| 1 | /* This example demonstrates the use of the time zone database and |
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| 2 | * local time to calculate the number of seconds since the UTC |
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| 3 | * time_t epoch 1970-01-01 00:00:00. Note that the selected timezone |
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| 4 | * could be any timezone supported in the time zone database file which |
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| 5 | * can be modified and updated as needed by the user. |
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| 6 | * |
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| 7 | * To solve this problem the following steps are required: |
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| 8 | * 1) Get a timezone from the tz database for the local time |
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| 9 | * 2) Construct a local time using the timezone |
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| 10 | * 3) Construct a posix_time::ptime for the time_t epoch time |
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| 11 | * 4) Convert the local_time to utc and subtract the epoch time |
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| 12 | * |
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| 13 | */ |
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| 14 | |
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| 15 | #include "boost/date_time/local_time/local_time.hpp" |
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| 16 | #include <iostream> |
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| 17 | |
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| 18 | int main() |
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| 19 | { |
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| 20 | using namespace boost::gregorian; |
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| 21 | using namespace boost::local_time; |
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| 22 | using namespace boost::posix_time; |
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| 23 | |
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| 24 | tz_database tz_db; |
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| 25 | try { |
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| 26 | tz_db.load_from_file(pathspec: "../data/date_time_zonespec.csv" ); |
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| 27 | }catch(const data_not_accessible& dna) { |
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| 28 | std::cerr << "Error with time zone data file: " << dna.what() << std::endl; |
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| 29 | exit(EXIT_FAILURE); |
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| 30 | }catch(const bad_field_count& bfc) { |
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| 31 | std::cerr << "Error with time zone data file: " << bfc.what() << std::endl; |
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| 32 | exit(EXIT_FAILURE); |
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| 33 | } |
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| 34 | |
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| 35 | time_zone_ptr nyc_tz = tz_db.time_zone_from_region(region: "America/New_York" ); |
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| 36 | date in_date(2004,10,04); |
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| 37 | time_duration td(12,14,32); |
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| 38 | // construct with local time value |
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| 39 | // create not-a-date-time if invalid (eg: in dst transition) |
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| 40 | local_date_time nyc_time(in_date, |
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| 41 | td, |
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| 42 | nyc_tz, |
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| 43 | local_date_time::NOT_DATE_TIME_ON_ERROR); |
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| 44 | |
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| 45 | std::cout << nyc_time << std::endl; |
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| 46 | |
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| 47 | ptime time_t_epoch(date(1970,1,1)); |
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| 48 | std::cout << time_t_epoch << std::endl; |
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| 49 | |
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| 50 | // first convert nyc_time to utc via the utc_time() |
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| 51 | // call and subtract the ptime. |
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| 52 | time_duration diff = nyc_time.utc_time() - time_t_epoch; |
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| 53 | |
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| 54 | //Expected 1096906472 |
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| 55 | std::cout << "Seconds diff: " << diff.total_seconds() << std::endl; |
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| 56 | |
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| 57 | } |
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| 58 | |
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| 59 | |
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| 60 | /* Copyright 2005: CrystalClear Software, Inc |
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| 61 | * http://www.crystalclearsoftware.com |
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| 62 | * |
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| 63 | * Subject to the Boost Software License, Version 1.0. |
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| 64 | * (See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt) |
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| 65 | */ |
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| 66 | |
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