fundu provides a flexible and fast parser to convert rust strings into a Duration. fundu parses into
its own Duration but provides methods to convert into [std::time::Duration],
[chrono::Duration] and [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.
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.Duration can represent negative durations but also implements TryFrom for [chrono::Duration]
and [time::Duration] if the corresponding 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 or gnu relative times. 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 = "1.0.0"
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 = "1.0.0", default-features = false, features = ["custom"] }
Activating the chrono or time feature provides a TryFrom implementation for [chrono::Duration] or [time::Duration].
Activating the serde feature allows some structs and enums to be serialized or deserialized with serde
If only the default configuration is required once, the parse_duration method can be used.
Note that parse_duration returns a [std::time::Duration] in contrast to the parse method of the other parsers which return a fundu::Duration.
```rust use std::time::Duration;
use fundu::parse_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::{Duration, DurationParser};
let input = "3m"; asserteq!( DurationParser::withalltimeunits().parse(input).unwrap(), Duration::positive(180, 0) ); ```
When no time units are configured, seconds is assumed.
```rust use fundu::{Duration, DurationParser};
let input = "1.0e2"; asserteq!( DurationParser::withouttime_units().parse(input).unwrap(), Duration::positive(100, 0) ); ```
However, the following will return an error because y (Years) is not a default time unit:
```rust use fundu::DurationParser;
let input = "3y"; assert!(DurationParser::new().parse(input).is_err()); ```
The parser is reusable and the set of time units is fully customizable
```rust use fundu::TimeUnit::*; use fundu::{Duration, DurationParser};
let parser = DurationParser::withtimeunits(&[NanoSecond, Minute, Hour]);
asserteq!(parser.parse("9e3ns").unwrap(), Duration::positive(0, 9000)); asserteq!(parser.parse("10m").unwrap(), Duration::positive(600, 0)); asserteq!(parser.parse("1.1h").unwrap(), Duration::positive(3960, 0)); asserteq!(parser.parse("7").unwrap(), Duration::positive(7, 0)); ```
Setting the default time unit (if no time unit is given in the input string) to something different than seconds is also easily possible
```rust use fundu::TimeUnit::*; use fundu::{Duration, DurationParser};
asserteq!( DurationParser::withouttimeunits() .defaultunit(MilliSecond) .parse("1000") .unwrap(), Duration::positive(1, 0) ); ```
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::TimeUnit::*; use fundu::{CustomTimeUnit, CustomDurationParser, Duration};
let parser = CustomDurationParser::withtimeunits(&[ CustomTimeUnit::withdefault(MilliSecond, &["χιλιοστό του δευτερολέπτου"]), CustomTimeUnit::withdefault(Second, &["s", "secs"]), CustomTimeUnit::with_default(Hour, &["⏳"]), ]);
asserteq!(parser.parse(".3χιλιοστό του δευτερολέπτου"), Ok(Duration::positive(0, 300000))); asserteq!(parser.parse("1e3secs"), Ok(Duration::positive(1000, 0))); asserteq!(parser.parse("1.1⏳"), Ok(Duration::positive(3960, 0))); ```
The custom feature can be used to customize a lot more. See the documentation of the exported
items of the custom feature (like CustomTimeUnit, TimeKeyword) for more information.
Also, fundu tries to give informative error messages
```rust use fundu::DurationParser;
asserteq!( DurationParser::withouttimeunits() .parse("1y") .unwraperr() .to_string(), "Time unit error: No time units allowed but found: 'y' at column 1" ); ```
The number format can be easily adjusted to your needs. For example to allow numbers being optional,
allow some ascii whitespace between the number and the time unit and restrict the number format to
whole numbers, without fractional part and an exponent (Also note that the DurationParserBuilder can
build a DurationParser at compile time in const context):
```rust use fundu::TimeUnit::*; use fundu::{Duration, DurationParser, ParseError};
const PARSER: DurationParser = DurationParser::builder() .timeunits(&[NanoSecond]) .allowdelimiter(|byte| matches!(byte, b'\t' | b'\n' | b'\r' | b' ')) .numberisoptional() .disablefraction() .disableexponent() .build();
asserteq!(PARSER.parse("ns").unwrap(), Duration::positive(0, 1)); asserteq!( PARSER.parse("1000\t\n\r ns").unwrap(), Duration::positive(0, 1000) );
asserteq!( PARSER.parse("1.0ns").unwraperr(), ParseError::Syntax(1, "No fraction allowed".tostring()) ); asserteq!( PARSER.parse("1e9ns").unwraperr(), ParseError::Syntax(1, "No exponent allowed".tostring()) ); ```
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 can also indicate a new duration.
```rust use fundu::{Duration, DurationParser};
let parser = DurationParser::builder() .defaulttimeunits() .parse_multiple(|byte| matches!(byte, b' ' | b'\t'), Some(&["and"])) .build();
asserteq!( parser.parse("1.5h 2e+2ns"), Ok(Duration::positive(5400, 200)) ); asserteq!( parser.parse("55s500ms"), Ok(Duration::positive(55, 500000000)) ); asserteq!(parser.parse("1\t1"), Ok(Duration::positive(2, 0))); asserteq!( parser.parse("1. .1"), Ok(Duration::positive(1, 100000000)) ); asserteq!(parser.parse("2h"), Ok(Duration::positive(2 * 60 * 60, 0))); asserteq!( parser.parse("300ms20s 5d"), Ok(Duration::positive(5 * 60 * 60 * 24 + 20, 300000000)) ); asserteq!( parser.parse("300.0ms and 5d"), Ok(Duration::positive(5 * 60 * 60 * 24, 300000_000)) ); ```
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. A lot of these aspects can be adjusted when
initializing or building the parser. Here's an incomplete example for possible customizations of the
number format:
```rust use fundu::TimeUnit::*; use fundu::{Duration, DurationParser, ParseError};
let parser = DurationParser::builder()
// Use a custom set of time units. For demonstration purposes just NanoSecond
.timeunits(&[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
.disableexponent()
// Finally, build a reusable DurationParser
.build();
// Some valid input asserteq!(parser.parse("ns").unwrap(), Duration::positive(0, 1)); asserteq!( parser.parse("1000\t\n\r ns").unwrap(), Duration::positive(0, 1000) );
// Some invalid input asserteq!( parser.parse("1.0ns").unwraperr(), ParseError::Syntax(1, "No fraction allowed".tostring()) ); asserteq!( parser.parse("1e9ns").unwraperr(), ParseError::Syntax(1, "No exponent allowed".tostring()) ); ```
Here's an example for fully-customizable time units which uses the CustomDurationParser from the
custom feature:
```rust use fundu::TimeUnit::*; use fundu::{CustomDurationParser, CustomTimeUnit, Duration, Multiplier, TimeKeyword};
// Let's define a custom time unit fortnight which is worth 2 weeks. Note the creation
// of CustomTimeUnits and TimeKeywords can be const and moved to compile time:
const FORTNIGHT: CustomTimeUnit = CustomTimeUnit::new(
Week,
&["f", "fortnight", "fortnights"],
Some(Multiplier(2, 0)),
);
let parser = CustomDurationParser::builder()
.timeunits(&[
CustomTimeUnit::withdefault(Second, &["s", "secs", "seconds"]),
CustomTimeUnit::withdefault(Minute, &["min"]),
CustomTimeUnit::withdefault(Hour, &["ώρα"]),
FORTNIGHT,
])
// Additionally, define tomorrow, a keyword of time which is worth 1 day in the future.
// In contrast to a CustomTimeUnit, a TimeKeyword doesn't accept a number in front of it
// in the source string.
.keyword(TimeKeyword::new(Day, &["tomorrow"], Some(Multiplier(1, 0))))
.build();
asserteq!( parser.parse("42e-1ώρα").unwrap(), Duration::positive(15120, 0) ); asserteq!( parser.parse("tomorrow").unwrap(), Duration::positive(60 * 60 * 24, 0) ); assert_eq!( parser.parse("1fortnight").unwrap(), Duration::positive(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
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 | 50.473 ns | 19_812_573.058
format!("{}.{}e-1022", "1".repeat(1022), "1".repeat(1022)) | 371.02 ns | 2_695_272.492
For comparison, the precision and additional features of fundu result in a very low performance
overhead due to the initial setup of structures, etc., and quickly catches up. Fundu even becomes
more performant 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
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 | fundu | 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
"1 2e-3 3e-9", 1s2ms3ns | can parse multiple durations as one Duration::new(1, 2_000_003) | not possible
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
-1, -1s, ... | can parse negative durations if enabled | panics or returns an error
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 for platforms on which fundu is tested.
MIT license (LICENSE or http://opensource.org/licenses/MIT)