time/era.c

   1 /* Helper functions used by strftime/strptime to handle locale-specific "eras".
   2    Copyright (C) 1995-2020 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 void
  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;
  47
  48   __libc_rwlock_wrlock (__libc_setlocale_lock);
  49
  50   if (current->private.time == NULL)
  51     {
  52       current->private.time = malloc (sizeof *current->private.time);
  53       if (current->private.time == NULL)
  54         goto out;
  55       memset (current->private.time, 0, sizeof *current->private.time);
  56       current->private.cleanup = &_nl_cleanup_time;
  57     }
  58   data = current->private.time;
  59
  60   if (! data->era_initialized)
  61     {
  62       size_t new_num_eras = CURRENT_WORD (_NL_TIME_ERA_NUM_ENTRIES);
  63       if (new_num_eras == 0)
  64         {
  65           if (data->eras != NULL)
  66             {
  67               free (data->eras);
  68               data->eras = NULL;
  69             }
  70         }
  71       else
  72         {
  73           struct era_entry *new_eras = data->eras;
  74
  75           if (data->num_eras != new_num_eras)
  76             new_eras =
  77               (struct era_entry *) realloc (data->eras,
  78                                             new_num_eras
  79                                             * sizeof (struct era_entry));
  80           if (new_eras == NULL)
  81             {
  82               free (data->eras);
  83               data->num_eras = 0;
  84               data->eras = NULL;
  85             }
  86           else
  87             {
  88               const char *ptr = CURRENT (_NL_TIME_ERA_ENTRIES);
  89               data->num_eras = new_num_eras;
  90               data->eras = new_eras;
  91
  92               for (cnt = 0; cnt < new_num_eras; ++cnt)
  93                 {
  94                   const char *base_ptr = ptr;
  95                   memcpy ((void *) (new_eras + cnt), (const void *) ptr,
  96                           sizeof (uint32_t) * 8);
  97
  98                   if (ERA_DATE_CMP(new_eras[cnt].start_date,
  99                                    new_eras[cnt].stop_date))
 100                     if (new_eras[cnt].direction == (uint32_t) '+')
 101                       new_eras[cnt].absolute_direction = 1;
 102                     else
 103                       new_eras[cnt].absolute_direction = -1;
 104                   else
 105                     if (new_eras[cnt].direction == (uint32_t) '+')
 106                       new_eras[cnt].absolute_direction = -1;
 107                     else
 108                       new_eras[cnt].absolute_direction = 1;
 109
 110                   /* Skip numeric values.  */
 111                   ptr += sizeof (uint32_t) * 8;
 112
 113                   /* Set and skip era name.  */
 114                   new_eras[cnt].era_name = ptr;
 115                   ptr = strchr (ptr, '\0') + 1;
 116
 117                   /* Set and skip era format.  */
 118                   new_eras[cnt].era_format = ptr;
 119                   ptr = strchr (ptr, '\0') + 1;
 120
 121                   ptr += 3 - (((ptr - (const char *) base_ptr) + 3) & 3);
 122
 123                   /* Set and skip wide era name.  */
 124                   new_eras[cnt].era_wname = (wchar_t *) ptr;
 125                   ptr = (char *) (__wcschr ((wchar_t *) ptr, L'\0') + 1);
 126
 127                   /* Set and skip wide era format.  */
 128                   new_eras[cnt].era_wformat = (wchar_t *) ptr;
 129                   ptr = (char *) (__wcschr ((wchar_t *) ptr, L'\0') + 1);
 130                 }
 131             }
 132         }
 133
 134       data->era_initialized = 1;
 135     }
 136
 137  out:
 138   __libc_rwlock_unlock (__libc_setlocale_lock);
 139 }
 140
 141 struct era_entry *
 142 _nl_get_era_entry (const struct tm *tp, struct __locale_data *current)
 143 {
 144   if (current->private.time == NULL || !current->private.time->era_initialized)
 145     _nl_init_era_entries (current);
 146
 147   if (current->private.time != NULL)
 148     {
 149       /* Now compare date with the available eras.  */
 150       const int32_t tdate[3] = { tp->tm_year, tp->tm_mon, tp->tm_mday };
 151       size_t cnt;
 152       for (cnt = 0; cnt < current->private.time->num_eras; ++cnt)
 153         if ((ERA_DATE_CMP (current->private.time->eras[cnt].start_date, tdate)
 154              && ERA_DATE_CMP (tdate,
 155                               current->private.time->eras[cnt].stop_date))
 156             || (ERA_DATE_CMP (current->private.time->eras[cnt].stop_date,
 157                               tdate)
 158                 && ERA_DATE_CMP (tdate,
 159                                  current->private.time->eras[cnt].start_date)))
 160           return &current->private.time->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   if (current->private.time == NULL || !current->private.time->era_initialized)
 171     _nl_init_era_entries (current);
 172
 173   return (current->private.time == NULL
 174           ? NULL : &current->private.time->eras[cnt]);
 175 }