4 releases (2 breaking)
0.3.1 | Sep 6, 2024 |
---|---|
0.3.0 | Aug 7, 2023 |
0.2.0 | Jul 9, 2023 |
0.1.0 | Jun 26, 2023 |
#121 in Parser tooling
161 downloads per month
250KB
2.5K
SLoC
Fast and precise systemd time span parser of rust strings to a Duration
Table of Contents
Overview
This crate provides a simple to use and fast parser based on fundu aiming for full compatibility with the systemd time span format as specified in their documentation.
fundu-systemd
can parse rust strings like
&str |
Duration |
---|---|
"2 h" |
Duration::positive(2 * 60 * 60, 0) |
"2hours" |
Duration::positive(2 * 60 * 60, 0) |
"second" |
Duration::positive(1, 0) |
"48hr" |
Duration::positive(48 * 60 * 60, 0) |
"12.3 seconds" |
Duration::positive(12, 300_000_000) |
"1y 12month" |
Duration::positive(63_115_200, 0) |
"999us +1d" |
Duration::positive(86_400, 999_000) |
"55s500ms" |
Duration::positive(55, 500_000_000) |
"300ms20s 5day" |
Duration::positive(20 + 5 * 60 * 60 * 24, 300_000_000) |
"123456789" |
Duration::positive(123_456_789, 0) (Default: Second) |
"100" |
Duration::positive(0, 100_000) (when default is set to MicroSecond) |
"infinity" |
variable: the maximum duration which is currently in use (see below) |
Note that fundu
parses into its own Duration
which is a superset of other Durations
like
std::time::Duration
, chrono::Duration
and time::Duration
. See the
documentation how to easily
handle the conversion between these durations.
Audience
This crate is for you if you
- seek a fast and reliable systemd compatible duration parser
- want it to simply just work without diving into many customizations
- just like the systemd format
- ...
This crate might not be for you if you want to customize the parser to a format which would not be
compatible with systemd
. See the main fundu project, if you want to use a parser
tailored to your needs.
Installation
Add this to Cargo.toml
[dependencies]
fundu-systemd = "0.3.1"
or install with cargo add fundu-systemd
.
Activating the chrono
or time
feature provides a TryFrom
implementation for
chrono::Duration
or time::Duration
. Converting from/to std::time::Duration
does not require
an additional feature. Activating the serde
feature allows some structs and enums to be serialized
or deserialized with serde
Description of the Format
Supported time units:
nsec
,ns
(can be switched on, per default these are not included)usec
,us
,µs
msec,
ms
seconds
,second
,sec
,s
minutes
,minute
,min
,m
hours
,hour
,hr
,h
days
,day
,d
weeks
,week
,w
months
,month
,M
(defined as30.44
days or a1/12
year)years
,year
,y
(defined as365.25
days)
Summary of the rest of the format:
- Only numbers like
"123 days"
or with fraction"1.2 days"
but without exponent (like"3e9 days"
) are allowed - For numbers without a time unit (like
"1234"
) the default time unit is usuallysecond
but can be changed since in some case systemd uses a different granularity. - Time units without a number (like in
"second"
) are allowed and a value of1
is assumed. - The parsed duration represents the value exactly (without rounding errors as would occur in floating point calculations) as it is specified in the source string (just like systemd).
- The maximum supported duration (
Duration::MAX
) hasu64::MAX
seconds (18_446_744_073_709_551_615
) and999_999_999
nano seconds. However, systemd usesu64::MAX
micro seconds as maximum duration when parsing without nanos andu64::MAX
nano seconds when parsing with nanos.fundu-systemd
provides theparse
andparse_nanos
functions to reflect that. If you don't like the maximum duration ofsystemd
it's still possible viaparse_with_max
andparse_nanos_with_max
to adjust this limit to a duration ranging fromDuration::ZERO
toDuration::MAX
. - The special value
"infinity"
evaluates to the maximum duration. Note the maximum duration depends on whether parsing with nano seconds or without. If the maximum duration is manually set to a different value then it evaluates to that maximum duration. - parsed durations larger than the maximum duration (like
"100000000000000years"
) saturate at the maximum duration - Negative durations are not allowed, also no intermediate negative durations like in
"5day -1ms"
although the final duration would not be negative. - Any leading, trailing whitespace or whitespace between the number and the time unit (like in
"1 \n sec"
) and multiple durations (like in"1week \n 2minutes"
) is ignored and follows the posix definition of whitespace which is:- Space (
' '
) - Horizontal Tab (
'\x09'
) - Line Feed (
'\x0A'
) - Vertical Tab (
'\x0B'
) - Form Feed (
'\x0C'
) - Carriage Return (
'\x0D'
)
- Space (
Please see also the systemd documentation for a description of their format.
Benchmarks
To run the benchmarks on your machine, clone the repository
git clone https://github.com/fundu-rs/fundu.git
cd fundu
and then run the fundu-systemd
benchmarks with
cargo bench --package fundu-systemd
The above won't run the flamegraph
and iai-callgrind
benchmarks.
The iai-callgrind
(feature = with-iai
) and flamegraph
(feature = with-flamegraph
) benchmarks
can only be run on unix. Use the --features
option of cargo to run the benchmarks with these
features.
To get a rough idea about the parsing times, here the average parsing speed of some inputs (Quad core 3000Mhz, 8GB DDR3, Linux):
Input | avg parsing time |
---|---|
1 |
55.572 ns |
123456789.123456789 |
88.750 ns |
format!("{}.{}", "1".repeat(1022), "1".repeat(1022)) |
475.07 ns |
s |
83.724 ns |
minutes |
133.26 ns |
1ns 1us |
200.59 ns |
1ns 1us 1ms 1s |
379.75 ns |
1ns 1us 1ns 1us |
391.54 ns |
"1ns 1us".repeat(100) |
18.644 µs |
License
MIT license (LICENSE or http://opensource.org/licenses/MIT)
Dependencies
~205–630KB
~12K SLoC