glibc/time/era.c
Florian Weimer 7ee41feba6 locale: Remove private union from struct __locale_data
This avoids an alias violation later.  This commit also fixes
an incorrect double-checked locking idiom in _nl_init_era_entries.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2022-05-23 11:06:31 +02:00

173 lines
5.0 KiB
C

/* Helper functions used by strftime/strptime to handle locale-specific "eras".
Copyright (C) 1995-2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include "../locale/localeinfo.h"
#include <libc-lock.h>
#include <stdlib.h>
#include <wchar.h>
#include <string.h>
#include <stdint.h>
/* Some of the functions here must not be used while setlocale is called. */
__libc_rwlock_define (extern, __libc_setlocale_lock attribute_hidden)
#define CURRENT(item) (current->values[_NL_ITEM_INDEX (item)].string)
#define CURRENT_WORD(item) (current->values[_NL_ITEM_INDEX (item)].word)
#define ERA_DATE_CMP(a, b) \
(a[0] < b[0] || (a[0] == b[0] && (a[1] < b[1] \
|| (a[1] == b[1] && a[2] <= b[2]))))
/* Look up the era information in CURRENT's locale strings and
cache it in CURRENT->private. */
static struct lc_time_data *
_nl_init_era_entries (struct __locale_data *current)
{
size_t cnt;
struct lc_time_data *data;
/* Avoid touching CURRENT if there is no data at all, for _nl_C_LC_TIME. */
if (CURRENT_WORD (_NL_TIME_ERA_NUM_ENTRIES) == 0)
return NULL;
data = current->private;
if (data != NULL && atomic_load_acquire (&data->era_initialized))
return data;
__libc_rwlock_wrlock (__libc_setlocale_lock);
data = current->private;
if (data == NULL)
{
data = calloc (sizeof *data, 1);
if (data == NULL)
goto out;
current->private = data;
}
if (! data->era_initialized)
{
size_t new_num_eras = CURRENT_WORD (_NL_TIME_ERA_NUM_ENTRIES);
if (new_num_eras == 0)
{
if (data->eras != NULL)
{
free (data->eras);
data->eras = NULL;
}
}
else
{
struct era_entry *new_eras = data->eras;
if (data->num_eras != new_num_eras)
new_eras =
(struct era_entry *) realloc (data->eras,
new_num_eras
* sizeof (struct era_entry));
if (new_eras == NULL)
{
free (data->eras);
data->num_eras = 0;
data->eras = NULL;
}
else
{
const char *ptr = CURRENT (_NL_TIME_ERA_ENTRIES);
data->num_eras = new_num_eras;
data->eras = new_eras;
for (cnt = 0; cnt < new_num_eras; ++cnt)
{
const char *base_ptr = ptr;
memcpy ((void *) (new_eras + cnt), (const void *) ptr,
sizeof (uint32_t) * 8);
if (ERA_DATE_CMP(new_eras[cnt].start_date,
new_eras[cnt].stop_date))
if (new_eras[cnt].direction == (uint32_t) '+')
new_eras[cnt].absolute_direction = 1;
else
new_eras[cnt].absolute_direction = -1;
else
if (new_eras[cnt].direction == (uint32_t) '+')
new_eras[cnt].absolute_direction = -1;
else
new_eras[cnt].absolute_direction = 1;
/* Skip numeric values. */
ptr += sizeof (uint32_t) * 8;
/* Set and skip era name. */
new_eras[cnt].era_name = ptr;
ptr = strchr (ptr, '\0') + 1;
/* Set and skip era format. */
new_eras[cnt].era_format = ptr;
ptr = strchr (ptr, '\0') + 1;
ptr += 3 - (((ptr - (const char *) base_ptr) + 3) & 3);
/* Set and skip wide era name. */
new_eras[cnt].era_wname = (wchar_t *) ptr;
ptr = (char *) (__wcschr ((wchar_t *) ptr, L'\0') + 1);
/* Set and skip wide era format. */
new_eras[cnt].era_wformat = (wchar_t *) ptr;
ptr = (char *) (__wcschr ((wchar_t *) ptr, L'\0') + 1);
}
}
}
atomic_store_release (&data->era_initialized, 1);
}
out:
__libc_rwlock_unlock (__libc_setlocale_lock);
return data;
}
struct era_entry *
_nl_get_era_entry (const struct tm *tp, struct __locale_data *current)
{
struct lc_time_data *data = _nl_init_era_entries (current);
if (data != NULL)
{
/* Now compare date with the available eras. */
const int32_t tdate[3] = { tp->tm_year, tp->tm_mon, tp->tm_mday };
size_t cnt;
for (cnt = 0; cnt < data->num_eras; ++cnt)
if ((ERA_DATE_CMP (data->eras[cnt].start_date, tdate)
&& ERA_DATE_CMP (tdate, data->eras[cnt].stop_date))
|| (ERA_DATE_CMP (data->eras[cnt].stop_date, tdate)
&& ERA_DATE_CMP (tdate, data->eras[cnt].start_date)))
return &data->eras[cnt];
}
return NULL;
}
struct era_entry *
_nl_select_era_entry (int cnt, struct __locale_data *current)
{
struct lc_time_data *data = _nl_init_era_entries (current);
return data == NULL ? NULL : &data->eras[cnt];
}