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

   { int B, bits, i, m, mask[MAXCHAR];

     if( pat[0]==EOS ) return( text );
     B = 1;
     for( m=0; m<MAXCHAR; m++ ) mask[m] = ~0;
     for( m=0; B != 0 && pat[m] != EOS; m++ ) {
          mask[pat[m]] &= ~B;
          B <<= 1;
          }

     B = 1<<(m-1);
     for( bits=~0; *text != EOS; text++ ) {
          bits = bits<<1 | mask[*text & (MAXCHAR-1)];
          if( (bits&B) == 0 ) {
               for( i=0; pat[m+i] != EOS && pat[m+i]==text[i+1]; i++ );
               if( pat[m+i]==EOS ) return( text-m+1 );
               }
          }
     return( NULL );
   }