156f54302d
Allthough most dive computers always use local time and don't support timezones at all, there are a few exceptions. There are two different sources of timezone information: - Some of the newer Uwatec/Scubapro devices use UTC internally and also support a timezone setting. This UTC offset is currently taken into account to obtain the dive date/time, but the UTC offset itself is lost. - Uwatec/Scubapro and Reefnet devices rely on the clock of the host system to synchronize the internal device clock and calculate the dive date/time. The consequence is that the resulting date/time is always in the timezone of the host system. In order to preserve this timezone information, the dc_datetime_t structure is extended with a new "timezone" field, containing the UTC offset in seconds. Devices without timezone support will set the field to the special value DC_TIMEZONE_NONE. The dc_datetime_localtime() and dc_datetime_gmtime() functions will automatically populate the new field with respectively the local timezone offset and zero. The dc_datetime_mktime() function will take into account the new timezone field for the conversion to UTC. The special value DC_TIMEZONE_NONE is interpreted as zero.
65 lines
1.5 KiB
C
65 lines
1.5 KiB
C
/*
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* libdivecomputer
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*
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* Copyright (C) 2010 Jef Driesen
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301 USA
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*/
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#ifndef DC_DATETIME_H
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#define DC_DATETIME_H
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#ifdef __cplusplus
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extern "C" {
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#endif /* __cplusplus */
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#define DC_TIMEZONE_NONE 0x80000000
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#if defined (_WIN32) && !defined (__GNUC__)
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typedef __int64 dc_ticks_t;
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#else
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typedef long long int dc_ticks_t;
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#endif
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typedef struct dc_datetime_t {
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int year;
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int month;
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int day;
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int hour;
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int minute;
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int second;
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int timezone;
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} dc_datetime_t;
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dc_ticks_t
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dc_datetime_now (void);
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dc_datetime_t *
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dc_datetime_localtime (dc_datetime_t *result,
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dc_ticks_t ticks);
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dc_datetime_t *
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dc_datetime_gmtime (dc_datetime_t *result,
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dc_ticks_t ticks);
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dc_ticks_t
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dc_datetime_mktime (const dc_datetime_t *dt);
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#ifdef __cplusplus
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}
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#endif /* __cplusplus */
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#endif /* DC_DATETIME_H */
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