Annotation of src/usr.bin/xargs/strnsubst.c, Revision 1.4
1.4 ! cloder 1: /* $OpenBSD: strnsubst.c,v 1.3 2005/11/01 04:52:58 deraadt Exp $ */
1.1 millert 2: /* $FreeBSD: strnsubst.c,v 1.6 2002/06/22 12:58:42 jmallett Exp $ */
3:
4: /*
5: * Copyright (c) 2002 J. Mallett. All rights reserved.
6: * You may do whatever you want with this file as long as
7: * the above copyright and this notice remain intact, along
8: * with the following statement:
9: * For the man who taught me vi, and who got too old, too young.
10: */
11:
12: #ifndef lint
1.4 ! cloder 13: static const char rcsid[] = "$OpenBSD: strnsubst.c,v 1.3 2005/11/01 04:52:58 deraadt Exp $";
1.1 millert 14: #endif /* not lint */
15:
16: #include <err.h>
17: #include <stdio.h>
18: #include <stdlib.h>
19: #include <string.h>
20: #include <unistd.h>
21:
22: void strnsubst(char **, const char *, const char *, size_t);
23:
24: /*
25: * Replaces str with a string consisting of str with match replaced with
26: * replstr as many times as can be done before the constructed string is
27: * maxsize bytes large. It does not free the string pointed to by str, it
28: * is up to the calling program to be sure that the original contents of
29: * str as well as the new contents are handled in an appropriate manner.
30: * If replstr is NULL, then that internally is changed to a nil-string, so
31: * that we can still pretend to do somewhat meaningful substitution.
32: * No value is returned.
33: */
34: void
35: strnsubst(char **str, const char *match, const char *replstr, size_t maxsize)
36: {
37: char *s1, *s2, *this;
1.4 ! cloder 38: size_t matchlen, repllen, s2len;
! 39: int n;
1.1 millert 40:
41: if ((s1 = *str) == NULL)
42: return;
43: if ((s2 = malloc(maxsize)) == NULL)
44: err(1, NULL);
45:
46: if (replstr == NULL)
47: replstr = "";
48:
49: if (match == NULL || *match == '\0' || strlen(s1) >= maxsize) {
50: strlcpy(s2, s1, maxsize);
51: goto done;
52: }
53:
54: *s2 = '\0';
55: s2len = 0;
56: matchlen = strlen(match);
57: repllen = strlen(replstr);
58: for (;;) {
59: if ((this = strstr(s1, match)) == NULL)
60: break;
61: n = snprintf(s2 + s2len, maxsize - s2len, "%.*s%s",
62: (int)(this - s1), s1, replstr);
1.2 millert 63: if (n == -1 || n + s2len + strlen(this + matchlen) >= maxsize)
1.1 millert 64: break; /* out of room */
65: s2len += n;
66: s1 = this + matchlen;
67: }
68: strlcpy(s2 + s2len, s1, maxsize - s2len);
69: done:
70: *str = s2;
71: return;
72: }
73:
74: #ifdef TEST
75: #include <stdio.h>
76:
1.3 deraadt 77: int
1.1 millert 78: main(void)
79: {
80: char *x, *y, *z, *za;
81:
82: x = "{}%$";
83: strnsubst(&x, "%$", "{} enpury!", 255);
84: y = x;
85: strnsubst(&y, "}{}", "ybir", 255);
86: z = y;
87: strnsubst(&z, "{", "v ", 255);
88: za = z;
89: strnsubst(&z, NULL, za, 255);
90: if (strcmp(z, "v ybir enpury!") == 0)
91: printf("strnsubst() seems to work!\n");
92: else
93: printf("strnsubst() is broken.\n");
94: printf("%s\n", z);
95: free(x);
96: free(y);
97: free(z);
98: free(za);
99: return 0;
100: }
101: #endif