add offset overflow check (#144)

* add offset overflow check

* also check negative cases

Author: johnnychen94

src/OffsetArrays.jl

@@ -15,10 +15,21 @@ include("axes.jl")
 struct OffsetArray{T,N,AA<:AbstractArray} <: AbstractArray{T,N}
     parent::AA
     offsets::NTuple{N,Int}
+    function OffsetArray{T, N, AA}(parent::AA, offsets::NTuple{N, Int}) where {T, N, AA<:AbstractArray}
+        overflow_check.(axes(parent), offsets)
+        new{T, N, AA}(parent, offsets)
+    end
 end
 OffsetVector{T,AA<:AbstractArray} = OffsetArray{T,1,AA}
 OffsetMatrix{T,AA<:AbstractArray} = OffsetArray{T,2,AA}
 
+function overflow_check(r, offset::T) where T
+    if offset > 0 && last(r) > typemax(T) - offset
+        throw(ArgumentError("Boundary overflow detected: offset $offset should be equal or less than $(typemax(T) - last(r))"))
+    elseif offset < 0 && first(r) < typemin(T) - offset
+        throw(ArgumentError("Boundary overflow detected: offset $offset should be equal or greater than $(typemin(T) - first(r))"))
+    end
+end
 ## OffsetArray constructors
 
 offset(axparent::AbstractUnitRange, ax::AbstractUnitRange) = first(ax) - first(axparent)

test/runtests.jl

@@ -1,5 +1,6 @@
 using OffsetArrays
 using OffsetArrays: IdentityUnitRange, no_offset_view
+using OffsetArrays: IdOffsetRange
 using Test, Aqua
 using LinearAlgebra
 using DelimitedFiles
@@ -125,6 +126,13 @@ end
     w = zeros(5:6)
     @test OffsetVector(w, :) == OffsetArray(w, (:,)) == OffsetArray(w, :) == OffsetArray(w, axes(w))
     @test axes(OffsetVector(w, :)) == axes(w)
+
+    @test axes(OffsetVector(v, typemax(Int)-length(v))) == (IdOffsetRange(axes(v)[1], typemax(Int)-length(v)), )
+    @test_throws ArgumentError OffsetVector(v, typemax(Int)-length(v)+1)
+    ao = OffsetArray(v, typemin(Int))
+    @test_nowarn OffsetArray{Float64, 1, typeof(ao)}(ao, (-1, ))
+    @test_throws ArgumentError OffsetArray{Float64, 1, typeof(ao)}(ao, (-2, )) # inner Constructor
+    @test_throws ArgumentError OffsetArray(ao, (-2, )) # convinient constructor accumulate offsets
 end
 
 @testset "OffsetMatrix constructors" begin
@@ -158,6 +166,10 @@ end
 
     @test axes(OffsetMatrix(w, :, CartesianIndices((0:1,)))) == (3:4, 0:1)
     @test axes(OffsetMatrix(w, CartesianIndices((0:1,)), :)) == (0:1, 5:6)
+
+    @test axes(OffsetMatrix(v, typemax(Int)-size(v, 1), 0)) == (IdOffsetRange(axes(v)[1], typemax(Int)-size(v, 1)), axes(v, 2))
+    @test_throws ArgumentError OffsetMatrix(v, typemax(Int)-size(v,1)+1, 0)
+    @test_throws ArgumentError OffsetMatrix(v, 0, typemax(Int)-size(v, 2)+1)
 end
 
 @testset "construct OffsetArray with CartesianIndices" begin