HAMMER VFS - Refactor merged search function to try to avoid missed entries
[dragonfly.git] / usr.bin / xargs / strnsubst.c
bloba22d0a40c85aad1d17e17d34820f1447cb7dc934
1 /* $xMach: strnsubst.c,v 1.3 2002/02/23 02:10:24 jmallett Exp $ */
3 /*
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.
10 * $FreeBSD: src/usr.bin/xargs/strnsubst.c,v 1.5.2.1 2002/06/17 04:44:46 jmallett Exp $
11 * $DragonFly: src/usr.bin/xargs/strnsubst.c,v 1.2 2003/06/17 04:29:34 dillon Exp $
14 #include <err.h>
15 #include <stdlib.h>
16 #include <string.h>
17 #include <unistd.h>
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.
31 void
32 strnsubst(char **str, const char *match, const char *replstr, size_t maxsize)
34 char *s1, *s2, *this;
36 s1 = *str;
37 if (s1 == NULL)
38 return;
39 s2 = calloc(maxsize, 1);
40 if (s2 == NULL)
41 err(1, "calloc");
43 if (replstr == NULL)
44 replstr = "";
46 if (match == NULL || replstr == NULL || maxsize == strlen(s1)) {
47 strlcpy(s2, s1, maxsize);
48 goto done;
51 for (;;) {
52 this = strstr(s1, match);
53 if (this == NULL)
54 break;
55 if ((strlen(s2) + ((uintptr_t)this - (uintptr_t)s1) +
56 (strlen(replstr) - 1)) > maxsize && *replstr != '\0') {
57 strlcat(s2, s1, maxsize);
58 goto done;
60 strncat(s2, s1, (uintptr_t)this - (uintptr_t)s1);
61 strcat(s2, replstr);
62 s1 = this + strlen(match);
64 strcat(s2, s1);
65 done:
66 *str = s2;
67 return;
70 #ifdef TEST
71 #include <stdio.h>
73 int
74 main(void)
76 char *x, *y;
78 y = x = "{}{}{}";
79 strnsubst(&x, "{}", "v ybir whyv! ", 12);
80 if (strcmp(x, "v ybir whyv! ") == 0)
81 printf("strnsubst() seems to work as expected.\n");
82 printf("x: %s\ny: %s\n", x, y);
83 free(x);
84 return 0;
86 #endif