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 <regexp.h>
22 #include <stdio.h>
23 #include <string.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 */
35 void
regsub(prog,source,dest)36 regsub(prog, source, dest)
37 const regexp *prog;
38 const char *source;
39 char *dest;
40 {
41 register char *src;
42 register char *dst;
43 register char c;
44 register int no;
45 register int len;
46 extern char *strncpy();
47
48 if (prog == NULL || source == NULL || dest == NULL) {
49 regerror("NULL parm to regsub");
50 return;
51 }
52 if (UCHARAT(prog->program) != MAGIC) {
53 regerror("damaged regexp fed to regsub");
54 return;
55 }
56
57 src = (char *)source;
58 dst = dest;
59 while ((c = *src++) != '\0') {
60 if (c == '&')
61 no = 0;
62 else if (c == '\\' && '0' <= *src && *src <= '9')
63 no = *src++ - '0';
64 else
65 no = -1;
66 if (no < 0) { /* Ordinary character. */
67 if (c == '\\' && (*src == '\\' || *src == '&'))
68 c = *src++;
69 *dst++ = c;
70 } else if (prog->startp[no] != NULL && prog->endp[no] != NULL) {
71 len = prog->endp[no] - prog->startp[no];
72 (void) strncpy(dst, prog->startp[no], len);
73 dst += len;
74 if (len != 0 && *(dst-1) == '\0') { /* strncpy hit NUL. */
75 regerror("damaged match string");
76 return;
77 }
78 }
79 }
80 *dst++ = '\0';
81 }
82