loose eltype when fillvalue is nothing or missing (#24)

loose eltype for nothing and missing
JuliaArrays · Mar 9, 2020 · 244f397 · 244f397
1 parent 1762776
commit 244f397
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Showing 2 changed files with 59 additions and 5 deletions.
diff --git a/src/PaddedViews.jl b/src/PaddedViews.jl
@@ -76,19 +76,23 @@ struct PaddedView{T,N,I,A} <: AbstractArray{T,N}
     data::A
     indices::I
 
-    function PaddedView{T,N,I,A}(fillvalue::T,
-                                 data::AbstractArray{T,N},
+    function PaddedView{T,N,I,A}(fillvalue,
+                                 data,
                                  indices::NTuple{N,AbstractUnitRange}) where {T,N,I,A}
+        ndims(data) == N || throw(DimensionMismatch("data and indices should have the same dimension, instead they're $(ndims(data)) and $N."))
         new{T,N,I,A}(fillvalue, data, indices)
     end
 end
 
-PaddedView(fillvalue, data::AbstractArray{T,N}, indices) where {T,N} =
-    PaddedView{T,N,typeof(indices),typeof(data)}(convert(T, fillvalue), data, indices)
+function PaddedView(fillvalue, data::AbstractArray{T,N}, indices) where {T,N}
+    _T = fillvalue isa Union{Missing, Nothing} ? Union{typeof(fillvalue), T} : T
+    PaddedView{_T,N,typeof(indices),typeof(data)}(convert(_T, fillvalue), data, indices)
+end
 
 function PaddedView(fillvalue, data::AbstractArray{T,N}, sz::Tuple{Integer,Vararg{Integer}}) where {T,N}
     inds = map(OneTo, sz)
-    PaddedView{T,N,typeof(inds),typeof(data)}(convert(T, fillvalue), data, inds)
+    _T = fillvalue isa Union{Missing, Nothing} ? Union{typeof(fillvalue), T} : T
+    PaddedView{_T,N,typeof(inds),typeof(data)}(convert(_T, fillvalue), data, inds)
 end
 
 # This method eliminates an ambiguity between the two below it

diff --git a/test/runtests.jl b/test/runtests.jl
@@ -165,3 +165,53 @@ end
     str = String(take!(io))
     @test endswith(str, "PaddedView(-1, ::Array{$Int,2}, (0:4, 1:3)) with eltype $Int with indices 0:4×1:3:\n -1  -1  -1\n  1   4   7\n  2   5   8\n  3   6   9\n -1  -1  -1")
 end
+
+@testset "similar" begin
+    for (T, v) in ((Int, 0),
+                   (Int, 0.),
+                   (Float64, 0.),
+                   (Missing, missing),
+                   (Nothing, nothing))
+        A = reshape(1:9, 3, 3)
+        Ap = @inferred(PaddedView(v, A, (0:4, 0:4)))
+        B = similar(Ap)
+        @test eltype(B) == eltype(Ap)
+        @test size(B) == size(Ap)
+        @test axes(B) == axes(Ap)
+
+        B = similar(Ap, (4, 4))
+        @test eltype(B) == eltype(Ap)
+        @test size(B) == (4, 4)
+        @test axes(B) == (Base.OneTo(4), Base.OneTo(4))
+
+        B = similar(Ap, (4, 4))
+        @test eltype(B) == eltype(Ap)
+        @test size(B) == (4, 4)
+        @test axes(B) == (Base.OneTo(4), Base.OneTo(4))
+
+        B = similar(Ap, Int, (4, 4))
+        @test eltype(B) == Int
+        @test size(B) == (4, 4)
+        @test axes(B) == (Base.OneTo(4), Base.OneTo(4))
+    end
+end
+
+@testset "nothing/missing" begin
+    for (T, v) in ((Missing, missing),
+                 (Nothing, nothing))
+        A = reshape(1:9, 3, 3)
+        Ap = @inferred(PaddedView(v, A, (0:4, 0:4)))
+        @test axes(Ap) == (OffsetArrays.IdOffsetRange(0:4), OffsetArrays.IdOffsetRange(0:4))
+        @test eltype(Ap) === Union{T, eltype(A)}
+        @test Ap[0, 0] === v
+        @test Ap[1, 1] === 1
+        @test Ap[axes(A)...] == A
+
+        Ap = @inferred(PaddedView(v, A, (5, 5)))
+        @test axes(Ap) === (Base.OneTo(5), Base.OneTo(5))
+        @test eltype(Ap) === Union{T, eltype(A)}
+        @test Ap[4, 4] === v
+        @test Ap[1, 1] === 1
+        @test Ap[axes(A)...] == A
+    end
+end