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 the chr arrays
38 * of a cvec as non-constant.
39 */
40
41 /*
42 * newcvec - allocate a new cvec
43 */
44 static struct cvec *
newcvec(int nchrs,int nranges)45 newcvec(int nchrs, /* to hold this many chrs... */
46 int nranges) /* ... and this many ranges */
47 {
48 size_t nc = (size_t) nchrs + (size_t) nranges * 2;
49 size_t n = sizeof(struct cvec) + nc * sizeof(chr);
50 struct cvec *cv = (struct cvec *) MALLOC(n);
51
52 if (cv == NULL)
53 return NULL;
54 cv->chrspace = nchrs;
55 cv->chrs = (chr *) (((char *) cv) + sizeof(struct cvec));
56 cv->ranges = cv->chrs + nchrs;
57 cv->rangespace = nranges;
58 return clearcvec(cv);
59 }
60
61 /*
62 * clearcvec - clear a possibly-new cvec
63 * Returns pointer as convenience.
64 */
65 static struct cvec *
clearcvec(struct cvec * cv)66 clearcvec(struct cvec *cv)
67 {
68 assert(cv != NULL);
69 cv->nchrs = 0;
70 cv->nranges = 0;
71 cv->cclasscode = -1;
72 return cv;
73 }
74
75 /*
76 * addchr - add a chr to a cvec
77 */
78 static void
addchr(struct cvec * cv,chr c)79 addchr(struct cvec *cv, /* character vector */
80 chr c) /* character to add */
81 {
82 assert(cv->nchrs < cv->chrspace);
83 cv->chrs[cv->nchrs++] = c;
84 }
85
86 /*
87 * addrange - add a range to a cvec
88 */
89 static void
addrange(struct cvec * cv,chr from,chr to)90 addrange(struct cvec *cv, /* character vector */
91 chr from, /* first character of range */
92 chr to) /* last character of range */
93 {
94 assert(cv->nranges < cv->rangespace);
95 cv->ranges[cv->nranges * 2] = from;
96 cv->ranges[cv->nranges * 2 + 1] = to;
97 cv->nranges++;
98 }
99
100 /*
101 * getcvec - get a transient cvec, initialized to empty
102 *
103 * The returned cvec is valid only until the next call of getcvec, which
104 * typically will recycle the space. Callers should *not* free the cvec
105 * explicitly; it will be cleaned up when the struct vars is destroyed.
106 *
107 * This is typically used while interpreting bracket expressions. In that
108 * usage the cvec is only needed momentarily until we build arcs from it,
109 * so transientness is a convenient behavior.
110 */
111 static struct cvec *
getcvec(struct vars * v,int nchrs,int nranges)112 getcvec(struct vars *v, /* context */
113 int nchrs, /* to hold this many chrs... */
114 int nranges) /* ... and this many ranges */
115 {
116 /* recycle existing transient cvec if large enough */
117 if (v->cv != NULL && nchrs <= v->cv->chrspace &&
118 nranges <= v->cv->rangespace)
119 return clearcvec(v->cv);
120
121 /* nope, make a new one */
122 if (v->cv != NULL)
123 freecvec(v->cv);
124 v->cv = newcvec(nchrs, nranges);
125 if (v->cv == NULL)
126 ERR(REG_ESPACE);
127
128 return v->cv;
129 }
130
131 /*
132 * freecvec - free a cvec
133 */
134 static void
freecvec(struct cvec * cv)135 freecvec(struct cvec *cv)
136 {
137 FREE(cv);
138 }
139