From e7d187511cd4b6237fc5c2a6bc61814d3e98070f Mon Sep 17 00:00:00 2001
From: Johnny Chen <johnnychen94@hotmail.com>
Date: Mon, 14 Sep 2020 01:47:47 +0800
Subject: [PATCH 1/2] add offset overflow check

---
 src/OffsetArrays.jl | 10 ++++++++++
 test/runtests.jl    |  8 ++++++++
 2 files changed, 18 insertions(+)

diff --git a/src/OffsetArrays.jl b/src/OffsetArrays.jl
index 195697f3..241f4190 100644
--- a/src/OffsetArrays.jl
+++ b/src/OffsetArrays.jl
@@ -15,10 +15,20 @@ 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
+    throw_offseterror() = throw(ArgumentError("Boundary overflow detected: offset $offset should be smaller than $(typemax(T) - last(r))"))
+    if offset > 0 && last(r) > typemax(T) - offset
+        throw_offseterror()
+    end
+end
 ## OffsetArray constructors
 
 offset(axparent::AbstractUnitRange, ax::AbstractUnitRange) = first(ax) - first(axparent)
diff --git a/test/runtests.jl b/test/runtests.jl
index d1cec2e2..4d86fc7d 100644
--- a/test/runtests.jl
+++ b/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 +126,9 @@ 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)
 end
 
 @testset "OffsetMatrix constructors" begin
@@ -158,6 +162,10 @@ 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

From 967873f196b722d86e97f7a1f2efed1be5d9ab77 Mon Sep 17 00:00:00 2001
From: Johnny Chen <johnnychen94@hotmail.com>
Date: Mon, 14 Sep 2020 03:14:29 +0800
Subject: [PATCH 2/2] also check negative cases

---
 src/OffsetArrays.jl | 5 +++--
 test/runtests.jl    | 4 ++++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/OffsetArrays.jl b/src/OffsetArrays.jl
index 241f4190..d8a7bae7 100644
--- a/src/OffsetArrays.jl
+++ b/src/OffsetArrays.jl
@@ -24,9 +24,10 @@ OffsetVector{T,AA<:AbstractArray} = OffsetArray{T,1,AA}
 OffsetMatrix{T,AA<:AbstractArray} = OffsetArray{T,2,AA}
 
 function overflow_check(r, offset::T) where T
-    throw_offseterror() = throw(ArgumentError("Boundary overflow detected: offset $offset should be smaller than $(typemax(T) - last(r))"))
     if offset > 0 && last(r) > typemax(T) - offset
-        throw_offseterror()
+        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
diff --git a/test/runtests.jl b/test/runtests.jl
index 4d86fc7d..da604adb 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -129,6 +129,10 @@ end
 
     @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