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libgrisu = dlopen("libgrisu")
module Grisu
import Base.*
export print_shortest
export @grisu_ccall, NEG, DIGITS, BUFLEN, LEN, POINT
const NEG = Array(Bool,1)
const DIGITS = Array(Uint8,309+17)
const BUFLEN = int32(length(DIGITS)+1)
const LEN = Array(Int32,1)
const POINT = Array(Int32,1)
macro grisu_ccall(value, mode, ndigits)
quote
ccall(dlsym(Base.libgrisu, :grisu), Void,
(Float64, Int32, Int32, Ptr{Uint8}, Int32,
Ptr{Bool}, Ptr{Int32}, Ptr{Int32}),
$(esc(value)), $(esc(mode)), $(esc(ndigits)),
DIGITS, BUFLEN, NEG, LEN, POINT)
end
end
const SHORTEST = int32(0) # shortest exact representation for doubles
const SHORTEST_SINGLE = int32(1) # shortest exact representation for singles
const FIXED = int32(2) # fixed number of trailing decimal points
const PRECISION = int32(3) # fixed precision regardless of magnitude
# wrapper for the core grisu function, primarily for debugging
global grisu, grisu_fix, grisu_sig
function grisu(x::Float64, mode::Integer, ndigits::Integer)
if !isfinite(x); error("non-finite value: $x"); end
if ndigits < 0; error("negative digits requested"); end
@grisu_ccall x mode ndigits
NEG[1], DIGITS[1:LEN[1]], POINT[1]
end
grisu(x::Float64) = grisu(x, SHORTEST, int32(0))
grisu(x::Float32) = grisu(float64(x), SHORTEST_SINGLE, int32(0))
grisu(x::Real) = grisu(float(x))
function grisu_fix(x::Real, n::Integer)
if n > 17; n = 17; end
grisu(float64(x), FIXED, int32(n))
end
function grisu_sig(x::Real, n::Integer)
if n > 309; n = 309; end
grisu(float64(x), PRECISION, int32(n))
end
function _show(io, x::FloatingPoint, mode::Int32, n::Int)
if isnan(x); return write(io, "NaN"); end
if isinf(x); return write(io, x < 0 ? "-Inf" : "Inf"); end
@grisu_ccall x mode n
pdigits = pointer(DIGITS)
neg = NEG[1]
len = LEN[1]
pt = POINT[1]
if mode == PRECISION
while len > 1 && DIGITS[len] == '0'
len -= 1
end
end
if neg
write(io, '-')
end
if pt <= -4 || pt > 6 # .00001 to 100000.
# => #.#######e###
write(io, pdigits, 1)
write(io, '.')
if len > 1
write(io, pdigits+1, len-1)
else
write(io, '0')
end
write(io, 'e')
write(io, dec(pt-1))
elseif pt <= 0
# => 0.00########
write(io, "0.")
while pt < 0
write(io, '0')
pt += 1
end
write(io, pdigits, len)
elseif pt >= len
# => ########00.0
write(io, pdigits, len)
while pt > len
write(io, '0')
len += 1
end
write(io, ".0")
else # => ####.####
write(io, pdigits, pt)
write(io, '.')
write(io, pdigits+pt, len-pt)
end
nothing
end
show(io, x::Float64) = _show(io, x, SHORTEST, 0)
show(io, x::Float32) = _show(io, x, SHORTEST_SINGLE, 0)
showcompact(io, x::FloatingPoint) = _show(io, x, PRECISION, 6)
# normal:
# 0 < pt < len ####.#### len+1
# pt <= 0 .000######## len-pt+1
# len <= pt (dot) ########000. pt+1
# len <= pt (no dot) ########000 pt
# exponential:
# pt <= 0 ########e-### len+k+2
# 0 < pt ########e### len+k+1
function _print_shortest(io, x::FloatingPoint, dot::Bool, mode::Int32)
if isnan(x); return write(io, "NaN"); end
if isinf(x); return write(io, x < 0 ? "-Inf" : "Inf"); end
@grisu_ccall x mode 0
pdigits = pointer(DIGITS)
neg = NEG[1]
len = LEN[1]
pt = POINT[1]
if neg
write(io, '-')
end
e = pt-len
k = -9<=e<=9 ? 1 : 2
if -pt > k+1 || e+dot > k+1
# => ########e###
write(io, pdigits+0, len)
write(io, 'e')
write(io, dec(e))
elseif pt <= 0
# => .000########
write(io, '.')
while pt < 0
write(io, '0')
pt += 1
end
write(io, pdigits+0, len)
elseif e >= dot
# => ########000.
write(io, pdigits+0, len)
while e > 0
write(io, '0')
e -= 1
end
if dot
write(io, '.')
end
else # => ####.####
write(io, pdigits+0, pt)
write(io, '.')
write(io, pdigits+pt, len-pt)
end
nothing
end
print_shortest(io, x::Float64, dot::Bool) = _print_shortest(io, x, dot, SHORTEST)
print_shortest(io, x::Float32, dot::Bool) = _print_shortest(io, x, dot, SHORTEST_SINGLE)
print_shortest(io, x::Union(FloatingPoint,Integer)) = print_shortest(io, float(x), false)
end # module
import Base.Grisu.print_shortest
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