Metadata-Version: 2.2
Name: fosu
Version: 0.5.2
Summary: Fast native osu! beatmap parsing with owned Python results
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: Implementation :: CPython
Classifier: Programming Language :: C++
Classifier: Operating System :: POSIX :: Linux
Classifier: Operating System :: MacOS
Classifier: Operating System :: Microsoft :: Windows
Project-URL: Repository, https://github.com/cmyui/fast-osu-beatmap-parser
Requires-Python: >=3.10
Requires-Dist: typing-extensions>=4.6; python_version < "3.12"
Provides-Extra: test
Requires-Dist: pytest>=8; extra == "test"
Requires-Dist: mypy==2.3.1; extra == "test"
Description-Content-Type: text/markdown

# Python API

FOSU is in active development; its API may change without compatibility shims.
Parsing returns eager objects and lists, detached from native memory. All records
are read-only native objects with eager Python fields, declared and typed in
`_model.py`. Attribute reads do not allocate numeric values. Lists remain ordinary
mutable Python lists.

## Install and use

Requires CPython 3.10+. Stable-ABI wheels target glibc and musl Linux on x86-64
and AArch64, plus macOS 11+ on Intel and Apple Silicon. One wheel per platform
supports every compatible CPython version. Windows x86-64 is supported both
natively and through the Linux x86-64 wheel under WSL.

```sh
python -m pip install fosu
```

Installing from a source checkout requires a C++20 compiler. An ordinary
isolated `pip install .` provisions CMake and Ninja when needed; Unix Makefiles
are also supported when Ninja is unavailable. `--no-build-isolation` makes the
caller responsible for all build tools.

```python
import fosu

beatmap = fosu.parse_file("map.osu")
for note in beatmap.hit_objects:
    if isinstance(note, fosu.Slider):
        print(note.time, note.length, note.control_points)
```

`parse_file(path)` accepts strings, bytes, and `os.PathLike`.
`parse(data)` accepts buffer-protocol objects, including bytes, bytearray,
memoryview, and arrays. Non-bytes buffers are copied to an immutable snapshot;
encode text explicitly.

Inputs are bounded by available address space. Allocation failures raise
`MemoryError`, and file failures raise `OSError`. Native parsing
releases the GIL; Python value construction holds it. Concurrent calls return
independent results. Malformed records are skipped and counted in
`beatmap.stats.malformed_lines`; success does not certify playability.

## Performance

FOSU 0.5.0 (`798b810`), measured on 2026-09-20 using CPython 3.12.14 on an
Intel Core i7-8700 under Linux/WSL2. All rows use the same 1,004 mutually accepted
all-mode maps. Times include eager result construction and release; lower is
better. Warm-file measurements include opening and reading page-cached files.

| Python interface | Resident bytes (µs/map) | Warm file (µs/map) |
|---|---:|---:|
| FOSU AVX2 | 165.1 | 174.7 |
| FOSU scalar | 224.4 | 231.6 |
| OsuPyParser 1.0.7 | Unsupported | 4,418.2 |

Figures are medians of complete passes, not fastest individual parses. Six
passes per API were collected; passes more than 5% above their API's unfiltered
median are excluded as presumed interference, leaving five or six per result.
The parsers expose different models: OsuPyParser also performs derived-statistic
work. See the [comparison and measured variation](https://github.com/cmyui/fast-osu-beatmap-parser/blob/master/docs/comparison.md)
for result contracts, or the [feature-cost tables](https://github.com/cmyui/fast-osu-beatmap-parser/blob/master/docs/performance.md)
for slider geometry, gameplay, mods, and ARM measurements.

## Section selection

```python
listing = fosu.parse_file(
    "map.osu",
    sections=fosu.Sections.METADATA | fosu.Sections.DIFFICULTY,
)
```

Both entry points accept keyword-only `sections`, defaulting to `Sections.ALL`.
Members are `GENERAL`, `EDITOR`, `METADATA`, `DIFFICULTY`, `EVENTS`,
`TIMING_POINTS`, `COLOURS`, and `HIT_OBJECTS`. Combine them with `|`.
Skipped sections retain defaults and empty lists; `Sections(0)` selects none.
Unsupported mask bits are rejected.

Include `GENERAL` for mode-dependent difficulty rules (such as mania CircleSize)
and `EVENTS` for break-dependent combo rules. Only selected sections contribute
malformed-line counts.

## Results and important distinctions

The model classes in
[_model.py](https://github.com/cmyui/fast-osu-beatmap-parser/blob/master/python/fosu/_model.py)
define the fields and convenience methods.
Shared fields use C++ names. Important Python-specific behavior:

- `hit_objects` contains `Circle`, `Slider`, `Spinner`, or `HoldNote`, in
  stable timestamp order. Narrow the union with `isinstance`.
- Times are milliseconds. Slider endpoints are `0` by
  default. Pass `calculate_slider_end_times=True` to `parse` or `parse_file` to
  calculate them using curve distance, timing and repeats.
  Do not use slider endpoints unless calculation was requested.
  Accessing the field never computes or caches anything.
  Other object types still have numeric endpoints. Omitted sections use their default settings.
  Hit samples and slider edge fields remain text.
- Slider `control_points` includes the head position, unlike the native point
  range. `curve_segments` preserves modern segment boundaries and explicit
  B-spline degrees. `slides=2` means forward and back.
- `tag_list` and `bookmark_list` are parsed conveniences alongside the
  `tags` and `bookmarks` text fields.
- IDs and preview time map the `-1` sentinel to `None`.
- Strings decode with UTF-8 `surrogateescape`, preserving undecodable bytes.
- Inherited timing-point NaN beat lengths are preserved; consumers must not
  treat them as ordinary slider velocities.

Records support equality, `repr`, `deepcopy`, and pickle. They are not dataclasses:
`dataclasses.asdict` and `dataclasses.replace` do not apply. Public record classes
cannot be subclassed, and attributes cannot be assigned or deleted. Constructors
accept positional or keyword arguments and retain the supplied values without
runtime type validation. Parsed numeric fields are always eagerly converted to
their documented Python types.

List contents can be changed without affecting the input or another parse result.
Such changes do not recompute derived data. All records participate in cyclic
garbage collection, including cycles consumers create through lists or values
passed to constructors.

Pass `calculate_slider_paths=True` to retain each slider's `path` (otherwise
`None`). `fosu.slider_position_at(slider.path, progress)` is a pure query over
that polyline, with progress clamped to [0, 1]. Returned `PathPoint` coordinates
are relative to the head; add the slider's x/y for playfield coordinates.
Paths alone do not calculate end times. Requesting both reuses their distance.
Native code exposes the same query and `Beatmap.slider_paths`, indexed by slider.

`calculate_slider_events=True` additionally populates `slider.events` with
`HEAD`, `TICK`, `REPEAT`, `LEGACY_LAST_TICK`, and `TAIL` records in official
generator order, grouped by slider-span traversal. This is not necessarily
timestamp order: a legacy last tick may be timed before a late tick or the
repeat beginning its final span. The legacy event is the effective historical
tail judgement, not an additional score or combo event; the real `TAIL` and
slider `end_time` remain unchanged. This option includes path and end-time
calculation. Each record has time, span index/start time, path progress, and a
position relative to the head. Native code exposes `Beatmap.slider_events`,
indexed by slider. Without the option, events are empty. These are path events
using the decoded slider's timing, not a converted ruleset's nested hitobjects:
no samples or catch conversion.
Expansion beyond 1,048,576 events per map raises `MemoryError` rather than
silently dropping events.

`apply_stacking=True` applies unmodded osu!standard stacking after parsing,
including the pre-v6 algorithm. Hit-object x/y and absolute slider control points
are adjusted before returning. `obj.raw_position()` subtracts the stacking offset
from the current x/y, or returns x/y when stacking is absent. It can have small
floating-point rounding differences. Coordinates are floats in both interfaces,
including when stacking is disabled. Each object also retains `stack_height` and `stack_offset`
in its `Stacking` value for inspection; do not add the offset again.
Relative path/event positions remain unchanged: add them to the adjusted head.
It includes path and end-time calculation, but not events. Native results use
`Beatmap.stacking`, indexed by hit object. Other modes are unchanged; Python
`stacking` is `None` when not calculated. Include GENERAL, DIFFICULTY,
TIMING_POINTS and HIT_OBJECTS when selecting sections for meaningful results.

`mods=` accepts combined `Mods` values. EZ and HR adjust difficulty settings for
osu!standard and osu!taiko; HR also reflects standard hit objects and slider
control points vertically. EZ/HR require GENERAL and DIFFICULTY in `sections`.
They are not yet supported for osu!catch or osu!mania because those modes require
converted fruit offsets or resolved hit windows; support is planned. DT,
NIGHTCORE, and HT support every mode and divide gameplay timeline values by
1.5, 1.5, and 0.75 respectively. This includes hit objects, calculated slider
events, timing-point offsets and uninherited beat lengths, and breaks. General
and Editor timestamp metadata remains in source-map time.

See
[compatibility](https://github.com/cmyui/fast-osu-beatmap-parser/blob/master/docs/compatibility.md)
for supported behavior and limitations;
there is no ruleset conversion.

## CPU selection

`fosu.backend` reports `"avx2"`, `"neon"`, or `"scalar"`.
Set `FOSU_BACKEND=auto|scalar|avx2|neon` before importing to select an engine.
Unsupported explicit requests raise `ImportError`; selection stays fixed for
the loaded extension. See
[development checks](https://github.com/cmyui/fast-osu-beatmap-parser/blob/master/docs/build.md).
