Limit dispatch of Random.rand! for ChaChaStream and CUDAChaChaStream

Change type signature of Random.rand! implementations for ChaChaStream
and CUDAChaChaStream so that they don't accept an arbitrary
AbstractVector, only Vector. Both of these methods actually require a
Vector for the way that they're implemented (technically they could
accept other inputs, but there isn't a well-defined interface for what
those inputs should do). With this change, errors from incorrect calls
to Random.rand! should be a little clearer.

Author: kernelmethod

src/generation.jl

@@ -30,7 +30,7 @@ Random.rand!(rng::AbstractChaChaStream, A::CuArray{<:BitInteger}) =
 
 Random.rand!(
     rng::AbstractChaChaStream,
-    A::AbstractArray{T},
+    A::Array{T},
     ::Type{T},
 ) where {T <: BitInteger} =
     (Random.rand!(rng, vec(A), T); A)
@@ -46,12 +46,7 @@ Random.rand(rng::ChaChaStream, T::Random.SamplerType{<:BitInteger}) =
     _fetch_one!(rng, T[])
 
 # Inplace operations
-function Random.rand!(
-    rng::ChaChaStream,
-    A::AbstractVector{T},
-    ::Type{T}
-) where {T <: BitInteger}
-
+function Random.rand!(rng::ChaChaStream, A::Vector{T}, ::Type{T}) where {T <: BitInteger}
     # Reinterpret the array as a byte array
     @GC.preserve A begin
         p = pointer(A)
@@ -68,11 +63,7 @@ end
 RNG methods for CUDAChaChaStream
 =#
 
-function Random.rand!(
-    rng::CUDAChaChaStream,
-    A::AbstractVector{T},
-    ::Type{T}
-) where {T <: BitInteger}
+function Random.rand!(rng::CUDAChaChaStream, A::Vector{T}, ::Type{T}) where {T <: BitInteger}
     # Perform sampling on GPU and then copy to CPU
     A_gpu = CuVector{T}(undef, length(A))
     Random.rand!(rng, A_gpu, T)

test/Project.toml

@@ -3,6 +3,7 @@ BenchmarkTools = "6e4b80f9-dd63-53aa-95a3-0cdb28fa8baf"
 CUDA = "052768ef-5323-5732-b1bb-66c8b64840ba"
 Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
+SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"

test/test_keystream.jl

@@ -2,6 +2,7 @@
 
 using ChaChaCiphers
 using Random
+using SparseArrays
 using Statistics
 using Test
 
@@ -96,6 +97,21 @@ using Test
         @test randn(stream, 1500) == randn(stream_copy, 1500)
     end
 
+    @testset "Generate random sparse array" begin
+        rng = ChaCha12Stream()
+        x = sprand(rng, Int32, 400, 400, 0.1)
+
+        @test x isa AbstractMatrix{Int32}
+        @test x isa SparseMatrixCSC{Int32}
+        @test isapprox(mean(x .== 0), 0.9, atol=1e-2)
+
+        Random.rand!(rng, x)
+
+        @test x isa AbstractMatrix{Int32}
+        @test x isa SparseMatrixCSC{Int32}
+        @test (x .!= 0) |> all
+    end
+
     @testset "Encrypt data with a keystream" begin
         # Ref: IETF RFC 8439, Sec. A.2
         # https://datatracker.ietf.org/doc/html/rfc8439#appendix-A.2