use isonebased in similar(::Type{<:AbstractArray}, ax...)

Author: jishnub

src/OffsetArrays.jl

@@ -327,30 +327,25 @@ to ensure that the axis offset is ignored, for example in `similar`.
 isonebased(_) = false
 isonebased(::Integer) = true
 isonebased(::Base.OneTo) = true
-isonebased(::IIUR{<:Base.OneTo}) = true
-
-to_length(i::Integer) = i
-to_length(i::AbstractUnitRange) = length(i)
+isonebased(r::IIUR) = isonebased(r.indices)
 
 # Since the following is committing type-piracy, we provide an opt-out mechanism to the users
 function Base.similar(A::AbstractArray, ::Type{T}, shape::Tuple{OffsetAxisKnownLength,Vararg{OffsetAxisKnownLength}}) where T
-    if all(isonebased, shape)
-        return similar(A, T, map(to_length, shape))
-    else
-        # strip IdOffsetRanges to extract the parent range and use it to generate the array
-        new_shape = map(_strip_IdOffsetRange, shape)
-        # route through _similar_axes_or_length to avoid a stack overflow if map(_strip_IdOffsetRange, shape) === shape
-        # This tries to use new_shape directly in similar if similar(A, T, ::typeof(new_shape)) is defined
-        # If this fails, it calls similar(A, T, map(_indexlength, new_shape)) to use the size along each axis
-        # to generate the new array
-        P = _similar_axes_or_length(A, T, new_shape, shape)
-        return OffsetArray(P, map(_offset, axes(P), shape))
-    end
+    # strip IdOffsetRanges to extract the parent range and use it to generate the array
+    new_shape = map(_strip_IdOffsetRange, shape)
+    # route through _similar_axes_or_length to avoid a stack overflow if map(_strip_IdOffsetRange, shape) === shape
+    # This tries to use new_shape directly in similar if similar(A, T, ::typeof(new_shape)) is defined
+    # If this fails, it calls similar(A, T, map(_indexlength, new_shape)) to use the size along each axis
+    # to generate the new array
+    P = _similar_axes_or_length(A, T, new_shape, shape)
+    all(isonebased, shape) && return P
+    return OffsetArray(P, map(_offset, axes(P), shape))
 end
 Base.similar(::Type{A}, sz::Tuple{Vararg{Int}}) where {A<:OffsetArray} = similar(Array{eltype(A)}, sz)
 function Base.similar(::Type{T}, shape::Tuple{OffsetAxisKnownLength,Vararg{OffsetAxisKnownLength}}) where {T<:AbstractArray}
     new_shape = map(_strip_IdOffsetRange, shape)
     P = _similar_axes_or_length(T, new_shape, shape)
+    all(isonebased, shape) && return P
     OffsetArray(P, map(_offset, axes(P), shape))
 end
 # Try to use the axes to generate the parent array type