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Add support for Normed construction from Rational (Fixes #157) #169

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Merged
merged 1 commit into from
Jan 21, 2020
Merged

Add support for Normed construction from Rational (Fixes #157) #169

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8 changes: 7 additions & 1 deletion src/fixed.jl
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Expand Up @@ -62,7 +62,13 @@ function _convert(::Type{F}, x::AbstractFloat) where {T, f, F <: Fixed{T,f}}
end

function _convert(::Type{F}, x::Rational) where {T, f, F <: Fixed{T,f}}
F(x.num)/F(x.den) # TODO: optimization and input range checking
xmin = widemul(denominator(x), widen1(T)(typemin(T)) << 0x1 - 0x1)
xmax = widemul(denominator(x), oneunit(widen1(T)) << bitwidth(T) - 0x1)
if xmin <= (widen1(numerator(x)) << UInt8(f + 1)) < xmax
reinterpret(F, round(T, convert(floattype(T), x) * @exp2(f)))
else
throw_converterror(F, x)
end
end

# unchecked arithmetic
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8 changes: 8 additions & 0 deletions src/normed.jl
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Expand Up @@ -100,6 +100,14 @@ function _convert(::Type{N}, x::Tf) where {T, f, N <: Normed{T,f}, Tf <: Union{F
return reinterpret(N, unsafe_trunc(T, yi >> (ex & bits)))
end

function _convert(::Type{N}, x::Rational) where {T, f, N <: Normed{T,f}}
if 0 <= x <= Rational(typemax(N))
reinterpret(N, round(T, convert(floattype(T), x) * rawone(N)))
else
throw_converterror(N, x)
end
end

rem(x::N, ::Type{N}) where {N <: Normed} = x
rem(x::Normed, ::Type{N}) where {T, N <: Normed{T}} = reinterpret(N, _unsafe_trunc(T, round((rawone(N)/rawone(x))*reinterpret(x))))
rem(x::Real, ::Type{N}) where {T, N <: Normed{T}} = reinterpret(N, _unsafe_trunc(T, round(rawone(N)*x)))
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7 changes: 4 additions & 3 deletions test/fixed.jl
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Expand Up @@ -99,9 +99,10 @@ end
@test_throws InexactError convert(Fixed{Int8, 7}, 128)

@test convert(Q2f5, -1//2) === -0.5Q2f5
@test_broken convert(Q1f6, Rational{Int8}(-3//4)) === -0.75Q1f6
@test_broken convert(Q0f7, Rational{Int16}(-3//4)) === -0.75Q0f7
@test_broken convert(Q0f7, Rational{UInt8}(3//4)) === 0.75Q0f7
@test convert(Q1f6, Rational{Int8}(-3//4)) === -0.75Q1f6
@test convert(Q0f7, Rational{Int16}(-3//4)) === -0.75Q0f7
@test convert(Q0f7, Rational{UInt8}(3//4)) === 0.75Q0f7
@test_throws ArgumentError convert(Q0f7, typemax(Rational{Int8}))

@test convert(Q0f7, Base.TwicePrecision(0.5)) === 0.5Q0f7
@test_throws InexactError convert(Q7f8, Base.TwicePrecision(0x80, 0x01))
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7 changes: 4 additions & 3 deletions test/normed.jl
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Expand Up @@ -92,9 +92,10 @@ end

@test convert(N0f8, 1.1f0/typemax(UInt8)) == eps(N0f8)

@test_broken convert(N0f8, 1//255) === eps(N0f8)
@test_broken convert(N0f8, Rational{Int8}(3//5)) === N0f8(3/5)
@test_broken convert(N0f8, Rational{UInt8}(3//5)) === N0f8(3/5)
@test convert(N0f8, 1//255) === eps(N0f8)
@test convert(N0f8, Rational{Int8}(3//5)) === N0f8(3/5)
@test convert(N0f8, Rational{UInt8}(3//5)) === N0f8(3/5)
@test_throws ArgumentError convert(N0f8, typemax(Rational{UInt8}))

@test convert(N0f8, Base.TwicePrecision(1.0)) === 1N0f8

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