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hash_uint: simplify definitions #36120

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hash_uint: simplify definitions #36120

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d27be66
hash_uint: simplify definitions
StefanKarpinski Jun 2, 2020
6506540
Merge branch 'master' into sk/hash_uint
oscardssmith Jan 10, 2025
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2 changes: 1 addition & 1 deletion base/char.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -220,7 +220,7 @@ in(x::AbstractChar, y::AbstractChar) = x == y
==(x::Char, y::Char) = bitcast(UInt32, x) == bitcast(UInt32, y)
isless(x::Char, y::Char) = bitcast(UInt32, x) < bitcast(UInt32, y)
hash(x::Char, h::UInt) =
hash_uint64(((bitcast(UInt32, x) + UInt64(0xd4d64234)) << 32) ⊻ UInt64(h))
hash_uint(((bitcast(UInt32, x) + UInt64(0xd4d64234)) << 32) ⊻ UInt64(h))

first_utf8_byte(c::Char) = (bitcast(UInt32, c) >> 24) % UInt8
first_utf8_byte(c::AbstractChar) = first_utf8_byte(Char(c)::Char)
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6 changes: 3 additions & 3 deletions base/float.jl
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Expand Up @@ -717,7 +717,7 @@ See also: [`Inf`](@ref), [`iszero`](@ref), [`isfinite`](@ref), [`isnan`](@ref).
isinf(x::Real) = !isnan(x) & !isfinite(x)
isinf(x::IEEEFloat) = abs(x) === oftype(x, Inf)

const hx_NaN = hash_uint64(reinterpret(UInt64, NaN))
const hx_NaN = hash_uint(reinterpret(UInt64, NaN))
function hash(x::Float64, h::UInt)
# see comments on trunc and hash(Real, UInt)
if typemin(Int64) <= x < typemax(Int64)
Expand All @@ -733,7 +733,7 @@ function hash(x::Float64, h::UInt)
elseif isnan(x)
return hx_NaN ⊻ h # NaN does not have a stable bit pattern
end
return hash_uint64(bitcast(UInt64, x)) - 3h
return hash_uint(bitcast(UInt64, x)) - 3h
end

hash(x::Float32, h::UInt) = hash(Float64(x), h)
Expand All @@ -748,7 +748,7 @@ function hash(x::Float16, h::UInt)
elseif isnan(x)
return hx_NaN ⊻ h # NaN does not have a stable bit pattern
end
return hash_uint64(bitcast(UInt64, Float64(x))) - 3h
return hash_uint(bitcast(UInt64, Float64(x))) - 3h
end

## generic hashing for rational values ##
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45 changes: 5 additions & 40 deletions base/hashing.jl
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Expand Up @@ -39,46 +39,11 @@ hash(x::Symbol) = objectid(x)

## core data hashing functions ##

function hash_64_64(n::UInt64)
a::UInt64 = n
a = ~a + a << 21
a = a ⊻ a >> 24
a = a + a << 3 + a << 8
a = a ⊻ a >> 14
a = a + a << 2 + a << 4
a = a ⊻ a >> 28
a = a + a << 31
return a
end

function hash_64_32(n::UInt64)
a::UInt64 = n
a = ~a + a << 18
a = a ⊻ a >> 31
a = a * 21
a = a ⊻ a >> 11
a = a + a << 6
a = a ⊻ a >> 22
return a % UInt32
end

function hash_32_32(n::UInt32)
a::UInt32 = n
a = a + 0x7ed55d16 + a << 12
a = a ⊻ 0xc761c23c ⊻ a >> 19
a = a + 0x165667b1 + a << 5
a = a + 0xd3a2646c ⊻ a << 9
a = a + 0xfd7046c5 + a << 3
a = a ⊻ 0xb55a4f09 ⊻ a >> 16
return a
end

if UInt === UInt64
hash_uint64(x::UInt64) = hash_64_64(x)
hash_uint(x::UInt) = hash_64_64(x)
else
hash_uint64(x::UInt64) = hash_64_32(x)
hash_uint(x::UInt) = hash_32_32(x)
function hash_uint(n::T) where {T <: Union{UInt64, UInt32}}
# random constants, last must be odd
n += 0xe391e8b4ff155ee5 % T
n ⊻= 0xb9d8ebf206d49927 % T
n *= 0xafa64689f53d9ee1 % T
end

## efficient value-based hashing of integers ##
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