time/era.c

   1 /* Helper functions used by strftime/strptime to handle locale-specific "eras".
   2    Copyright (C) 1995-2024 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 }