expand.h
1/* $OpenBSD: expand.h,v 1.15 2018/01/06 16:28:58 millert Exp $ */
2
3/*
4 * Expanding strings
5 */
6
7#define X_EXTRA 8 /* this many extra bytes in X string */
8
9#if 0 /* Usage */
10 XString xs;
11 char *xp;
12
13 Xinit(xs, xp, 128, ATEMP); /* allocate initial string */
14 while ((c = generate()) {
15 Xcheck(xs, xp); /* expand string if necessary */
16 Xput(xs, xp, c); /* add character */
17 }
18 return Xclose(xs, xp); /* resize string */
19/*
20 * NOTE:
21 * The Xcheck and Xinit macros have a magic + X_EXTRA in the lengths.
22 * This is so that you can put up to X_EXTRA characters in a XString
23 * before calling Xcheck. (See yylex in lex.c)
24 */
25#endif /* 0 */
26
27typedef struct XString {
28 char *end, *beg; /* end, begin of string */
29 size_t len; /* length */
30 Area *areap; /* area to allocate/free from */
31} XString;
32
33typedef char * XStringP;
34
35/* initialize expandable string */
36#define Xinit(xs, xp, length, area) do { \
37 (xs).len = length; \
38 (xs).areap = (area); \
39 (xs).beg = alloc((xs).len + X_EXTRA, (xs).areap); \
40 (xs).end = (xs).beg + (xs).len; \
41 xp = (xs).beg; \
42 } while (0)
43
44/* stuff char into string */
45#define Xput(xs, xp, c) (*xp++ = (c))
46
47/* check if there are at least n bytes left */
48#define XcheckN(xs, xp, n) do { \
49 ptrdiff_t more = ((xp) + (n)) - (xs).end; \
50 if (more > 0) \
51 xp = Xcheck_grow_(&xs, xp, more); \
52 } while (0)
53
54/* check for overflow, expand string */
55#define Xcheck(xs, xp) XcheckN(xs, xp, 1)
56
57/* free string */
58#define Xfree(xs, xp) afree((xs).beg, (xs).areap)
59
60/* close, return string */
61#define Xclose(xs, xp) aresize((xs).beg, ((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
71char * Xcheck_grow_(XString *xsp, char *xp, size_t more);
72
73/*
74 * expandable vector of generic pointers
75 */
76
77typedef 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 void **vp__; \
84 vp__ = areallocarray(NULL, n, sizeof(void *), 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 = areallocarray((x).beg, n, \
93 2 * sizeof(void *), 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) areallocarray((x).beg, XPsize(x), \
104 sizeof(void *), ATEMP)
105
106#define XPfree(x) afree((x).beg, ATEMP)
