honeycomb_core/cmap/dim2/basic_ops.rs
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//! Basic operations implementation
//!
//! This module contains code used to implement basic operations of combinatorial maps, such as
//! (but not limited to):
//!
//! - Dart addition / insertion / removal
//! - Beta function interfaces
//! - i-cell computations
// ------ IMPORTS
use crate::prelude::{
CMap2, DartIdType, EdgeIdType, FaceIdType, Orbit2, OrbitPolicy, VertexIdType, NULL_DART_ID,
};
use crate::{attributes::UnknownAttributeStorage, geometry::CoordsFloat};
use itertools::Itertools;
use stm::{atomically, StmResult, Transaction};
// ------ CONTENT
/// **Dart-related methods**
impl<T: CoordsFloat> CMap2<T> {
// --- read
/// Return the current number of darts.
#[must_use = "unused return value"]
pub fn n_darts(&self) -> usize {
self.n_darts
}
/// Return the current number of unused darts.
#[must_use = "unused return value"]
pub fn n_unused_darts(&self) -> usize {
self.unused_darts.iter().filter(|v| v.read_atomic()).count()
}
// --- edit
/// Add a new free dart to the map.
///
/// # Return
///
/// Return the ID of the new dart.
pub fn add_free_dart(&mut self) -> DartIdType {
let new_id = self.n_darts as DartIdType;
self.n_darts += 1;
self.betas.extend(1);
self.unused_darts.extend(1);
self.vertices.extend(1);
self.attributes.extend_storages(1);
new_id
}
/// Add `n_darts` new free darts to the map.
///
/// # Return
///
/// Return the ID of the first new dart. Other IDs are in the range `ID..ID+n_darts`.
pub fn add_free_darts(&mut self, n_darts: usize) -> DartIdType {
let new_id = self.n_darts as DartIdType;
self.n_darts += n_darts;
self.betas.extend(n_darts);
self.unused_darts.extend(n_darts);
self.vertices.extend(n_darts);
self.attributes.extend_storages(n_darts);
new_id
}
/// Insert a new free dart in the map.
///
/// The dart may be inserted into an unused spot of the existing dart list. If no free spots
/// exist, it will be pushed to the end of the list.
///
/// # Return
///
/// Return the ID of the new dart.
pub fn insert_free_dart(&mut self) -> DartIdType {
if let Some((new_id, _)) = self
.unused_darts
.iter()
.enumerate()
.find(|(_, u)| u.read_atomic())
{
atomically(|trans| self.unused_darts[new_id as DartIdType].write(trans, false));
new_id as DartIdType
} else {
self.add_free_dart()
}
}
/// Remove a free dart from the map.
///
/// The removed dart identifier is added to the list of free dart. This way of proceeding is
/// necessary as the structure relies on darts indexing for encoding data, making reordering of
/// any sort extremely costly.
///
/// # Arguments
///
/// - `dart_id: DartIdentifier` -- Identifier of the dart to remove.
///
/// # Panics
///
/// This method may panic if:
/// - the dart is not *i*-free for all *i*,
/// - the dart is already marked as unused.
pub fn remove_free_dart(&mut self, dart_id: DartIdType) {
atomically(|trans| {
assert!(self.is_free(dart_id)); // all beta images are 0
assert!(!self.unused_darts[dart_id as DartIdType].replace(trans, true)?);
Ok(())
});
}
}
/// **Beta-related methods**
impl<T: CoordsFloat> CMap2<T> {
// --- read
/// Return β<sub>`I`</sub>(`dart_id`).
///
/// # Panics
///
/// The method will panic if `I` is not 0, 1 or 2.
#[must_use = "unused return value"]
pub fn beta<const I: u8>(&self, dart_id: DartIdType) -> DartIdType {
assert!(I < 3);
self.betas[(I, dart_id)].read_atomic()
}
/// Return β<sub>`i`</sub>(`dart_id`).
///
/// # Panics
///
/// The method will panic if `i` is not 0, 1 or 2.
#[must_use = "unused return value"]
pub fn beta_rt(&self, i: u8, dart_id: DartIdType) -> DartIdType {
assert!(i < 3);
match i {
0 => self.beta::<0>(dart_id),
1 => self.beta::<1>(dart_id),
2 => self.beta::<2>(dart_id),
_ => unreachable!(),
}
}
/// Return β<sub>`I`</sub>(`dart_id`).
///
/// # Errors
///
/// This method is meant to be called in a context where the returned `Result` is used to
/// validate the transaction passed as argument. Errors should not be processed manually,
/// only processed via the `?` operator.
///
/// # Panics
///
/// The method will panic if `I` is not 0, 1 or 2.
pub fn beta_transac<const I: u8>(
&self,
trans: &mut Transaction,
dart_id: DartIdType,
) -> StmResult<DartIdType> {
assert!(I < 3);
self.betas[(I, dart_id)].read(trans)
}
/// Return β<sub>`i`</sub>(`dart_id`).
///
/// # Errors
///
/// This method is meant to be called in a context where the returned `Result` is used to
/// validate the transaction passed as argument. Errors should not be processed manually,
/// only processed via the `?` operator.
///
/// # Panics
///
/// The method will panic if `i` is not 0, 1 or 2.
pub fn beta_rt_transac(
&self,
trans: &mut Transaction,
i: u8,
dart_id: DartIdType,
) -> StmResult<DartIdType> {
assert!(i < 3);
match i {
0 => self.beta_transac::<0>(trans, dart_id),
1 => self.beta_transac::<1>(trans, dart_id),
2 => self.beta_transac::<2>(trans, dart_id),
_ => unreachable!(),
}
}
/// Check if a given dart is `I`-free.
///
/// # Return
///
/// Return a boolean indicating if the dart is `I`-free, i.e.:
/// - `true` if β<sub>`I`</sub>(`dart_id`) = `NULL_DART_ID`,
/// - `false` else.
///
/// # Panics
///
/// The function will panic if *I* is not 0, 1 or 2.
///
#[must_use = "unused return value"]
pub fn is_i_free<const I: u8>(&self, dart_id: DartIdType) -> bool {
self.beta::<I>(dart_id) == NULL_DART_ID
}
/// Check if a given dart is `i`-free, for all `i`.
///
/// # Return
///
/// Return a boolean indicating if the dart is 0-free, 1-free **and** 2-free.
#[must_use = "unused return value"]
pub fn is_free(&self, dart_id: DartIdType) -> bool {
self.beta::<0>(dart_id) == NULL_DART_ID
&& self.beta::<1>(dart_id) == NULL_DART_ID
&& self.beta::<2>(dart_id) == NULL_DART_ID
}
}
/// **I-cell-related methods**
impl<T: CoordsFloat> CMap2<T> {
/// Compute the ID of the vertex a given dart is part of.
///
/// This corresponds to the minimum dart ID among darts composing the 0-cell orbit.
#[must_use = "unused return value"]
pub fn vertex_id(&self, dart_id: DartIdType) -> VertexIdType {
atomically(|trans| self.vertex_id_transac(trans, dart_id))
}
/// Compute the ID of the vertex a given dart is part of.
///
/// This corresponds to the minimum dart ID among darts composing the 0-cell orbit.
///
/// # Errors
///
/// This method is meant to be called in a context where the returned `Result` is used to
/// validate the transaction passed as argument. Errors should not be processed manually,
/// only processed via the `?` operator.
pub fn vertex_id_transac(
&self,
trans: &mut Transaction,
dart_id: DartIdType,
) -> StmResult<VertexIdType> {
// min encountered / current dart
let mut min = dart_id;
let mut crt = self.betas[(1, self.betas[(2, dart_id)].read(trans)?)].read(trans)?;
// we first iterate in direct direction (B1oB2)
while crt != NULL_DART_ID && crt != dart_id {
min = min.min(crt);
crt = self.betas[(1, self.betas[(2, crt)].read(trans)?)].read(trans)?;
}
// if we landed on the null dart, the vertex is open
// we need to iterate in the opposite dir (B2oB0)
if crt == NULL_DART_ID {
crt = self.betas[(2, self.betas[(0, dart_id)].read(trans)?)].read(trans)?;
while crt != NULL_DART_ID {
min = min.min(crt);
crt = self.betas[(2, self.betas[(0, crt)].read(trans)?)].read(trans)?;
}
}
Ok(min)
}
/// Compute the ID of the edge a given dart is part of.
///
/// This corresponds to the minimum dart ID among darts composing the 1-cell orbit.
#[must_use = "unused return value"]
pub fn edge_id(&self, dart_id: DartIdType) -> EdgeIdType {
atomically(|trans| self.edge_id_transac(trans, dart_id))
}
/// Compute the ID of the edge a given dart is part of.
///
/// This corresponds to the minimum dart ID among darts composing the 1-cell orbit.
///
/// # Errors
///
/// This method is meant to be called in a context where the returned `Result` is used to
/// validate the transaction passed as argument. Errors should not be processed manually,
/// only processed via the `?` operator.
pub fn edge_id_transac(
&self,
trans: &mut Transaction,
dart_id: DartIdType,
) -> StmResult<EdgeIdType> {
// optimizing this one bc I'm tired
let b2 = self.beta_transac::<2>(trans, dart_id)?;
if b2 == NULL_DART_ID {
Ok(dart_id as EdgeIdType)
} else {
Ok(b2.min(dart_id) as EdgeIdType)
}
}
/// Compute the ID of the face a given dart is part of.
///
/// This corresponds to the minimum dart ID among darts composing the 2-cell orbit.
#[must_use = "unused return value"]
pub fn face_id(&self, dart_id: DartIdType) -> FaceIdType {
atomically(|trans| self.face_id_transac(trans, dart_id))
}
/// Compute the ID of the face a given dart is part of.
///
/// This corresponds to the minimum dart ID among darts composing the 2-cell orbit.
///
/// # Errors
///
/// This method is meant to be called in a context where the returned `Result` is used to
/// validate the transaction passed as argument. Errors should not be processed manually,
/// only processed via the `?` operator.
pub fn face_id_transac(
&self,
trans: &mut Transaction,
dart_id: DartIdType,
) -> StmResult<FaceIdType> {
// min encountered / current dart
let mut min = dart_id;
let mut crt = self.beta_transac::<1>(trans, dart_id)?;
// we first iterate in direct direction (B1)
while crt != NULL_DART_ID && crt != dart_id {
min = min.min(crt);
crt = self.beta_transac::<1>(trans, crt)?;
}
// if we landed on the null dart, the face is open
// we need to iterate in the opposite dir (B0)
if crt == NULL_DART_ID {
crt = self.beta_transac::<0>(trans, dart_id)?;
while crt != NULL_DART_ID {
min = min.min(crt);
crt = self.beta_transac::<0>(trans, crt)?;
}
}
Ok(min)
}
/// Return the orbit defined by a dart and its `I`-cell.
///
/// # Usage
///
/// The [`Orbit2`] can be iterated upon to retrieve all dart member of the cell. Note that
/// **the dart passed as an argument is included as the first element of the returned orbit**.
///
/// # Panics
///
/// The method will panic if *I* is not 0, 1 or 2.
#[must_use = "unused return value"]
pub fn i_cell<const I: u8>(&self, dart_id: DartIdType) -> Orbit2<T> {
assert!(I < 3);
match I {
0 => Orbit2::<'_, T>::new(self, OrbitPolicy::Vertex, dart_id),
1 => Orbit2::<'_, T>::new(self, OrbitPolicy::Edge, dart_id),
2 => Orbit2::<'_, T>::new(self, OrbitPolicy::Face, dart_id),
_ => unreachable!(),
}
}
/// Return an iterator over IDs of all the map's vertices.
#[must_use = "unused return value"]
pub fn iter_vertices(&self) -> impl Iterator<Item = VertexIdType> + '_ {
(1..self.n_darts() as DartIdType)
.zip(self.unused_darts.iter().skip(1))
.filter_map(|(d, unused)| {
if unused.read_atomic() {
None
} else {
Some(self.vertex_id(d))
}
})
.unique()
}
/// Return an iterator over IDs of all the map's edges.
#[must_use = "unused return value"]
pub fn iter_edges(&self) -> impl Iterator<Item = EdgeIdType> + '_ {
(1..self.n_darts() as DartIdType)
.zip(self.unused_darts.iter().skip(1))
.filter_map(|(d, unused)| {
if unused.read_atomic() {
None
} else {
Some(self.edge_id(d))
}
})
.unique()
}
/// Return an iterator over IDs of all the map's faces.
#[must_use = "unused return value"]
pub fn iter_faces(&self) -> impl Iterator<Item = FaceIdType> + '_ {
(1..self.n_darts() as DartIdType)
.zip(self.unused_darts.iter().skip(1))
.filter_map(|(d, unused)| {
if unused.read_atomic() {
None
} else {
Some(self.face_id(d))
}
})
.unique()
}
}