ref: 2e8a4a690e1c5a2cf515432e73cd24ab2a9446a7
dir: /sys/src/ape/cmd/pdksh/expand.h/
/*
* Expanding strings
*/
/* $Id$ */
#define X_EXTRA 8 /* this many extra bytes in X string */
#if 0 /* Usage */
XString xs;
char *xp;
Xinit(xs, xp, 128, ATEMP); /* allocate initial string */
while ((c = generate()) {
Xcheck(xs, xp); /* expand string if neccessary */
Xput(xs, xp, c); /* add character */
}
return Xclose(xs, xp); /* resize string */
/*
* NOTE:
* The Xcheck and Xinit macros have a magic + X_EXTRA in the lengths.
* This is so that you can put up to X_EXTRA characters in a XString
* before calling Xcheck. (See yylex in lex.c)
*/
#endif /* 0 */
typedef struct XString {
char *end, *beg; /* end, begin of string */
size_t len; /* length */
Area *areap; /* area to allocate/free from */
} XString;
typedef char * XStringP;
/* initialize expandable string */
#define Xinit(xs, xp, length, area) do { \
(xs).len = length; \
(xs).areap = (area); \
(xs).beg = alloc((xs).len + X_EXTRA, (xs).areap); \
(xs).end = (xs).beg + (xs).len; \
xp = (xs).beg; \
} while (0)
/* stuff char into string */
#define Xput(xs, xp, c) (*xp++ = (c))
/* check if there are at least n bytes left */
#define XcheckN(xs, xp, n) do { \
int more = ((xp) + (n)) - (xs).end; \
if (more > 0) \
xp = Xcheck_grow_(&xs, xp, more); \
} while (0)
/* check for overflow, expand string */
#define Xcheck(xs, xp) XcheckN(xs, xp, 1)
/* free string */
#define Xfree(xs, xp) afree((void*) (xs).beg, (xs).areap)
/* close, return string */
#define Xclose(xs, xp) (char*) aresize((void*)(xs).beg, \
(size_t)((xp) - (xs).beg), (xs).areap)
/* begin of string */
#define Xstring(xs, xp) ((xs).beg)
#define Xnleft(xs, xp) ((xs).end - (xp)) /* may be less than 0 */
#define Xlength(xs, xp) ((xp) - (xs).beg)
#define Xsize(xs, xp) ((xs).end - (xs).beg)
#define Xsavepos(xs, xp) ((xp) - (xs).beg)
#define Xrestpos(xs, xp, n) ((xs).beg + (n))
char * Xcheck_grow_ ARGS((XString *xsp, char *xp, int more));
/*
* expandable vector of generic pointers
*/
typedef struct XPtrV {
void **cur; /* next avail pointer */
void **beg, **end; /* begin, end of vector */
} XPtrV;
#define XPinit(x, n) do { \
register void **vp__; \
vp__ = (void**) alloc(sizeofN(void*, n), ATEMP); \
(x).cur = (x).beg = vp__; \
(x).end = vp__ + n; \
} while (0)
#define XPput(x, p) do { \
if ((x).cur >= (x).end) { \
int n = XPsize(x); \
(x).beg = (void**) aresize((void*) (x).beg, \
sizeofN(void*, n*2), ATEMP); \
(x).cur = (x).beg + n; \
(x).end = (x).cur + n; \
} \
*(x).cur++ = (p); \
} while (0)
#define XPptrv(x) ((x).beg)
#define XPsize(x) ((x).cur - (x).beg)
#define XPclose(x) (void**) aresize((void*)(x).beg, \
sizeofN(void*, XPsize(x)), ATEMP)
#define XPfree(x) afree((void*) (x).beg, ATEMP)