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Add 5 arg copyto! into Vector with matching type #264

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8925127
Add 5 arg `copyto!` into `Vector`
nhz2 Jun 22, 2025
bb1ae13
add support for views and different types
nhz2 Jun 22, 2025
760c378
remove copyto! with different types
nhz2 Jun 28, 2025
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36 changes: 36 additions & 0 deletions src/array.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,30 @@ function _disk_copyto!(dest, Rdest, src, Rsrc)
return dest
end
view(dest, Rdest) .= view(src, Rsrc)
return dest
end
function _disk_copyto_same_type_vector!(dest, dstart, src, sstart, n)
if iszero(n)
return dest
end
if n < 0
throw(ArgumentError(LazyString("tried to copy n=",
n," elements, but n should be non-negative")))
end
destv = view(dest, range(dstart, length=n))
DiskArrays.readblock!(src, destv, range(sstart, length=n))
return dest
end
function _disk_copyto_vector!(dest, dstart, src, sstart, n)
if iszero(n)
return dest
end
if n < 0
throw(ArgumentError(LazyString("tried to copy n=",
n," elements, but n should be non-negative")))
end
view(dest, range(dstart, length=n)) .= view(src, range(dstart, length=n))
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Depending on the use case it might be better for performance to avoid the DiskArray broadcast machinery, broadcast on views should work but might be a bit slow if chunk sizes are too small. Instead we might instantiate the result and copy with coptyo!(dest,dstart,src[range(dstart, length=n)])

Can we assume that the amount of data we copy fits in memory, or is dest mmapped in your case?

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I'm not doing any mmapping in InputBuffers.jl, though there is nothing stopping someone from passing a mmapped out to Base.readbytes!(b::InputBuffer, out::AbstractArray{UInt8}, nb=length(out))
Also, the copyto! in InputBuffers.jl should end up calling _disk_copyto_same_type_vector with the direct readblock! call since src and dest both have eltype UInt8.

return dest
end

# Use a view for lazy reverse
Expand Down Expand Up @@ -76,6 +100,18 @@ macro implement_array_methods(t)
function Base.copyto!(dest::PermutedDimsArray{T,N}, src::$t{T,N}) where {T,N}
return $_disk_copyto!(dest, src)
end
function Base.copyto!(dest::Vector{T}, dstart::Integer, src::$t{T, 1}, sstart::Integer, n::Integer) where {T}
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@rafaqz rafaqz Jun 22, 2025 •
edited
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Is T always identical for scr and dest in Base copyto! ? What if you have different Real types

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No, the copyto! in Base uses setindex! so will call convert on each element.
I added a version that uses broadcasting to support that case.

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I'm assuming here that readblock! requires the element types to match, and aout to be stored in contiguous memory.

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@rafaqz rafaqz Jun 23, 2025 •
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We also use setindex! when writing into the chunk buffer, so it should be the same?

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Maybe. Looking at the docs, it just says "The results shall be written into aout" but I'm not sure if there are implementations of readblock! that make other assumptions about aout's eltype, or memory layout.

return $_disk_copyto_same_type_vector!(dest, dstart, src, sstart, n)
end
function Base.copyto!(dest::SubArray{T, 1, Vector{T}, <:Tuple{AbstractUnitRange}, true}, dstart::Integer, src::$t{T, 1}, sstart::Integer, n::Integer) where {T}
return $_disk_copyto_same_type_vector!(dest, dstart, src, sstart, n)
end
function Base.copyto!(dest::Vector, dstart::Integer, src::$t{T, 1}, sstart::Integer, n::Integer) where {T}
return $_disk_copyto_vector!(dest, dstart, src, sstart, n)
end
function Base.copyto!(dest::SubArray{TD, 1, Vector{TD}}, dstart::Integer, src::$t{TS, 1}, sstart::Integer, n::Integer) where {TD, TS}
return $_disk_copyto_vector!(dest, dstart, src, sstart, n)
end

Base.reverse(a::$t; dims=:) = $_disk_reverse(a, dims)
Base.reverse(a::$t{<:Any,1}) = $_disk_reverse1(a)
Expand Down
27 changes: 23 additions & 4 deletions test/runtests.jl
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Expand Up @@ -770,15 +770,34 @@ end
@test Array(a_disk) == a
@testset "copyto" begin
x = zero(a)
copyto!(x, a_disk)
@test copyto!(x, a_disk) === x
@test x == a
copyto!(x, CartesianIndices((1:3, 1:2)), a_disk, CartesianIndices((8:10, 8:9)))
@test copyto!(x, CartesianIndices((1:3, 1:2)), a_disk, CartesianIndices((8:10, 8:9))) === x
# Test copyto! with zero length index
x_empty = Matrix{Int64}(undef, 0, 2)
copyto!(x_empty, CartesianIndices((1:0, 1:2)), a_disk, CartesianIndices((8:7, 8:9)))
# copyto! with different length should throw an error
@test_throws ArgumentError copyto!(x, CartesianIndices((1:1, 1:2)), a_disk, CartesianIndices((4:6, 8:9)))

# 5 arg copyto!
a_vec = collect(0x00:0x90)
test_dests = [
zero(a_vec),
zeros(Float32, length(a_vec)),
view(zero(a_vec), 1:10),
view(zero(a_vec), 1:2:20),
view(zeros(Float32, length(a_vec)), 1:10),
view(zeros(Float32, length(a_vec)), 1:2:20),
]
for x in test_dests
local a_disk = AccessCountDiskArray(a_vec; chunksize=(15,))
x = zero(a_vec)
@test_throws ArgumentError copyto!(x, 1, a_disk, 1, -1)
@test copyto!(x, 1, a_disk, 1, 0) === x
@test copyto!(x, 6, a_disk, 3, 2) === x
@test x[6] == a_vec[3]
@test x[7] == a_vec[4]
@test getindex_count(a_disk) == 1
end
end

@test collect(reverse(a_disk)) == reverse(a)
Expand All @@ -804,7 +823,7 @@ end
@test vcat(a_disk, a_disk) == vcat(a, a)
@test hcat(a_disk, a_disk) == hcat(a, a)
@test cat(a_disk, a_disk; dims=3) == cat(a, a; dims=3)
@test_broken circshift(a_disk, 2) == circshift(a, 2) # This one is super weird. The size changes.
@test circshift(a_disk, 2) == circshift(a, 2)
end

@testset "Reshape" begin
Expand Down
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