time/alt_digit.c

   1 /* Helper functions used by strftime/strptime to handle alternate digits.
   2    Copyright (C) 1995-2022 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_WSTR(item) \
  31   ((wchar_t *) current->values[_NL_ITEM_INDEX (item)].wstr)
  32
  33 static struct lc_time_data *
  34 _nl_init_alt_digit (struct __locale_data *current)
  35 {
  36   struct lc_time_data *data = current->private;
  37
  38   if (data == NULL)
  39     {
  40       data = calloc (sizeof *data, 1);
  41       if (data == NULL)
  42         return NULL;
  43       current->private = data;
  44     }
  45
  46   if (! data->alt_digits_initialized)
  47     {
  48       const char *ptr = CURRENT (ALT_DIGITS);
  49       size_t cnt;
  50
  51       data->alt_digits_initialized = 1;
  52
  53       if (ptr != NULL)
  54         {
  55           data->alt_digits = malloc (100 * sizeof (const char *));
  56           if (data->alt_digits != NULL)
  57             for (cnt = 0; cnt < 100; ++cnt)
  58               {
  59                 data->alt_digits[cnt] = ptr;
  60
  61                 /* Skip digit format. */
  62                 ptr = strchr (ptr, '\0') + 1;
  63               }
  64         }
  65     }
  66
  67   return data;
  68 }
  69
  70 const char *
  71 _nl_get_alt_digit (unsigned int number, struct __locale_data *current)
  72 {
  73   const char *result;
  74
  75   if (number >= 100 || CURRENT (ALT_DIGITS)[0] == '\0')
  76     return NULL;
  77
  78   __libc_rwlock_wrlock (__libc_setlocale_lock);
  79
  80   struct lc_time_data *data = _nl_init_alt_digit (current);
  81
  82   result = ((data != NULL
  83              && data->alt_digits != NULL)
  84             ? data->alt_digits[number]
  85             : NULL);
  86
  87   __libc_rwlock_unlock (__libc_setlocale_lock);
  88
  89   return result;
  90 }
  91
  92
  93 const wchar_t *
  94 _nl_get_walt_digit (unsigned int number, struct __locale_data *current)
  95 {
  96   const wchar_t *result = NULL;
  97
  98   if (number >= 100 || CURRENT_WSTR (_NL_WALT_DIGITS)[0] == L'\0')
  99     return NULL;
 100
 101   __libc_rwlock_wrlock (__libc_setlocale_lock);
 102
 103   struct lc_time_data *data = current->private;
 104   if (data == NULL)
 105     {
 106       data = calloc (sizeof *data, 1);
 107       if (data == NULL)
 108         goto out;
 109       current->private = data;
 110     }
 111
 112   if (! data->walt_digits_initialized)
 113     {
 114       const wchar_t *ptr = CURRENT_WSTR (_NL_WALT_DIGITS);
 115       size_t cnt;
 116
 117       data->walt_digits_initialized = 1;
 118
 119       if (ptr != NULL)
 120         {
 121           data->walt_digits = malloc (100 * sizeof (const uint32_t *));
 122           if (data->walt_digits != NULL)
 123             for (cnt = 0; cnt < 100; ++cnt)
 124               {
 125                 data->walt_digits[cnt] = ptr;
 126
 127                 /* Skip digit format. */
 128                 ptr = __wcschr (ptr, L'\0') + 1;
 129               }
 130         }
 131     }
 132
 133   if (data->walt_digits != NULL)
 134     result = data->walt_digits[number];
 135
 136  out:
 137   __libc_rwlock_unlock (__libc_setlocale_lock);
 138
 139   return (wchar_t *) result;
 140 }
 141
 142
 143 int
 144 _nl_parse_alt_digit (const char **strp, struct __locale_data *current)
 145 {
 146   const char *str = *strp;
 147   int result = -1;
 148   size_t cnt;
 149   size_t maxlen = 0;
 150
 151   if (CURRENT_WSTR (_NL_WALT_DIGITS)[0] == L'\0')
 152     return result;
 153
 154   __libc_rwlock_wrlock (__libc_setlocale_lock);
 155
 156   struct lc_time_data *data = _nl_init_alt_digit (current);
 157   if (data != NULL && data->alt_digits != NULL)
 158     /* Matching is not unambiguous.  The alternative digits could be like
 159        I, II, III, ... and the first one is a substring of the second
 160        and third.  Therefore we must keep on searching until we found
 161        the longest possible match.  Note that this is not specified in
 162        the standard.  */
 163     for (cnt = 0; cnt < 100; ++cnt)
 164       {
 165         const char *const dig = data->alt_digits[cnt];
 166         size_t len = strlen (dig);
 167
 168         if (len > maxlen && strncmp (dig, str, len) == 0)
 169           {
 170             maxlen = len;
 171             result = (int) cnt;
 172           }
 173       }
 174
 175   __libc_rwlock_unlock (__libc_setlocale_lock);
 176
 177   if (result != -1)
 178     *strp += maxlen;
 179
 180   return result;
 181 }