ckwart.c

linux终端仿真程序

	  cur->actno = ++nacts;
	  cur->inchr = (char) (tokval[0] - 32);
	  if (head == NULL)
	    head = cur;
	  else
	    prev->nxt = cur;
	  prev = cur;
	  cur = NULL;
	  copyact(fp,out,nacts);
	  break; 
	default: fatal("bad input format");
      }
    return(head);
}

/*
 * read a list of (comma-separated) states, set them in the
 * given transition.
 *
 */
VOID
statelist(fp,t) FILE *fp; trans t; {
    int curtok,sval;
    curtok = COMMA;
    while (curtok != RBRACK) {
	if (curtok != COMMA) fatal("missing comma");
	if ((curtok = gettoken(fp)) != WORD) fatal("missing state name");
        if ((sval = lkup(tokval)) == -1) {
	    fprintf(stderr,"state %s undefined\n",tokval);
	    fatal("undefined state");
	}
        setwstate(sval,t);	
	curtok = gettoken(fp);
    }
}

/*
 * copy an action from the input to the output file
 *
 */
VOID
copyact(inp,outp,actno) FILE *inp,*outp; int actno; {
    int c,bcnt;
    fprintf(outp,"case %d:\n",actno);
    while (c = getc(inp), (isspace(c) || c == C_L))
      if (c == '\n') lines++;
    if (c == '{') {
	bcnt = 1;
	fputs("    {",outp);
	while (bcnt > 0 && (c = getc(inp)) != EOF) {
	    if (c == '{') bcnt++;
	    else if (c == '}') bcnt--;
	    else if (c == '\n') lines++;
	    putc(c,outp);
	}
	if (bcnt > 0) fatal("action doesn't end");
    } else {
	while (c != '\n' && c != EOF) {
	    putc(c,outp);
	    c = getc(inp);
	}
	lines++;
    }
    fprintf(outp,"\n    break;\n");
}

/*
 * find the action associated with a given character and state.
 * returns -1 if one can't be found.
 *
 */
int
faction(hd,state,chr) trans hd; int state,chr; {
    while (hd != NULL) {
	if (hd->anyst || teststate(state,hd))
	  if (hd->inchr == ('.' - 32) || hd->inchr == (char) chr)
	    return(hd->actno);
	hd = hd->nxt;
    }
    return(-1);
}

/*
 * empty the table...
 *
 */
VOID
emptytbl() {
    int i;
    for (i=0; i<nstates*96; i++) tbl[i] = -1;
}

/*
 * add the specified action to the output for the given state and chr.
 *
 */
VOID
addaction(act,state,chr) int act,state,chr; {
    tbl[state*96 + chr] = act;
}

VOID
writetbl(fp) FILE *fp; {
    warray(fp,"tbl",tbl,96*(nstates+1),TBL_TYPE);
}


/*
 * write an array to the output file, given its name and size.
 *
 */
VOID
warray(fp,nam,cont,siz,typ) FILE *fp; char *nam; int cont[],siz; char *typ; {
    int i;
    fprintf(fp,"%s %s[] = {\n",typ,nam);
    for (i = 0; i < siz - 1; ) {
	fprintf(fp,"%2d, ",cont[i]);
	if ((++i % 16) == 0) putc('\n',fp);
    }
    fprintf(fp,"%2d ",cont[siz-1]);
    fprintf(fp,"};\n");
}

#ifdef __DECC
#ifdef __ALPHA
int
#else
VOID
#endif /* __ALPHA */
#else
#ifdef STRATUS
int
#else
VOID
#endif /* STRATUS */
#endif /* __DECC */
main(argc,argv) int argc; char *argv[]; {
    trans head;
    int state,c;
    FILE *infile,*outfile;

    if (argc > 1) {
	if ((infile = fopen(argv[1],"r")) == NULL) {
	    fprintf(stderr,"Can't open %s\n",argv[1]);
	    fatal("unreadable input file");
	}
    } else infile = stdin;

    if (argc > 2) {
	if ((outfile = fopen(argv[2],"w")) == NULL) {
	    fprintf(stderr,"Can't write to %s\n",argv[2]);
	    fatal("bad output file");
	}
    } else outfile = stdout;

    clrhash();				/* empty hash table */
    head = rdinput(infile,outfile);	/* read input file */
    emptytbl();				/* empty our tables */
    for (state = 0; state <= nstates; state++)
      for (c = 1; c < 96; c++)		/* find actions, */
	addaction(faction(head,state,c),state,c); /* add to tbl */
    writetbl(outfile);
    copyrest(infile,outfile);
    printf("%d states, %d actions\n",nstates,nacts);
    exit(GOOD_EXIT);
}


/*
 * fatal error handler
 *
 */

VOID
fatal(msg) char *msg; {
    fprintf(stderr,"error in line %d: %s\n",lines,msg);
    exit(BAD_EXIT);
}

VOID
prolog(outfp) FILE *outfp; {
    int c;
    while ((c = *txt1++)     != '\0') putc(c,outfp);
    while ((c = *fname++)    != '\0') putc(c,outfp);
    while ((c = *txt2++)     != '\0') putc(c,outfp);
    while ((c = *tbl_type++) != '\0') putc(c,outfp);
    while ((c = *txt2a++)    != '\0') putc(c,outfp);
    while ((c = *txt2b++)    != '\0') putc(c,outfp);
}

VOID
epilogue(outfp) FILE *outfp; {
    int c;
    while ((c = *txt3++) != '\0') putc(c,outfp);
}

VOID
copyrest(in,out) FILE *in,*out; {
    int c;
    while ((c = getc(in)) != EOF) putc(c,out);
}

/*
 * gettoken - returns token type of next token, sets tokval
 * to the string value of the token if appropriate.
 *
 */

int
gettoken(fp) FILE *fp; {
    int c;
    while (1) {				/* loop if reading comments... */
	do {
	    c = getc(fp);
	    if (c == '\n') lines++;
	} while ((isspace(c) || c == C_L)); /* skip whitespace */
	switch(c) {
	  case EOF:
	    return(SEP);
	  case '%':
	    if ((c = getc(fp)) == '%') return(SEP);
	    tokval[0] = '%';
	    tokval[1] = (char) c;
	    rdword(fp,tokval+2);
	    return(WORD);
	  case '<':
	    return(LBRACK);
	  case '>':
	    return(RBRACK);
	  case ',':
	    return(COMMA);
	  case '/':
	    if ((c = getc(fp)) == '*') {
		rdcmnt(fp);		/* skip over the comment */
		continue;
	    } else {			/* and keep looping */
		ungetc(c,fp);		/* put this back into input */
		c = '/';		/* put character back, fall thru */
	    }

	  default:
	    if (isword(c)) {
		ungetc(c,fp);
		rdword(fp,tokval);
		return(WORD);
	    } else fatal("Invalid character in input");
	}
    }
}

/*
 * skip over a comment
 *
 */

VOID
rdcmnt(fp) FILE *fp; {
    int c,star,prcnt;
    prcnt = star = 0;			/* no star seen yet */
    while (!((c = getc(fp)) == '/' && star)) {
	if (c == EOF || (prcnt && c == '%')) fatal("Unterminated comment");
	prcnt = (c == '%');
	star = (c == '*');
	if (c == '\n') lines++;
    }
}

/*
 * symbol table management for wart
 *
 * entry points:
 *   clrhash - empty hash table.
 *   enter - enter a name into the symbol table
 *   lkup - find a name's value in the symbol table.
 *
 */

#define HASHSIZE 101			/* # of entries in hash table */

struct sym {
    char *name;				/* symbol name */
    int val;				/* value */
    struct sym *hnxt;			/* next on collision chain */
} *htab[HASHSIZE];			/* the hash table */

/*
 * empty the hash table before using it...
 *
 */
VOID
clrhash() {
    int i;
    for (i=0; i<HASHSIZE; i++) htab[i] = NULL;
}

/*
 * compute the value of the hash for a symbol
 *
 */
int
hash(name) char *name; {
    int sum;
    for (sum = 0; *name != '\0'; name++) sum += (sum + *name);
    sum %= HASHSIZE;			/* take sum mod hashsize */
    if (sum < 0) sum += HASHSIZE;	/* disallow negative hash value */
    return(sum);
}

/*
 * make a private copy of a string...
 *
 */
static char*
copy(s) char *s; {
    char *new;
    new = (char *) malloc((int)strlen(s) + 1);
    strcpy(new,s);
    return(new);
}

/*
 * enter state name into the hash table
 *
 */
VOID
enter(name,svalue) char *name; int svalue; {
    int h;
    struct sym *cur;
    if (lkup(name) != -1) {
	fprintf(stderr,"state \"%s\" appears twice...\n", name);
	exit(BAD_EXIT);
    }
    h = hash(name);
    cur = (struct sym *)malloc(sizeof (struct sym));
    cur->name = copy(name);
    cur->val = svalue;
    cur->hnxt = htab[h];
    htab[h] = cur;
}

/*
 * find name in the symbol table, return its value.  Returns -1
 * if not found.
 *
 */
int
lkup(name) char *name; {
    struct sym *cur;
    for (cur = htab[hash(name)]; cur != NULL; cur = cur->hnxt)
      if (strcmp(cur->name,name) == 0) return(cur->val);
    return(-1);
}