void preprocpat( pat, skip, d )
	char *pat;
	int skip[], d[];
	
	{ 	int j, k, m, t, t1, q, q1;
		int f[MAXPATLEN];          /*** auxiliary table ***/
	
		m = strlen( pat );
		for( k=0; k<MAXCHAR; k++ ) skip[k] = m;
		for( k=1; k<=m; k++ ) {
			d[k-1] = (m << 1) - k;  
			skip[pat[k-1]] = m-k;
		}
		t = m + 1;
		for( j=m; j > 0; j-- ) {
			f[j-1] = t;
			while( t <= m && pat[j-1] != pat[t-1] )
			{
				d[t-1] = min( d[t-1], m-j );
				t = f[t-1];
			}
			t--;
		}
		q = t;  t = m + 1 - q;  q1 = 1;  t1 = 0;
		for( j=1; j<=t; j++ ) {
			f[j-1] = t1;
			while( t1 >= 1 && pat[j-1] != pat[t1-1] ) 
				t1 = f[t1-1];
			t1++; 
		}
		while( q < m )
		{
			for( k=q1; k<=q; k++ ) d[k-1] = min( d[k-1], m+q-k );
			q1 = q + 1;  q = q + t - f[t-1];  t = f[t-1];
		}
	}