Should the Origin constructor call no_offset_view first?

[jishnub]

This seems to lead to some overflow bugs otherwise, which might be avoided by a more careful offset calculation, or more simply by just calling no_offset_view on the argument before passing it to the constructor.

julia> A = Origin(typemin(Int)+1)(rand(3,3))
3×3 OffsetArray(::Matrix{Float64}, -9223372036854775807:-9223372036854775805, -9223372036854775807:-9223372036854775805) with eltype Float64 with indices -9223372036854775807:-9223372036854775805×-9223372036854775807:-9223372036854775805:
 0.31876   0.827393   0.132595
 0.764406  0.364263   0.83437
 0.733822  0.0985983  0.309434

julia> Origin(typemax(Int)-4)(A)
ERROR: OverflowError: offset should be >= -1 corresponding to the axis OffsetArrays.IdOffsetRange(values=-9223372036854775807:-9223372036854775805, indices=-9223372036854775807:-9223372036854775805), received an offset -6
Stacktrace:
 [1] (::OffsetArrays.var"#throw_lower_overflow_error#8"{OffsetArrays.IdOffsetRange{Int64, Base.OneTo{Int64}}, Int64})(val::Int64)
   @ OffsetArrays ~/.julia/packages/OffsetArrays/N7ji6/src/OffsetArrays.jl:141
 [2] overflow_check
   @ ~/.julia/packages/OffsetArrays/N7ji6/src/OffsetArrays.jl:150 [inlined]
 [3] map
   @ ./tuple.jl:299 [inlined]
 [4] #OffsetArray#14
   @ ~/.julia/packages/OffsetArrays/N7ji6/src/OffsetArrays.jl:182 [inlined]
 [5] #OffsetArray#21
   @ ~/.julia/packages/OffsetArrays/N7ji6/src/OffsetArrays.jl:210 [inlined]
 [6] OffsetArray
   @ ~/.julia/packages/OffsetArrays/N7ji6/src/OffsetArrays.jl:210 [inlined]
 [7] (::Origin{Int64})(A::OffsetMatrix{Float64, Matrix{Float64}})
   @ OffsetArrays ~/.julia/packages/OffsetArrays/N7ji6/src/OffsetArrays.jl:213
 [8] top-level scope
   @ REPL[15]:1

julia> Origin(typemax(Int)-4)(OffsetArrays.no_offset_view(A))
3×3 OffsetArray(::Matrix{Float64}, 9223372036854775803:9223372036854775805, 9223372036854775803:9223372036854775805) with eltype Float64 with indices 9223372036854775803:9223372036854775805×9223372036854775803:9223372036854775805:
 0.31876   0.827393   0.132595
 0.764406  0.364263   0.83437
 0.733822  0.0985983  0.309434

[johnnychen94]

simply by just calling no_offset_view on the argument before passing it to the constructor.

This seems a more reasonable approach to me since we only need to calculate the offset once. In contrast, "a more careful offset calculation" might add an extra if-branch to the innermost getindex call and hurt the overall performance (e.g., disable the SIMD).

[jishnub]

Yes, I'm ok with this. It'll change the return types in some cases, but I guess that's not too concerning. I'll make a PR to see how things go.