1 /* Helper functions used by strftime/strptime to handle locale-specific "eras".
2 Copyright (C) 1995-2023 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 "../locale/localeinfo.h"
20 #include <libc-lock.h>
21 #include <stdlib.h>
22 #include <wchar.h>
23 #include <string.h>
24 #include <stdint.h>
25
26 /* Some of the functions here must not be used while setlocale is called. */
27 __libc_rwlock_define (extern, __libc_setlocale_lock attribute_hidden)
28
29 #define CURRENT(item) (current->values[_NL_ITEM_INDEX (item)].string)
30 #define CURRENT_WORD(item) (current->values[_NL_ITEM_INDEX (item)].word)
31
32 #define ERA_DATE_CMP(a, b) \
33 (a[0] < b[0] || (a[0] == b[0] && (a[1] < b[1] \
34 || (a[1] == b[1] && a[2] <= b[2]))))
35
36 /* Look up the era information in CURRENT's locale strings and
37 cache it in CURRENT->private. */
38 static struct lc_time_data *
39 _nl_init_era_entries (struct __locale_data *current)
40 {
41 size_t cnt;
42 struct lc_time_data *data;
43
44 /* Avoid touching CURRENT if there is no data at all, for _nl_C_LC_TIME. */
45 if (CURRENT_WORD (_NL_TIME_ERA_NUM_ENTRIES) == 0)
46 return NULL;
47
48 data = current->private;
49 if (data != NULL && atomic_load_acquire (&data->era_initialized))
50 return data;
51
52 __libc_rwlock_wrlock (__libc_setlocale_lock);
53
54 data = current->private;
55 if (data == NULL)
56 {
57 data = calloc (sizeof *data, 1);
58 if (data == NULL)
59 goto out;
60 current->private = data;
61 }
62
63 if (! data->era_initialized)
64 {
65 size_t new_num_eras = CURRENT_WORD (_NL_TIME_ERA_NUM_ENTRIES);
66 if (new_num_eras == 0)
67 {
68 if (data->eras != NULL)
69 {
70 free (data->eras);
71 data->eras = NULL;
72 }
73 }
74 else
75 {
76 struct era_entry *new_eras = data->eras;
77
78 if (data->num_eras != new_num_eras)
79 new_eras =
80 (struct era_entry *) realloc (data->eras,
81 new_num_eras
82 * sizeof (struct era_entry));
83 if (new_eras == NULL)
84 {
85 free (data->eras);
86 data->num_eras = 0;
87 data->eras = NULL;
88 }
89 else
90 {
91 const char *ptr = CURRENT (_NL_TIME_ERA_ENTRIES);
92 data->num_eras = new_num_eras;
93 data->eras = new_eras;
94
95 for (cnt = 0; cnt < new_num_eras; ++cnt)
96 {
97 const char *base_ptr = ptr;
98 memcpy ((void *) (new_eras + cnt), (const void *) ptr,
99 sizeof (uint32_t) * 8);
100
101 if (ERA_DATE_CMP(new_eras[cnt].start_date,
102 new_eras[cnt].stop_date))
103 if (new_eras[cnt].direction == (uint32_t) '+')
104 new_eras[cnt].absolute_direction = 1;
105 else
106 new_eras[cnt].absolute_direction = -1;
107 else
108 if (new_eras[cnt].direction == (uint32_t) '+')
109 new_eras[cnt].absolute_direction = -1;
110 else
111 new_eras[cnt].absolute_direction = 1;
112
113 /* Skip numeric values. */
114 ptr += sizeof (uint32_t) * 8;
115
116 /* Set and skip era name. */
117 new_eras[cnt].era_name = ptr;
118 ptr = strchr (ptr, '\0') + 1;
119
120 /* Set and skip era format. */
121 new_eras[cnt].era_format = ptr;
122 ptr = strchr (ptr, '\0') + 1;
123
124 ptr += 3 - (((ptr - (const char *) base_ptr) + 3) & 3);
125
126 /* Set and skip wide era name. */
127 new_eras[cnt].era_wname = (wchar_t *) ptr;
128 ptr = (char *) (__wcschr ((wchar_t *) ptr, L'\0') + 1);
129
130 /* Set and skip wide era format. */
131 new_eras[cnt].era_wformat = (wchar_t *) ptr;
132 ptr = (char *) (__wcschr ((wchar_t *) ptr, L'\0') + 1);
133 }
134 }
135 }
136
137 atomic_store_release (&data->era_initialized, 1);
138 }
139
140 out:
141 __libc_rwlock_unlock (__libc_setlocale_lock);
142 return data;
143 }
144
145 struct era_entry *
146 _nl_get_era_entry (const struct tm *tp, struct __locale_data *current)
147 {
148 struct lc_time_data *data = _nl_init_era_entries (current);
149
150 if (data != NULL)
151 {
152 /* Now compare date with the available eras. */
153 const int32_t tdate[3] = { tp->tm_year, tp->tm_mon, tp->tm_mday };
154 size_t cnt;
155 for (cnt = 0; cnt < data->num_eras; ++cnt)
156 if ((ERA_DATE_CMP (data->eras[cnt].start_date, tdate)
157 && ERA_DATE_CMP (tdate, data->eras[cnt].stop_date))
158 || (ERA_DATE_CMP (data->eras[cnt].stop_date, tdate)
159 && ERA_DATE_CMP (tdate, data->eras[cnt].start_date)))
160 return &data->eras[cnt];
161 }
162
163 return NULL;
164 }
165
166
167 struct era_entry *
168 _nl_select_era_entry (int cnt, struct __locale_data *current)
169 {
170 struct lc_time_data *data = _nl_init_era_entries (current);
171 return data == NULL ? NULL : &data->eras[cnt];
172 }