3 releases
0.1.2 | Aug 17, 2024 |
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0.1.1 | Mar 11, 2024 |
0.1.0 | Feb 27, 2024 |
#418 in Parser implementations
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SLoC
rosu-map
Library to de- and encode .osu
files from osu!.
What
At it's core, rosu-map
provides the DecodeBeatmap
trait. The trait is responsible for
decoding the file itself, error handling, and section parsing. All that's left to do for
implementators of the trait is to keep a state of parsed data and, given a section and a line
of text, to modify that state.
rosu-map
also provides multiple types that already implement this trait, namely one for each
section (see Editor
, TimingPoints
, ...) and one for the (almost) full content, Beatmap
.
Why
Exposing functionality through the trait allows for flexibility when deciding which content to parse and thus make it more efficient when not all data is needed.
If only the difficulty attributes are required, parsing via the Difficulty
struct will discard
everything except for the few lines within the [Difficulty]
section of the .osu
file.
Similarly, if only the artist, title, and version is of interest, the Metadata
struct can be
used.
Additionally, it's worth noting that Beatmap
parses (almost) everything which might be
overkill for many use-cases. The work-around would be to define a new custom type, copy-paste
Beatmap
's DecodeBeatmap
implementation, and then throw out everything that's not needed.
How
The simplest way to make use of a type's DecodeBeatmap
implementation is by using
rosu-map
s functions from_bytes
, from_path
, and from_str
.
use rosu_map::section::difficulty::Difficulty;
let content = "[Difficulty]
ApproachRate: 9.2
SliderMultiplier: 1.9
[Metadata]
Creator: peppy";
let difficulty = rosu_map::from_str::<Difficulty>(content).unwrap();
assert_eq!(difficulty.approach_rate, 9.2);
let path = "./resources/Soleily - Renatus (Gamu) [Insane].osu";
let map = rosu_map::from_path::<Beatmap>(path).unwrap();
assert_eq!(map.audio_file, "03. Renatus - Soleily 192kbps.mp3");
For information on implementing the DecodeBeatmap
trait on a new type, check out the
trait's documentation. For examples, check how types like General
or HitObjects
implement the trait.
Encoding
The Beatmap
struct provides a built-in way to turn itself into the content of a .osu
file
through its encode*
methods.
let path = "./resources/Within Temptation - The Unforgiving (Armin) [Marathon].osu";
let mut map: Beatmap = rosu_map::from_path(path).unwrap();
map.approach_rate = 10.0;
map.encode_to_path("./new_file.osu").unwrap();
let metadata = rosu_map::section::metadata::Metadata {
title: "song title".to_string(),
artist: "artist name".to_string(),
..Default::default()
};
let content = Beatmap::from(metadata).encode_to_string().unwrap();
assert!(content.contains("Title: song title"));
Features
Flag | Description | Dependencies |
---|---|---|
default |
No features | |
tracing |
Any error encountered during decoding will be logged through tracing::error . If this features is not enabled, errors will be ignored. |
tracing |
Misc
Internals
A sizable section of rosu-map
is a port of osu!lazer's beatmap
{de/en}coding. Not only does its functionality mirror osu!, but many test cases were
translated too, providing a solid degree of correctness even on fringe edge cases.
Async
After some testing and benchmarking, it turns out that async IO does not provide any improvements
or performance gains even in a concurrent context. In fact, regular sequential IO consistently
outperformed its async counterpart. As such rosu-map
does not provide an async interface.
Storyboard
rosu-map
does not provide types that parse storyboards, but the crate rosu-storyboard
does.