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*/
1 /*
2 Functions for escaping and unescaping strings
3
4 Copyright (C) 2009-2021
5 Free Software Foundation, Inc.
6
7 Written by:
8 Slava Zanko <slavazanko@gmail.com>, 2009;
9 Patrick Winnertz <winnie@debian.org>, 2009
10
11 This file is part of the Midnight Commander.
12
13 The Midnight Commander is free software: you can redistribute it
14 and/or modify it under the terms of the GNU General Public License as
15 published by the Free Software Foundation, either version 3 of the License,
16 or (at your option) any later version.
17
18 The Midnight Commander is distributed in the hope that it will be useful,
19 but WITHOUT ANY WARRANTY; without even the implied warranty of
20 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 GNU General Public License for more details.
22
23 You should have received a copy of the GNU General Public License
24 along with this program. If not, see <http://www.gnu.org/licenses/>.
25 */
26
27 #include <config.h>
28
29 #include "lib/global.h"
30 #include "lib/strescape.h"
31
32 /*** global variables ****************************************************************************/
33
34 /*** file scope macro definitions ****************************************************************/
35
36 /*** file scope type declarations ****************************************************************/
37
38 /*** file scope variables ************************************************************************/
39
40 static const char ESCAPE_SHELL_CHARS[] = " !#$%()&{}[]`?|<>;*\\\"'";
41 static const char ESCAPE_REGEX_CHARS[] = "^!#$%()&{}[]`?|<>;*+.\\";
42 static const char ESCAPE_GLOB_CHARS[] = "$*\\?";
43
44 /*** file scope functions ************************************************************************/
45
46 /*** public functions ****************************************************************************/
47
48 char *
49 strutils_escape (const char *src, gsize src_len, const char *escaped_chars,
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*/
50 gboolean escape_non_printable)
51 {
52 GString *ret;
53 gsize curr_index;
54 /* do NOT break allocation semantics */
55 if (src == NULL)
56 return NULL;
57
58 if (*src == '\0')
59 return strdup ("");
60
61 ret = g_string_new ("");
62
63 if (src_len == (gsize) (-1))
64 src_len = strlen (src);
65
66 for (curr_index = 0; curr_index < src_len; curr_index++)
67 {
68 if (escape_non_printable)
69 {
70 switch (src[curr_index])
71 {
72 case '\n':
73 g_string_append (ret, "\\n");
74 continue;
75 case '\t':
76 g_string_append (ret, "\\t");
77 continue;
78 case '\b':
79 g_string_append (ret, "\\b");
80 continue;
81 case '\0':
82 g_string_append (ret, "\\0");
83 continue;
84 default:
85 break;
86 }
87 }
88
89 if (strchr (escaped_chars, (int) src[curr_index]))
90 g_string_append_c (ret, '\\');
91
92 g_string_append_c (ret, src[curr_index]);
93 }
94 return g_string_free (ret, FALSE);
95 }
96
97 /* --------------------------------------------------------------------------------------------- */
98 char *
99 strutils_unescape (const char *src, gsize src_len, const char *unescaped_chars,
/* ![[previous]](../icons/left.png)
*/
100 gboolean unescape_non_printable)
101 {
102 GString *ret;
103 gsize curr_index;
104
105 if (src == NULL)
106 return NULL;
107
108 if (*src == '\0')
109 return strdup ("");
110
111 ret = g_string_sized_new (16);
112
113 if (src_len == (gsize) (-1))
114 src_len = strlen (src);
115 src_len--;
116
117 for (curr_index = 0; curr_index < src_len; curr_index++)
118 {
119 if (src[curr_index] != '\\')
120 {
121 g_string_append_c (ret, src[curr_index]);
122 continue;
123 }
124
125 curr_index++;
126
127 if (unescaped_chars == ESCAPE_SHELL_CHARS && src[curr_index] == '$')
128 {
129 /* special case: \$ is used to disallow variable substitution */
130 g_string_append_c (ret, '\\');
131 }
132 else
133 {
134 if (unescape_non_printable)
135 {
136 switch (src[curr_index])
137 {
138 case 'n':
139 g_string_append_c (ret, '\n');
140 continue;
141 case 't':
142 g_string_append_c (ret, '\t');
143 continue;
144 case 'b':
145 g_string_append_c (ret, '\b');
146 continue;
147 case '0':
148 g_string_append_c (ret, '\0');
149 continue;
150 default:
151 break;
152 }
153 }
154
155 if (strchr (unescaped_chars, (int) src[curr_index]) == NULL)
156 g_string_append_c (ret, '\\');
157 }
158
159 g_string_append_c (ret, src[curr_index]);
160 }
161 g_string_append_c (ret, src[curr_index]);
162
163 return g_string_free (ret, FALSE);
164 }
165
166 /* --------------------------------------------------------------------------------------------- */
167
168 /**
169 * To be compatible with the general posix command lines we have to escape
170 * strings for the command line
171 *
172 * @param src string for escaping
173 *
174 * @return escaped string (which needs to be freed later) or NULL when NULL string is passed.
175 */
176
177 char *
178 strutils_shell_escape (const char *src)
/* */
179 {
180 return strutils_escape (src, -1, ESCAPE_SHELL_CHARS, FALSE);
181 }
182
183 /* --------------------------------------------------------------------------------------------- */
184
185 char *
186 strutils_glob_escape (const char *src)
/* */
187 {
188 return strutils_escape (src, -1, ESCAPE_GLOB_CHARS, TRUE);
189 }
190
191 /* --------------------------------------------------------------------------------------------- */
192
193 char *
194 strutils_regex_escape (const char *src)
/* */
195 {
196 return strutils_escape (src, -1, ESCAPE_REGEX_CHARS, TRUE);
197 }
198
199 /* --------------------------------------------------------------------------------------------- */
200
201 /**
202 * Unescape paths or other strings for e.g the internal cd
203 * shell-unescape within a given buffer (writing to it!)
204 *
205 * @param text string for unescaping
206 *
207 * @return unescaped string (which needs to be freed)
208 */
209
210 char *
211 strutils_shell_unescape (const char *text)
/* */
212 {
213 return strutils_unescape (text, -1, ESCAPE_SHELL_CHARS, TRUE);
214 }
215
216 /* --------------------------------------------------------------------------------------------- */
217
218 char *
219 strutils_glob_unescape (const char *text)
/* */
220 {
221 return strutils_unescape (text, -1, ESCAPE_GLOB_CHARS, TRUE);
222 }
223
224 /* --------------------------------------------------------------------------------------------- */
225 char *
226 strutils_regex_unescape (const char *text)
/* */
227 {
228 return strutils_unescape (text, -1, ESCAPE_REGEX_CHARS, TRUE);
229 }
230
231 /* --------------------------------------------------------------------------------------------- */
232
233 /**
234 * Check if char in pointer contain escape'd chars
235 *
236 * @param start string for checking
237 * @param current pointer to checked character
238 *
239 * @return TRUE if string contain escaped chars otherwise return FALSE
240 */
241
242 gboolean
243 strutils_is_char_escaped (const char *start, const char *current)
/* ![[last]](../icons/n_last.png)
*/
244 {
245 int num_esc = 0;
246
247 if (start == NULL || current == NULL || current <= start)
248 return FALSE;
249
250 current--;
251 while (current >= start && *current == '\\')
252 {
253 num_esc++;
254 current--;
255 }
256 return (gboolean) num_esc % 2;
257 }
258
259 /* --------------------------------------------------------------------------------------------- */
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*/