exr/image/
recursive.rs

1//! A generic wrapper which can be used to represent recursive types.
2//! Supports conversion from and to tuples of the same size.
3
4/// No more recursion. Can be used within any `Recursive<NoneMore, YourValue>` type.
5#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
6pub struct NoneMore;
7
8/// A recursive type-level linked list of `Value` entries.
9/// Mainly used to represent an arbitrary number of channels.
10/// The recursive architecture removes the need to implement traits for many different tuples.
11#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
12pub struct Recursive<Inner, Value> {
13    /// The remaining values of this linked list,
14    /// probably either `NoneMore` or another instance of the same `Recursive<Inner - 1, Value>`.
15    pub inner: Inner,
16
17    /// The next item in this linked list.
18    pub value: Value,
19}
20
21impl<Inner, Value> Recursive<Inner, Value> {
22    /// Create a new recursive type. Equivalent to the manual constructor, but less verbose.
23    pub fn new(inner: Inner, value: Value) -> Self { Self { inner, value } }
24}
25
26/// Convert this recursive type into a tuple.
27/// This is nice as it will require less typing for the same type.
28/// A type might or might not be convertible to the specified `Tuple` type.
29pub trait IntoTuple<Tuple> {
30    /// Convert this recursive type to a nice tuple.
31    fn into_tuple(self) -> Tuple;
32}
33
34/// Convert this recursive type into a tuple.
35/// This is nice as it will require less typing for the same type.
36/// A type will be converted to the specified `Self::NonRecursive` type.
37pub trait IntoNonRecursive {
38    /// The resulting tuple type.
39    type NonRecursive;
40
41    /// Convert this recursive type to a nice tuple.
42    fn into_non_recursive(self) -> Self::NonRecursive;
43}
44
45/// Create a recursive type from this tuple.
46pub trait IntoRecursive {
47    /// The recursive type resulting from this tuple.
48    type Recursive;
49
50    /// Create a recursive type from this tuple.
51    fn into_recursive(self) -> Self::Recursive;
52}
53
54impl IntoRecursive for NoneMore {
55    type Recursive = Self;
56    fn into_recursive(self) -> Self::Recursive { self }
57}
58
59impl<Inner: IntoRecursive, Value> IntoRecursive for Recursive<Inner, Value> {
60    type Recursive = Recursive<Inner::Recursive, Value>;
61    fn into_recursive(self) -> Self::Recursive { Recursive::new(self.inner.into_recursive(), self.value) }
62}
63
64// Automatically implement IntoTuple so we have to generate less code in the macros
65impl<I: IntoNonRecursive> IntoTuple<I::NonRecursive> for I {
66    fn into_tuple(self) -> <I as IntoNonRecursive>::NonRecursive {
67        self.into_non_recursive()
68    }
69}
70
71//Implement traits for the empty tuple, the macro doesn't handle that
72impl IntoRecursive for () {
73    type Recursive = NoneMore;
74    fn into_recursive(self) -> Self::Recursive { NoneMore }
75}
76
77impl IntoNonRecursive for NoneMore {
78    type NonRecursive = ();
79
80    fn into_non_recursive(self) -> Self::NonRecursive {
81        ()
82    }
83}
84
85/// Generates the recursive type corresponding to this tuple:
86/// ```nocheck
87/// gen_recursive_type!(A, B, C)
88/// => Recursive<Recursive<Recursive<NoneMore, A>, B>, C>
89/// ```
90macro_rules! gen_recursive_type {
91    () => { NoneMore };
92    ($last:ident $(,$not_last:ident)*) => {
93        Recursive<gen_recursive_type!($($not_last),*), $last>
94    };
95}
96
97/// Generates the recursive value corresponding to the given indices:
98/// ```nocheck
99/// gen_recursive_value(self; 1, 0)
100/// => Recursive { inner: Recursive {  inner: NoneMore, value: self.0 }, value: self.1 }
101/// ```
102macro_rules! gen_recursive_value {
103    ($self:ident;) => { NoneMore };
104    ($self:ident; $last:tt $(,$not_last:tt)*) => {
105        Recursive { inner: gen_recursive_value!($self; $($not_last),*), value: $self.$last }
106    };
107}
108
109/// Generates the into_tuple value corresponding to the given type names:
110/// ```nocheck
111/// gen_tuple_value(self; A, B, C)
112/// => (self.inner.inner.value, self.inner.value, self.value)
113/// ```
114macro_rules! gen_tuple_value {
115    ($self:ident; $($all:ident),* ) => {
116        gen_tuple_value!(@ $self; (); $($all),*  )
117    };
118
119    (@ $self:ident; ($($state:expr),*);) => { ($($state .value,)*) };
120    (@ $self:ident; ($($state:expr),*); $last:ident $(,$not_last:ident)* ) => {
121        gen_tuple_value!(@ $self; ($($state .inner,)* $self); $($not_last),*  )
122    };
123}
124
125/// Generate the trait implementations given a sequence of type names in both directions and the indices backwards:
126/// ```nocheck
127/// generate_single(A, B, C; C, B, A; 2, 1, 0)
128/// ```
129macro_rules! generate_single {
130    ( $($name_fwd:ident),* ; $($name_back:ident),* ; $($index_back:tt),*) => {
131        impl<$($name_fwd),*> IntoNonRecursive for gen_recursive_type!($($name_back),*) {
132            type NonRecursive = ($($name_fwd,)*);
133            fn into_non_recursive(self) -> Self::NonRecursive {
134                gen_tuple_value!(self; $($name_fwd),*)
135            }
136        }
137
138        impl<$($name_fwd),*> IntoRecursive for ($($name_fwd,)*) {
139            type Recursive = gen_recursive_type!($($name_back),*);
140            fn into_recursive(self) -> Self::Recursive {
141                gen_recursive_value!(self; $($index_back),*)
142            }
143        }
144    };
145}
146
147generate_single!(A; A; 0);
148generate_single!(A,B; B,A; 1,0);
149generate_single!(A,B,C; C,B,A; 2,1,0);
150generate_single!(A,B,C,D; D,C,B,A; 3,2,1,0);
151generate_single!(A,B,C,D,E; E,D,C,B,A; 4,3,2,1,0);
152generate_single!(A,B,C,D,E,F; F,E,D,C,B,A; 5,4,3,2,1,0);
153generate_single!(A,B,C,D,E,F,G; G,F,E,D,C,B,A; 6,5,4,3,2,1,0);
154generate_single!(A,B,C,D,E,F,G,H; H,G,F,E,D,C,B,A; 7,6,5,4,3,2,1,0);
155generate_single!(A,B,C,D,E,F,G,H,I; I,H,G,F,E,D,C,B,A; 8,7,6,5,4,3,2,1,0);
156generate_single!(A,B,C,D,E,F,G,H,I,J; J,I,H,G,F,E,D,C,B,A; 9,8,7,6,5,4,3,2,1,0);
157generate_single!(A,B,C,D,E,F,G,H,I,J,K; K,J,I,H,G,F,E,D,C,B,A; 10,9,8,7,6,5,4,3,2,1,0);
158generate_single!(A,B,C,D,E,F,G,H,I,J,K,L; L,K,J,I,H,G,F,E,D,C,B,A; 11,10,9,8,7,6,5,4,3,2,1,0);
159generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M; M,L,K,J,I,H,G,F,E,D,C,B,A; 12,11,10,9,8,7,6,5,4,3,2,1,0);
160generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N; N,M,L,K,J,I,H,G,F,E,D,C,B,A; 13,12,11,10,9,8,7,6,5,4,3,2,1,0);
161generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O; O,N,M,L,K,J,I,H,G,F,E,D,C,B,A; 14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
162generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P; P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A; 15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
163generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q; Q,P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A; 16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
164generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R; R,Q,P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A; 17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
165generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S; S,R,Q,P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A; 18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
166generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T; T,S,R,Q,P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A; 19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
167generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U; U,T,S,R,Q,P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A; 20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
168generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V; V,U,T,S,R,Q,P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A; 21,20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
169generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W; W,V,U,T,S,R,Q,P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A; 22,21,20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
170generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X; X,W,V,U,T,S,R,Q,P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A; 23,22,21,20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
171generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y; Y,X,W,V,U,T,S,R,Q,P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A; 24,23,22,21,20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
172generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z; Z,Y,X,W,V,U,T,S,R,Q,P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A; 25,24,23,22,21,20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
173generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,A1; A1,Z,Y,X,W,V,U,T,S,R,Q,P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A; 26,25,24,23,22,21,20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
174generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,A1,B1; B1,A1,Z,Y,X,W,V,U,T,S,R,Q,P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A; 27,26,25,24,23,22,21,20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
175generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,A1,B1,C1; C1,B1,A1,Z,Y,X,W,V,U,T,S,R,Q,P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A; 28,27,26,25,24,23,22,21,20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
176generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,A1,B1,C1,D1; D1,C1,B1,A1,Z,Y,X,W,V,U,T,S,R,Q,P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A; 29,28,27,26,25,24,23,22,21,20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
177generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,A1,B1,C1,D1,E1; E1,D1,C1,B1,A1,Z,Y,X,W,V,U,T,S,R,Q,P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A; 30,29,28,27,26,25,24,23,22,21,20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
178generate_single!(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,A1,B1,C1,D1,E1,F1; F1,E1,D1,C1,B1,A1,Z,Y,X,W,V,U,T,S,R,Q,P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A; 31,30,29,28,27,26,25,24,23,22,21,20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
exr/image/recursive.rs

exr/image/
recursive.rs
