automata stringautom( pat )
     char *pat;

     { short back, i, st;
       char ch;
       automata a;

       a = (automata)malloc(sizeof(struct automrec));
       a->d = MAXCHAR;
       a->st = strlen(pat)+1;
       a->nextst = (short **)calloc( a->st, sizeof(short *) );
       a->final = (short *)calloc( a->st, sizeof(short) );

       for( st=0; st < a->st; st++ ) {
            a->nextst[st] = (short *)calloc( MAXCHAR, sizeof(short) );
            if( st < a->st-2 ) a->nextst[st][pat[st]] = st+1;
            }
       a->nextst[a->st-2][pat[a->st-2]] = 1-a->st;
       /* set final state (with the match length) */
       a->final[a->st-1] = a->st-1;

       /* Set backwards transitions */
       for( st=1; st < a->st; st++ )
            for( back=st-1; back >= 0; back-- ) {
                 ch = pat[back];
                 if( a->nextst[st][ch] == 0 )
                      for( i=1; i<=st; i++ )
                           if( (st==i || strncmp(pat,pat+i,st-i)==0)
                               && ch == pat[st-i] ) {
                                a->nextst[st][ch] = st-i+1;
                                break;
                                }
                 }

       return( a );
            
     }