 +1,300 @@
+#ifndef KISSFFT_CLASS_HH
+#define KISSFFT_CLASS_HH
+#include <complex>
+#include <vector>
+
+namespace kissfft_utils {
+
+template <typename T_scalar>
+struct traits
+{
+ typedef T_scalar scalar_type;
+ typedef std::complex<scalar_type> cpx_type;
+ void fill_twiddles( std::complex<T_scalar> * dst ,int nfft,bool inverse)
+ {
+ T_scalar phinc = (inverse?2:-2)* acos( (T_scalar) -1) / nfft;
+ for (int i=0;i<nfft;++i)
+ dst[i] = exp( std::complex<T_scalar>(0,i*phinc) );
+ }
+
+ void prepare(
+ std::vector< std::complex<T_scalar> > & dst,
+ int nfft,bool inverse,
+ std::vector<int> & stageRadix,
+ std::vector<int> & stageRemainder )
+ {
+ _twiddles.resize(nfft);
+ fill_twiddles( &_twiddles[0],nfft,inverse);
+ dst = _twiddles;
+
+ //factorize
+ //start factoring out 4's, then 2's, then 3,5,7,9,...
+ int n= nfft;
+ int p=4;
+ do {
+ while (n % p) {
+ switch (p) {
+ case 4: p = 2; break;
+ case 2: p = 3; break;
+ default: p += 2; break;
+ }
+ if (p*p>n)
+ p=n;// no more factors
+ }
+ n /= p;
+ stageRadix.push_back(p);
+ stageRemainder.push_back(n);
+ }while(n>1);
+ }
+ std::vector<cpx_type> _twiddles;
+
+
+ const cpx_type twiddle(int i) { return _twiddles[i]; }
+};
+
+}
+
+template <typename T_Scalar,
+ typename T_traits=kissfft_utils::traits<T_Scalar>
+ >
+class kissfft
+{
+ public:
+ typedef T_traits traits_type;
+ typedef typename traits_type::scalar_type scalar_type;
+ typedef typename traits_type::cpx_type cpx_type;
+
+ kissfft(int nfft,bool inverse,const traits_type & traits=traits_type() )
+ :_nfft(nfft),_inverse(inverse),_traits(traits)
+ {
+ _traits.prepare(_twiddles, _nfft,_inverse ,_stageRadix, _stageRemainder);
+ }
+
+ void transform(const cpx_type * src , cpx_type * dst)
+ {
+ kf_work(0, dst, src, 1,1);
+ }
+
+ private:
+ void kf_work( int stage,cpx_type * Fout, const cpx_type * f, size_t fstride,size_t in_stride)
+ {
+ int p = _stageRadix[stage];
+ int m = _stageRemainder[stage];
+ cpx_type * Fout_beg = Fout;
+ cpx_type * Fout_end = Fout + p*m;
+
+ if (m==1) {
+ do{
+ *Fout = *f;
+ f += fstride*in_stride;
+ }while(++Fout != Fout_end );
+ }else{
+ do{
+ // recursive call:
+ // DFT of size m*p performed by doing
+ // p instances of smaller DFTs of size m,
+ // each one takes a decimated version of the input
+ kf_work(stage+1, Fout , f, fstride*p,in_stride);
+ f += fstride*in_stride;
+ }while( (Fout += m) != Fout_end );
+ }
+
+ Fout=Fout_beg;
+
+ // recombine the p smaller DFTs
+ switch (p) {
+ case 2: kf_bfly2(Fout,fstride,m); break;
+ case 3: kf_bfly3(Fout,fstride,m); break;
+ case 4: kf_bfly4(Fout,fstride,m); break;
+ case 5: kf_bfly5(Fout,fstride,m); break;
+ default: kf_bfly_generic(Fout,fstride,m,p); break;
+ }
+ }
+
+ // these were #define macros in the original kiss_fft
+ void C_ADD( cpx_type & c,const cpx_type & a,const cpx_type & b) { c=a+b;}
+ void C_MUL( cpx_type & c,const cpx_type & a,const cpx_type & b) { c=a*b;}
+ void C_SUB( cpx_type & c,const cpx_type & a,const cpx_type & b) { c=a-b;}
+ void C_ADDTO( cpx_type & c,const cpx_type & a) { c+=a;}
+ void C_FIXDIV( cpx_type & ,int ) {} // NO-OP for float types
+ scalar_type S_MUL( const scalar_type & a,const scalar_type & b) { return a*b;}
+ scalar_type HALF_OF( const scalar_type & a) { return a*.5;}
+ void C_MULBYSCALAR(cpx_type & c,const scalar_type & a) {c*=a;}
+
+ void kf_bfly2( cpx_type * Fout, const size_t fstride, int m)
+ {
+ for (int k=0;k<m;++k) {
+ cpx_type t = Fout[m+k] * _traits.twiddle(k*fstride);
+ Fout[m+k] = Fout[k] - t;
+ Fout[k] += t;
+ }
+ }
+
+ void kf_bfly4( cpx_type * Fout, const size_t fstride, const size_t m)
+ {
+ cpx_type scratch[7];
+ int negative_if_inverse = _inverse * -2 +1;
+ for (size_t k=0;k<m;++k) {
+ scratch[0] = Fout[k+m] * _traits.twiddle(k*fstride);
+ scratch[1] = Fout[k+2*m] * _traits.twiddle(k*fstride*2);
+ scratch[2] = Fout[k+3*m] * _traits.twiddle(k*fstride*3);
+ scratch[5] = Fout[k] - scratch[1];
+
+ Fout[k] += scratch[1];
+ scratch[3] = scratch[0] + scratch[2];
+ scratch[4] = scratch[0] - scratch[2];
+ scratch[4] = cpx_type( scratch[4].imag()*negative_if_inverse , -scratch[4].real()* negative_if_inverse );
+
+ Fout[k+2*m] = Fout[k] - scratch[3];
+ Fout[k] += scratch[3];
+ Fout[k+m] = scratch[5] + scratch[4];
+ Fout[k+3*m] = scratch[5] - scratch[4];
+ }
+ }
+
+ void kf_bfly3( cpx_type * Fout, const size_t fstride, const size_t m)
+ {
+ size_t k=m;
+ const size_t m2 = 2*m;
+ cpx_type *tw1,*tw2;
+ cpx_type scratch[5];
+ cpx_type epi3;
+ epi3 = _twiddles[fstride*m];
+
+ tw1=tw2=&_twiddles[0];
+
+ do{
+ C_FIXDIV(*Fout,3); C_FIXDIV(Fout[m],3); C_FIXDIV(Fout[m2],3);
+
+ C_MUL(scratch[1],Fout[m] , *tw1);
+ C_MUL(scratch[2],Fout[m2] , *tw2);
+
+ C_ADD(scratch[3],scratch[1],scratch[2]);
+ C_SUB(scratch[0],scratch[1],scratch[2]);
+ tw1 += fstride;
+ tw2 += fstride*2;
+
+ Fout[m] = cpx_type( Fout->real() - HALF_OF(scratch[3].real() ) , Fout->imag() - HALF_OF(scratch[3].imag() ) );
+
+ C_MULBYSCALAR( scratch[0] , epi3.imag() );
+
+ C_ADDTO(*Fout,scratch[3]);
+
+ Fout[m2] = cpx_type( Fout[m].real() + scratch[0].imag() , Fout[m].imag() - scratch[0].real() );
+
+ C_ADDTO( Fout[m] , cpx_type( -scratch[0].imag(),scratch[0].real() ) );
+ ++Fout;
+ }while(--k);
+ }
+
+ void kf_bfly5( cpx_type * Fout, const size_t fstride, const size_t m)
+ {
+ cpx_type *Fout0,*Fout1,*Fout2,*Fout3,*Fout4;
+ size_t u;
+ cpx_type scratch[13];
+ cpx_type * twiddles = &_twiddles[0];
+ cpx_type *tw;
+ cpx_type ya,yb;
+ ya = twiddles[fstride*m];
+ yb = twiddles[fstride*2*m];
+
+ Fout0=Fout;
+ Fout1=Fout0+m;
+ Fout2=Fout0+2*m;
+ Fout3=Fout0+3*m;
+ Fout4=Fout0+4*m;
+
+ tw=twiddles;
+ for ( u=0; u<m; ++u ) {
+ C_FIXDIV( *Fout0,5); C_FIXDIV( *Fout1,5); C_FIXDIV( *Fout2,5); C_FIXDIV( *Fout3,5); C_FIXDIV( *Fout4,5);
+ scratch[0] = *Fout0;
+
+ C_MUL(scratch[1] ,*Fout1, tw[u*fstride]);
+ C_MUL(scratch[2] ,*Fout2, tw[2*u*fstride]);
+ C_MUL(scratch[3] ,*Fout3, tw[3*u*fstride]);
+ C_MUL(scratch[4] ,*Fout4, tw[4*u*fstride]);
+
+ C_ADD( scratch[7],scratch[1],scratch[4]);
+ C_SUB( scratch[10],scratch[1],scratch[4]);
+ C_ADD( scratch[8],scratch[2],scratch[3]);
+ C_SUB( scratch[9],scratch[2],scratch[3]);
+
+ C_ADDTO( *Fout0, scratch[7]);
+ C_ADDTO( *Fout0, scratch[8]);
+
+ scratch[5] = scratch[0] + cpx_type(
+ S_MUL(scratch[7].real(),ya.real() ) + S_MUL(scratch[8].real() ,yb.real() ),
+ S_MUL(scratch[7].imag(),ya.real()) + S_MUL(scratch[8].imag(),yb.real())
+ );
+
+ scratch[6] = cpx_type(
+ S_MUL(scratch[10].imag(),ya.imag()) + S_MUL(scratch[9].imag(),yb.imag()),
+ -S_MUL(scratch[10].real(),ya.imag()) - S_MUL(scratch[9].real(),yb.imag())
+ );
+
+ C_SUB(*Fout1,scratch[5],scratch[6]);
+ C_ADD(*Fout4,scratch[5],scratch[6]);
+
+ scratch[11] = scratch[0] +
+ cpx_type(
+ S_MUL(scratch[7].real(),yb.real()) + S_MUL(scratch[8].real(),ya.real()),
+ S_MUL(scratch[7].imag(),yb.real()) + S_MUL(scratch[8].imag(),ya.real())
+ );
+
+ scratch[12] = cpx_type(
+ -S_MUL(scratch[10].imag(),yb.imag()) + S_MUL(scratch[9].imag(),ya.imag()),
+ S_MUL(scratch[10].real(),yb.imag()) - S_MUL(scratch[9].real(),ya.imag())
+ );
+
+ C_ADD(*Fout2,scratch[11],scratch[12]);
+ C_SUB(*Fout3,scratch[11],scratch[12]);
+
+ ++Fout0;++Fout1;++Fout2;++Fout3;++Fout4;
+ }
+ }
+
+ /* perform the butterfly for one stage of a mixed radix FFT */
+ void kf_bfly_generic(
+ cpx_type * Fout,
+ const size_t fstride,
+ int m,
+ int p
+ )
+ {
+ int u,k,q1,q;
+ cpx_type * twiddles = &_twiddles[0];
+ cpx_type t;
+ int Norig = _nfft;
+ cpx_type scratchbuf[p];
+
+ for ( u=0; u<m; ++u ) {
+ k=u;
+ for ( q1=0 ; q1<p ; ++q1 ) {
+ scratchbuf[q1] = Fout[ k ];
+ C_FIXDIV(scratchbuf[q1],p);
+ k += m;
+ }
+
+ k=u;
+ for ( q1=0 ; q1<p ; ++q1 ) {
+ int twidx=0;
+ Fout[ k ] = scratchbuf[0];
+ for (q=1;q<p;++q ) {
+ twidx += fstride * k;
+ if (twidx>=Norig) twidx-=Norig;
+ C_MUL(t,scratchbuf[q] , twiddles[twidx] );
+ C_ADDTO( Fout[ k ] ,t);
+ }
+ k += m;
+ }
+ }
+ }
+
+ int _nfft;
+ bool _inverse;
+ std::vector<cpx_type> _twiddles;
+ std::vector<int> _stageRadix;
+ std::vector<int> _stageRemainder;
+ traits_type _traits;
+};
+#endif
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