1/* String replacement in an argz vector
2 Copyright (C) 1997-2020 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Written by Miles Bader <miles@gnu.ai.mit.edu>
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20#include <stdlib.h>
21#include <string.h>
22#include <argz.h>
23
24/* Append BUF, of length BUF_LEN to *TO, of length *TO_LEN, reallocating and
25 updating *TO & *TO_LEN appropriately. If an allocation error occurs,
26 *TO's old value is freed, and *TO is set to 0. */
27static void
28str_append (char **to, size_t *to_len, const char *buf, const size_t buf_len)
29{
30 size_t new_len = *to_len + buf_len;
31 char *new_to = realloc (*to, new_len + 1);
32
33 if (new_to)
34 {
35 *((char *) __mempcpy (new_to + *to_len, buf, buf_len)) = '\0';
36 *to = new_to;
37 *to_len = new_len;
38 }
39 else
40 {
41 free (*to);
42 *to = 0;
43 }
44}
45
46/* Replace any occurrences of the string STR in ARGZ with WITH, reallocating
47 ARGZ as necessary. If REPLACE_COUNT is non-zero, *REPLACE_COUNT will be
48 incremented by number of replacements performed. */
49error_t
50__argz_replace (char **argz, size_t *argz_len, const char *str, const char *with,
51 unsigned *replace_count)
52{
53 error_t err = 0;
54
55 if (str && *str)
56 {
57 char *arg = 0;
58 char *src = *argz;
59 size_t src_len = *argz_len;
60 char *dst = 0;
61 size_t dst_len = 0;
62 int delayed_copy = 1; /* True while we've avoided copying anything. */
63 size_t str_len = strlen (str), with_len = strlen (with);
64
65 while (!err && (arg = argz_next (src, src_len, arg)))
66 {
67 char *match = strstr (arg, str);
68 if (match)
69 {
70 char *from = match + str_len;
71 size_t to_len = match - arg;
72 char *to = __strndup (arg, to_len);
73
74 while (to && from)
75 {
76 str_append (&to, &to_len, with, with_len);
77 if (to)
78 {
79 match = strstr (from, str);
80 if (match)
81 {
82 str_append (&to, &to_len, from, match - from);
83 from = match + str_len;
84 }
85 else
86 {
87 str_append (&to, &to_len, from, strlen (from));
88 from = 0;
89 }
90 }
91 }
92
93 if (to)
94 {
95 if (delayed_copy)
96 /* We avoided copying SRC to DST until we found a match;
97 now that we've done so, copy everything from the start
98 of SRC. */
99 {
100 if (arg > src)
101 err = __argz_append (&dst, &dst_len, src, (arg - src));
102 delayed_copy = 0;
103 }
104 if (! err)
105 err = __argz_add (&dst, &dst_len, to);
106 free (to);
107 }
108 else
109 err = ENOMEM;
110
111 if (replace_count)
112 (*replace_count)++;
113 }
114 else if (! delayed_copy)
115 err = __argz_add (&dst, &dst_len, arg);
116 }
117
118 if (! err)
119 {
120 if (! delayed_copy)
121 /* We never found any instances of str. */
122 {
123 free (src);
124 *argz = dst;
125 *argz_len = dst_len;
126 }
127 }
128 else if (dst_len > 0)
129 free (dst);
130 }
131
132 return err;
133}
134weak_alias (__argz_replace, argz_replace)
135