fundu provides a flexible and fast parser to convert rust strings into a [std::time::Duration] and for
negative durations into a [time::Duration]. Some examples for valid input strings with the
standard feature:
"1.41""42""2e-8", "2e+8" (or likewise "2.0e8")".5" or likewise "0.5""3." or likewise "3.0""inf", "+inf", "infinity", "+infinity""1w" (1 week) or likewise "7d", "168h", "10080m", "604800s", ...For examples of the custom feature see Customization section.
A quick summary of features provided by this crate:
Duration. (See also
Comparison)TimeUnits, the number format and other aspects are
easily configurable (Customization)Duration::MAX] if the input number was larger than
that maximum or if the input string was positive infinity.time::Duration]s when the
negative feature is activated.fundu aims for good performance and being a lightweight crate. It is purely built on top of the
rust stdlib, and there are no additional dependencies required in the standard configuration. The
accepted number format is per default the scientific floating point format and compatible with
[f64::from_str]. However, the number format and other aspects can be customized
up to formats like systemd time
spans. See also the examples
Examples section and the examples folder. For a direct comparison of
fundu vs the rust native methods Duration::(try_)from_secs_f64 see
Comparison.
For further details see the Documentation!
Add this to Cargo.toml for fundu with the standard feature.
toml
[dependencies]
fundu = "0.5.1"
fundu is split into two main features, standard (providing DurationParser and parse_duration)
and custom (providing the CustomDurationParser). The first is described here in in detail, the
latter adds fully customizable identifiers for time units. Most of the time only one
of the parsers is needed. To include only the CustomDurationParser add the following to
Cargo.toml:
toml
[dependencies]
fundu = { version = "0.5.1", default-features = false, features = ["custom"] }
Activating the negative feature allows parsing negative numbers to negative [time::Duration]s.
If only the default parser is required once, then the parse_duration method can be used.
```rust use fundu::parse_duration; use std::time::Duration;
let input = "1.0e2s"; asserteq!(parseduration(input).unwrap(), Duration::new(100, 0)); ```
When a customization of the accepted TimeUnits is required, then
[DurationParser::with_time_units] can be used.
```rust use fundu::DurationParser; use fundu::TimeUnit::*; use std::time::Duration;
let input = "3m"; asserteq!( DurationParser::withtime_units(&[Minute]).parse(input).unwrap(), Duration::new(180, 0) ); ```
When no time units are configured, seconds is assumed.
```rust use fundu::DurationParser; use std::time::Duration;
let input = "1.0e2"; asserteq!( DurationParser::withouttime_units().parse(input).unwrap(), Duration::new(100, 0) ); ```
However, setting the default time unit to something different than seconds can be achieved with
```rust use fundu::{DurationParser, TimeUnit::*}; use std::time::Duration;
asserteq!( DurationParser::withouttimeunits() .defaultunit(MilliSecond) .parse("1000") .unwrap(), Duration::new(1, 0) ); ```
Note the following will return an error because y (Years) is not in the default set of
TimeUnits.
```rust use fundu::DurationParser;
asserteq!( DurationParser::new().parse("3y").unwraperr().to_string(), "Time unit error: Invalid time unit: 'y' at column 1" ); ```
The parser is reusable and the set of time units is fully customizable
```rust use fundu::{DurationParser, TimeUnit::*}; use std::time::Duration;
let parser = DurationParser::withtimeunits(&[NanoSecond, Minute, Hour]); for (input, expected) in &[ ("9e3ns", Duration::new(0, 9000)), ("10m", Duration::new(600, 0)), ("1.1h", Duration::new(3960, 0)), ("7", Duration::new(7, 0)), ] { assert_eq!(parser.parse(input).unwrap(), *expected); } ```
The identifiers for time units can be fully customized with any number of valid
utf-8 sequences if the custom feature is activated:
```rust use fundu::{CustomDurationParser, TimeUnit::*}; use std::time::Duration;
let parser = CustomDurationParser::withtimeunits( &[ (MilliSecond, &["χιλιοστό του δευτερολέπτου"]), (Second, &["s", "secs"]), (Hour, &["⏳"]) ] ); for (input, expected) in &[ (".3χιλιοστό του δευτερολέπτου", Duration::new(0, 300000)), ("1e3secs", Duration::new(1000, 0)), ("1.1⏳", Duration::new(3960, 0)), ] { asserteq!(parser.parse(input).unwrap(), *expected); } ```
It's also possible to parse multiple durations at once with parse_multiple. The different
durations can be separated by an optional delimiter (a closure matching a u8) defined with
parse_multiple. If the delimiter is not encountered, a number also indicates a new duration.
```rust use std::time::Duration;
use fundu::DurationParser;
let mut parser = DurationParser::new(); parser.parse_multiple(Some(|byte| matches!(byte, b' ' | b'\t')));
asserteq!(parser.parse("1.5h 2e+2ns"), Ok(Duration::new(5400, 200))); asserteq!(parser.parse("55s500ms"), Ok(Duration::new(55, 500000000))); asserteq!(parser.parse("1\t1"), Ok(Duration::new(2, 0))); asserteq!(parser.parse("1. .1"), Ok(Duration::new(1, 100000000))); asserteq!(parser.parse("2h"), Ok(Duration::new(2 * 60 * 60, 0))); asserteq!( parser.parse("300ms20s 5d"), Ok(Duration::new(5 * 60 * 60 * 24 + 20, 300000000)) ); ```
See also the examples folder for common recipes and integration with other crates. Run an example with
shell
cargo run --example $FILE_NAME_WITHOUT_FILETYPE_SUFFIX
like the systemd time span parser example
```shell
--$ cargo run --example systemd --features custom --no-default-features -- --help ...
$ cargo run --example systemd --features custom --no-default-features '300ms20s 5day' Original: 300ms20s 5day μs: 432020300000 Human: 5d 20s 300ms ```
Second is the default time unit (if not specified otherwise for example with
[DurationParser::default_unit]) which is applied when no time unit was encountered in the input
string. The table below gives an overview of the constructor methods and which time units are
available. If a custom set of time units is required, DurationParser::with_time_units can be used.
TimeUnit | Default identifier | Calculation | Default time unit
---:| ---:| ---:|:---:
Nanosecond | ns | 1e-9s | ☑
Microsecond | Ms | 1e-6s | ☑
Millisecond | ms | 1e-3s | ☑
Second | s | SI definition | ☑
Minute | m | 60s | ☑
Hour | h | 60m | ☑
Day | d | 24h | ☑
Week | w | 7d | ☑
Month | M | Year / 12 | ☐
Year | y | 365.25d | ☐
Note that Months and Years are not included in the default set of time units. The current
implementation uses an approximate calculation of Months and Years in seconds and if they are
included in the final configuration, the Julian
year based calculation is used. (See table
above)
With the CustomDurationParser from the custom feature, the identifiers for time units can be
fully customized.
Unlike other crates, fundu does not try to establish a standard for time units and their
identifiers or a specific number format. So, a lot of these aspects can be adjusted with ease when
initializing or building the parser. Here's an incomplete example for possible customizations of the
number format:
```rust use std::time::Duration;
use fundu::TimeUnit::*; use fundu::{DurationParser, ParseError};
let parser = DurationParser::builder()
// Use a custom set of time units. For demonstration purposes just NanoSecond = ns
.customtimeunits(&[NanoSecond])
// Allow some whitespace characters as delimiter between the number and the time unit
.allowdelimiter(|byte| matches!(byte, b'\t' | b'\n' | b'\r' | b' '))
// Makes the number optional. If no number was encountered 1 is assumed
.numberisoptional()
// Disable parsing the fractional part of the number => 1.0 will return an error
.disablefraction()
// Disable parsing the exponent => 1e0 will return an error
.disable_exponent()
// Finally, build a reusable DurationParser
.build();
// Some valid input for (input, expected) in &[ ("ns", Duration::new(0, 1)), ("1000\t\n\r ns", Duration::new(0, 1000)), ] { assert_eq!(parser.parse(input).unwrap(), *expected); }
// Some invalid input for (input, expected) in &[ ( "1.0ns", ParseError::Syntax(1, "No fraction allowed".tostring()), ), ( "1e9ns", ParseError::Syntax(1, "No exponent allowed".tostring()), ), ] { asserteq!(parser.parse(input).unwraperr(), *expected); } ```
Here's an example for fully-customizable time units which uses the CustomDurationParser from the
custom feature:
```rust use std::time::Duration;
use fundu::TimeUnit::*; use fundu::{CustomDurationParser, Multiplier};
let mut parser = CustomDurationParser::withtimeunits(&[ (Second, &["s", "secs", "seconds"]), (Minute, &["min"]), (Hour, &["ώρα"]), ]);
// Let's define a custom time unit fortnight == 2 weeks which isn't part of the basic
// [TimeUnit]s:
parser.customtimeunit(Week, Multiplier(2, 0), &["f", "fortnight", "fortnights"]);
asserteq!(parser.parse("42e-1ώρα").unwrap(), Duration::new(15120, 0)); asserteq!( parser.parse("1fortnight").unwrap(), Duration::new(60 * 60 * 24 * 7 * 2, 0) ); ```
To run the benchmarks on your machine, clone the repository
shell
git clone https://github.com/Joining7943/fundu.git
cd fundu
and then run all benchmarks with
shell
cargo bench --all-features
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 for specific
features:
shell
cargo bench --features standard,custom,negative
The above won't run the flamegraph and iai-callgrind benchmarks.
Benchmarks can be further filtered for example with
shell
cargo bench --bench benchmarks_standard
cargo bench --bench benchmarks_standard -- 'parsing speed'
cargo bench --features custom --no-default-features --bench benchmarks_custom
For more infos, see the help with
shell
cargo bench --help # The cargo help for bench
cargo bench --bench benchmarks_standard -- --help # The criterion help
To get a rough idea about the parsing times, here the average parsing speed of some inputs on a comparatively slow machine (Quad core 3000Mhz, 8GB DDR3, Linux)
Input | avg parsing time | ~ samples / s
--- | ---:| ---:
1 | 37.925 ns | 26_367_831.245
123456789.123456789 | 73.162 ns | 13_668_297.750
format!("{}.{}e-1022", "1".repeat(1022), "1".repeat(1022)) | 551.59 ns | 1_812_940.771
For comparison, fundu's precision and additional features only add a very low performance overhead
for small and some mixed input and performs better than the reference function from the stdlib as
the input gets larger (the reference function is Duration::from_secs_f64(input.parse().unwrap())):
Input | avg parsing time | ~ samples / s
--- | ---:| ---:
1 | 25.630 ns | 39_016_777.214
123456789.123456789 | 45.007 ns | 22_218_765.969
format!("{}.{}e-1022", "1".repeat(1022), "1".repeat(1022)) | 1.7457 µs | 572_836.111
The initialization for fixed size time unit sets with DurationParser::new,
DurationParser::with_all_time_units takes around 1-2 ns and is negligibly small. The
initialization time for custom sets with DurationParser::with_time_units has a maximum of around
10 ns.
fundu vs Duration::from_secs_f64Here's a short incomplete overview of differences and advantages of fundu over using
Duration::from_secs_f64(input.parse().unwrap()) (and
Duration::try_from_secs_f64(input.parse().unwrap()))
Input | Result fundu | Result Duration::(try_)from_secs_f64
---:| --- | ---
01271480964981728917.1 | Duration::new(1_271_480_964_981_728_917, 100_000_000) | Duration::new(1_271_480_964_981_729_024, 0)
1.11111111111e10 | Duration::new(11_111_111_111, 100_000_000) | Duration::new(11_111_111_111, 100_000_381)
1ns | Duration::new(0, 1) | cannot parse time units
1000 | When changing the default unit to MilliSecond -> Duration::new(1, 0) | is always seconds based
1e20 | Duration::MAX | panics or returns an error due to: can not convert float seconds to Duration: value is either too big or NaN
infinity | Duration::MAX | panics or returns an error due to: can not convert float seconds to Duration: value is either too big or NaN
fundu has a small impact on performance when the input is small but performs better for large
input (See performance). Depending on the input data and if you need to parse a
massive amount of inputs and don't need the full precision or any of fundu's features, you may
prefer using the native methods from the rust stdlib.
Since fundu is purely built on top of the rust stdlib without platform specific code, this
library should be compatible with all platforms. Please open an issue if you find any unsupported
platforms which rust itself supports.
See also the CI
See also Changelog
MIT license (LICENSE or http://opensource.org/licenses/MIT)