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//! An enum mapping type. //! //! It is implemented using an array type, so using it is as fast as using Rust //! arrays. //! //! # Examples //! //! ``` //! #[macro_use] //! extern crate enum_map; //! //! use enum_map::EnumMap; //! //! #[derive(Debug, EnumMap)] //! enum Example { //! A, //! B, //! C, //! } //! //! fn main() { //! let mut map = enum_map! { //! Example::A => 1, //! Example::B => 2, //! Example::C => 3, //! }; //! map[Example::C] = 4; //! //! assert_eq!(map[Example::A], 1); //! //! for (key, &value) in &map { //! println!("{:?} has {} as value.", key, value); //! } //! } //! ``` #![no_std] #![deny(missing_docs)] #[macro_use] extern crate array_macro; // This allows to quiet "proc macro crates and `#[no_link]` crates have no // effect without `#[macro_use]`" warning. Just using extern DOES have // an effect of letting me export the macro. #[allow(unused_imports)] #[macro_use] extern crate enum_map_derive; mod enummap_impls; mod internal; mod iter; mod serde; pub use internal::Internal; pub use iter::{Iter, IterMut}; // `*` here means re-exporting a derive procedural macro. pub use enum_map_derive::*; use core::slice; /// An enum mapping. /// /// This internally uses an array which stores a value for each possible /// enum value. To work, it requires implementation of internal (private, /// although public due to macro limitations) trait which allows extracting /// information about an enum, which can be automatically generated using /// `#[derive(EnumMap)]` from `enum_map_derive` crate. /// /// Additionally, `bool` and `u8` automatically derives from `EnumMap`. While /// `u8` is not technically an enum, it's convenient to consider it like one. /// In particular, [reverse-complement in benchmark game] could be using `u8` /// as an enum. /// /// # Examples /// /// ``` /// #[macro_use] /// extern crate enum_map; /// /// use enum_map::EnumMap; /// /// #[derive(EnumMap)] /// enum Example { /// A, /// B, /// C, /// } /// /// fn main() { /// let mut map = EnumMap::new(); /// // new initializes map with default values /// assert_eq!(map[Example::A], 0); /// map[Example::A] = 3; /// assert_eq!(map[Example::A], 3); /// } /// ``` /// /// [reverse-complement in benchmark game]: /// http://benchmarksgame.alioth.debian.org/u64q/program.php?test=revcomp&lang=rust&id=2 #[derive(Debug)] pub struct EnumMap<K: Internal<V>, V> { array: K::Array, } impl<K: Internal<V>, V: Default> EnumMap<K, V> where K::Array: Default, { /// Creates an enum map with default values. /// /// # Examples /// /// ``` /// #[macro_use] /// extern crate enum_map; /// /// use enum_map::EnumMap; /// /// #[derive(EnumMap)] /// enum Example { /// A, /// } /// /// fn main() { /// let enum_map = EnumMap::<_, i32>::new(); /// assert_eq!(enum_map[Example::A], 0); /// } /// ``` pub fn new() -> Self { EnumMap::default() } } impl<K: Internal<V>, V> EnumMap<K, V> { /// Returns an iterator over enum map. pub fn iter(&self) -> Iter<K, V> { self.into_iter() } /// Returns a mutable iterator over enum map. pub fn iter_mut(&mut self) -> IterMut<K, V> { self.into_iter() } /// Returns number of elements in enum map. pub fn len(&self) -> usize { self.as_slice().len() } /// Returns whether the enum variant set is empty. /// /// This isn't particularly useful, as there is no real reason to use /// enum map for enums without variants. However, it is provided for /// consistency with data structures providing len method (and I will /// admit, to avoid clippy warnings). /// /// # Examples /// /// ``` /// #[macro_use] /// extern crate enum_map; /// /// use enum_map::EnumMap; /// /// #[derive(EnumMap)] /// enum Void {} /// /// #[derive(EnumMap)] /// enum SingleVariant { /// Variant, /// } /// /// fn main() { /// assert_eq!(EnumMap::<Void, ()>::new().is_empty(), true); /// assert_eq!(EnumMap::<SingleVariant, ()>::new().is_empty(), false); /// } pub fn is_empty(&self) -> bool { self.as_slice().is_empty() } /// Swaps two indexes. /// /// # Examples /// /// ``` /// #[macro_use] /// extern crate enum_map; /// /// fn main() { /// let mut map = enum_map! { false => 0, true => 1 }; /// map.swap(false, true); /// assert_eq!(map[false], 1); /// assert_eq!(map[true], 0); /// } /// ``` pub fn swap(&mut self, a: K, b: K) { self.as_mut_slice().swap(a.to_usize(), b.to_usize()) } /// An iterator visiting all values. The iterator type is `&V`. /// /// # Examples /// /// ``` /// #[macro_use] /// extern crate enum_map; /// /// fn main() { /// let map = enum_map! { false => 3, true => 4 }; /// let mut values = map.values(); /// assert_eq!(values.next(), Some(&3)); /// assert_eq!(values.next(), Some(&4)); /// assert_eq!(values.next(), None); /// } /// ``` pub fn values(&self) -> slice::Iter<V> { self.as_slice().iter() } /// Converts an enum map to a slice representing values. pub fn as_slice(&self) -> &[V] { K::slice(&self.array) } /// Converts a mutable enum map to a mutable slice representing values. pub fn as_mut_slice(&mut self) -> &mut [V] { K::slice_mut(&mut self.array) } /// An iterator visiting all values mutably. The iterator type is `&mut V`. /// /// # Examples /// /// ``` /// #[macro_use] /// extern crate enum_map; /// /// fn main() { /// let mut map = enum_map! { _ => 2 }; /// for value in map.values_mut() { /// *value += 2; /// } /// assert_eq!(map[false], 4); /// assert_eq!(map[true], 4); /// } /// ``` pub fn values_mut(&mut self) -> slice::IterMut<V> { self.as_mut_slice().iter_mut() } /// Returns a raw pointer to the enum map's buffer. /// /// The caller must ensure that the slice outlives the pointer this /// function returns, or else it will end up pointing to garbage. /// /// Modifying the container referenced by this slice may cause its buffer /// to be reallocated, which would also make any pointers to it invalid. /// /// # Examples /// /// ``` /// #[macro_use] /// extern crate enum_map; /// /// use enum_map::EnumMap; /// /// fn main() { /// let map = enum_map! { 5 => 42, _ => 0 }; /// assert_eq!(unsafe { *map.as_ptr().offset(5) }, 42); /// } /// ``` pub fn as_ptr(&self) -> *const V { self.as_slice().as_ptr() } /// Returns an unsafe mutable pointer to the enum map's buffer. /// /// The caller must ensure that the slice outlives the pointer this /// function returns, or else it will end up pointing to garbage. /// /// Modifying the container referenced by this slice may cause its buffer /// to be reallocated, which would also make any pointers to it invalid. /// /// # Examples /// /// ``` /// #[macro_use] /// extern crate enum_map; /// /// use enum_map::EnumMap; /// /// fn main() { /// let mut map = enum_map! { _ => 0 }; /// unsafe { /// *map.as_mut_ptr().offset(11) = 23 /// }; /// assert_eq!(map[11], 23); /// } /// ``` pub fn as_mut_ptr(&mut self) -> *mut V { self.as_mut_slice().as_mut_ptr() } } impl<F: FnMut(K) -> V, K: Internal<V>, V> From<F> for EnumMap<K, V> { fn from(f: F) -> Self { EnumMap { array: K::from_function(f) } } } /// Enum map constructor. /// /// This macro allows to create a new enum map in a type safe way. It takes /// a list of `,` separated pairs separated by `=>`. Left side is `|` /// separated list of enum keys, or `_` to match all unmatched enum keys, /// while right side is a value. /// /// # Examples /// /// ``` /// #[macro_use] /// extern crate enum_map; /// /// #[derive(EnumMap)] /// enum Example { /// A, /// B, /// C, /// D, /// } /// /// fn main() { /// let enum_map = enum_map! { /// Example::A | Example::B => 1, /// Example::C => 2, /// _ => 3, /// }; /// assert_eq!(enum_map[Example::A], 1); /// assert_eq!(enum_map[Example::B], 1); /// assert_eq!(enum_map[Example::C], 2); /// assert_eq!(enum_map[Example::D], 3); /// } /// ``` #[macro_export] macro_rules! enum_map { {$($t:tt)*} => { $crate::EnumMap::from(|k| match k { $($t)* }) }; }