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
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164

use std::any::{Any, TypeId};

use polymap::PolyMap;

/// A container for values of varying types.
///
/// Values contained in a `TypeMap` are stored uniquely according to their type.
/// This means that, for each possible type, only one value may be stored in
/// a single `TypeMap` instance.
///
/// If you would like to store multiple values of a given type, mapped to
/// individual keys, use [`PolyMap`](../polymap/struct.PolyMap.html).
///
/// # Example
///
/// ```
/// use polymap::TypeMap;
///
/// let mut map = TypeMap::new();
///
/// // Stores a `&str` value
/// map.insert("Hello, world!");
///
/// // Stores an `i32` value
/// map.insert(123);
///
/// // Gets a reference to the stored value
/// let &foo: &&str = map.get().unwrap();
/// assert_eq!(foo, "Hello, world!");
///
/// let &bar: &i32 = map.get().unwrap();
/// assert_eq!(bar, 123);
/// ```
///
/// # Notes
///
/// Values are stored in an internal buffer that is reallocated when filled.
/// Methods `reserve_data`, `reserve_data_exact`, and constructor `with_capacity`
/// can be used to reserve a larger buffer ahead of time to prevent expensive
/// reallocation and move operations.
#[derive(Default)]
pub struct TypeMap {
    map: PolyMap<TypeId>,
}

impl TypeMap {
    /// Constructs a new `TypeMap`.
    pub fn new() -> TypeMap {
        TypeMap{map: PolyMap::new()}
    }

    /// Constructs a new `PolyMap` with space reserved for `n` fields
    /// and `size` bytes of data.
    pub fn with_capacity(n: usize, size: usize) -> TypeMap {
        TypeMap{map: PolyMap::with_capacity(n, size)}
    }

    /// Removes all key-value pairs from the map, calling any destructors on
    /// stored values.
    pub fn clear(&mut self) {
        self.map.clear();
    }

    /// Returns whether the map contains a value of the given type.
    pub fn contains<T: Any>(&self) -> bool {
        self.map.contains_key(&TypeId::of::<T>())
    }

    /// Returns the capacity, in bytes, of the internal data buffer.
    pub fn data_capacity(&self) -> usize {
        self.map.data_capacity()
    }

    /// Returns the size, in bytes, of the internal data buffer.
    pub fn data_size(&self) -> usize {
        self.map.data_size()
    }

    /// Returns a reference to the value of the given type.
    ///
    /// If no value of the given type exists, `None` is returned.
    pub fn get<T: Any>(&self) -> Option<&T> {
        self.map.get(&TypeId::of::<T>())
    }

    /// Returns a mutable reference to the value of the given type.
    ///
    /// If no value of the given type exists, `None` is returned.
    pub fn get_mut<T: Any>(&mut self) -> Option<&mut T> {
        self.map.get_mut(&TypeId::of::<T>())
    }

    /// Inserts a value into the map. If a value of the same type is
    /// already present, that value is returned. Otherwise, `None` is returned.
    pub fn insert<T: Any>(&mut self, t: T) -> Option<T> {
        self.map.insert(TypeId::of::<T>(), t)
    }

    /// Returns the number of elements in the map.
    pub fn len(&self) -> usize {
        self.map.len()
    }

    /// Removes a value of the given type from the map, returning it.
    /// If no value of the type exists, `None` is returned.
    pub fn remove<T: Any>(&mut self) -> Option<T> {
        self.map.remove(&TypeId::of::<T>())
    }

    /// Reserves capacity for at least `additional` additional bytes of storage
    /// space within the internal data buffer.
    pub fn reserve_data(&mut self, additional: usize) {
        self.map.reserve_data(additional);
    }

    /// Reserves space for at least `n` bytes in the internal data buffer.
    /// Does nothing if the capacity is already sufficient.
    pub fn reserve_data_exact(&mut self, additional: usize) {
        self.map.reserve_data_exact(additional);
    }

    /// Reserves capacity for at least `additional` additional fields.
    pub fn reserve_fields(&mut self, additional: usize) {
        self.map.reserve_fields(additional);
    }

    /// Reserves space for at least `n` fields.
    /// Does nothing if the capacity is already sufficient.
    pub fn reserve_fields_exact(&mut self, additional: usize) {
        self.map.reserve_fields_exact(additional);
    }

    /// Shrinks the internal data buffer as close as possible to the size of
    /// the currently contained elements.
    pub fn shrink_data_to_fit(&mut self) {
        self.map.shrink_data_to_fit();
    }
}

#[cfg(test)]
mod test {
    use super::TypeMap;

    #[derive(Debug, Eq, PartialEq)]
    struct Foo {
        a: i32,
        b: i32,
    }

    #[test]
    fn test_typemap() {
        let mut m = TypeMap::new();

        m.insert(123);
        m.insert(456_u32);
        m.insert("foo");
        m.insert(Foo{a: 1, b: 2});

        assert_eq!(m.get::<i32>(), Some(&123));
        assert_eq!(m.get::<u32>(), Some(&456));
        assert_eq!(m.get::<&str>(), Some(&"foo"));
        assert_eq!(m.get::<Foo>(), Some(&Foo{a: 1, b: 2}));
    }
}