1/* String replacement in an argz vector
2 Copyright (C) 1997-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <stdlib.h>
20#include <string.h>
21#include <argz.h>
22
23/* Append BUF, of length BUF_LEN to *TO, of length *TO_LEN, reallocating and
24 updating *TO & *TO_LEN appropriately. If an allocation error occurs,
25 *TO's old value is freed, and *TO is set to 0. */
26static void
27str_append (char **to, size_t *to_len, const char *buf, const size_t buf_len)
28{
29 size_t new_len = *to_len + buf_len;
30 char *new_to = realloc (*to, new_len + 1);
31
32 if (new_to)
33 {
34 *((char *) __mempcpy (new_to + *to_len, buf, buf_len)) = '\0';
35 *to = new_to;
36 *to_len = new_len;
37 }
38 else
39 {
40 free (*to);
41 *to = 0;
42 }
43}
44
45/* Replace any occurrences of the string STR in ARGZ with WITH, reallocating
46 ARGZ as necessary. If REPLACE_COUNT is non-zero, *REPLACE_COUNT will be
47 incremented by number of replacements performed. */
48error_t
49__argz_replace (char **argz, size_t *argz_len, const char *str, const char *with,
50 unsigned *replace_count)
51{
52 error_t err = 0;
53
54 if (str && *str)
55 {
56 char *arg = 0;
57 char *src = *argz;
58 size_t src_len = *argz_len;
59 char *dst = 0;
60 size_t dst_len = 0;
61 int delayed_copy = 1; /* True while we've avoided copying anything. */
62 size_t str_len = strlen (str), with_len = strlen (with);
63
64 while (!err && (arg = argz_next (src, src_len, arg)))
65 {
66 char *match = strstr (arg, str);
67 if (match)
68 {
69 char *from = match + str_len;
70 size_t to_len = match - arg;
71 char *to = __strndup (arg, to_len);
72
73 while (to && from)
74 {
75 str_append (&to, &to_len, with, with_len);
76 if (to)
77 {
78 match = strstr (from, str);
79 if (match)
80 {
81 str_append (&to, &to_len, from, match - from);
82 from = match + str_len;
83 }
84 else
85 {
86 str_append (&to, &to_len, from, strlen (from));
87 from = 0;
88 }
89 }
90 }
91
92 if (to)
93 {
94 if (delayed_copy)
95 /* We avoided copying SRC to DST until we found a match;
96 now that we've done so, copy everything from the start
97 of SRC. */
98 {
99 if (arg > src)
100 err = __argz_append (&dst, &dst_len, src, (arg - src));
101 delayed_copy = 0;
102 }
103 if (! err)
104 err = __argz_add (&dst, &dst_len, to);
105 free (to);
106 }
107 else
108 err = ENOMEM;
109
110 if (replace_count)
111 (*replace_count)++;
112 }
113 else if (! delayed_copy)
114 err = __argz_add (&dst, &dst_len, arg);
115 }
116
117 if (! err)
118 {
119 if (! delayed_copy)
120 /* We never found any instances of str. */
121 {
122 free (src);
123 *argz = dst;
124 *argz_len = dst_len;
125 }
126 }
127 else if (dst_len > 0)
128 free (dst);
129 }
130
131 return err;
132}
133weak_alias (__argz_replace, argz_replace)
134