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*/
1 /*
2 Copyright (C) 1995 Ian Jackson <iwj10@cus.cam.ac.uk>
3 Copyright (C) 2001 Anthony Towns <aj@azure.humbug.org.au>
4 Copyright (C) 2008-2018 Free Software Foundation, Inc.
5
6 This program is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
10
11 This program 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
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <https://www.gnu.org/licenses/>.
18 */
19
20 #include <config.h>
21
22 #include <sys/types.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <limits.h>
26
27 #include "lib/strutil.h"
28
29 /*** global variables ****************************************************************************/
30
31 /*** file scope macro definitions ****************************************************************/
32
33 /*** file scope type declarations ****************************************************************/
34
35 /*** file scope variables ************************************************************************/
36
37 /* --------------------------------------------------------------------------------------------- */
38 /*** file scope functions ************************************************************************/
39 /* --------------------------------------------------------------------------------------------- */
40
41 /* Match a file suffix defined by this regular expression: /(\.[A-Za-z~][A-Za-z0-9~]*)*$/
42 *
43 * @str pointer to string to scan.
44 *
45 * @return pointer to the matching suffix, or NULL if not found.
46 * Upon return, @str points to terminating NUL.
47 */
48 static const char *
49 match_suffix (const char **str)
/* ![[next]](../icons/right.png)
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*/
50 {
51 const char *match = NULL;
52 gboolean read_alpha = FALSE;
53
54 while (**str != '\0')
55 {
56 if (read_alpha)
57 {
58 read_alpha = FALSE;
59 if (!g_ascii_isalpha (**str) && **str != '~')
60 match = NULL;
61 }
62 else if (**str == '.')
63 {
64 read_alpha = TRUE;
65 if (match == NULL)
66 match = *str;
67 }
68 else if (!g_ascii_isalnum (**str) && **str != '~')
69 match = NULL;
70 (*str)++;
71 }
72
73 return match;
74 }
75
76 /* --------------------------------------------------------------------------------------------- */
77
78 /* verrevcmp helper function */
79 static int
80 order (unsigned char c)
/* ![[previous]](../icons/left.png)
*/
81 {
82 if (g_ascii_isdigit (c))
83 return 0;
84 if (g_ascii_isalpha (c))
85 return c;
86 if (c == '~')
87 return -1;
88 return (int) c + UCHAR_MAX + 1;
89 }
90
91 /* --------------------------------------------------------------------------------------------- */
92
93 /* Slightly modified verrevcmp function from dpkg
94 *
95 * This implements the algorithm for comparison of version strings
96 * specified by Debian and now widely adopted. The detailed
97 * specification can be found in the Debian Policy Manual in the
98 * section on the 'Version' control field. This version of the code
99 * implements that from s5.6.12 of Debian Policy v3.8.0.1
100 * https://www.debian.org/doc/debian-policy/ch-controlfields.html#s-f-Version
101 *
102 * @s1 first string to compare
103 * @s1_len length of @s1
104 * @s2 second string to compare
105 * @s2_len length of @s2
106 *
107 * @return an integer less than, equal to, or greater than zero, if @s1 is <, == or > than @s2.
108 */
109 static int
110 verrevcmp (const char *s1, size_t s1_len, const char *s2, size_t s2_len)
/* */
111 {
112 size_t s1_pos = 0;
113 size_t s2_pos = 0;
114
115 while (s1_pos < s1_len || s2_pos < s2_len)
116 {
117 int first_diff = 0;
118
119 while ((s1_pos < s1_len && !g_ascii_isdigit (s1[s1_pos]))
120 || (s2_pos < s2_len && !g_ascii_isdigit (s2[s2_pos])))
121 {
122 int s1_c = 0;
123 int s2_c = 0;
124
125 if (s1_pos != s1_len)
126 s1_c = order (s1[s1_pos]);
127 if (s2_pos != s2_len)
128 s2_c = order (s2[s2_pos]);
129
130 if (s1_c != s2_c)
131 return (s1_c - s2_c);
132
133 s1_pos++;
134 s2_pos++;
135 }
136
137 while (s1[s1_pos] == '0')
138 s1_pos++;
139 while (s2[s2_pos] == '0')
140 s2_pos++;
141
142 while (g_ascii_isdigit (s1[s1_pos]) && g_ascii_isdigit (s2[s2_pos]))
143 {
144 if (first_diff == 0)
145 first_diff = s1[s1_pos] - s2[s2_pos];
146
147 s1_pos++;
148 s2_pos++;
149 }
150
151 if (g_ascii_isdigit (s1[s1_pos]))
152 return 1;
153 if (g_ascii_isdigit (s2[s2_pos]))
154 return -1;
155 if (first_diff != 0)
156 return first_diff;
157 }
158
159 return 0;
160 }
161
162 /* --------------------------------------------------------------------------------------------- */
163 /*** public functions ****************************************************************************/
164 /* --------------------------------------------------------------------------------------------- */
165
166 /* Compare version strings.
167 *
168 * @s1 first string to compare
169 * @s2 second string to compare
170 *
171 * @return an integer less than, equal to, or greater than zero, if @s1 is <, == or > than @s2.
172 */
173 int
174 filevercmp (const char *s1, const char *s2)
/* ![[last]](../icons/n_last.png)
*/
175 {
176 const char *s1_pos, *s2_pos;
177 const char *s1_suffix, *s2_suffix;
178 size_t s1_len, s2_len;
179 int simple_cmp, result;
180
181 /* easy comparison to see if strings are identical */
182 simple_cmp = strcmp (s1, s2);
183 if (simple_cmp == 0)
184 return 0;
185
186 /* special handle for "", "." and ".." */
187 if (*s1 == '\0')
188 return -1;
189 if (*s2 == '\0')
190 return 1;
191 if (DIR_IS_DOT (s1))
192 return -1;
193 if (DIR_IS_DOT (s2))
194 return 1;
195 if (DIR_IS_DOTDOT (s1))
196 return -1;
197 if (DIR_IS_DOTDOT (s2))
198 return 1;
199
200 /* special handle for other hidden files */
201 if (*s1 == '.' && *s2 != '.')
202 return -1;
203 if (*s1 != '.' && *s2 == '.')
204 return 1;
205 if (*s1 == '.' && *s2 == '.')
206 {
207 s1++;
208 s2++;
209 }
210
211 /* "cut" file suffixes */
212 s1_pos = s1;
213 s2_pos = s2;
214 s1_suffix = match_suffix (&s1_pos);
215 s2_suffix = match_suffix (&s2_pos);
216 s1_len = (s1_suffix != NULL ? s1_suffix : s1_pos) - s1;
217 s2_len = (s2_suffix != NULL ? s2_suffix : s2_pos) - s2;
218
219 /* restore file suffixes if strings are identical after "cut" */
220 if ((s1_suffix != NULL || s2_suffix != NULL) && (s1_len == s2_len)
221 && strncmp (s1, s2, s1_len) == 0)
222 {
223 s1_len = s1_pos - s1;
224 s2_len = s2_pos - s2;
225 }
226
227 result = verrevcmp (s1, s1_len, s2, s2_len);
228
229 return result == 0 ? simple_cmp : result;
230 }
231
232 /* --------------------------------------------------------------------------------------------- */
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*/