#define NRANSI#include "nrutil.h"#define RX 256.0void mpmul(unsigned char w[], unsigned char u[], unsigned char v[], int n,	int m){	void drealft(double data[], unsigned long n, int isign);	int j,mn,nn=1;	double cy,t,*a,*b;	mn=IMAX(m,n);	while (nn < mn) nn <<= 1;	nn <<= 1;	a=dvector(1,nn);	b=dvector(1,nn);	for (j=1;j<=n;j++)		a[j]=(double)u[j];	for (j=n+1;j<=nn;j++) a[j]=0.0;	for (j=1;j<=m;j++)		b[j]=(double)v[j];	for (j=m+1;j<=nn;j++) b[j]=0.0;	drealft(a,nn,1);	drealft(b,nn,1);	b[1] *= a[1];	b[2] *= a[2];	for (j=3;j<=nn;j+=2) {		b[j]=(t=b[j])*a[j]-b[j+1]*a[j+1];		b[j+1]=t*a[j+1]+b[j+1]*a[j];	}	drealft(b,nn,-1);	cy=0.0;	for (j=nn;j>=1;j--) {		t=b[j]/(nn>>1)+cy+0.5;		cy=(unsigned long) (t/RX);		b[j]=t-cy*RX;	}	if (cy >= RX) nrerror("cannot happen in fftmul");	w[1]=(unsigned char) cy;	for (j=2;j<=n+m;j++)		w[j]=(unsigned char) b[j-1];	free_dvector(b,1,nn);	free_dvector(a,1,nn);}#undef RX#undef NRANSI