https://github.com/dmitryme/erlang_localtime

Erlang library for conversion from one local time to another
https://github.com/dmitryme/erlang_localtime

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Erlang library for conversion from one local time to another

• Host: GitHub
• URL: https://github.com/dmitryme/erlang_localtime
• Owner: dmitryme
• License: apache-2.0
• Created: 2010-08-23T11:45:41.000Z (about 14 years ago)
• Default Branch: master
• Last Pushed: 2017-02-04T14:04:23.000Z (almost 8 years ago)
• Last Synced: 2024-05-02T12:41:33.369Z (6 months ago)
• Language: Erlang
• Homepage:
• Size: 186 KB
• Stars: 57
• Watchers: 8
• Forks: 51
• Open Issues: 13
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-erlang - erlang_localtime - Erlang library for conversion from one local time to another. (Date and Time)

README

        

Erlang Localtime

===

### Public exports

* `utc_to_local/2` – Converts UTC time to local according to specified Timezone

* `local_to_utc/2` – Converts local time to UTC

* `local_to_local/3` – Converts local time to local

* `tz_name/2` – Returns a timezone name (E.g. MSK, MSD, etc)

* `tz_shift/2` – Returns time difference between local datetime and GMT

* `tz_shift/3` – Returns time difference between local datetime and required timezone

### Details

#### Types

* `DateTime` = `{date(), time()}`.

* `TimeZone` = `TimeZoneFrom` = `TimeZoneTo` = `list()`, e.g. `"Europe/Moscow"`, `"America/NewYork"` or abbreviations `"MSK"`, `"MSD"`, etc.

* `ZoneName` =  `{StdAbbr :: list(), StdName :: list()}`, e.g. `{"MSK","MSK"}`

* `ZoneShift` = `{Sign :: '+' | '-', Offset :: non_neg_integer(), RemOffset :: non_neg_integer()}`

#### Dialyzer

`utc_to_local(DateTime, TimeZone) → DateTime | {error, Reason}`

`local_to_utc(DateTime, TimeZone) → DateTime | {error, Reason}`

`local_to_local(DateTime, TimeZoneFrom, TimeZoneTo) → DateTime | {error, Reason}`

`tz_name(DateTime, TimeZone) → ZoneName | {error, Reason}`

`tz_shift(DateTime, TimeZone) → 0 | ZoneShift | {error, Reason}`

`tz_shift(DateTime, TimeZoneFrom, TimeZoneTo) → 0 | ZoneShift | {error, Reason}`

#### Note

Aabbreviation is just used to find appropriate timezone name. If you want to convert `"MSK"` → `"PDT"`, but source timezone is not in daylight saving, it will be corrected by library and `"MSK"` → `"PST"` conversion will be made.

### Examples of usage

#### Converts UTC time to local one

```erlang

localtime:utc_to_local({{2010, 7, 22}, {17, 56, 23}}, "Europe/Moscow").

{{2010,10,10},{21,56,23}}

```

#### Converts local time to UTC one

```erlang

localtime:local_to_utc({{2010, 10, 10}, {21, 56, 23}}, "Europe/Moscow").

{{2010,10,10},{17,56,23}}

```

#### Converts time from one local timezone to another local one

```erlang

localtime:local_to_local({{2010, 10, 10}, {21, 56, 23}}, "Europe/Moscow", "Australia/Sydney").

{{2010,10,11},{3,56,23}}

```

#### Returns timezone name

```erlang

localtime:tz_name({{2010, 10, 10}, {21, 56, 23}}, "Europe/Moscow").

{"MSK","MSK"}

localtime:tz_name({{2010,10,11},{3,56,23}}, "Australia/Sydney").

{"EST","EST"}

```

#### Calculates time difference between UTC and local one

```erlang

localtime:tz_shift({{2013, 01, 22}, {18, 17, 00}}, "Europe/Moscow").

{'+',4,0}

localtime:tz_shift({{2013, 01, 22}, {18, 17, 00}}, "America/New York").

{'-',5,0}

```

#### Calculates time difference between two local timezones

```erlang

localtime:tz_shift({{2013, 01, 22}, {18, 17, 00}}, "America/New York", "Europe/Moscow").

{'+',9,0}

```