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ndigits with negative base: error out instead of giving incorrect result #29148

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Merged
merged 2 commits into from
Sep 13, 2018
Merged

ndigits with negative base: error out instead of giving incorrect result #29148

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d8e001f
ndigits with negative base: error out instead of giving incorrect result
rfourquet Sep 12, 2018
d2c92b8
we might as well give a correct answer! (StefanKarpinski)
rfourquet Sep 13, 2018
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3 changes: 2 additions & 1 deletion base/intfuncs.jl
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Expand Up @@ -440,7 +440,8 @@ function ndigits0znb(x::Integer, b::Integer)
return d
end

ndigits0znb(x::Unsigned, b::Integer) = ndigits0znb(signed(x), b)
# do first division before conversion with signed here, which can otherwise overflow
ndigits0znb(x::Unsigned, b::Integer) = ndigits0znb(-signed(fld(x, -b)), b) + (x != 0)
ndigits0znb(x::Bool, b::Integer) = x % Int

# The suffix "pb" stands for "positive base"
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9 changes: 9 additions & 0 deletions test/intfuncs.jl
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Expand Up @@ -139,6 +139,15 @@ end
@test iszero([Base.ndigits0z(false, b) for b in [-20:-2;2:20]])
@test all(n -> n == 1, Base.ndigits0z(true, b) for b in [-20:-2;2:20])
@test all(n -> n == 1, ndigits(x, base=b) for b in [-20:-2;2:20] for x in [true, false])

# issue #29148
@test ndigits(typemax(UInt64), base=-2) == ndigits(big(typemax(UInt64)), base=-2)
for T in Base.BitInteger_types
n = rand(T)
b = -rand(2:100)
@test ndigits(n, base=b) == ndigits(big(n), base=b)
end

end
@testset "bin/oct/dec/hex/bits" begin
@test string(UInt32('3'), base = 2) == "110011"
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