qmi 0.1.5

An ECS with too much macro usage
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137

use serde::{Deserialize, Serialize, ser::SerializeTuple};

use crate::EntityID;

#[derive(Debug, Clone, Copy)]
struct Page(pub [Option<usize>; 128]);

impl serde::Serialize for Page {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: serde::Serializer,
    {
        let mut tup = serializer.serialize_tuple(128)?;
        for item in &self.0 {
            tup.serialize_element(item)?;
        }
        tup.end()
    }
}
impl<'de> serde::Deserialize<'de> for Page {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: serde::Deserializer<'de>,
    {
        struct PageVisitor;
        impl<'de> serde::de::Visitor<'de> for PageVisitor {
            type Value = Page;
            fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
                formatter.write_str("a tuple/sequence of exactly 128 Option<usize> elements")
            }
            fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
            where
                A: serde::de::SeqAccess<'de>,
            {
                let mut items = [None; 128];
                for (i, slot) in items.iter_mut().enumerate() {
                    if let Some(element) = seq.next_element()? {
                        *slot = element;
                    } else {
                        return Err(serde::de::Error::invalid_length(i, &self));
                    }
                }
                Ok(Page(items))
            }
        }
        deserializer.deserialize_tuple(128, PageVisitor)
    }
}

#[derive(Serialize, Deserialize, Debug)]
pub struct PageMap {
    pages: Vec<Option<Box<Page>>>,
}
impl PageMap {
    pub fn new() -> Self {
        Self { pages: Vec::new() }
    }
    #[inline]
    pub fn insert(&mut self, entity_id: usize, dense_id: usize) {
        let page_id = entity_id / 128;
        let local_id = entity_id % 128;
        if page_id >= self.pages.len() {
            self.pages.resize(page_id + 1, None);
        }
        if self.pages[page_id].is_none() {
            self.pages[page_id] = Some(Box::new(Page([None; 128])));
        }
        self.pages[page_id].as_mut().unwrap().0[local_id] = Some(dense_id);
    }
    #[inline]
    pub fn get(&self, entity_id: usize) -> Option<usize> {
        let page_id = entity_id / 128;
        let local_id = entity_id % 128;
        self.pages
            .get(page_id)
            .and_then(|page_opt| page_opt.as_ref())
            .and_then(|page| page.0[local_id])
    }
}

pub trait ComponentStorage {
    fn as_any(&self) -> &dyn std::any::Any;
    fn as_any_mut(&mut self) -> &mut dyn std::any::Any;
    fn serialize(&self) -> Result<Vec<u8>, postcard::Error>;
    fn type_name(&self) -> &'static str;
}

pub struct ComponentPool<T> {
    pub dense_data: Vec<T>,
    pub dense_entities: Vec<EntityID>,
    pub sparse_map: PageMap,
}

impl<T: 'static + serde::Serialize + for<'de> serde::Deserialize<'de>> ComponentStorage
    for ComponentPool<T>
{
    fn as_any(&self) -> &dyn std::any::Any {
        self
    }
    fn as_any_mut(&mut self) -> &mut dyn std::any::Any {
        self
    }
    fn serialize(&self) -> Result<Vec<u8>, postcard::Error> {
        postcard::to_allocvec(&(&self.sparse_map, &self.dense_entities, &self.dense_data))
    }
    fn type_name(&self) -> &'static str {
        std::any::type_name::<T>()
    }
}

impl<T: for<'de> serde::Deserialize<'de>> ComponentPool<T> {
    pub fn deserialize(bytes: &[u8]) -> Result<Self, postcard::Error> {
        let (sparse_map, dense_entities, dense_data): (PageMap, Vec<EntityID>, Vec<T>) =
            postcard::from_bytes(bytes)?;

        Ok(Self {
            dense_data,
            dense_entities,
            sparse_map,
        })
    }
}

impl<T> ComponentPool<T> {
    pub fn iter_entities(&self) -> impl Iterator<Item = (EntityID, &T)> {
        self.dense_entities
            .iter()
            .copied()
            .zip(self.dense_data.iter())
    }
    pub fn iter_entities_mut(&mut self) -> impl Iterator<Item = (EntityID, &mut T)> {
        self.dense_entities
            .iter()
            .copied()
            .zip(self.dense_data.iter_mut())
    }
}