# 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 1.9.0
Erlang 22.0
Benchmark suite executing with the following configuration:
warmup: 2 s
time: 5 s
memory time: 0 μs
parallel: 1
inputs: none specified
Estimated total run time: 35 s
Benchmarking datetime...
Benchmarking datetime_only...
Benchmarking fast_local_datetime...
Benchmarking timex...
Benchmarking timex_only...
Name ips average deviation median 99th %
fast_local_datetime 69.93 K 14.30 μs ±84.46% 13 μs 34 μs
datetime_only 31.07 K 32.19 μs ±25.00% 31 μs 65 μs
datetime 29.52 K 33.87 μs ±23.98% 32 μs 68 μs
timex_only 10.28 K 97.26 μs ±17.24% 95 μs 176 μs
timex 9.85 K 101.53 μs ±18.81% 98 μs 190 μs
Comparison:
fast_local_datetime 69.93 K
datetime_only 31.07 K - 2.25x slower
datetime 29.52 K - 2.37x slower
timex_only 10.28 K - 6.80x slower
timex 9.85 K - 7.10x 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
```
