1 /*
2 * Utility functions for handling cvecs
3 * This file is #included by regcomp.c.
4 *
5 * Copyright (c) 1998, 1999 Henry Spencer. All rights reserved.
6 *
7 * Development of this software was funded, in part, by Cray Research Inc.,
8 * UUNET Communications Services Inc., Sun Microsystems Inc., and Scriptics
9 * Corporation, none of whom are responsible for the results. The author
10 * thanks all of them.
11 *
12 * Redistribution and use in source and binary forms -- with or without
13 * modification -- are permitted for any purpose, provided that
14 * redistributions in source form retain this entire copyright notice and
15 * indicate the origin and nature of any modifications.
16 *
17 * I'd appreciate being given credit for this package in the documentation
18 * of software which uses it, but that is not a requirement.
19 *
20 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
21 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
22 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
23 * HENRY SPENCER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
26 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
27 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
28 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
29 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 *
31 * src/backend/regex/regc_cvec.c
32 *
33 */
34
35 /*
36 * Notes:
37 * Only (selected) functions in _this_ file should treat chr* as non-constant.
38 */
39
40 /*
41 * newcvec - allocate a new cvec
42 */
43 static struct cvec *
newcvec(int nchrs,int nranges)44 newcvec(int nchrs, /* to hold this many chrs... */
45 int nranges) /* ... and this many ranges */
46 {
47 size_t nc = (size_t) nchrs + (size_t) nranges * 2;
48 size_t n = sizeof(struct cvec) + nc * sizeof(chr);
49 struct cvec *cv = (struct cvec *) MALLOC(n);
50
51 if (cv == NULL)
52 return NULL;
53 cv->chrspace = nchrs;
54 cv->chrs = (chr *) (((char *) cv) + sizeof(struct cvec));
55 cv->ranges = cv->chrs + nchrs;
56 cv->rangespace = nranges;
57 return clearcvec(cv);
58 }
59
60 /*
61 * clearcvec - clear a possibly-new cvec
62 * Returns pointer as convenience.
63 */
64 static struct cvec *
clearcvec(struct cvec * cv)65 clearcvec(struct cvec * cv)
66 {
67 assert(cv != NULL);
68 cv->nchrs = 0;
69 cv->nranges = 0;
70 return cv;
71 }
72
73 /*
74 * addchr - add a chr to a cvec
75 */
76 static void
addchr(struct cvec * cv,chr c)77 addchr(struct cvec * cv, /* character vector */
78 chr c) /* character to add */
79 {
80 assert(cv->nchrs < cv->chrspace);
81 cv->chrs[cv->nchrs++] = (chr) c;
82 }
83
84 /*
85 * addrange - add a range to a cvec
86 */
87 static void
addrange(struct cvec * cv,chr from,chr to)88 addrange(struct cvec * cv, /* character vector */
89 chr from, /* first character of range */
90 chr to) /* last character of range */
91 {
92 assert(cv->nranges < cv->rangespace);
93 cv->ranges[cv->nranges * 2] = (chr) from;
94 cv->ranges[cv->nranges * 2 + 1] = (chr) to;
95 cv->nranges++;
96 }
97
98 /*
99 * getcvec - get a transient cvec, initialized to empty
100 *
101 * The returned cvec is valid only until the next call of getcvec, which
102 * typically will recycle the space. Callers should *not* free the cvec
103 * explicitly; it will be cleaned up when the struct vars is destroyed.
104 *
105 * This is typically used while interpreting bracket expressions. In that
106 * usage the cvec is only needed momentarily until we build arcs from it,
107 * so transientness is a convenient behavior.
108 */
109 static struct cvec *
getcvec(struct vars * v,int nchrs,int nranges)110 getcvec(struct vars * v, /* context */
111 int nchrs, /* to hold this many chrs... */
112 int nranges) /* ... and this many ranges */
113 {
114 /* recycle existing transient cvec if large enough */
115 if (v->cv != NULL && nchrs <= v->cv->chrspace &&
116 nranges <= v->cv->rangespace)
117 return clearcvec(v->cv);
118
119 /* nope, make a new one */
120 if (v->cv != NULL)
121 freecvec(v->cv);
122 v->cv = newcvec(nchrs, nranges);
123 if (v->cv == NULL)
124 ERR(REG_ESPACE);
125
126 return v->cv;
127 }
128
129 /*
130 * freecvec - free a cvec
131 */
132 static void
freecvec(struct cvec * cv)133 freecvec(struct cvec * cv)
134 {
135 FREE(cv);
136 }
137