1 /**
2 * collectd - src/utils_subst.c
3 * Copyright (C) 2008 Sebastian Harl
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 * and/or sell copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be included in
13 * all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
21 * DEALINGS IN THE SOFTWARE.
22 *
23 * Authors:
24 * Sebastian "tokkee" Harl <sh at tokkee.org>
25 **/
27 /*
28 * This module provides functions for string substitution.
29 */
31 #include "collectd.h"
33 #include "common.h"
34 #include "utils_subst.h"
36 char *subst (char *buf, size_t buflen, const char *string, size_t off1, size_t off2,
37 const char *replacement)
38 {
39 char *out = buf;
41 char const *front;
42 char const *back;
43 size_t front_len;
44 size_t replacement_len;
45 size_t back_len;
47 if ((NULL == buf) || (0 == buflen) || (NULL == string) || (NULL == replacement))
48 return NULL;
50 size_t string_len = strlen (string);
51 if ((off1 > string_len) || (off2 > string_len) || (off1 > off2))
52 return NULL;
54 front = string;
55 back = string + off2;
56 front_len = off1;
57 replacement_len = strlen (replacement);
58 back_len = strlen (back);
60 if (front_len >= buflen) {
61 front_len = buflen - 1;
62 replacement_len = 0;
63 back_len = 0;
64 } else if ((front_len + replacement_len) >= buflen) {
65 replacement_len = buflen - (front_len + 1);
66 back_len = 0;
67 } else if ((front_len + replacement_len + back_len) >= buflen) {
68 back_len = buflen - (front_len + replacement_len + 1);
69 } else {
70 buflen = front_len + replacement_len + back_len + 1;
71 }
72 assert ((front_len + replacement_len + back_len) == (buflen - 1));
74 if (front_len != 0) {
75 sstrncpy (out, front, front_len + 1);
76 out += front_len;
77 }
79 if (replacement_len != 0) {
80 sstrncpy (out, replacement, replacement_len + 1);
81 out += replacement_len;
82 }
84 if (back_len != 0) {
85 sstrncpy (out, back, back_len + 1);
86 out += back_len;
87 }
89 out[0] = 0;
90 return buf;
91 } /* subst */
93 char *asubst (const char *string, int off1, int off2, const char *replacement)
94 {
95 char *buf;
96 int len;
98 char *ret;
100 if ((NULL == string) || (0 > off1) || (0 > off2) || (off1 > off2)
101 || (NULL ==replacement))
102 return NULL;
104 len = off1 + strlen (replacement) + strlen (string) - off2 + 1;
106 buf = malloc (len);
107 if (NULL == buf)
108 return NULL;
110 ret = subst (buf, len, string, off1, off2, replacement);
111 if (NULL == ret)
112 free (buf);
113 return ret;
114 } /* asubst */
116 char *subst_string (char *buf, size_t buflen, const char *string,
117 const char *needle, const char *replacement)
118 {
119 size_t needle_len;
120 size_t i;
122 if ((buf == NULL) || (string == NULL)
123 || (needle == NULL) || (replacement == NULL))
124 return (NULL);
126 needle_len = strlen (needle);
127 sstrncpy (buf, string, buflen);
129 /* Limit the loop to prevent endless loops. */
130 for (i = 0; i < buflen; i++)
131 {
132 char temp[buflen];
133 char *begin_ptr;
134 size_t begin;
136 /* Find `needle' in `buf'. */
137 begin_ptr = strstr (buf, needle);
138 if (begin_ptr == NULL)
139 break;
141 /* Calculate the start offset. */
142 begin = begin_ptr - buf;
144 /* Substitute the region using `subst'. The result is stored in
145 * `temp'. */
146 begin_ptr = subst (temp, buflen, buf,
147 begin, begin + needle_len,
148 replacement);
149 if (begin_ptr == NULL)
150 {
151 WARNING ("subst_string: subst failed.");
152 break;
153 }
155 /* Copy the new string in `temp' to `buf' for the next round. */
156 strncpy (buf, temp, buflen);
157 }
159 if (i >= buflen)
160 {
161 WARNING ("subst_string: Loop exited after %zu iterations: "
162 "string = %s; needle = %s; replacement = %s;",
163 i, string, needle, replacement);
164 }
166 return (buf);
167 } /* char *subst_string */
169 /* vim: set sw=4 ts=4 tw=78 noexpandtab : */