1 /* $xMach: strnsubst.c,v 1.3 2002/02/23 02:10:24 jmallett Exp $ */
4 * Copyright (c) 2002 J. Mallett. All rights reserved.
5 * You may do whatever you want with this file as long as
6 * the above copyright and this notice remain intact, along
7 * with the following statement:
8 * For the man who taught me vi, and who got too old, too young.
11 #include <sys/cdefs.h>
12 __FBSDID("$FreeBSD$");
19 void strnsubst(char **, const char *, const char *, size_t);
22 * Replaces str with a string consisting of str with match replaced with
23 * replstr as many times as can be done before the constructed string is
24 * maxsize bytes large. It does not free the string pointed to by str, it
25 * is up to the calling program to be sure that the original contents of
26 * str as well as the new contents are handled in an appropriate manner.
27 * If replstr is NULL, then that internally is changed to a nil-string, so
28 * that we can still pretend to do somewhat meaningful substitution.
29 * No value is returned.
32 strnsubst(char **str, const char *match, const char *replstr, size_t maxsize)
40 * If maxsize is 0 then set it to to the length of s1, because we have
41 * to duplicate s1. XXX we maybe should double-check whether the match
42 * appears in s1. If it doesn't, then we also have to set the length
43 * to the length of s1, to avoid modifying the argument. It may make
44 * sense to check if maxsize is <= strlen(s1), because in that case we
45 * want to return the unmodified string, too.
49 maxsize = strlen(s1) + 1;
51 s2 = calloc(maxsize, 1);
58 if (match == NULL || replstr == NULL || maxsize == strlen(s1)) {
59 strlcpy(s2, s1, maxsize);
64 this = strstr(s1, match);
67 if ((strlen(s2) + strlen(s1) + strlen(replstr) -
68 strlen(match) + 1) > maxsize) {
69 strlcat(s2, s1, maxsize);
72 strncat(s2, s1, (uintptr_t)this - (uintptr_t)s1);
74 s1 = this + strlen(match);
91 strnsubst(&x, "%$", "{} enpury!", 255);
93 strnsubst(&y, "}{}", "ybir", 255);
95 strnsubst(&z, "{", "v ", 255);
97 strnsubst(&z, NULL, za, 255);
98 if (strcmp(z, "v ybir enpury!") == 0)
99 printf("strnsubst() seems to work!\n");
101 printf("strnsubst() is broken.\n");