async_ecs/entity/
entity.rs

1use std::cmp::Ordering;
2use std::fmt::{Debug, Display, Formatter, Result as FmtResult};
3use std::hash::{Hash, Hasher};
4
5/// `Entity` type, as seen by the user.
6#[derive(Clone, Copy)]
7pub struct Entity(EntityRaw);
8
9/// Index of the entity.
10pub type Index = u32;
11
12/// Generation of the entity.
13pub type Generation = u32;
14
15/// Raw data of the entity.
16#[repr(C, packed)]
17#[derive(Clone, Copy)]
18union EntityRaw {
19    id: u64,
20    data: EntityData,
21}
22
23#[repr(C, packed)]
24#[derive(Clone, Copy)]
25struct EntityData {
26    index: Index,
27    generation: Generation,
28}
29
30impl Entity {
31    /// Create new entity with the given ID.
32    pub fn from_id(id: u64) -> Self {
33        Self(EntityRaw { id })
34    }
35
36    /// Create new entity with the given given index and generation.
37    pub fn from_parts(index: Index, generation: Generation) -> Self {
38        Self(EntityRaw {
39            data: EntityData { index, generation },
40        })
41    }
42
43    /// Get the id of the entity.
44    #[inline]
45    pub fn id(&self) -> u64 {
46        unsafe { self.0.id }
47    }
48
49    /// Get the index of the entity.
50    #[inline]
51    pub fn index(&self) -> Index {
52        unsafe { self.0.data.index }
53    }
54
55    // Get the generation of the entity.
56    #[inline]
57    pub fn generation(&self) -> Generation {
58        unsafe { self.0.data.generation }
59    }
60}
61
62impl Display for Entity {
63    fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
64        write!(f, "{:08X}", self.id())
65    }
66}
67
68impl Debug for Entity {
69    fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
70        write!(f, "{:08X}", self.id())
71    }
72}
73
74impl Hash for Entity {
75    fn hash<H: Hasher>(&self, state: &mut H) {
76        self.index().hash(state);
77        self.generation().hash(state);
78    }
79}
80
81impl Eq for Entity {}
82
83impl PartialEq<Entity> for Entity {
84    fn eq(&self, other: &Entity) -> bool {
85        self.id() == other.id()
86    }
87}
88
89impl Ord for Entity {
90    fn cmp(&self, other: &Self) -> Ordering {
91        if self.generation() < other.generation() {
92            Ordering::Less
93        } else if self.generation() > other.generation() {
94            Ordering::Greater
95        } else if self.index() < other.index() {
96            Ordering::Less
97        } else if self.index() > other.index() {
98            Ordering::Greater
99        } else {
100            Ordering::Equal
101        }
102    }
103}
104
105impl PartialOrd for Entity {
106    fn partial_cmp(&self, other: &Entity) -> Option<Ordering> {
107        Some(Ord::cmp(self, other))
108    }
109}
async_ecs/entity/entity.rs

async_ecs/entity/
entity.rs
