1/*
2 * regsub
3 * @(#)regsub.c	1.3 of 2 April 86
4 *
5 *	Copyright (c) 1986 by University of Toronto.
6 *	Written by Henry Spencer.  Not derived from licensed software.
7 *
8 *	Permission is granted to anyone to use this software for any
9 *	purpose on any computer system, and to redistribute it freely,
10 *	subject to the following restrictions:
11 *
12 *	1. The author is not responsible for the consequences of use of
13 *		this software, no matter how awful, even if they arise
14 *		from defects in it.
15 *
16 *	2. The origin of this software must not be misrepresented, either
17 *		by explicit claim or by omission.
18 *
19 *	3. Altered versions must be plainly marked as such, and must not
20 *		be misrepresented as being the original software.
21 *
22 *
23 * This code was modified by Ethan Sommer to work within the kernel
24 * (it now uses kmalloc etc..)
25 *
26 */
27#include "regexp.h"
28#include "regmagic.h"
29#include <linux/string.h>
30
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#if 0
39//void regerror(char * s)
40//{
41//        printk("regexp(3): %s", s);
42//        /* NOTREACHED */
43//}
44#endif
45
46/*
47 - regsub - perform substitutions after a regexp match
48 */
49void
50regsub(regexp * prog, char * source, char * dest)
51{
52	register char *src;
53	register char *dst;
54	register char c;
55	register int no;
56	register int len;
57
58	/* Not necessary and gcc doesn't like it -MLS */
59	/*extern char *strncpy();*/
60
61	if (prog == NULL || source == NULL || dest == NULL) {
62		regerror("NULL parm to regsub");
63		return;
64	}
65	if (UCHARAT(prog->program) != MAGIC) {
66		regerror("damaged regexp fed to regsub");
67		return;
68	}
69
70	src = source;
71	dst = dest;
72	while ((c = *src++) != '\0') {
73		if (c == '&')
74			no = 0;
75		else if (c == '\\' && '0' <= *src && *src <= '9')
76			no = *src++ - '0';
77		else
78			no = -1;
79
80		if (no < 0) {	/* Ordinary character. */
81			if (c == '\\' && (*src == '\\' || *src == '&'))
82				c = *src++;
83			*dst++ = c;
84		} else if (prog->startp[no] != NULL && prog->endp[no] != NULL) {
85			len = prog->endp[no] - prog->startp[no];
86			(void) strncpy(dst, prog->startp[no], len);
87			dst += len;
88			if (len != 0 && *(dst-1) == '\0') {	/* strncpy hit NUL. */
89				regerror("damaged match string");
90				return;
91			}
92		}
93	}
94	*dst++ = '\0';
95}
96