Edinburgh Speech Tools 2.4-release
regsub.c
1/*
2 * regsub
3 *
4 * Copyright (c) 1986 by University of Toronto.
5 * Written by Henry Spencer. Not derived from licensed software.
6 *
7 * Permission is granted to anyone to use this software for any
8 * purpose on any computer system, and to redistribute it freely,
9 * subject to the following restrictions:
10 *
11 * 1. The author is not responsible for the consequences of use of
12 * this software, no matter how awful, even if they arise
13 * from defects in it.
14 *
15 * 2. The origin of this software must not be misrepresented, either
16 * by explicit claim or by omission.
17 *
18 * 3. Altered versions must be plainly marked as such, and must not
19 * be misrepresented as being the original software.
20 */
21#include <stdio.h>
22#include <string.h>
23#include "regexp.h"
24#include "regmagic.h"
25
26#ifndef CHARBITS
27#define UCHARAT(p) ((int)*(unsigned char *)(p))
28#else
29#define UCHARAT(p) ((int)*(p)&CHARBITS)
30#endif
31
32/*
33 - regsub - perform substitutions after a regexp match
34 */
35void
36hs_regsub(prog, source, dest)
37const hs_regexp *prog;
38const char *source;
39char *dest;
40{
41 register char *src;
42 register char *dst;
43 register char c;
44 register int no;
45 register int len;
46
47 if (prog == NULL || source == NULL || dest == NULL) {
48 hs_regerror("NULL parm to regsub");
49 return;
50 }
51 if (UCHARAT(prog->program) != MAGIC) {
52 hs_regerror("damaged regexp fed to regsub");
53 return;
54 }
55
56 src = (char *)source;
57 dst = dest;
58 while ((c = *src++) != '\0') {
59 if (c == '&')
60 no = 0;
61 else if (c == '\\' && '0' <= *src && *src <= '9')
62 no = *src++ - '0';
63 else
64 no = -1;
65 if (no < 0) { /* Ordinary character. */
66 if (c == '\\' && (*src == '\\' || *src == '&'))
67 c = *src++;
68 *dst++ = c;
69 } else if (prog->startp[no] != NULL && prog->endp[no] != NULL) {
70 len = prog->endp[no] - prog->startp[no];
71 (void) strncpy(dst, prog->startp[no], len);
72 dst += len;
73 if (len != 0 && *(dst-1) == '\0') { /* strncpy hit NUL. */
74 hs_regerror("damaged match string");
75 return;
76 }
77 }
78 }
79 *dst++ = '\0';
80}