csvorbis.Lsp.lsp_to_curve C# (CSharp) Method

        internal static void lsp_to_curve(float[] curve,
            int[] map, int n, int ln,
            float[] lsp, int m,
            float amp, float ampoffset)
        {
            int i;
            float wdel=M_PI/ln;
            for(i=0;i<m;i++)lsp[i]=Lookup.coslook(lsp[i]);
            int m2=(m/2)*2;

            i=0;
            while(i<n)
            {
                FloatHack fh = new FloatHack();
                int k=map[i];
                float p=.7071067812f;
                float q=.7071067812f;
                float w=Lookup.coslook(wdel*k);
                //int ftmp=0;
                int c=(int)((uint)m >> 1);

                for(int j=0;j<m2;j+=2)
                {
                    q*=lsp[j]-w;
                    p*=lsp[j+1]-w;
                }

                if((m&1)!=0)
                {
                    /* odd order filter; slightly assymetric */
                    /* the last coefficient */
                    q*=lsp[m-1]-w;
                    q*=q;
                    p*=p*(1.0f-w*w);
                }
                else
                {
                    /* even order filter; still symmetric */
                    q*=q*(1.0f+w);
                    p*=p*(1.0f-w);
                }

                //  q=frexp(p+q,&qexp);
                q=p+q;
                fh.fh_float = q;
                int hx=fh.fh_int;
                int ix=0x7fffffff&hx;
                int qexp=0;

                if(ix>=0x7f800000||(ix==0))
                {
                    // 0,inf,nan
                }
                else
                {
                    if(ix<0x00800000)
                    {            // subnormal
                        q*=3.3554432000e+07F;        // 0x4c000000
                        fh.fh_float = q;
                        hx=fh.fh_int;
                        ix=0x7fffffff&hx;
                        qexp=-25;
                    }
                    qexp += (int)(((uint)ix >> 23)-126);
                    hx=(int)((hx&0x807fffff)|0x3f000000);
                    fh.fh_int = hx;
                    q=fh.fh_float;
                }

                q=Lookup.fromdBlook(amp*
                    Lookup.invsqlook(q)*
                    Lookup.invsq2explook(qexp+m)-ampoffset);

                do{curve[i]*=q; i++;}
                    //    do{curve[i++]=q;}
                while(i<n&&map[i]==k);

            }
        }

        public override int inverse2(Block vb, Object i, Object memo, float[] fout)
        {
            LookFloor0 look = (LookFloor0)i;
            InfoFloor0 info = look.vi;

            if (memo != null)
            {
                float[] lsp = (float[])memo;
                float   amp = lsp[look.m];

                Lsp.lsp_to_curve(fout, look.linearmap, look.n, look.ln,
                                 lsp, look.m, amp, info.ampdB);
                return(1);
            }

            for (int j = 0; j < look.n; j++)
            {
                fout[j] = 0.0f;
            }

            return(0);
        }