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Reimplement show #60

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merged 2 commits into from
Feb 16, 2018
Merged

Reimplement show #60

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59f64e9
Reimplement show
jmkuhn Feb 14, 2018
d12a43c
Review updates
jmkuhn Feb 16, 2018
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2 changes: 1 addition & 1 deletion REQUIRE
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Original file line number Diff line number Diff line change
@@ -1,3 +1,3 @@
julia 0.6
Compat 0.46.0
Compat 0.53.0
BinDeps
87 changes: 79 additions & 8 deletions src/DecFP.jl
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Expand Up @@ -3,6 +3,23 @@ module DecFP

using Compat, Compat.Printf, Compat.Unicode

# When Compat PR #491 is merged, REQUIRE that version and delete this
# 0.7.0-DEV.3469
@static if !isdefined(Base, :GC)
@eval module GC
using Base: gc
const enable = Base.gc_enable
@static if !isdefined(Base, Symbol("@gc_preserve"))
macro preserve(args...)
esc(args[end])
end
else
@eval const $(Symbol("@preserve")) = Base.$(Symbol("@gc_preserve"))
end
end
export GC
end

export Dec32, Dec64, Dec128, @d_str, @d32_str, @d64_str, @d128_str

const libbid = joinpath(dirname(@__FILE__), "..", "deps", "libbid$(Sys.WORD_SIZE)")
Expand Down Expand Up @@ -71,14 +88,6 @@ function isnanstr(s::AbstractString)
return true
end

function Base.show(io::IO, x::DecimalFloatingPoint)
s = @sprintf("%g", x)
if contains(s, r"^-?\d+$")
s *= ".0"
end
print(io, s)
end

for w in (32,64,128)
BID = Symbol(string("Dec",w))
Ti = eval(Symbol(string("UInt",w)))
Expand All @@ -105,6 +114,62 @@ for w in (32,64,128)

$BID(x::AbstractString) = parse($BID, x)

function Base.show(io::IO, x::$BID)
isnan(x) && (write(io, "NaN"); return)
isinf(x) && (write(io, signbit(x) ? "-Inf" : "Inf"); return)
x == 0 && (write(io, signbit(x) ? "-0.0" : "0.0"); return)
ccall(($(bidsym(w,"to_string")), libbid), Cvoid, (Ptr{UInt8}, $BID), _buffer, x)
if _buffer[1] == UInt8('-')
write(io, '-')
end
normalized_exponent = nox(ccall(($(bidsym(w,"ilogb")), libbid), Cint, ($BID,), x))
lastdigitindex = Compat.findfirst(equalto(UInt8('E')), _buffer) - 1
lastnonzeroindex = Compat.findlast(!equalto(UInt8('0')), view(_buffer, 1:lastdigitindex))
if -5 < normalized_exponent < 6
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Why not just set a variable here for the pointer to _buffer, i.e. pnt = pointer(buffer)?
pointer(_buffer, 2) would become pnt + 1.

# %f
if normalized_exponent >= 0
if normalized_exponent >= lastnonzeroindex - 2
GC.@preserve _buffer unsafe_write(io, pointer(_buffer, 2), lastnonzeroindex - 1)
writezeros(io, normalized_exponent - lastnonzeroindex + 2)
write(io, ".0")
else
GC.@preserve _buffer unsafe_write(io, pointer(_buffer, 2), normalized_exponent + 1)
write(io, '.')
GC.@preserve _buffer unsafe_write(io, pointer(_buffer, normalized_exponent + 3), lastnonzeroindex - normalized_exponent - 2)
end
else
write(io, "0.")
writezeros(io, -normalized_exponent - 1)
GC.@preserve _buffer unsafe_write(io, pointer(_buffer, 2), lastnonzeroindex - 1)
end
else
# %e
write(io, _buffer[2], '.')
if lastnonzeroindex == 2
write(io, '0')
else
GC.@preserve _buffer unsafe_write(io, pointer(_buffer, 3), lastnonzeroindex - 2)
end
write(io, 'e')
if normalized_exponent < 0
write(io, '-')
normalized_exponent = -normalized_exponent
end
b_lb = div(normalized_exponent, 10)
b = 1
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Shouldn't this use a table, or in some way do fewer multiplications?

while b <= b_lb
b *= 10
end
r = normalized_exponent
while b > 0
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This whole loop concerns me, it seems to be doing quite a lot of divisions for each digit output.
Can't you start outputting from the end, and then divide by 10, and get the remainder, every time through the loop.

q, r = divrem(r, b)
write(io, UInt8('0') + (q%UInt8))
b = div(b, 10)
end
end
return
end

function Base.Printf.fix_dec(x::$BID, n::Int)
if n > length(DIGITS) - 1
n = length(DIGITS) - 1
Expand Down Expand Up @@ -369,4 +434,10 @@ function xchk(x, exc::Type{E}, args...; mask::Integer=0x3f) where {E<:Exception}
return x
end

function writezeros(io::IO, n::Int)
for i = 1:n
write(io, UInt8('0'))
end
end

end # module
19 changes: 19 additions & 0 deletions test/runtests.jl
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Expand Up @@ -42,6 +42,25 @@ for T in (Dec32, Dec64, Dec128)
@test parse(T, "0.1")::T == T(1//10)
@test T("0.1")::T == T(1//10)

io = IOBuffer()
show(io, T("NaN")); @test String(take!(io)) == "NaN"
show(io, T("Inf")); @test String(take!(io)) == "Inf"
show(io, T("-Inf")); @test String(take!(io)) == "-Inf"
show(io, T("0")); @test String(take!(io)) == "0.0"
show(io, T("-0")); @test String(take!(io)) == "-0.0"
show(io, T("1")); @test String(take!(io)) == "1.0"
show(io, T("-1")); @test String(take!(io)) == "-1.0"
show(io, T("1.000")); @test String(take!(io)) == "1.0"
show(io, T("1e5")); @test String(take!(io)) == "100000.0"
show(io, T("1e6")); @test String(take!(io)) == "1.0e6"
show(io, T("1.23456e6")); @test String(take!(io)) == "1.23456e6"
show(io, T("1e-1")); @test String(take!(io)) == "0.1"
show(io, T("1e-4")); @test String(take!(io)) == "0.0001"
show(io, T("1e-5")); @test String(take!(io)) == "1.0e-5"
show(io, T("1.20e3")); @test String(take!(io)) == "1200.0"
show(io, T("123.456")); @test String(take!(io)) == "123.456"
show(io, T("0.00123456")); @test String(take!(io)) == "0.00123456"

# some Dec128 tests fail due to Issue #47
if T != Dec128
@test @sprintf("%7.2f", T("1.2345")) == " 1.23"
Expand Down