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
22#include <sys/cdefs.h>
23#if defined(LIBC_SCCS) && !defined(lint)
24__RCSID("$NetBSD: regsub.c,v 1.8 1999/05/06 17:09:31 christos Exp $");
25#endif /* LIBC_SCCS and not lint */
26
27#include <regexp.h>
28#include <stdio.h>
29#include <string.h>
30#include "regmagic.h"
31
32#ifndef CHARBITS
33#define	UCHARAT(p)	((int)*(unsigned char *)(p))
34#else
35#define	UCHARAT(p)	((int)*(p)&CHARBITS)
36#endif
37
38/*
39 - regsub - perform substitutions after a regexp match
40 */
41void
42__compat_regsub(prog, source, dest)
43const regexp *prog;
44const char *source;
45char *dest;
46{
47	char *src;
48	char *dst;
49	char c;
50	int no;
51	int len;
52
53	if (prog == NULL || source == NULL || dest == NULL) {
54		regerror("NULL parm to regsub");
55		return;
56	}
57	if (UCHARAT(prog->program) != MAGIC) {
58		regerror("damaged regexp fed to regsub");
59		return;
60	}
61
62	/* LINTED const castaway */
63	src = (char *)source;
64	dst = dest;
65	while ((c = *src++) != '\0') {
66		if (c == '&')
67			no = 0;
68		else if (c == '\\' && '0' <= *src && *src <= '9')
69			no = *src++ - '0';
70		else
71			no = -1;
72 		if (no < 0) {	/* Ordinary character. */
73 			if (c == '\\' && (*src == '\\' || *src == '&'))
74 				c = *src++;
75 			*dst++ = c;
76 		} else if (prog->startp[no] != NULL && prog->endp[no] != NULL) {
77			len = prog->endp[no] - prog->startp[no];
78			(void) strncpy(dst, prog->startp[no], (size_t)len);
79			dst += len;
80			if (len != 0 && *(dst-1) == '\0') {	/* strncpy hit NUL. */
81				regerror("damaged match string");
82				return;
83			}
84		}
85	}
86	*dst++ = '\0';
87}
88