[WIP] Xoshiro: allow any non-negative integer as a seed, via SHA2_256

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JuliaLang · Jul 12, 2021 · 6177901 · 6177901
1 parent e3a06c4
commit 6177901
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Showing 3 changed files with 9 additions and 42 deletions.
diff --git a/stdlib/Random/Project.toml b/stdlib/Random/Project.toml
@@ -3,6 +3,7 @@ uuid = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 
 [deps]
 Serialization = "9e88b42a-f829-5b0c-bbe9-9e923198166b"
+SHA = "ea8e919c-243c-51af-8825-aaa63cd721ce"
 
 [extras]
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"

diff --git a/stdlib/Random/src/Random.jl b/stdlib/Random/src/Random.jl
@@ -13,6 +13,7 @@ include("DSFMT.jl")
 using .DSFMT
 using Base.GMP.MPZ
 using Base.GMP: Limb
+import SHA
 
 using Base: BitInteger, BitInteger_types, BitUnsigned, require_one_based_indexing
 

diff --git a/stdlib/Random/src/Xoshiro.jl b/stdlib/Random/src/Xoshiro.jl
@@ -117,65 +117,30 @@ end
 
 # Shared implementation between Xoshiro and TaskLocalRNG -- seeding
 
-function seed!(x::Union{TaskLocalRNG,Xoshiro})
+function seed!(rng::Union{TaskLocalRNG,Xoshiro})
     # as we get good randomness from RandomDevice, we can skip hashing
     parent = RandomDevice()
     # Constants have nothing up their sleeve, see task.c
     # 0x02011ce34bce797f == hash(UInt(1))|0x01
     # 0x5a94851fb48a6e05 == hash(UInt(2))|0x01
     # 0x3688cf5d48899fa7 == hash(UInt(3))|0x01
     # 0x867b4bb4c42e5661 == hash(UInt(4))|0x01
-    setstate!(x,
+    setstate!(rng,
               0x02011ce34bce797f * rand(parent, UInt64),
               0x5a94851fb48a6e05 * rand(parent, UInt64),
               0x3688cf5d48899fa7 * rand(parent, UInt64),
               0x867b4bb4c42e5661 * rand(parent, UInt64))
 end
 
-function seed!(rng::Union{TaskLocalRNG,Xoshiro}, seed::NTuple{4,UInt64})
-    # TODO: Consider a less ad-hoc construction
-    # We can afford burning a handful of cycles here, and we don't want any
-    # surprises with respect to bad seeds / bad interactions.
-
-    s0 = s  = Base.hash_64_64(seed[1])
-    s1 = s += Base.hash_64_64(seed[2])
-    s2 = s += Base.hash_64_64(seed[3])
-    s3 = s += Base.hash_64_64(seed[4])
-
+function seed!(rng::Union{TaskLocalRNG,Xoshiro}, seed::Vector{UInt32})
+    c = SHA.SHA2_256_CTX()
+    SHA.update!(c, reinterpret(UInt8, seed))
+    s0, s1, s2, s3 = reinterpret(UInt64, SHA.digest!(c))
     setstate!(rng, s0, s1, s2, s3)
-
-    rand(rng, UInt64)
-    rand(rng, UInt64)
-    rand(rng, UInt64)
-    rand(rng, UInt64)
-    rng
 end
 
-function seed!(rng::Union{TaskLocalRNG, Xoshiro}, seed::UInt128)
-    seed0 = seed % UInt64
-    seed1 = (seed>>>64) % UInt64
-    seed!(rng, (seed0, seed1, zero(UInt64), zero(UInt64)))
-end
-seed!(rng::Union{TaskLocalRNG, Xoshiro}, seed::Integer) = seed!(rng, UInt128(seed))
-
-function seed!(rng::Union{TaskLocalRNG, Xoshiro}, seed::AbstractVector{UInt64})
-    if length(seed) > 4
-        throw(ArgumentError("seed should have no more than 256 bits"))
-    end
-    seed0 = length(seed)>0 ? seed[1] : UInt64(0)
-    seed1 = length(seed)>1 ? seed[2] : UInt64(0)
-    seed2 = length(seed)>2 ? seed[3] : UInt64(0)
-    seed3 = length(seed)>3 ? seed[4] : UInt64(0)
-    seed!(rng, (seed0, seed1, seed2, seed3))
-end
+seed!(rng::Union{TaskLocalRNG, Xoshiro}, seed::Integer) = seed!(rng, make_seed(seed))
 
-function seed!(rng::Union{TaskLocalRNG, Xoshiro}, seed::AbstractVector{UInt32})
-    if iseven(length(seed))
-        seed!(rng, reinterpret(UInt64, seed))
-    else
-        seed!(rng, UInt64[reinterpret(UInt64, @view(seed[begin:end-1])); seed[end] % UInt64])
-    end
-end
 
 @inline function rand(rng::Union{TaskLocalRNG, Xoshiro}, ::SamplerType{UInt128})
     first = rand(rng, UInt64)