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expand.h revision 1.1 
      1 /*
      2  * Expanding strings
      3  */
      4 /* $Id: expand.h,v 1.1 1996/09/21 23:35:14 jtc Exp $ */
      5 
      6 
      7 #if 0				/* Usage */
      8 	XString xs;
      9 	char *xp;
     10 
     11 	Xinit(xs, xp, 128, ATEMP); /* allocate initial string */
     12 	while ((c = generate()) {
     13 		Xcheck(xs, xp);	/* expand string if neccessary */
     14 		Xput(xs, xp, c); /* add character */
     15 	}
     16 	return Xclose(xs, xp);	/* resize string */
     17 /*
     18  * NOTE:
     19  *	The Xcheck and Xinit macros have a magic + 8 in the lengths.  This is
     20  *	so that you can put up to 4 characters in a XString before calling
     21  *	Xcheck.  (See yylex in lex.c)
     22  */
     23 #endif /* 0 */
     24 
     25 typedef struct XString {
     26 	char   *end, *beg;	/* end, begin of string */
     27 	size_t	len;		/* length */
     28 	Area	*areap;		/* area to allocate/free from */
     29 } XString;
     30 
     31 typedef char * XStringP;
     32 
     33 /* initialize expandable string */
     34 #define	Xinit(xs, xp, length, area) do { \
     35 			(xs).len = length; \
     36 			(xs).areap = (area); \
     37 			(xs).beg = alloc((xs).len + 8, (xs).areap); \
     38 			(xs).end = (xs).beg + (xs).len; \
     39 			xp = (xs).beg; \
     40 		} while (0)
     41 
     42 /* stuff char into string */
     43 #define	Xput(xs, xp, c)	(*xp++ = (c))
     44 
     45 /* check if there are at least n bytes left */
     46 #define	XcheckN(xs, xp, n) do { \
     47 		    int more = ((xp) + (n)) - (xs).end; \
     48 		    if (more > 0) \
     49 			xp = Xcheck_grow_(&xs, xp, more); \
     50 		} while (0)
     51 
     52 /* check for overflow, expand string */
     53 #define Xcheck(xs, xp)	XcheckN(xs, xp, 1)
     54 
     55 /* free string */
     56 #define	Xfree(xs, xp)	afree((void*) (xs).beg, (xs).areap)
     57 
     58 /* close, return string */
     59 #define	Xclose(xs, xp)	(char*) aresize((void*)(xs).beg, \
     60 					(size_t)((xp) - (xs).beg), (xs).areap)
     61 /* begin of string */
     62 #define	Xstring(xs, xp)	((xs).beg)
     63 
     64 #define Xnleft(xs, xp) ((xs).end - (xp))	/* may be less than 0 */
     65 #define	Xlength(xs, xp) ((xp) - (xs).beg)
     66 #define Xsize(xs, xp) ((xs).end - (xs).beg)
     67 #define	Xsavepos(xs, xp) ((xp) - (xs).beg)
     68 #define	Xrestpos(xs, xp, n) ((xs).beg + (n))
     69 
     70 char *	Xcheck_grow_	ARGS((XString *xsp, char *xp, int more));
     71 
     72 /*
     73  * expandable vector of generic pointers
     74  */
     75 
     76 typedef struct XPtrV {
     77 	void  **cur;		/* next avail pointer */
     78 	void  **beg, **end;	/* begin, end of vector */
     79 } XPtrV;
     80 
     81 #define	XPinit(x, n) do { \
     82 			register void **vp__; \
     83 			vp__ = (void**) alloc(sizeofN(void*, n), ATEMP); \
     84 			(x).cur = (x).beg = vp__; \
     85 			(x).end = vp__ + n; \
     86 		    } while (0)
     87 
     88 #define	XPput(x, p) do { \
     89 			if ((x).cur >= (x).end) { \
     90 				int n = XPsize(x); \
     91 				(x).beg = (void**) aresize((void*) (x).beg, \
     92 						   sizeofN(void*, n*2), ATEMP); \
     93 				(x).cur = (x).beg + n; \
     94 				(x).end = (x).cur + n; \
     95 			} \
     96 			*(x).cur++ = (p); \
     97 		} while (0)
     98 
     99 #define	XPptrv(x)	((x).beg)
    100 #define	XPsize(x)	((x).cur - (x).beg)
    101 
    102 #define	XPclose(x)	(void**) aresize((void*)(x).beg, \
    103 					 sizeofN(void*, XPsize(x)), ATEMP)
    104 
    105 #define	XPfree(x)	afree((void*) (x).beg, ATEMP)
    106