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Implement Base.unsafe_wrap for OffsetArrays (pull request) #290

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31 changes: 31 additions & 0 deletions src/OffsetArrays.jl
Original file line number Diff line number Diff line change
Expand Up @@ -623,6 +623,37 @@ function Base.replace_in_print_matrix(A::OffsetArray{<:Any,1}, i::Integer, j::In
Base.replace_in_print_matrix(parent(A), ip, j, s)
end

# Actual unsafe_wrap implementation
@inline function _unsafe_wrap(pointer::Ptr{T}, inds::NTuple{N}; own = false, kw...) where {T,N}
_checkindices(N, inds, "indices")
AA = Base.unsafe_wrap(Array, pointer, map(_indexlength, inds); own=own)
OffsetArray{T, N, typeof(AA)}(AA, map(_indexoffset, inds); kw...)
end
const OffsetArrayUnion{T,N} = Union{Type{OffsetArray}, Type{OffsetArray{T}}, Type{OffsetArray{T,N}}, Type{OffsetArray{T1, N} where T1}} where {T,N}

"""
Base.unsafe_wrap(OffsetArray, pointer::Ptr{T}, inds...; own=false, kw...)
Base.unsafe_wrap(OffsetArray, pointer::Ptr{T}, inds::Tuple; own=false, kw...)

Construct an `OffsetArray` around a pointer with axes defined by `inds` which may be Integers or AbstractUnitRanges.
If the keyword `own` is true, then Julia will free the pointer when the array is garbage collected.
Other keywords are forwarded to the `OffsetArray` constructor.
"""
@inline function Base.unsafe_wrap(::OffsetArrayUnion{T,N}, pointer::Ptr{T}, inds::NTuple{N, OffsetAxisKnownLength}; kw...) where {T,N}
_unsafe_wrap(pointer, inds; kw...)
end
# Avoid ambiguity
@inline function Base.unsafe_wrap(::OffsetArrayUnion{T,N}, pointer::Ptr{T}, inds::NTuple{N, <:Integer}; kw...) where {T,N}
_unsafe_wrap(pointer, inds; kw...)
end
@inline function Base.unsafe_wrap(::OffsetArrayUnion{T,N}, pointer::Ptr{T}, inds::Vararg{OffsetAxisKnownLength,N}; kw...) where {T,N}
_unsafe_wrap(pointer, inds; kw...)
end
# Avoid ambiguity
@inline function Base.unsafe_wrap(::OffsetArrayUnion{T,N}, pointer::Ptr{T}, inds::Vararg{<:Integer,N}; kw...) where {T,N}
_unsafe_wrap(pointer, inds; kw...)
end

"""
no_offset_view(A)

Expand Down
16 changes: 16 additions & 0 deletions test/runtests.jl
Original file line number Diff line number Diff line change
Expand Up @@ -2683,3 +2683,19 @@ end
A = reshape(collect(1:9), 3, 3)
@test OffsetArrays.centered(A, RoundDown) == OffsetArrays.centered(A, RoundUp)
end
@testset "unsafe_wrap" begin
p = Ptr{UInt16}(Libc.malloc(2*3*4*2))
@test unsafe_wrap(OffsetArray, p, 2, 3, 4) isa OffsetArray{UInt16, 3}
@test unsafe_wrap(OffsetArray, p, (2, 3, 4)) isa OffsetArray{UInt16, 3}
@test unsafe_wrap(OffsetVector, p, 2*3*4) isa OffsetVector{UInt16}
@test unsafe_wrap(OffsetMatrix, p, 2*3, 4) isa OffsetMatrix{UInt16}
@test unsafe_wrap(OffsetArray{UInt16}, p, 2, 3, 4) isa OffsetArray{UInt16, 3}
@test unsafe_wrap(OffsetArray{UInt16}, p, (2, 3, 4)) isa OffsetArray{UInt16, 3}
@test unsafe_wrap(OffsetVector{UInt16}, p, 2*3*4) isa OffsetVector{UInt16}
@test unsafe_wrap(OffsetMatrix{UInt16}, p, 2*3, 4) isa OffsetMatrix{UInt16}
p = Ptr{UInt8}(p)
@test unsafe_wrap(OffsetArray, p, 2:3, 3:5, 4:7) isa OffsetArray{UInt8, 3}
@test unsafe_wrap(OffsetArray, p, (2:3, 3:5, 4:7)) isa OffsetArray{UInt8, 3}
@test unsafe_wrap(OffsetVector, p, 1:(2*3*4) .- 1) isa OffsetVector{UInt8}
@test unsafe_wrap(OffsetMatrix, p, 1:(2*3) .+ 6, 4:7; own = true) isa OffsetMatrix{UInt8}
end