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-rw-r--r--vendor/generic-array-0.12.4/src/sequence.rs320
1 files changed, 320 insertions, 0 deletions
diff --git a/vendor/generic-array-0.12.4/src/sequence.rs b/vendor/generic-array-0.12.4/src/sequence.rs
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+//! Useful traits for manipulating sequences of data stored in `GenericArray`s
+
+use super::*;
+use core::{mem, ptr};
+use core::ops::{Add, Sub};
+use typenum::operator_aliases::*;
+
+/// Defines some sequence with an associated length and iteration capabilities.
+///
+/// This is useful for passing N-length generic arrays as generics.
+pub unsafe trait GenericSequence<T>: Sized + IntoIterator {
+ /// `GenericArray` associated length
+ type Length: ArrayLength<T>;
+
+ /// Concrete sequence type used in conjuction with reference implementations of `GenericSequence`
+ type Sequence: GenericSequence<T, Length = Self::Length> + FromIterator<T>;
+
+ /// Initializes a new sequence instance using the given function.
+ ///
+ /// If the generator function panics while initializing the sequence,
+ /// any already initialized elements will be dropped.
+ fn generate<F>(f: F) -> Self::Sequence
+ where
+ F: FnMut(usize) -> T;
+
+ #[doc(hidden)]
+ fn inverted_zip<B, U, F>(
+ self,
+ lhs: GenericArray<B, Self::Length>,
+ mut f: F,
+ ) -> MappedSequence<GenericArray<B, Self::Length>, B, U>
+ where
+ GenericArray<B, Self::Length>: GenericSequence<B, Length = Self::Length>
+ + MappedGenericSequence<B, U>,
+ Self: MappedGenericSequence<T, U>,
+ Self::Length: ArrayLength<B> + ArrayLength<U>,
+ F: FnMut(B, Self::Item) -> U,
+ {
+ unsafe {
+ let mut left = ArrayConsumer::new(lhs);
+
+ let (left_array_iter, left_position) = left.iter_position();
+
+ FromIterator::from_iter(
+ left_array_iter
+ .zip(self.into_iter())
+ .map(|(l, right_value)| {
+ let left_value = ptr::read(l);
+
+ *left_position += 1;
+
+ f(left_value, right_value)
+ })
+ )
+ }
+ }
+
+ #[doc(hidden)]
+ fn inverted_zip2<B, Lhs, U, F>(self, lhs: Lhs, mut f: F) -> MappedSequence<Lhs, B, U>
+ where
+ Lhs: GenericSequence<B, Length = Self::Length> + MappedGenericSequence<B, U>,
+ Self: MappedGenericSequence<T, U>,
+ Self::Length: ArrayLength<B> + ArrayLength<U>,
+ F: FnMut(Lhs::Item, Self::Item) -> U,
+ {
+ FromIterator::from_iter(lhs.into_iter().zip(self.into_iter()).map(|(l, r)| f(l, r)))
+ }
+}
+
+/// Accessor for `GenericSequence` item type, which is really `IntoIterator::Item`
+///
+/// For deeply nested generic mapped sequence types, like shown in `tests/generics.rs`,
+/// this can be useful for keeping things organized.
+pub type SequenceItem<T> = <T as IntoIterator>::Item;
+
+unsafe impl<'a, T: 'a, S: GenericSequence<T>> GenericSequence<T> for &'a S
+where
+ &'a S: IntoIterator,
+{
+ type Length = S::Length;
+ type Sequence = S::Sequence;
+
+ #[inline]
+ fn generate<F>(f: F) -> Self::Sequence
+ where
+ F: FnMut(usize) -> T,
+ {
+ S::generate(f)
+ }
+}
+
+unsafe impl<'a, T: 'a, S: GenericSequence<T>> GenericSequence<T> for &'a mut S
+where
+ &'a mut S: IntoIterator,
+{
+ type Length = S::Length;
+ type Sequence = S::Sequence;
+
+ #[inline]
+ fn generate<F>(f: F) -> Self::Sequence
+ where
+ F: FnMut(usize) -> T,
+ {
+ S::generate(f)
+ }
+}
+
+/// Defines any `GenericSequence` which can be lengthened or extended by appending
+/// or prepending an element to it.
+///
+/// Any lengthened sequence can be shortened back to the original using `pop_front` or `pop_back`
+pub unsafe trait Lengthen<T>: Sized + GenericSequence<T> {
+ /// `GenericSequence` that has one more element than `Self`
+ type Longer: Shorten<T, Shorter = Self>;
+
+ /// Returns a new array with the given element appended to the end of it.
+ ///
+ /// Example:
+ ///
+ /// ```ignore
+ /// let a = arr![i32; 1, 2, 3];
+ ///
+ /// let b = a.append(4);
+ ///
+ /// assert_eq!(b, arr![i32; 1, 2, 3, 4]);
+ /// ```
+ fn append(self, last: T) -> Self::Longer;
+
+ /// Returns a new array with the given element prepended to the front of it.
+ ///
+ /// Example:
+ ///
+ /// ```ignore
+ /// let a = arr![i32; 1, 2, 3];
+ ///
+ /// let b = a.prepend(4);
+ ///
+ /// assert_eq!(b, arr![i32; 4, 1, 2, 3]);
+ /// ```
+ fn prepend(self, first: T) -> Self::Longer;
+}
+
+/// Defines a `GenericSequence` which can be shortened by removing the first or last element from it.
+///
+/// Additionally, any shortened sequence can be lengthened by
+/// appending or prepending an element to it.
+pub unsafe trait Shorten<T>: Sized + GenericSequence<T> {
+ /// `GenericSequence` that has one less element than `Self`
+ type Shorter: Lengthen<T, Longer = Self>;
+
+ /// Returns a new array without the last element, and the last element.
+ ///
+ /// Example:
+ ///
+ /// ```ignore
+ /// let a = arr![i32; 1, 2, 3, 4];
+ ///
+ /// let (init, last) = a.pop_back();
+ ///
+ /// assert_eq!(init, arr![i32; 1, 2, 3]);
+ /// assert_eq!(last, 4);
+ /// ```
+ fn pop_back(self) -> (Self::Shorter, T);
+
+ /// Returns a new array without the first element, and the first element.
+ /// Example:
+ ///
+ /// ```ignore
+ /// let a = arr![i32; 1, 2, 3, 4];
+ ///
+ /// let (head, tail) = a.pop_front();
+ ///
+ /// assert_eq!(head, 1);
+ /// assert_eq!(tail, arr![i32; 2, 3, 4]);
+ /// ```
+ fn pop_front(self) -> (T, Self::Shorter);
+}
+
+unsafe impl<T, N: ArrayLength<T>> Lengthen<T> for GenericArray<T, N>
+where
+ N: Add<B1>,
+ Add1<N>: ArrayLength<T>,
+ Add1<N>: Sub<B1, Output = N>,
+ Sub1<Add1<N>>: ArrayLength<T>,
+{
+ type Longer = GenericArray<T, Add1<N>>;
+
+ fn append(self, last: T) -> Self::Longer {
+ let mut longer: Self::Longer = unsafe { mem::uninitialized() };
+
+ unsafe {
+ ptr::write(longer.as_mut_ptr() as *mut _, self);
+ ptr::write(&mut longer[N::to_usize()], last);
+ }
+
+ longer
+ }
+
+ fn prepend(self, first: T) -> Self::Longer {
+ let mut longer: Self::Longer = unsafe { mem::uninitialized() };
+
+ let longer_ptr = longer.as_mut_ptr();
+
+ unsafe {
+ ptr::write(longer_ptr as *mut _, first);
+ ptr::write(longer_ptr.offset(1) as *mut _, self);
+ }
+
+ longer
+ }
+}
+
+unsafe impl<T, N: ArrayLength<T>> Shorten<T> for GenericArray<T, N>
+where
+ N: Sub<B1>,
+ Sub1<N>: ArrayLength<T>,
+ Sub1<N>: Add<B1, Output = N>,
+ Add1<Sub1<N>>: ArrayLength<T>,
+{
+ type Shorter = GenericArray<T, Sub1<N>>;
+
+ fn pop_back(self) -> (Self::Shorter, T) {
+ let init_ptr = self.as_ptr();
+ let last_ptr = unsafe { init_ptr.offset(Sub1::<N>::to_usize() as isize) };
+
+ let init = unsafe { ptr::read(init_ptr as _) };
+ let last = unsafe { ptr::read(last_ptr as _) };
+
+ mem::forget(self);
+
+ (init, last)
+ }
+
+ fn pop_front(self) -> (T, Self::Shorter) {
+ let head_ptr = self.as_ptr();
+ let tail_ptr = unsafe { head_ptr.offset(1) };
+
+ let head = unsafe { ptr::read(head_ptr as _) };
+ let tail = unsafe { ptr::read(tail_ptr as _) };
+
+ mem::forget(self);
+
+ (head, tail)
+ }
+}
+
+/// Defines a `GenericSequence` that can be split into two parts at a given pivot index.
+pub unsafe trait Split<T, K>: GenericSequence<T>
+where
+ K: ArrayLength<T>,
+{
+ /// First part of the resulting split array
+ type First: GenericSequence<T>;
+ /// Second part of the resulting split array
+ type Second: GenericSequence<T>;
+
+ /// Splits an array at the given index, returning the separate parts of the array.
+ fn split(self) -> (Self::First, Self::Second);
+}
+
+unsafe impl<T, N, K> Split<T, K> for GenericArray<T, N>
+where
+ N: ArrayLength<T>,
+ K: ArrayLength<T>,
+ N: Sub<K>,
+ Diff<N, K>: ArrayLength<T>,
+{
+ type First = GenericArray<T, K>;
+ type Second = GenericArray<T, Diff<N, K>>;
+
+ fn split(self) -> (Self::First, Self::Second) {
+ let head_ptr = self.as_ptr();
+ let tail_ptr = unsafe { head_ptr.offset(K::to_usize() as isize) };
+
+ let head = unsafe { ptr::read(head_ptr as _) };
+ let tail = unsafe { ptr::read(tail_ptr as _) };
+
+ mem::forget(self);
+
+ (head, tail)
+ }
+}
+
+/// Defines `GenericSequence`s which can be joined together, forming a larger array.
+pub unsafe trait Concat<T, M>: GenericSequence<T>
+where
+ M: ArrayLength<T>,
+{
+ /// Sequence to be concatenated with `self`
+ type Rest: GenericSequence<T, Length = M>;
+
+ /// Resulting sequence formed by the concatenation.
+ type Output: GenericSequence<T>;
+
+ /// Concatenate, or join, two sequences.
+ fn concat(self, rest: Self::Rest) -> Self::Output;
+}
+
+unsafe impl<T, N, M> Concat<T, M> for GenericArray<T, N>
+where
+ N: ArrayLength<T> + Add<M>,
+ M: ArrayLength<T>,
+ Sum<N, M>: ArrayLength<T>,
+{
+ type Rest = GenericArray<T, M>;
+ type Output = GenericArray<T, Sum<N, M>>;
+
+ fn concat(self, rest: Self::Rest) -> Self::Output {
+ let mut output: Self::Output = unsafe { mem::uninitialized() };
+
+ let output_ptr = output.as_mut_ptr();
+
+ unsafe {
+ ptr::write(output_ptr as *mut _, self);
+ ptr::write(output_ptr.offset(N::to_usize() as isize) as *mut _, rest);
+ }
+
+ output
+ }
+}
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