honeycomb_core/cmap/dim3/links/
three.rs

1//! 3D link implementations
2
3use crate::cmap::{CMap3, DartIdType, LinkError, NULL_DART_ID};
4use crate::geometry::CoordsFloat;
5use crate::stm::{Transaction, TransactionClosureResult, abort, atomically_with_err};
6
7/// 3-links
8impl<T: CoordsFloat> CMap3<T> {
9    /// 3-link operation.
10    pub(crate) fn three_link(
11        &self,
12        trans: &mut Transaction,
13        ld: DartIdType,
14        rd: DartIdType,
15    ) -> TransactionClosureResult<(), LinkError> {
16        self.betas.three_link_core(trans, ld, rd)?;
17        let (mut lside, mut rside) = (
18            self.beta_transac::<1>(trans, ld)?,
19            self.beta_transac::<0>(trans, rd)?,
20        );
21        // while we haven't completed the loop, or reached an end
22        while lside != ld && lside != NULL_DART_ID {
23            if rside == NULL_DART_ID {
24                // (*)
25                abort(LinkError::AsymmetricalFaces(ld, rd))?;
26            }
27            self.betas.three_link_core(trans, lside, rside)?;
28            (lside, rside) = (
29                self.beta_transac::<1>(trans, lside)?,
30                self.beta_transac::<0>(trans, rside)?,
31            );
32        }
33        // the face was open, so we need to cover the other direction
34        // for meshes, we should be working on complete faces at all times,
35        // so branch prediction will hopefully save use
36        if lside == NULL_DART_ID {
37            if rside != NULL_DART_ID {
38                // (*)
39                abort(LinkError::AsymmetricalFaces(ld, rd))?;
40            }
41            (lside, rside) = (
42                self.beta_transac::<0>(trans, ld)?,
43                self.beta_transac::<1>(trans, rd)?,
44            );
45            while lside != NULL_DART_ID {
46                if rside == NULL_DART_ID {
47                    // (*)
48                    abort(LinkError::AsymmetricalFaces(ld, rd))?;
49                }
50                self.betas.three_link_core(trans, lside, rside)?;
51                (lside, rside) = (
52                    self.beta_transac::<0>(trans, lside)?,
53                    self.beta_transac::<1>(trans, rside)?,
54                );
55            }
56        }
57        // (*): if we land on NULL on one side, the other side should be NULL as well
58        //      if that is not the case, it means (either):
59        //      - we're trying to sew open faces with a different number of darts
60        //      - we're trying to sew open faces that are offset by one (or more) dart(s)
61        //      in both case, this is way too clunky to be considered valid
62        Ok(())
63    }
64
65    /// 3-link operation.
66    pub(crate) fn force_three_link(&self, ld: DartIdType, rd: DartIdType) -> Result<(), LinkError> {
67        atomically_with_err(|trans| self.three_link(trans, ld, rd))
68    }
69}
70
71/// 3-unlinks
72impl<T: CoordsFloat> CMap3<T> {
73    /// 3-unlink operation.
74    pub(crate) fn three_unlink(
75        &self,
76        trans: &mut Transaction,
77        ld: DartIdType,
78    ) -> TransactionClosureResult<(), LinkError> {
79        let rd = self.beta_transac::<3>(trans, ld)?;
80
81        self.betas.three_unlink_core(trans, ld)?;
82        let (mut lside, mut rside) = (
83            self.beta_transac::<1>(trans, ld)?,
84            self.beta_transac::<0>(trans, rd)?,
85        );
86        // while we haven't completed the loop, or reached an end
87        while lside != ld && lside != NULL_DART_ID {
88            if lside != self.beta_transac::<3>(trans, rside)? {
89                // (*); FIXME: add dedicated err ~LinkError::DivergentStructures ?
90                abort(LinkError::AsymmetricalFaces(ld, rd))?;
91            }
92            self.betas.three_unlink_core(trans, lside)?;
93            (lside, rside) = (
94                self.beta_transac::<1>(trans, lside)?,
95                self.beta_transac::<0>(trans, rside)?,
96            );
97        }
98        // the face was open, so we need to cover the other direction
99        // for meshes, we should be working on complete faces at all times,
100        // so branch prediction will hopefully save use
101        if lside == NULL_DART_ID {
102            if rside != NULL_DART_ID {
103                // (**)
104                abort(LinkError::AsymmetricalFaces(ld, rd))?;
105            }
106            (lside, rside) = (
107                self.beta_transac::<0>(trans, ld)?,
108                self.beta_transac::<1>(trans, rd)?,
109            );
110            while lside != NULL_DART_ID {
111                if lside != self.beta_transac::<3>(trans, rside)? {
112                    // (*); FIXME: add dedicated err ~LinkError::DivergentStructures ?
113                    abort(LinkError::AsymmetricalFaces(ld, rd))?;
114                }
115                assert_eq!(lside, self.beta_transac::<3>(trans, rside)?); // (*)
116                self.betas.three_unlink_core(trans, lside)?;
117                (lside, rside) = (
118                    self.beta_transac::<0>(trans, lside)?,
119                    self.beta_transac::<1>(trans, rside)?,
120                );
121            }
122        }
123        // (*) : this can be changed, but the idea here is to ensure we're unlinking the expected
124        //       construct
125        // (**): if we land on NULL on one side, the other side should be NULL as well
126        Ok(())
127    }
128
129    /// 3-unlink operation.
130    pub(crate) fn force_three_unlink(&self, ld: DartIdType) -> Result<(), LinkError> {
131        atomically_with_err(|trans| self.three_unlink(trans, ld))
132    }
133}
honeycomb_core/cmap/dim3/links/three.rs

honeycomb_core/cmap/dim3/links/
three.rs
