/********************************************************************
 *                                                                  *
 * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
 *                                                                  *
 * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2007             *
 * by the Xiph.Org Foundation http://www.xiph.org/                  *
 *                                                                  *
 ********************************************************************

Copyright (c) 2002-2007 Xiph.org Foundation

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:

- Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.

- Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.

- Neither the name of the Xiph.org Foundation nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
`AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION
OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 ********************************************************************/

#include "smallft.h"

#include <cmath>
#include <cstdlib>
#include <cstring>

static void drfti1(int n, float *wa, int *ifac) {
	static int ntryh[4] = { 4,2,3,5 };
	static float tpi = 6.28318530717958648f;
	float arg,argh,argld,fi;
	int ntry=0,i,j=-1;
	int k1, l1, l2, ib;
	int ld, ii, ip, is, nq, nr;
	int ido, ipm, nfm1;
	int nl=n;
	int nf=0;

L101:
	j++;
	if (j < 4)
		ntry=ntryh[j];
	else
		ntry+=2;

L104:
	nq=nl/ntry;
	nr=nl-ntry*nq;
	if (nr!=0) goto L101;

	nf++;
	ifac[nf+1]=ntry;
	nl=nq;
	if (ntry!=2)goto L107;
	if (nf==1)goto L107;

	for (i=1;i<nf;i++) {
		ib=nf-i+1;
		ifac[ib+1]=ifac[ib];
	}
	ifac[2] = 2;

L107:
	if (nl!=1)goto L104;
	ifac[0]=n;
	ifac[1]=nf;
	argh=tpi/static_cast<float>(n);
	is=0;
	nfm1=nf-1;
	l1=1;

	if (nfm1==0)return;

	for (k1=0;k1<nfm1;k1++) {
		ip=ifac[k1+2];
		ld=0;
		l2=l1*ip;
		ido=n/l2;
		ipm=ip-1;

		for (j=0;j<ipm;j++) {
			ld+=l1;
			i=is;
			argld=static_cast<float>(ld)*argh;
			fi=0.f;
			for (ii=2;ii<ido;ii+=2) {
				fi+=1.f;
				arg=fi*argld;
				wa[i++]=cosf(arg);
				wa[i++]=sinf(arg);
			}
			is+=ido;
		}
		l1=l2;
	}
}

static void fdrffti(int n, float *wsave, int *ifac) {

	if (n == 1) return;
	drfti1(n, wsave+n, ifac);
}

static void dradf2(int ido,int l1,float *cc,float *ch,float *wa1) {
	int i,k;
	float ti2,tr2;
	int t0,t1,t2,t3,t4,t5,t6;

	t1=0;
	t0=(t2=l1*ido);
	t3=ido<<1;
	for (k=0;k<l1;k++) {
		ch[t1<<1]=cc[t1]+cc[t2];
		ch[(t1<<1)+t3-1]=cc[t1]-cc[t2];
		t1+=ido;
		t2+=ido;
	}

	if (ido<2)return;
	if (ido==2)goto L105;

	t1=0;
	t2=t0;
	for (k=0;k<l1;k++) {
		t3=t2;
		t4=(t1<<1)+(ido<<1);
		t5=t1;
		t6=t1+t1;
		for (i=2;i<ido;i+=2) {
			t3+=2;
			t4-=2;
			t5+=2;
			t6+=2;
			tr2=wa1[i-2]*cc[t3-1]+wa1[i-1]*cc[t3];
			ti2=wa1[i-2]*cc[t3]-wa1[i-1]*cc[t3-1];
			ch[t6]=cc[t5]+ti2;
			ch[t4]=ti2-cc[t5];
			ch[t6-1]=cc[t5-1]+tr2;
			ch[t4-1]=cc[t5-1]-tr2;
		}
		t1+=ido;
		t2+=ido;
	}

	if (ido%2==1)return;

L105:
	t3=(t2=(t1=ido)-1);
	t2+=t0;
	for (k=0;k<l1;k++) {
		ch[t1]=-cc[t2];
		ch[t1-1]=cc[t3];
		t1+=ido<<1;
		t2+=ido;
		t3+=ido;
	}
}

static void dradf4(int ido,int l1,float *cc,float *ch,float *wa1,
                   float *wa2,float *wa3) {
	static float hsqt2 = .70710678118654752f;
	int i,k,t0,t1,t2,t3,t4,t5,t6;
	float ci2,ci3,ci4,cr2,cr3,cr4,ti1,ti2,ti3,ti4,tr1,tr2,tr3,tr4;
	t0=l1*ido;

	t1=t0;
	t4=t1<<1;
	t2=t1+(t1<<1);
	t3=0;

	for (k=0;k<l1;k++) {
		tr1=cc[t1]+cc[t2];
		tr2=cc[t3]+cc[t4];

		ch[t5=t3<<2]=tr1+tr2;
		ch[(ido<<2)+t5-1]=tr2-tr1;
		ch[(t5+=(ido<<1))-1]=cc[t3]-cc[t4];
		ch[t5]=cc[t2]-cc[t1];

		t1+=ido;
		t2+=ido;
		t3+=ido;
		t4+=ido;
	}

	if (ido<2)return;
	if (ido==2)goto L105;


	t1=0;
	for (k=0;k<l1;k++) {
		t2=t1;
		t4=t1<<2;
		t5=(t6=ido<<1)+t4;
		for (i=2;i<ido;i+=2) {
			t3=(t2+=2);
			t4+=2;
			t5-=2;

			t3+=t0;
			cr2=wa1[i-2]*cc[t3-1]+wa1[i-1]*cc[t3];
			ci2=wa1[i-2]*cc[t3]-wa1[i-1]*cc[t3-1];
			t3+=t0;
			cr3=wa2[i-2]*cc[t3-1]+wa2[i-1]*cc[t3];
			ci3=wa2[i-2]*cc[t3]-wa2[i-1]*cc[t3-1];
			t3+=t0;
			cr4=wa3[i-2]*cc[t3-1]+wa3[i-1]*cc[t3];
			ci4=wa3[i-2]*cc[t3]-wa3[i-1]*cc[t3-1];

			tr1=cr2+cr4;
			tr4=cr4-cr2;
			ti1=ci2+ci4;
			ti4=ci2-ci4;

			ti2=cc[t2]+ci3;
			ti3=cc[t2]-ci3;
			tr2=cc[t2-1]+cr3;
			tr3=cc[t2-1]-cr3;

			ch[t4-1]=tr1+tr2;
			ch[t4]=ti1+ti2;

			ch[t5-1]=tr3-ti4;
			ch[t5]=tr4-ti3;

			ch[t4+t6-1]=ti4+tr3;
			ch[t4+t6]=tr4+ti3;

			ch[t5+t6-1]=tr2-tr1;
			ch[t5+t6]=ti1-ti2;
		}
		t1+=ido;
	}
	if (ido&1)return;

L105:

	t2=(t1=t0+ido-1)+(t0<<1);
	t3=ido<<2;
	t4=ido;
	t5=ido<<1;
	t6=ido;

	for (k=0;k<l1;k++) {
		ti1=-hsqt2*(cc[t1]+cc[t2]);
		tr1=hsqt2*(cc[t1]-cc[t2]);

		ch[t4-1]=tr1+cc[t6-1];
		ch[t4+t5-1]=cc[t6-1]-tr1;

		ch[t4]=ti1-cc[t1+t0];
		ch[t4+t5]=ti1+cc[t1+t0];

		t1+=ido;
		t2+=ido;
		t4+=t3;
		t6+=ido;
	}
}

static void dradfg(int ido,int ip,int l1,int idl1,float *cc,float *c1,
                   float *c2,float *ch,float *ch2,float *wa) {

	static float tpi=6.283185307179586f;
	int idij,ipph,i,j,k,l,ic,ik,is;
	int t0,t1,t2,t3,t4,t5,t6,t7,t8,t9,t10;
	float dc2,ai1,ai2,ar1,ar2,ds2;
	int nbd;
	float dcp,arg,dsp,ar1h,ar2h;
	int idp2,ipp2;

	arg=tpi/static_cast<float>(ip);
	dcp=cosf(arg);
	dsp=sinf(arg);
	ipph=(ip+1)>>1;
	ipp2=ip;
	idp2=ido;
	nbd=(ido-1)>>1;
	t0=l1*ido;
	t10=ip*ido;

	if (ido==1)goto L119;
	for (ik=0;ik<idl1;ik++)ch2[ik]=c2[ik];

	t1=0;
	for (j=1;j<ip;j++) {
		t1+=t0;
		t2=t1;
		for (k=0;k<l1;k++) {
			ch[t2]=c1[t2];
			t2+=ido;
		}
	}

	is=-ido;
	t1=0;
	if (nbd>l1) {
		for (j=1;j<ip;j++) {
			t1+=t0;
			is+=ido;
			t2= -ido+t1;
			for (k=0;k<l1;k++) {
				idij=is-1;
				t2+=ido;
				t3=t2;
				for (i=2;i<ido;i+=2) {
					idij+=2;
					t3+=2;
					ch[t3-1]=wa[idij-1]*c1[t3-1]+wa[idij]*c1[t3];
					ch[t3]=wa[idij-1]*c1[t3]-wa[idij]*c1[t3-1];
				}
			}
		}
	} else {

		for (j=1;j<ip;j++) {
			is+=ido;
			idij=is-1;
			t1+=t0;
			t2=t1;
			for (i=2;i<ido;i+=2) {
				idij+=2;
				t2+=2;
				t3=t2;
				for (k=0;k<l1;k++) {
					ch[t3-1]=wa[idij-1]*c1[t3-1]+wa[idij]*c1[t3];
					ch[t3]=wa[idij-1]*c1[t3]-wa[idij]*c1[t3-1];
					t3+=ido;
				}
			}
		}
	}

	t1=0;
	t2=ipp2*t0;
	if (nbd<l1) {
		for (j=1;j<ipph;j++) {
			t1+=t0;
			t2-=t0;
			t3=t1;
			t4=t2;
			for (i=2;i<ido;i+=2) {
				t3+=2;
				t4+=2;
				t5=t3-ido;
				t6=t4-ido;
				for (k=0;k<l1;k++) {
					t5+=ido;
					t6+=ido;
					c1[t5-1]=ch[t5-1]+ch[t6-1];
					c1[t6-1]=ch[t5]-ch[t6];
					c1[t5]=ch[t5]+ch[t6];
					c1[t6]=ch[t6-1]-ch[t5-1];
				}
			}
		}
	} else {
		for (j=1;j<ipph;j++) {
			t1+=t0;
			t2-=t0;
			t3=t1;
			t4=t2;
			for (k=0;k<l1;k++) {
				t5=t3;
				t6=t4;
				for (i=2;i<ido;i+=2) {
					t5+=2;
					t6+=2;
					c1[t5-1]=ch[t5-1]+ch[t6-1];
					c1[t6-1]=ch[t5]-ch[t6];
					c1[t5]=ch[t5]+ch[t6];
					c1[t6]=ch[t6-1]-ch[t5-1];
				}
				t3+=ido;
				t4+=ido;
			}
		}
	}

L119:
	for (ik=0;ik<idl1;ik++)c2[ik]=ch2[ik];

	t1=0;
	t2=ipp2*idl1;
	for (j=1;j<ipph;j++) {
		t1+=t0;
		t2-=t0;
		t3=t1-ido;
		t4=t2-ido;
		for (k=0;k<l1;k++) {
			t3+=ido;
			t4+=ido;
			c1[t3]=ch[t3]+ch[t4];
			c1[t4]=ch[t4]-ch[t3];
		}
	}

	ar1=1.f;
	ai1=0.f;
	t1=0;
	t2=ipp2*idl1;
	t3=(ip-1)*idl1;
	for (l=1;l<ipph;l++) {
		t1+=idl1;
		t2-=idl1;
		ar1h=dcp*ar1-dsp*ai1;
		ai1=dcp*ai1+dsp*ar1;
		ar1=ar1h;
		t4=t1;
		t5=t2;
		t6=t3;
		t7=idl1;

		for (ik=0;ik<idl1;ik++) {
			ch2[t4++]=c2[ik]+ar1*c2[t7++];
			ch2[t5++]=ai1*c2[t6++];
		}

		dc2=ar1;
		ds2=ai1;
		ar2=ar1;
		ai2=ai1;

		t4=idl1;
		t5=(ipp2-1)*idl1;
		for (j=2;j<ipph;j++) {
			t4+=idl1;
			t5-=idl1;

			ar2h=dc2*ar2-ds2*ai2;
			ai2=dc2*ai2+ds2*ar2;
			ar2=ar2h;

			t6=t1;
			t7=t2;
			t8=t4;
			t9=t5;
			for (ik=0;ik<idl1;ik++) {
				ch2[t6++]+=ar2*c2[t8++];
				ch2[t7++]+=ai2*c2[t9++];
			}
		}
	}

	t1=0;
	for (j=1;j<ipph;j++) {
		t1+=idl1;
		t2=t1;
		for (ik=0;ik<idl1;ik++)ch2[ik]+=c2[t2++];
	}

	if (ido<l1)goto L132;

	t1=0;
	t2=0;
	for (k=0;k<l1;k++) {
		t3=t1;
		t4=t2;
		for (i=0;i<ido;i++)cc[t4++]=ch[t3++];
		t1+=ido;
		t2+=t10;
	}

	goto L135;

L132:
	for (i=0;i<ido;i++) {
		t1=i;
		t2=i;
		for (k=0;k<l1;k++) {
			cc[t2]=ch[t1];
			t1+=ido;
			t2+=t10;
		}
	}

L135:
	t1=0;
	t2=ido<<1;
	t3=0;
	t4=ipp2*t0;
	for (j=1;j<ipph;j++) {

		t1+=t2;
		t3+=t0;
		t4-=t0;

		t5=t1;
		t6=t3;
		t7=t4;

		for (k=0;k<l1;k++) {
			cc[t5-1]=ch[t6];
			cc[t5]=ch[t7];
			t5+=t10;
			t6+=ido;
			t7+=ido;
		}
	}

	if (ido==1)return;
	if (nbd<l1)goto L141;

	t1=-ido;
	t3=0;
	t4=0;
	t5=ipp2*t0;
	for (j=1;j<ipph;j++) {
		t1+=t2;
		t3+=t2;
		t4+=t0;
		t5-=t0;
		t6=t1;
		t7=t3;
		t8=t4;
		t9=t5;
		for (k=0;k<l1;k++) {
			for (i=2;i<ido;i+=2) {
				ic=idp2-i;
				cc[i+t7-1]=ch[i+t8-1]+ch[i+t9-1];
				cc[ic+t6-1]=ch[i+t8-1]-ch[i+t9-1];
				cc[i+t7]=ch[i+t8]+ch[i+t9];
				cc[ic+t6]=ch[i+t9]-ch[i+t8];
			}
			t6+=t10;
			t7+=t10;
			t8+=ido;
			t9+=ido;
		}
	}
	return;

L141:

	t1=-ido;
	t3=0;
	t4=0;
	t5=ipp2*t0;
	for (j=1;j<ipph;j++) {
		t1+=t2;
		t3+=t2;
		t4+=t0;
		t5-=t0;
		for (i=2;i<ido;i+=2) {
			t6=idp2+t1-i;
			t7=i+t3;
			t8=i+t4;
			t9=i+t5;
			for (k=0;k<l1;k++) {
				cc[t7-1]=ch[t8-1]+ch[t9-1];
				cc[t6-1]=ch[t8-1]-ch[t9-1];
				cc[t7]=ch[t8]+ch[t9];
				cc[t6]=ch[t9]-ch[t8];
				t6+=t10;
				t7+=t10;
				t8+=ido;
				t9+=ido;
			}
		}
	}
}

static void drftf1(int n,float *c,float *ch,float *wa,int *ifac) {
	int i,k1,l1,l2;
	int na,kh,nf;
	int ip,iw,ido,idl1,ix2,ix3;

	nf=ifac[1];
	na=1;
	l2=n;
	iw=n;

	for (k1=0;k1<nf;k1++) {
		kh=nf-k1;
		ip=ifac[kh+1];
		l1=l2/ip;
		ido=n/l2;
		idl1=ido*l1;
		iw-=(ip-1)*ido;
		na=1-na;

		if (ip!=4)goto L102;

		ix2=iw+ido;
		ix3=ix2+ido;
		if (na!=0)
			dradf4(ido,l1,ch,c,wa+iw-1,wa+ix2-1,wa+ix3-1);
		else
			dradf4(ido,l1,c,ch,wa+iw-1,wa+ix2-1,wa+ix3-1);
		goto L110;

L102:
		if (ip!=2)goto L104;
		if (na!=0)goto L103;

		dradf2(ido,l1,c,ch,wa+iw-1);
		goto L110;

L103:
		dradf2(ido,l1,ch,c,wa+iw-1);
		goto L110;

L104:
		if (ido==1)na=1-na;
		if (na!=0)goto L109;

		dradfg(ido,ip,l1,idl1,c,c,c,ch,ch,wa+iw-1);
		na=1;
		goto L110;

L109:
		dradfg(ido,ip,l1,idl1,ch,ch,ch,c,c,wa+iw-1);
		na=0;

L110:
		l2=l1;
	}

	if (na==1)return;

	for (i=0;i<n;i++)c[i]=ch[i];
}

static void dradb2(int ido,int l1,float *cc,float *ch,float *wa1) {
	int i,k,t0,t1,t2,t3,t4,t5,t6;
	float ti2,tr2;

	t0=l1*ido;

	t1=0;
	t2=0;
	t3=(ido<<1)-1;
	for (k=0;k<l1;k++) {
		ch[t1]=cc[t2]+cc[t3+t2];
		ch[t1+t0]=cc[t2]-cc[t3+t2];
		t2=(t1+=ido)<<1;
	}

	if (ido<2)return;
	if (ido==2)goto L105;

	t1=0;
	t2=0;
	for (k=0;k<l1;k++) {
		t3=t1;
		t5=(t4=t2)+(ido<<1);
		t6=t0+t1;
		for (i=2;i<ido;i+=2) {
			t3+=2;
			t4+=2;
			t5-=2;
			t6+=2;
			ch[t3-1]=cc[t4-1]+cc[t5-1];
			tr2=cc[t4-1]-cc[t5-1];
			ch[t3]=cc[t4]-cc[t5];
			ti2=cc[t4]+cc[t5];
			ch[t6-1]=wa1[i-2]*tr2-wa1[i-1]*ti2;
			ch[t6]=wa1[i-2]*ti2+wa1[i-1]*tr2;
		}
		t2=(t1+=ido)<<1;
	}

	if (ido%2==1)return;

L105:
	t1=ido-1;
	t2=ido-1;
	for (k=0;k<l1;k++) {
		ch[t1]=cc[t2]+cc[t2];
		ch[t1+t0]=-(cc[t2+1]+cc[t2+1]);
		t1+=ido;
		t2+=ido<<1;
	}
}

static void dradb3(int ido,int l1,float *cc,float *ch,float *wa1,
                   float *wa2) {
	static float taur = -.5f;
	static float taui = .8660254037844386f;
	int i,k,t0,t1,t2,t3,t4,t5,t6,t7,t8,t9,t10;
	float ci2,ci3,di2,di3,cr2,cr3,dr2,dr3,ti2,tr2;
	t0=l1*ido;

	t1=0;
	t2=t0<<1;
	t3=ido<<1;
	t4=ido+(ido<<1);
	t5=0;
	for (k=0;k<l1;k++) {
		tr2=cc[t3-1]+cc[t3-1];
		cr2=cc[t5]+(taur*tr2);
		ch[t1]=cc[t5]+tr2;
		ci3=taui*(cc[t3]+cc[t3]);
		ch[t1+t0]=cr2-ci3;
		ch[t1+t2]=cr2+ci3;
		t1+=ido;
		t3+=t4;
		t5+=t4;
	}

	if (ido==1)return;

	t1=0;
	t3=ido<<1;
	for (k=0;k<l1;k++) {
		t7=t1+(t1<<1);
		t6=(t5=t7+t3);
		t8=t1;
		t10=(t9=t1+t0)+t0;

		for (i=2;i<ido;i+=2) {
			t5+=2;
			t6-=2;
			t7+=2;
			t8+=2;
			t9+=2;
			t10+=2;
			tr2=cc[t5-1]+cc[t6-1];
			cr2=cc[t7-1]+(taur*tr2);
			ch[t8-1]=cc[t7-1]+tr2;
			ti2=cc[t5]-cc[t6];
			ci2=cc[t7]+(taur*ti2);
			ch[t8]=cc[t7]+ti2;
			cr3=taui*(cc[t5-1]-cc[t6-1]);
			ci3=taui*(cc[t5]+cc[t6]);
			dr2=cr2-ci3;
			dr3=cr2+ci3;
			di2=ci2+cr3;
			di3=ci2-cr3;
			ch[t9-1]=wa1[i-2]*dr2-wa1[i-1]*di2;
			ch[t9]=wa1[i-2]*di2+wa1[i-1]*dr2;
			ch[t10-1]=wa2[i-2]*dr3-wa2[i-1]*di3;
			ch[t10]=wa2[i-2]*di3+wa2[i-1]*dr3;
		}
		t1+=ido;
	}
}

static void dradb4(int ido,int l1,float *cc,float *ch,float *wa1,
                   float *wa2,float *wa3) {
	static float sqrt2=1.414213562373095f;
	int i,k,t0,t1,t2,t3,t4,t5,t6,t7,t8;
	float ci2,ci3,ci4,cr2,cr3,cr4,ti1,ti2,ti3,ti4,tr1,tr2,tr3,tr4;
	t0=l1*ido;

	t1=0;
	t2=ido<<2;
	t3=0;
	t6=ido<<1;
	for (k=0;k<l1;k++) {
		t4=t3+t6;
		t5=t1;
		tr3=cc[t4-1]+cc[t4-1];
		tr4=cc[t4]+cc[t4];
		tr1=cc[t3]-cc[(t4+=t6)-1];
		tr2=cc[t3]+cc[t4-1];
		ch[t5]=tr2+tr3;
		ch[t5+=t0]=tr1-tr4;
		ch[t5+=t0]=tr2-tr3;
		ch[t5+=t0]=tr1+tr4;
		t1+=ido;
		t3+=t2;
	}

	if (ido<2)return;
	if (ido==2)goto L105;

	t1=0;
	for (k=0;k<l1;k++) {
		t5=(t4=(t3=(t2=t1<<2)+t6))+t6;
		t7=t1;
		for (i=2;i<ido;i+=2) {
			t2+=2;
			t3+=2;
			t4-=2;
			t5-=2;
			t7+=2;
			ti1=cc[t2]+cc[t5];
			ti2=cc[t2]-cc[t5];
			ti3=cc[t3]-cc[t4];
			tr4=cc[t3]+cc[t4];
			tr1=cc[t2-1]-cc[t5-1];
			tr2=cc[t2-1]+cc[t5-1];
			ti4=cc[t3-1]-cc[t4-1];
			tr3=cc[t3-1]+cc[t4-1];
			ch[t7-1]=tr2+tr3;
			cr3=tr2-tr3;
			ch[t7]=ti2+ti3;
			ci3=ti2-ti3;
			cr2=tr1-tr4;
			cr4=tr1+tr4;
			ci2=ti1+ti4;
			ci4=ti1-ti4;

			ch[(t8=t7+t0)-1]=wa1[i-2]*cr2-wa1[i-1]*ci2;
			ch[t8]=wa1[i-2]*ci2+wa1[i-1]*cr2;
			ch[(t8+=t0)-1]=wa2[i-2]*cr3-wa2[i-1]*ci3;
			ch[t8]=wa2[i-2]*ci3+wa2[i-1]*cr3;
			ch[(t8+=t0)-1]=wa3[i-2]*cr4-wa3[i-1]*ci4;
			ch[t8]=wa3[i-2]*ci4+wa3[i-1]*cr4;
		}
		t1+=ido;
	}

	if (ido%2 == 1)return;

L105:

	t1=ido;
	t2=ido<<2;
	t3=ido-1;
	t4=ido+(ido<<1);
	for (k=0;k<l1;k++) {
		t5=t3;
		ti1=cc[t1]+cc[t4];
		ti2=cc[t4]-cc[t1];
		tr1=cc[t1-1]-cc[t4-1];
		tr2=cc[t1-1]+cc[t4-1];
		ch[t5]=tr2+tr2;
		ch[t5+=t0]=sqrt2*(tr1-ti1);
		ch[t5+=t0]=ti2+ti2;
		ch[t5+=t0]=-sqrt2*(tr1+ti1);

		t3+=ido;
		t1+=t2;
		t4+=t2;
	}
}

static void dradbg(int ido,int ip,int l1,int idl1,float *cc,float *c1,
                   float *c2,float *ch,float *ch2,float *wa) {
	static float tpi=6.283185307179586f;
	int idij,ipph,i,j,k,l,ik,is,t0,t1,t2,t3,t4,t5,t6,t7,t8,t9,t10,
	t11,t12;
	float dc2,ai1,ai2,ar1,ar2,ds2;
	int nbd;
	float dcp,arg,dsp,ar1h,ar2h;
	int ipp2;

	t10=ip*ido;
	t0=l1*ido;
	arg=tpi/static_cast<float>(ip);
	dcp=cosf(arg);
	dsp=sinf(arg);
	nbd=(ido-1)>>1;
	ipp2=ip;
	ipph=(ip+1)>>1;
	if (ido<l1)goto L103;

	t1=0;
	t2=0;
	for (k=0;k<l1;k++) {
		t3=t1;
		t4=t2;
		for (i=0;i<ido;i++) {
			ch[t3]=cc[t4];
			t3++;
			t4++;
		}
		t1+=ido;
		t2+=t10;
	}
	goto L106;

L103:
	t1=0;
	for (i=0;i<ido;i++) {
		t2=t1;
		t3=t1;
		for (k=0;k<l1;k++) {
			ch[t2]=cc[t3];
			t2+=ido;
			t3+=t10;
		}
		t1++;
	}

L106:
	t1=0;
	t2=ipp2*t0;
	t7=(t5=ido<<1);
	for (j=1;j<ipph;j++) {
		t1+=t0;
		t2-=t0;
		t3=t1;
		t4=t2;
		t6=t5;
		for (k=0;k<l1;k++) {
			ch[t3]=cc[t6-1]+cc[t6-1];
			ch[t4]=cc[t6]+cc[t6];
			t3+=ido;
			t4+=ido;
			t6+=t10;
		}
		t5+=t7;
	}

	if (ido == 1)goto L116;
	if (nbd<l1)goto L112;

	t1=0;
	t2=ipp2*t0;
	t7=0;
	for (j=1;j<ipph;j++) {
		t1+=t0;
		t2-=t0;
		t3=t1;
		t4=t2;

		t7+=(ido<<1);
		t8=t7;
		for (k=0;k<l1;k++) {
			t5=t3;
			t6=t4;
			t9=t8;
			t11=t8;
			for (i=2;i<ido;i+=2) {
				t5+=2;
				t6+=2;
				t9+=2;
				t11-=2;
				ch[t5-1]=cc[t9-1]+cc[t11-1];
				ch[t6-1]=cc[t9-1]-cc[t11-1];
				ch[t5]=cc[t9]-cc[t11];
				ch[t6]=cc[t9]+cc[t11];
			}
			t3+=ido;
			t4+=ido;
			t8+=t10;
		}
	}
	goto L116;

L112:
	t1=0;
	t2=ipp2*t0;
	t7=0;
	for (j=1;j<ipph;j++) {
		t1+=t0;
		t2-=t0;
		t3=t1;
		t4=t2;
		t7+=(ido<<1);
		t8=t7;
		t9=t7;
		for (i=2;i<ido;i+=2) {
			t3+=2;
			t4+=2;
			t8+=2;
			t9-=2;
			t5=t3;
			t6=t4;
			t11=t8;
			t12=t9;
			for (k=0;k<l1;k++) {
				ch[t5-1]=cc[t11-1]+cc[t12-1];
				ch[t6-1]=cc[t11-1]-cc[t12-1];
				ch[t5]=cc[t11]-cc[t12];
				ch[t6]=cc[t11]+cc[t12];
				t5+=ido;
				t6+=ido;
				t11+=t10;
				t12+=t10;
			}
		}
	}

L116:
	ar1=1.f;
	ai1=0.f;
	t1=0;
	t9=(t2=ipp2*idl1);
	t3=(ip-1)*idl1;
	for (l=1;l<ipph;l++) {
		t1+=idl1;
		t2-=idl1;

		ar1h=dcp*ar1-dsp*ai1;
		ai1=dcp*ai1+dsp*ar1;
		ar1=ar1h;
		t4=t1;
		t5=t2;
		t6=0;
		t7=idl1;
		t8=t3;
		for (ik=0;ik<idl1;ik++) {
			c2[t4++]=ch2[t6++]+ar1*ch2[t7++];
			c2[t5++]=ai1*ch2[t8++];
		}
		dc2=ar1;
		ds2=ai1;
		ar2=ar1;
		ai2=ai1;

		t6=idl1;
		t7=t9-idl1;
		for (j=2;j<ipph;j++) {
			t6+=idl1;
			t7-=idl1;
			ar2h=dc2*ar2-ds2*ai2;
			ai2=dc2*ai2+ds2*ar2;
			ar2=ar2h;
			t4=t1;
			t5=t2;
			t11=t6;
			t12=t7;
			for (ik=0;ik<idl1;ik++) {
				c2[t4++]+=ar2*ch2[t11++];
				c2[t5++]+=ai2*ch2[t12++];
			}
		}
	}

	t1=0;
	for (j=1;j<ipph;j++) {
		t1+=idl1;
		t2=t1;
		for (ik=0;ik<idl1;ik++)ch2[ik]+=ch2[t2++];
	}

	t1=0;
	t2=ipp2*t0;
	for (j=1;j<ipph;j++) {
		t1+=t0;
		t2-=t0;
		t3=t1;
		t4=t2;
		for (k=0;k<l1;k++) {
			ch[t3]=c1[t3]-c1[t4];
			ch[t4]=c1[t3]+c1[t4];
			t3+=ido;
			t4+=ido;
		}
	}

	if (ido==1)goto L132;
	if (nbd<l1)goto L128;

	t1=0;
	t2=ipp2*t0;
	for (j=1;j<ipph;j++) {
		t1+=t0;
		t2-=t0;
		t3=t1;
		t4=t2;
		for (k=0;k<l1;k++) {
			t5=t3;
			t6=t4;
			for (i=2;i<ido;i+=2) {
				t5+=2;
				t6+=2;
				ch[t5-1]=c1[t5-1]-c1[t6];
				ch[t6-1]=c1[t5-1]+c1[t6];
				ch[t5]=c1[t5]+c1[t6-1];
				ch[t6]=c1[t5]-c1[t6-1];
			}
			t3+=ido;
			t4+=ido;
		}
	}
	goto L132;

L128:
	t1=0;
	t2=ipp2*t0;
	for (j=1;j<ipph;j++) {
		t1+=t0;
		t2-=t0;
		t3=t1;
		t4=t2;
		for (i=2;i<ido;i+=2) {
			t3+=2;
			t4+=2;
			t5=t3;
			t6=t4;
			for (k=0;k<l1;k++) {
				ch[t5-1]=c1[t5-1]-c1[t6];
				ch[t6-1]=c1[t5-1]+c1[t6];
				ch[t5]=c1[t5]+c1[t6-1];
				ch[t6]=c1[t5]-c1[t6-1];
				t5+=ido;
				t6+=ido;
			}
		}
	}

L132:
	if (ido==1)return;

	for (ik=0;ik<idl1;ik++)c2[ik]=ch2[ik];

	t1=0;
	for (j=1;j<ip;j++) {
		t2=(t1+=t0);
		for (k=0;k<l1;k++) {
			c1[t2]=ch[t2];
			t2+=ido;
		}
	}

	if (nbd>l1)goto L139;

	is= -ido-1;
	t1=0;
	for (j=1;j<ip;j++) {
		is+=ido;
		t1+=t0;
		idij=is;
		t2=t1;
		for (i=2;i<ido;i+=2) {
			t2+=2;
			idij+=2;
			t3=t2;
			for (k=0;k<l1;k++) {
				c1[t3-1]=wa[idij-1]*ch[t3-1]-wa[idij]*ch[t3];
				c1[t3]=wa[idij-1]*ch[t3]+wa[idij]*ch[t3-1];
				t3+=ido;
			}
		}
	}
	return;

L139:
	is= -ido-1;
	t1=0;
	for (j=1;j<ip;j++) {
		is+=ido;
		t1+=t0;
		t2=t1;
		for (k=0;k<l1;k++) {
			idij=is;
			t3=t2;
			for (i=2;i<ido;i+=2) {
				idij+=2;
				t3+=2;
				c1[t3-1]=wa[idij-1]*ch[t3-1]-wa[idij]*ch[t3];
				c1[t3]=wa[idij-1]*ch[t3]+wa[idij]*ch[t3-1];
			}
			t2+=ido;
		}
	}
}

static void drftb1(int n, float *c, float *ch, float *wa, int *ifac) {
	int i,k1,l1,l2;
	int na;
	int nf,ip,iw,ix2,ix3,ido,idl1;

	nf=ifac[1];
	na=0;
	l1=1;
	iw=1;

	for (k1=0;k1<nf;k1++) {
		ip=ifac[k1 + 2];
		l2=ip*l1;
		ido=n/l2;
		idl1=ido*l1;
		if (ip!=4)goto L103;
		ix2=iw+ido;
		ix3=ix2+ido;

		if (na!=0)
			dradb4(ido,l1,ch,c,wa+iw-1,wa+ix2-1,wa+ix3-1);
		else
			dradb4(ido,l1,c,ch,wa+iw-1,wa+ix2-1,wa+ix3-1);
		na=1-na;
		goto L115;

L103:
		if (ip!=2)goto L106;

		if (na!=0)
			dradb2(ido,l1,ch,c,wa+iw-1);
		else
			dradb2(ido,l1,c,ch,wa+iw-1);
		na=1-na;
		goto L115;

L106:
		if (ip!=3)goto L109;

		ix2=iw+ido;
		if (na!=0)
			dradb3(ido,l1,ch,c,wa+iw-1,wa+ix2-1);
		else
			dradb3(ido,l1,c,ch,wa+iw-1,wa+ix2-1);
		na=1-na;
		goto L115;

L109:
		/*    The radix five case can be translated later..... */
		/*    if(ip!=5)goto L112;

		    ix2=iw+ido;
		    ix3=ix2+ido;
		    ix4=ix3+ido;
		    if(na!=0)
		      dradb5(ido,l1,ch,c,wa+iw-1,wa+ix2-1,wa+ix3-1,wa+ix4-1);
		    else
		      dradb5(ido,l1,c,ch,wa+iw-1,wa+ix2-1,wa+ix3-1,wa+ix4-1);
		    na=1-na;
		    goto L115;

		  L112:*/
		if (na!=0)
			dradbg(ido,ip,l1,idl1,ch,ch,ch,c,c,wa+iw-1);
		else
			dradbg(ido,ip,l1,idl1,c,c,c,ch,ch,wa+iw-1);
		if (ido==1)na=1-na;

L115:
		l1=l2;
		iw+=(ip-1)*ido;
	}

	if (na==0)return;

	for (i=0;i<n;i++)c[i]=ch[i];
}

void mumble_drft_forward(drft_lookup *l,float *data) {
	if (l->n==1)return;
	drftf1(l->n,data,l->trigcache,l->trigcache+l->n,l->splitcache);
}

void mumble_drft_backward(drft_lookup *l,float *data) {
	if (l->n==1)return;
	drftb1(l->n,data,l->trigcache,l->trigcache+l->n,l->splitcache);
}

void mumble_drft_init(drft_lookup *l,int n) {
	l->n=n;
	l->trigcache=reinterpret_cast<float *>(calloc(3*n,sizeof(*l->trigcache)));
	l->splitcache=reinterpret_cast<int *>(calloc(32,sizeof(*l->splitcache)));
	fdrffti(n, l->trigcache, l->splitcache);
}

void mumble_drft_clear(drft_lookup *l) {
	if (l) {
		free(l->trigcache);
		free(l->splitcache);
		memset(l,0,sizeof(*l));
	}
}
