Skip to content

Bugfix: Use Base.aligned_sizeof instead of sizeof in Mmap.mmap #58998

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 3 commits into from
Jul 18, 2025
Merged

Bugfix: Use Base.aligned_sizeof instead of sizeof in Mmap.mmap #58998

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
5d81681
Use aligned_sizeof instead of sizeof
JonasIsensee Jul 14, 2025
3f88efa
non isbits now (correctly) throws an ArgumentError
JonasIsensee Jul 14, 2025
9b4ba24
wrap new test into testset
JonasIsensee Jul 17, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
8 changes: 4 additions & 4 deletions stdlib/Mmap/src/Mmap.jl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -187,16 +187,16 @@ like HDF5 (which can be used with memory-mapping).
"""
function mmap(io::IO,
::Type{Array{T,N}}=Vector{UInt8},
dims::NTuple{N,Integer}=(div(filesize(io)-position(io),sizeof(T)),),
dims::NTuple{N,Integer}=(div(filesize(io)-position(io),Base.aligned_sizeof(T)),),
offset::Integer=position(io); grow::Bool=true, shared::Bool=true) where {T,N}
# check inputs
isopen(io) || throw(ArgumentError("$io must be open to mmap"))
isbitstype(T) || throw(ArgumentError("unable to mmap $T; must satisfy isbitstype(T) == true"))

len = sizeof(T)
len = Base.aligned_sizeof(T)
for l in dims
len, overflow = Base.Checked.mul_with_overflow(promote(len, l)...)
overflow && throw(ArgumentError("requested size prod($((sizeof(T), dims...))) too large, would overflow typeof(size(T)) == $(typeof(len))"))
overflow && throw(ArgumentError("requested size prod($((len, dims...))) too large, would overflow typeof(size(T)) == $(typeof(len))"))
end
len >= 0 || throw(ArgumentError("requested size must be ≥ 0, got $len"))
len == 0 && return Array{T}(undef, ntuple(x->0,Val(N)))
Expand Down Expand Up @@ -267,7 +267,7 @@ end

mmap(file::AbstractString,
::Type{T}=Vector{UInt8},
dims::NTuple{N,Integer}=(div(filesize(file),sizeof(eltype(T))),),
dims::NTuple{N,Integer}=(div(filesize(file),Base.aligned_sizeof(eltype(T))),),
offset::Integer=Int64(0); grow::Bool=true, shared::Bool=true) where {T<:Array,N} =
open(io->mmap(io, T, dims, offset; grow=grow, shared=shared), file, isfile(file) ? "r" : "w+")::Array{eltype(T),N}

Expand Down
15 changes: 14 additions & 1 deletion stdlib/Mmap/test/runtests.jl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -44,7 +44,7 @@ s = open(file)
@test length(@inferred mmap(s, Vector{Int8}, 12, 0; grow=false)) == 12
@test length(@inferred mmap(s, Vector{Int8}, 12, 0; shared=false)) == 12
close(s)
@test_throws ErrorException mmap(file, Vector{Ref}) # must be bit-type
@test_throws ArgumentError mmap(file, Vector{Ref}) # must be bit-type
GC.gc(); GC.gc()

file = tempname() # new name to reduce chance of issues due slow windows fs
Expand Down Expand Up @@ -343,6 +343,19 @@ end
GC.gc()
rm(file)

@testset "test for #58982 - mmap with primitive types" begin
file = tempname()
primitive type PrimType9Bytes 9*8 end
arr = Vector{PrimType9Bytes}(undef, 2)
write(file, arr)
m = mmap(file, Vector{PrimType9Bytes})
@test length(m) == 2
@test m[1] == arr[1]
@test m[2] == arr[2]
finalize(m); m = nothing; GC.gc()
rm(file)
end

@testset "Docstrings" begin
@test isempty(Docs.undocumented_names(Mmap))
end