expand.h

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