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*/
1 /*
2 Search text engine.
3 HEX-style pattern matching
4
5 Copyright (C) 2009-2025
6 Free Software Foundation, Inc.
7
8 Written by:
9 Slava Zanko <slavazanko@gmail.com>, 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 <https://www.gnu.org/licenses/>.
25 */
26
27 #include <config.h>
28
29 #include <stdio.h>
30
31 #include "lib/global.h"
32 #include "lib/strutil.h"
33 #include "lib/search.h"
34
35 #include "internal.h"
36
37 /*** global variables ****************************************************************************/
38
39 /*** file scope macro definitions ****************************************************************/
40
41 typedef enum
42 {
43 MC_SEARCH_HEX_E_OK,
44 MC_SEARCH_HEX_E_NUM_OUT_OF_RANGE,
45 MC_SEARCH_HEX_E_INVALID_CHARACTER,
46 MC_SEARCH_HEX_E_UNMATCHED_QUOTES
47 } mc_search_hex_parse_error_t;
48
49 /*** file scope type declarations ****************************************************************/
50
51 /*** forward declarations (file scope functions) *************************************************/
52
53 /*** file scope variables ************************************************************************/
54
55 /* --------------------------------------------------------------------------------------------- */
56 /*** file scope functions ************************************************************************/
57 /* --------------------------------------------------------------------------------------------- */
58
59 static GString *
60 mc_search__hex_translate_to_regex (const GString *astr, mc_search_hex_parse_error_t *error_ptr,
/* ![[next]](../icons/right.png)
![[first]](../icons/n_first.png)
![[top]](../icons/top.png)
*/
61 int *error_pos_ptr)
62 {
63 GString *buff;
64 const char *str;
65 gsize str_len;
66 gsize loop = 0;
67 mc_search_hex_parse_error_t error = MC_SEARCH_HEX_E_OK;
68
69 buff = g_string_sized_new (64);
70 str = astr->str;
71 str_len = astr->len;
72
73 while (loop < str_len && error == MC_SEARCH_HEX_E_OK)
74 {
75 unsigned int val;
76 int ptr;
77
78 if (g_ascii_isspace (str[loop]))
79 {
80 // Eat-up whitespace between tokens.
81 while (g_ascii_isspace (str[loop]))
82 loop++;
83 }
84 // cppcheck-suppress invalidscanf
85 else if (sscanf (str + loop, "%x%n", &val, &ptr) == 1)
86 {
87 if (val > 255)
88 error = MC_SEARCH_HEX_E_NUM_OUT_OF_RANGE;
89 else
90 {
91 g_string_append_printf (buff, "\\x%02X", val);
92 loop += ptr;
93 }
94 }
95 else if (str[loop] == '"')
96 {
97 gsize loop2;
98
99 loop2 = loop + 1;
100
101 while (loop2 < str_len)
102 {
103 if (str[loop2] == '"')
104 break;
105 if (str[loop2] == '\\' && loop2 + 1 < str_len)
106 loop2++;
107 g_string_append_c (buff, str[loop2]);
108 loop2++;
109 }
110
111 if (str[loop2] == '\0')
112 error = MC_SEARCH_HEX_E_UNMATCHED_QUOTES;
113 else
114 loop = loop2 + 1;
115 }
116 else
117 error = MC_SEARCH_HEX_E_INVALID_CHARACTER;
118 }
119
120 if (error != MC_SEARCH_HEX_E_OK)
121 {
122 g_string_free (buff, TRUE);
123 if (error_ptr != NULL)
124 *error_ptr = error;
125 if (error_pos_ptr != NULL)
126 *error_pos_ptr = loop;
127 return NULL;
128 }
129
130 return buff;
131 }
132
133 /* --------------------------------------------------------------------------------------------- */
134 /*** public functions ****************************************************************************/
135 /* --------------------------------------------------------------------------------------------- */
136
137 void
138 mc_search__cond_struct_new_init_hex (const char *charset, mc_search_t *lc_mc_search,
/* ![[previous]](../icons/left.png)
*/
139 mc_search_cond_t *mc_search_cond)
140 {
141 GString *tmp;
142 mc_search_hex_parse_error_t error = MC_SEARCH_HEX_E_OK;
143 int error_pos = 0;
144
145 /*
146 * We may be searching in binary data, which is often invalid UTF-8.
147 *
148 * We have to create a non UTF-8 regex (that is, G_REGEX_RAW) or else, as
149 * the data is invalid UTF-8, both GLib's PCRE and our
150 * mc_search__g_regex_match_full_safe() are going to fail us. The former by
151 * not finding all bytes, the latter by overwriting the supposedly invalid
152 * UTF-8 with NULs.
153 *
154 * To do this, we specify "ASCII" as the charset.
155 *
156 * In fact, we can specify any charset other than "UTF-8": any such charset
157 * will trigger G_REGEX_RAW (see [1]). The output of [2] will be the same
158 * for all charsets because it skips the \xXX symbols
159 * mc_search__hex_translate_to_regex() outputs.
160 *
161 * But "ASCII" is the best choice because a hex pattern may contain a
162 * quoted string: this way we know [2] will ignore any characters outside
163 * ASCII letters range (these ignored chars will be copied verbatim to the
164 * output and will match as-is; in other words, in a case-sensitive manner;
165 * If the user is interested in case-insensitive searches of international
166 * text, he shouldn't be using hex search in the first place.)
167 *
168 * Switching out of UTF-8 has another advantage:
169 *
170 * When doing case-insensitive searches, GLib treats \xXX symbols as normal
171 * letters and therefore matches both "a" and "A" for the hex pattern
172 * "0x61". When we switch out of UTF-8, we're switching to using [2], which
173 * doesn't have this issue.
174 *
175 * [1] mc_search__cond_struct_new_init_regex
176 * [2] mc_search__cond_struct_new_regex_ci_str
177 */
178 if (str_isutf8 (charset))
179 charset = "ASCII";
180
181 tmp = mc_search__hex_translate_to_regex (mc_search_cond->str, &error, &error_pos);
182 if (tmp != NULL)
183 {
184 g_string_free (mc_search_cond->str, TRUE);
185 mc_search_cond->str = tmp;
186 mc_search__cond_struct_new_init_regex (charset, lc_mc_search, mc_search_cond);
187 }
188 else
189 {
190 const char *desc;
191
192 switch (error)
193 {
194 case MC_SEARCH_HEX_E_NUM_OUT_OF_RANGE:
195 desc = _ (
196 "Number out of range (should be in byte range, 0 <= n <= 0xFF, expressed in hex)");
197 break;
198 case MC_SEARCH_HEX_E_INVALID_CHARACTER:
199 desc = _ ("Invalid character");
200 break;
201 case MC_SEARCH_HEX_E_UNMATCHED_QUOTES:
202 desc = _ ("Unmatched quotes character");
203 break;
204 default:
205 desc = "";
206 }
207
208 lc_mc_search->error = MC_SEARCH_E_INPUT;
209 lc_mc_search->error_str =
210 g_strdup_printf (_ ("Hex pattern error at position %d:\n%s."), error_pos + 1, desc);
211 }
212 }
213
214 /* --------------------------------------------------------------------------------------------- */
215
216 gboolean
217 mc_search__run_hex (mc_search_t *lc_mc_search, const void *user_data, off_t start_search,
/* */
218 off_t end_search, gsize *found_len)
219 {
220 return mc_search__run_regex (lc_mc_search, user_data, start_search, end_search, found_len);
221 }
222
223 /* --------------------------------------------------------------------------------------------- */
224
225 GString *
226 mc_search_hex_prepare_replace_str (mc_search_t *lc_mc_search, GString *replace_str)
/* ![[last]](../icons/n_last.png)
*/
227 {
228 (void) lc_mc_search;
229
230 return mc_g_string_dup (replace_str);
231 }
232
233 /* --------------------------------------------------------------------------------------------- */
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*/