/usr/share/julia/base/grisu/fastprecision.jl is in julia-common 0.4.7-6.
This file is owned by root:root, with mode 0o644.
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# https://github.com/floitsch/double-conversion which has the following license
#
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#
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function roundweed(buffer,len,rest,tk,unit,kappa)
unit >= tk && return false, kappa
tk - unit <= unit && return false, kappa
tk - rest > rest && (tk - 2 * rest >= 2 * unit) && return true, kappa
if rest > unit && (tk - (rest - unit) <= (rest - unit))
buffer[len-1] += 1
for i = (len-1):-1:2
buffer[i] != 0x30 + 10 && break
buffer[i] = 0x30
buffer[i-1] += 1
end
if buffer[1] == 0x30 + 10
buffer[1] = 0x31
kappa += 1
end
return true, kappa
end
return false, kappa
end
function digitgen(w,buffer,requested_digits=1000)
unit::UInt64 = 1
one = Float(unit << -w.e, w.e)
integrals = w.s >> -one.e
fractionals = w.s & (one.s-1)
divisor, kappa = bigpowten(integrals, 64 + one.e)
len = 1
rest = 0
while kappa > 0
digit = div(integrals,divisor)
buffer[len] = 0x30 + digit
len += 1
requested_digits -= 1
integrals %= divisor
kappa -= 1
if requested_digits == 0
rest = (UInt64(integrals) << -one.e) + fractionals
r, kappa = roundweed(buffer, len, rest, UInt64(divisor) << -one.e,
unit,kappa)
return r, kappa, len
end
divisor = div(divisor,10)
end
while requested_digits > 0 && fractionals > unit
fractionals *= 10
unit *= 10
digit = fractionals >> -one.e
buffer[len] = 0x30 + digit
len += 1
requested_digits -= 1
fractionals &= one.s - 1
kappa -= 1
end
requested_digits != 0 && return false, kappa, len
r, kappa = roundweed(buffer,len,fractionals,one.s,
unit,kappa)
return r, kappa, len
end
function fastprecision(v,requested_digits,buffer=Array(UInt8,100))
f = normalize(Float64(v))
ten_mk_min_exp = kMinExp - (f.e + FloatSignificandSize)
ten_mk_max_exp = kMaxExp - (f.e + FloatSignificandSize)
cp = binexp_cache(ten_mk_min_exp,ten_mk_max_exp)
scaled_w = f * cp
r, kappa, len = digitgen(scaled_w,buffer,requested_digits)
decimal_exponent = -cp.de + kappa
return r, len, decimal_exponent+len-1
end
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