PostgreSQL Source Code  git master
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros
regc_cvec.c
Go to the documentation of this file.
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 *
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 *
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
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
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 *
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
135 freecvec(struct cvec * cv)
136 {
137  FREE(cv);
138 }
#define ERR
Definition: _int.h:146
#define REG_ESPACE
Definition: regex.h:149
static void addrange(struct cvec *cv, chr from, chr to)
Definition: regc_cvec.c:90
#define FREE(p)
Definition: regcustom.h:54
static struct cvec * newcvec(int nchrs, int nranges)
Definition: regc_cvec.c:45
int chrspace
Definition: regguts.h:259
#define MALLOC(n)
Definition: regcustom.h:53
pg_wchar chr
Definition: regcustom.h:59
static struct cvec * clearcvec(struct cvec *cv)
Definition: regc_cvec.c:66
chr * ranges
Definition: regguts.h:263
int nchrs
Definition: regguts.h:258
int cclasscode
Definition: regguts.h:264
char * c
#define assert(TEST)
Definition: imath.c:37
Definition: regguts.h:256
struct cvec * cv
Definition: regcomp.c:251
static void freecvec(struct cvec *cv)
Definition: regc_cvec.c:135
chr * chrs
Definition: regguts.h:260
#define NULL
Definition: c.h:226
int rangespace
Definition: regguts.h:262
static void addchr(struct cvec *cv, chr c)
Definition: regc_cvec.c:79
Definition: regcomp.c:226
static struct cvec * getcvec(struct vars *v, int nchrs, int nranges)
Definition: regc_cvec.c:112
int nranges
Definition: regguts.h:261