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Fix indexing BigInt axes with large indices #142

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merged 2 commits into from
Sep 6, 2023
Merged

Fix indexing BigInt axes with large indices #142

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7a80b80
Fix indexing BigInt axes
jishnub Aug 28, 2023
ae64dc9
Reinstate inbounds
jishnub Sep 5, 2023
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2 changes: 1 addition & 1 deletion Project.toml
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
name = "InfiniteArrays"
uuid = "4858937d-0d70-526a-a4dd-2d5cb5dd786c"
version = "0.13.1"
version = "0.13.2"

[deps]
ArrayLayouts = "4c555306-a7a7-4459-81d9-ec55ddd5c99a"
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12 changes: 6 additions & 6 deletions src/InfiniteArrays.jl
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Expand Up @@ -161,10 +161,10 @@ axistype(::OneToInf{V}, ::OneTo{T}) where {T,V} = OneToInf{promote_type(T,V)}()
# returns the range of indices of v equal to x
# if v does not contain x, returns a 0-length range
# indicating the insertion point of x
function searchsorted(v::AbstractVector, x, ilo::Int, ::PosInfinity, o::Ordering)
function searchsorted(v::AbstractVector, x, ilo::Integer, ::PosInfinity, o::Ordering)
lo = ilo-1
hi = ℵ₀
@inbounds while lo < hi-1
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Why were the inbounds removed?

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The access may not be within bounds, unless we consider this to be an internal method that is never directly called by a user. Otherwise, a call like

julia> v = [1,2]
2-element Vector{Int64}:
 1
 2

julia> searchsorted(v, 2, firstindex(v), ∞, Base.Order.ForwardOrdering())
ERROR: BoundsError: attempt to access 2-element Vector{Int64} at index [1000]

may lead to memory corruption through out-of-bounds access.

The alternative is to add a bounds-check to the function, in which case we may retain the inbounds annotations.

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Hmm I copied this code from Base which has the exact same issue:

julia> searchsorted([1,2], 2, 1, 10, Base.Order.ForwardOrdering())
2:3

I've started an issue: JuliaLang/julia#51176

I think its best to just check that hi ≤ length(v) here and keep the inbounds

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I have reverted the inbounds for now. This is unlikely to be an issue in practice, as these are internal methods. We may revisit this in the future, if necessary.

while lo < hi-1
m = isinf(hi) ? lo + 1000 : (lo+hi)>>>1
if lt(o, v[m], x)
lo = m
Expand All @@ -182,11 +182,11 @@ end

# index of the first value of vector a that is greater than or equal to x;
# returns length(v)+1 if x is greater than all values in v.
function searchsortedfirst(v::AbstractVector, x, lo::Int, hi::PosInfinity, o::Ordering)
function searchsortedfirst(v::AbstractVector, x, lo::Integer, hi::PosInfinity, o::Ordering)
u = 1
lo = lo - u
hi = ℵ₀
@inbounds while lo < hi - u
while lo < hi - u
m = isinf(hi) ? lo + 1000 : (lo+hi)>>>1
if lt(o, v[m], x)
lo = m
Expand All @@ -199,11 +199,11 @@ end

# index of the last value of vector a that is less than or equal to x;
# returns 0 if x is less than all values of v.
function searchsortedlast(v::AbstractVector, x, lo::Int, hi::PosInfinity, o::Ordering)
function searchsortedlast(v::AbstractVector, x, lo::Integer, hi::PosInfinity, o::Ordering)
u = 1
lo = lo - u
hi = ℵ₀
@inbounds while lo < hi - u
while lo < hi - u
m = isinf(hi) ? lo + 1000 : (lo+hi)>>>1
if lt(o, x, v[m])
hi = m
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1 change: 1 addition & 0 deletions src/infrange.jl
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Expand Up @@ -144,6 +144,7 @@ AbstractVector{T}(a::OneToInf) where T<:Real = InfUnitRange{T}(a)
## interface implementations

size(r::InfRanges) = (ℵ₀,)
axes(r::InfRanges{<:Integer}) = (OneToInf{promote_type(Int,eltype(r))}(),)
axes(r::InfRanges) = (OneToInf(),)

isempty(r::InfRanges) = false
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5 changes: 5 additions & 0 deletions test/runtests.jl
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Expand Up @@ -125,6 +125,11 @@ end
@test ∞:1 ≡ 1:0

@testset "indexing" begin
@testset "axes" begin
r = axes(big(1):∞,1)
@test r == axes(r,1)
@test r[typemax(Int)+big(1)] == typemax(Int)+big(1)
end
L32 = @inferred(Int32(1):∞)
L64 = @inferred(Int64(1):∞)
@test @inferred(L32[1]) === Int32(1) && @inferred(L64[1]) === Int64(1)
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