Generalize strides for ReshapedArray

Generalize `strides` for `ReshapedArray`

base/reinterpretarray.jl

@@ -175,6 +175,8 @@ function _checked_strides(stp, N)
  map(first, drs)
 end
 
+_checkcontiguous(::Type{Bool}, A::ReinterpretArray) = _checkcontiguous(parent(A))
+
 similar(a::ReinterpretArray, T::Type, d::Dims) = similar(a.parent, T, d)
 
 function check_readable(a::ReinterpretArray{T, N, S} where N) where {T,S}

base/reshapedarray.jl

@@ -292,3 +292,16 @@ substrides(strds::NTuple{N,Int}, I::Tuple{ReshapedUnitRange, Vararg{Any}}) where
  (size_to_strides(strds[1], size(I[1])...)..., substrides(tail(strds), tail(I))...)
 unsafe_convert(::Type{Ptr{T}}, V::SubArray{T,N,P,<:Tuple{Vararg{Union{RangeIndex,ReshapedUnitRange}}}}) where {T,N,P} =
  unsafe_convert(Ptr{T}, V.parent) + (first_index(V)-1)*sizeof(T)
+
+
+_checkcontiguous(::Type{Bool}, A::AbstractArray) = size_to_strides(1, size(A)...) == strides(A)
+_checkcontiguous(::Type{Bool}, A::DenseArray) = true
+_checkcontiguous(::Type{Bool}, A::ReshapedArray) = _checkcontiguous(Bool, parent(A))
+_checkcontiguous(::Type{Bool}, A::FastContiguousSubArray) = _checkcontiguous(Bool, parent(A))
+
+function strides(a::ReshapedArray)
+ # We can handle non-contiguous parent if it's a StridedVector
+ ndims(parent(a)) == 1 && return size_to_strides(only(strides(parent(a))), size(a)...)
+ _checkcontiguous(Bool, a) || throw(ArgumentError("Parent must be contiguous."))
+ size_to_strides(1, size(a)...)
+end

test/abstractarray.jl

@@ -1561,3 +1561,10 @@ end
  r = Base.IdentityUnitRange(3:4)
  @test reshape(r, :) === reshape(r, (:,)) === r
 end
+
+@testset "strides for ReshapedArray" begin
+ a = reshape(view(collect(1:100), 1:2:100), 5, 10)
+ @test strides(a) == (2, 10)
+ a = reshape(view(collect(1:100), 1:2:100, 1:1), 5, 10)
+ @test_throws ArgumentError strides(a)
+end