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>
14 __FBSDID("$FreeBSD: src/usr.bin/xargs/strnsubst.c,v 1.8 2005/12/30 23:22:50 jmallett Exp $");
25 void strnsubst(char **, const char *, const char *, size_t);
28 * Replaces str with a string consisting of str with match replaced with
29 * replstr as many times as can be done before the constructed string is
30 * maxsize bytes large. It does not free the string pointed to by str, it
31 * is up to the calling program to be sure that the original contents of
32 * str as well as the new contents are handled in an appropriate manner.
33 * If replstr is NULL, then that internally is changed to a nil-string, so
34 * that we can still pretend to do somewhat meaningful substitution.
35 * No value is returned.
38 strnsubst(char **str
, const char *match
, const char *replstr
, size_t maxsize
)
46 * If maxsize is 0 then set it to to the length of s1, because we have
47 * to duplicate s1. XXX we maybe should double-check whether the match
48 * appears in s1. If it doesn't, then we also have to set the length
49 * to the length of s1, to avoid modifying the argument. It may make
50 * sense to check if maxsize is <= strlen(s1), because in that case we
51 * want to return the unmodified string, too.
55 maxsize
= strlen(s1
) + 1;
57 s2
= calloc(maxsize
, 1);
64 if (match
== NULL
|| replstr
== NULL
|| maxsize
== strlen(s1
)) {
65 (void)strlcpy(s2
, s1
, maxsize
);
70 this = strstr(s1
, match
);
73 if ((strlen(s2
) + strlen(s1
) + strlen(replstr
) -
74 strlen(match
) + 1) > maxsize
) {
75 (void)strlcat(s2
, s1
, maxsize
);
78 (void)strncat(s2
, s1
, (uintptr_t)this - (uintptr_t)s1
);
79 (void)strcat(s2
, replstr
);
80 s1
= this + strlen(match
);
97 strnsubst(&x
, "%$", "{} enpury!", 255);
99 strnsubst(&y
, "}{}", "ybir", 255);
101 strnsubst(&z
, "{", "v ", 255);
103 strnsubst(&z
, NULL
, za
, 255);
104 if (strcmp(z
, "v ybir enpury!") == 0)
105 (void)printf("strnsubst() seems to work!\n");
107 (void)printf("strnsubst() is broken.\n");
108 (void)printf("%s\n", z
);