Forward length to parent (#304)

* forward length to parent

* version bump to v1.12.6

Author: jishnub

Project.toml

@@ -1,6 +1,6 @@
 name = "OffsetArrays"
 uuid = "6fe1bfb0-de20-5000-8ca7-80f57d26f881"
-version = "1.12.5"
+version = "1.12.6"
 
 [deps]
 Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"

src/OffsetArrays.jl

@@ -287,6 +287,10 @@ Base.parent(A::OffsetArray) = A.parent
 # Base.Broadcast.BroadcastStyle(::Type{<:OffsetArray{<:Any, <:Any, AA}}) where AA = Base.Broadcast.BroadcastStyle(AA)
 
 @inline Base.size(A::OffsetArray) = size(parent(A))
+# specializing length isn't necessary, as length(A) = prod(size(A)),
+# but specializing length enables constant-propagation for statically sized arrays
+# see https://github.com/JuliaArrays/OffsetArrays.jl/pull/304
+@inline Base.length(A::OffsetArray) = length(parent(A))
 
 @inline Base.axes(A::OffsetArray) = map(IdOffsetRange, axes(parent(A)), A.offsets)
 @inline Base.axes(A::OffsetArray, d) = d <= ndims(A) ? IdOffsetRange(axes(parent(A), d), A.offsets[d]) : IdOffsetRange(axes(parent(A), d))

test/runtests.jl

@@ -907,6 +907,18 @@ Base.Int(a::WeirdInteger) = a
             @test axes(y) == (r, )
         end
     end
+
+    @testset "size/length" begin
+        for p in Any[SA[1,2,3,4], 1:4, [1:4;]]
+            for A in Any[OffsetArray(p, 4),
+                    OffsetArray(reshape(p, 2, 2), 3, 4),
+                    OffsetArray(reshape(p, 2, 1, 2), 3, 0, 4),
+                    OffsetArray(reshape(p, Val(1)), 2)]
+                @test size(A) == size(parent(A))
+                @test length(A) == length(parent(A))
+            end
+        end
+    end
 end
 
 @testset "Axes supplied to constructor correspond to final result" begin