# FastLocalDatetime
[](https://gitlab.com/paulswartz/fast_local_datetime/commits/master) [](https://gitlab.com/paulswartz/fast_local_datetime/commits/master)
Fast conversion of a UTC epoch timestamp (Unix timestamp) into a DateTime in
a given timezone.
## Examples
```elixir
iex> {:ok, dt} = unix_to_datetime(1522888537, "America/New_York")
iex> dt
#DateTime<2018-04-04 20:35:37-04:00 EDT America/New_York>
iex> unix_to_datetime(1522888537, "not found")
{:error, :not_found}
```
## Benchmarks
```
$ mix run bench/unix.exs
Operating System: macOS
CPU Information: Intel(R) Core(TM) i7-7820HQ CPU @ 2.90GHz
Number of Available Cores: 8
Available memory: 16 GB
Elixir 1.6.4
Erlang 20.3
Benchmark suite executing with the following configuration:
warmup: 2 s
time: 5 s
parallel: 1
inputs: none specified
Estimated total run time: 35 s
Benchmarking calendar...
Benchmarking calendar_only...
Benchmarking fast_local_datetime...
Benchmarking timex...
Benchmarking timex_only...
Name ips average deviation median 99th %
fast_local_datetime 79.97 K 12.50 μs ±174.96% 11 μs 31 μs
calendar_only 19.47 K 51.35 μs ±33.97% 44 μs 117.44 μs
calendar 18.46 K 54.17 μs ±28.64% 47 μs 119 μs
timex_only 6.47 K 154.55 μs ±29.99% 140 μs 358 μs
timex 6.33 K 157.93 μs ±25.77% 145 μs 305.14 μs
Comparison:
fast_local_datetime 79.97 K
calendar_only 19.47 K - 4.11x slower
calendar 18.46 K - 4.33x slower
timex_only 6.47 K - 12.36x slower
timex 6.33 K - 12.63x slower
```
The `*_only` benchmarks don't include the conversion from a Unix timestamp to
a DateTime: they only test the timezone conversion of the given library.
## Installation
The package can be installed by adding `fast_local_datetime` to your list of
dependencies in `mix.exs`:
```elixir
def deps do
[
{:fast_local_datetime, "~> 0.1.0"}
]
end
```
Documentation can be found at [https://hexdocs.pm/fast_local_datetime](https://hexdocs.pm/fast_local_datetime).
## Updates
`fast_local_datetime` keeps the tables up-to-date with `tzdata` by checking
periodically whether a new database has been loaded. By default, they're
checked every hour. This can be overriden in the configuration:
```elixir
# refresh once per day
config :fast_local_datetime, refresh_check_interval: 86_400_00
```
