void preprocpat( pat, next )
     char *pat;
     int next[];

     { int i, j;
       i = 0;
       j = next[0] = -1;
       do { if( j==(-1) || pat[i]==pat[j] ) {
                 i++;
                 j++;
                 next[i] = (pat[j]==pat[i]) ? next[j] : j;
            }
            else j = next[j]; }
          while( pat[i] != EOS );
     }

     char *search( pat, text )
     char *pat, *text;

     { int next[MAXPATLEN], j;

       if( *pat == EOS ) return( text );
       preprocpat( pat, next );

       for( j=0; *text != EOS; ) {
          if( j==(-1) || pat[j] == *text ) { 
              text++; j++; 
              if( pat[j] == EOS ) return( text-j );
          }
          else j = next[j];
       }
       return( NULL );
     }