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Fix bug in v0.5.1 for comparisons that underflow (large negatives) (#89)
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* Fix bug in v0.5.1 for comparisons that underflow (large negatives)

* Bump version to v0.5.2 for this bug fix
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@NHDaly
NHDaly authored Dec 20, 2023
1 parent 507185c commit ddee978
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2 changes: 1 addition & 1 deletion Project.toml
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
name = "FixedPointDecimals"
uuid = "fb4d412d-6eee-574d-9565-ede6634db7b0"
authors = ["Fengyang Wang <fengyang.wang.0@gmail.com>", "Curtis Vogt <curtis.vogt@gmail.com>"]
version = "0.5.1"
version = "0.5.2"

[deps]
Parsers = "69de0a69-1ddd-5017-9359-2bf0b02dc9f0"
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70 changes: 50 additions & 20 deletions src/FixedPointDecimals.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -558,19 +558,34 @@ for comp_op in (:(==), :(<), :(<=))
xi, yi = promote(x.i, y.i)
if f1 > f2
C = coefficient(newFD) ÷ coefficient(FD{T2,f2})
yi, overflowed = Base.mul_with_overflow(yi, C)
if $(comp_op == :(==))
overflowed && return false
else
# y overflowed, so it's bigger than x, since it doesn't fit in x's type
overflowed && return true
yi, wrapped = Base.mul_with_overflow(yi, C)
if wrapped
is_underflow = (y.i < 0)
if !is_underflow
# Whether we're computing `==`, `<` or `<=`, if y overflowed, it
# means it's bigger than x.
return $(comp_op == :(==)) ? false : true
else # underflow
# If y is negative, then y is definitely less than x, since y is so
# small, it doesn't even fit in y's type.
return false
end
end
else
C = coefficient(newFD) ÷ coefficient(FD{T1,f1})
xi, overflowed = Base.mul_with_overflow(xi, C)
# Whether we're computing `==`, `<` or `<=`, if x overflowed, it means it's
# bigger than y, so this is false.
overflowed && return false
xi, wrapped = Base.mul_with_overflow(xi, C)
if wrapped
is_underflow = (x.i < 0)
if !is_underflow
# Whether we're computing `==`, `<` or `<=`, if x overflowed, it
# means it's bigger than y, so this is false.
return false
else # underflow
# If x is negative, then x is definitely less than y, since x is so
# small, it doesn't even fit in y's type.
return $(comp_op == :(==)) ? false : true
end
end
end
return $comp_op(xi, yi)
end
Expand All @@ -593,10 +608,19 @@ for comp_op in (:(==), :(<), :(<=))
end
# Now it's safe to truncate x down to y's type.
xi = x % T
xi, overflowed = Base.mul_with_overflow(xi, coefficient(FD{T,f}))
# Whether we're computing `==`, `<` or `<=`, if x overflowed, it means it's
# bigger than y, so this is false.
overflowed && return false
xi, wrapped = Base.mul_with_overflow(xi, coefficient(FD{T,f}))
if wrapped
is_underflow = (x < 0)
if !is_underflow
# Whether we're computing `==`, `<` or `<=`, if x overflowed, it means it's
# bigger than y, so this is false.
return false
else # underflow
# If x is negative, then x is definitely less than y, since x is so
# small, it doesn't even fit in y's type.
return $(comp_op == :(==)) ? false : true
end
end
return $comp_op(xi, y.i)
end
end
Expand All @@ -618,12 +642,18 @@ for comp_op in (:(==), :(<), :(<=))
end
# Now it's safe to truncate x down to y's type.
yi = y % T
yi, overflowed = Base.mul_with_overflow(yi, coefficient(FD{T,f}))
if $(comp_op == :(==))
overflowed && return false
else
# y overflowed, so it's bigger than x, since it doesn't fit in x's type
overflowed && return true
yi, wrapped = Base.mul_with_overflow(yi, coefficient(FD{T,f}))
if wrapped
is_underflow = (y < 0)
if !is_underflow
# Whether we're computing `==`, `<` or `<=`, if y overflowed, it means it's
# bigger than x.
return $(comp_op == :(==)) ? false : true
else # underflow
# If y is negative, then y is definitely less than x, since y is so
# small, it doesn't even fit in y's type.
return false
end
end
return $comp_op(x.i, yi)
end
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126 changes: 91 additions & 35 deletions test/FixedDecimal.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -297,6 +297,10 @@ end
@test FD{Int8, 2}(0) != typemax(Int16)
@test FD{Int8, 0}(0) != typemin(Int16)
@test FD{Int8, 2}(0) != typemin(Int16)

# less precision allows smaller and bigger numbers
@test typemin(FD{Int8, 1}) != typemin(FD{Int8,2})
@test typemax(FD{Int8, 1}) != typemax(FD{Int8,2})
end
@testset "inequality between types" begin
@test FD{Int8, 0}(1) <= FD{Int8, 2}(1)
Expand All @@ -312,41 +316,93 @@ end
@test FD{Int8, 0}(4) >= FD{Int16, 4}(1) # FD{Int16,4}(4) doesn't fit
@test FD{Int16, 4}(1) < FD{Int8, 0}(4) # FD{Int16,4}(4) doesn't fit

# Integer == FD
@test 1 <= FD{Int8, 2}(1) <= 1
@test 1 >= FD{Int8, 2}(1) >= 1
@test 2 > FD{Int8, 2}(1)
@test FD{Int8, 2}(1) < 2
@test 2 >= FD{Int8, 2}(1)
@test FD{Int8, 2}(1) <= 2
@test 1 <= FD{Int8, 0}(1) < 2

@test typemax(Int16) > FD{Int8, 0}(1) > typemin(Int16)
@test typemax(Int16) > FD{Int8, 2}(1) > typemin(Int16)
@test typemin(Int16) < FD{Int8, 0}(1) < typemax(Int16)
@test typemin(Int16) < FD{Int8, 2}(1) < typemax(Int16)
@test !(typemax(Int16) < FD{Int8, 0}(1) < typemin(Int16))
@test !(typemax(Int16) < FD{Int8, 2}(1) < typemin(Int16))
@test !(typemin(Int16) > FD{Int8, 0}(1) > typemax(Int16))
@test !(typemin(Int16) > FD{Int8, 2}(1) > typemax(Int16))

@test typemax(Int16) > FD{Int8, 0}(-1) > typemin(Int16)
@test typemax(Int16) > FD{Int8, 2}(-1) > typemin(Int16)
@test typemin(Int16) < FD{Int8, 0}(-1) < typemax(Int16)
@test typemin(Int16) < FD{Int8, 2}(-1) < typemax(Int16)
@test !(typemax(Int16) < FD{Int8, 0}(-1) < typemin(Int16))
@test !(typemax(Int16) < FD{Int8, 2}(-1) < typemin(Int16))
@test !(typemin(Int16) > FD{Int8, 0}(-1) > typemax(Int16))
@test !(typemin(Int16) > FD{Int8, 2}(-1) > typemax(Int16))

@test typemax(Int16) >= FD{Int8, 0}(0) >= typemin(Int16)
@test typemax(Int16) >= FD{Int8, 2}(0) >= typemin(Int16)
@test typemin(Int16) <= FD{Int8, 0}(0) <= typemax(Int16)
@test typemin(Int16) <= FD{Int8, 2}(0) <= typemax(Int16)
@test !(typemax(Int16) <= FD{Int8, 0}(-1) <= typemin(Int16))
@test !(typemax(Int16) <= FD{Int8, 2}(-1) <= typemin(Int16))
@test !(typemin(Int16) >= FD{Int8, 0}(-1) >= typemax(Int16))
@test !(typemin(Int16) >= FD{Int8, 2}(-1) >= typemax(Int16))
# less precision allows smaller numbers
@test typemin(FD{Int8, 1}) < typemin(FD{Int8,2})
@test typemin(FD{Int8, 1}) <= typemin(FD{Int8,2})
@test typemin(FD{Int8, 2}) > typemin(FD{Int8,1})
@test typemin(FD{Int8, 2}) >= typemin(FD{Int8,1})
# less precision allows bigger numbers
@test typemax(FD{Int8, 1}) > typemax(FD{Int8,2})
@test typemax(FD{Int8, 1}) >= typemax(FD{Int8,2})
@test typemax(FD{Int8, 2}) < typemax(FD{Int8,1})
@test typemax(FD{Int8, 2}) <= typemax(FD{Int8,1})

@test !(typemin(FD{Int8, 2}) <= typemin(FD{Int8,1}))
@test !(typemin(FD{Int8, 1}) >= typemin(FD{Int8,2}))
@test !(typemin(FD{Int8, 1}) > typemin(FD{Int8,2}))
@test !(typemin(FD{Int8, 1}) >= typemin(FD{Int8,2}))
@test !(typemin(FD{Int8, 2}) < typemin(FD{Int8,1}))
@test !(typemin(FD{Int8, 2}) <= typemin(FD{Int8,1}))
@test !(typemax(FD{Int8, 1}) < typemax(FD{Int8,2}))
@test !(typemax(FD{Int8, 1}) <= typemax(FD{Int8,2}))
@test !(typemax(FD{Int8, 2}) > typemax(FD{Int8,1}))
@test !(typemax(FD{Int8, 2}) >= typemax(FD{Int8,1}))

@testset "Integer and FD" begin
@test 1 <= FD{Int8, 2}(1) <= 1
@test 1 >= FD{Int8, 2}(1) >= 1
@test 2 > FD{Int8, 2}(1)
@test FD{Int8, 2}(1) < 2
@test 2 >= FD{Int8, 2}(1)
@test FD{Int8, 2}(1) <= 2
@test 1 <= FD{Int8, 0}(1) < 2

# negatives
@test -1 <= FD{Int8, 2}(-1) <= -1
@test -1 >= FD{Int8, 2}(-1) >= -1
@test -2 < FD{Int8, 2}(-1)
@test FD{Int8, 2}(-1) > -2
@test -2 <= FD{Int8, 2}(-1)
@test FD{Int8, 2}(-1) >= -2
@test -1 <= FD{Int8, 0}(-1) < 2

# Same types
@test typemax(Int8) > FD{Int8, 0}(1) > typemin(Int8)
@test typemax(Int8) > FD{Int8, 2}(1) > typemin(Int8)
@test typemin(Int8) < FD{Int8, 0}(1) < typemax(Int8)
@test typemin(Int8) < FD{Int8, 2}(1) < typemax(Int8)
@test !(typemax(Int8) < FD{Int8, 0}(1) < typemin(Int8))
@test !(typemax(Int8) < FD{Int8, 2}(1) < typemin(Int8))
@test !(typemin(Int8) > FD{Int8, 0}(1) > typemax(Int8))
@test !(typemin(Int8) > FD{Int8, 2}(1) > typemax(Int8))

@test typemax(Int8) > FD{Int8, 0}(-1) > typemin(Int8)
@test typemax(Int8) > FD{Int8, 2}(-1) > typemin(Int8)
@test typemin(Int8) < FD{Int8, 0}(-1) < typemax(Int8)
@test typemin(Int8) < FD{Int8, 2}(-1) < typemax(Int8)
@test !(typemax(Int8) < FD{Int8, 0}(-1) < typemin(Int8))
@test !(typemax(Int8) < FD{Int8, 2}(-1) < typemin(Int8))
@test !(typemin(Int8) > FD{Int8, 0}(-1) > typemax(Int8))
@test !(typemin(Int8) > FD{Int8, 2}(-1) > typemax(Int8))

# Different types
@test typemax(Int16) > FD{Int8, 0}(1) > typemin(Int16)
@test typemax(Int16) > FD{Int8, 2}(1) > typemin(Int16)
@test typemin(Int16) < FD{Int8, 0}(1) < typemax(Int16)
@test typemin(Int16) < FD{Int8, 2}(1) < typemax(Int16)
@test !(typemax(Int16) < FD{Int8, 0}(1) < typemin(Int16))
@test !(typemax(Int16) < FD{Int8, 2}(1) < typemin(Int16))
@test !(typemin(Int16) > FD{Int8, 0}(1) > typemax(Int16))
@test !(typemin(Int16) > FD{Int8, 2}(1) > typemax(Int16))

@test typemax(Int16) > FD{Int8, 0}(-1) > typemin(Int16)
@test typemax(Int16) > FD{Int8, 2}(-1) > typemin(Int16)
@test typemin(Int16) < FD{Int8, 0}(-1) < typemax(Int16)
@test typemin(Int16) < FD{Int8, 2}(-1) < typemax(Int16)
@test !(typemax(Int16) < FD{Int8, 0}(-1) < typemin(Int16))
@test !(typemax(Int16) < FD{Int8, 2}(-1) < typemin(Int16))
@test !(typemin(Int16) > FD{Int8, 0}(-1) > typemax(Int16))
@test !(typemin(Int16) > FD{Int8, 2}(-1) > typemax(Int16))

@test typemax(Int16) >= FD{Int8, 0}(0) >= typemin(Int16)
@test typemax(Int16) >= FD{Int8, 2}(0) >= typemin(Int16)
@test typemin(Int16) <= FD{Int8, 0}(0) <= typemax(Int16)
@test typemin(Int16) <= FD{Int8, 2}(0) <= typemax(Int16)
@test !(typemax(Int16) <= FD{Int8, 0}(-1) <= typemin(Int16))
@test !(typemax(Int16) <= FD{Int8, 2}(-1) <= typemin(Int16))
@test !(typemin(Int16) >= FD{Int8, 0}(-1) >= typemax(Int16))
@test !(typemin(Int16) >= FD{Int8, 2}(-1) >= typemax(Int16))
end
end

@testset "128-bit conversion correctness" begin
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@NHDaly
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@NHDaly NHDaly commented on ddee978 Dec 20, 2023

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Registration pull request created: JuliaRegistries/General/97511

Tip: Release Notes

Did you know you can add release notes too? Just add markdown formatted text underneath the comment after the text
"Release notes:" and it will be added to the registry PR, and if TagBot is installed it will also be added to the
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@JuliaRegistrator register

Release notes:

## Breaking changes

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To add them here just re-invoke and the PR will be updated.

Tagging

After the above pull request is merged, it is recommended that a tag is created on this repository for the registered package version.

This will be done automatically if the Julia TagBot GitHub Action is installed, or can be done manually through the github interface, or via:

git tag -a v0.5.2 -m "<description of version>" ddee9788c7085a5a1ceed2dd924750427a85d61d
git push origin v0.5.2

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