Add bitstring for FixedPoint numbers (#195)

Author: kimikage

src/FixedPointNumbers.jl

@@ -1,8 +1,8 @@
 module FixedPointNumbers
 
 import Base: ==, <, <=, -, +, *, /, ~, isapprox,
-             convert, promote_rule, show, isinteger, abs, decompose,
-             isnan, isinf, isfinite,
+             convert, promote_rule, show, bitstring, abs, decompose,
+             isnan, isinf, isfinite, isinteger,
              zero, oneunit, one, typemin, typemax, floatmin, floatmax, eps, reinterpret,
              float, trunc, round, floor, ceil, bswap,
              div, fld, rem, mod, mod1, fld1, min, max, minmax,
@@ -171,6 +171,8 @@ function minmax(x::X, y::X) where {X <: FixedPoint}
     X(a,0), X(b,0)
 end
 
+bitstring(x::FixedPoint) = bitstring(x.i)
+
 bswap(x::X) where {X <: FixedPoint} = sizeof(X) == 1 ? x : X(bswap(x.i), 0)
 
 for f in (:zero, :oneunit, :one, :eps, :rawone, :rawtype, :floattype)

test/fixed.jl

@@ -59,14 +59,17 @@ end
     @test_throws DomainError zero(Fixed{Int16,17})
 end
 
-@testset "reinterpret" begin
+@testset "reinterpret/bitstring" begin
     @test reinterpret(Q0f7, signed(0xa2)) === -0.734375Q0f7
     @test reinterpret(Q5f10, signed(0x00a2)) === 0.158203125Q5f10
 
     @test reinterpret(reinterpret(Q0f7, signed(0xa2))) === signed(0xa2)
     @test reinterpret(reinterpret(Q5f10, signed(0x00a2))) === signed(0x00a2)
 
     @test reinterpret(Int8, 0.5Q0f7) === signed(0x40)
+
+    @test bitstring(reinterpret(Q0f7, signed(0xa2)))    === "10100010"
+    @test bitstring(reinterpret(Q5f10, signed(0x00a2))) === "0000000010100010"
 end
 
 @testset "masks" begin

test/normed.jl

@@ -8,7 +8,7 @@ using FixedPointNumbers: bitwidth
     @test_throws DomainError zero(Normed{UInt16,17})
 end
 
-@testset "reinterpret" begin
+@testset "reinterpret/bitstring" begin
     @test reinterpret(N0f8, 0xa2).i  === 0xa2
     @test reinterpret(N6f10, 0x1fa2).i === 0x1fa2
     @test reinterpret(N4f12, 0x1fa2).i === 0x1fa2
@@ -23,6 +23,9 @@ end
 
     @test reinterpret(UInt8, 1N0f8) === 0xff
 
+    @test bitstring(reinterpret(N0f8, 0xa2))    === "10100010"
+    @test bitstring(reinterpret(N6f10, 0x00a2)) === "0000000010100010"
+
     @test 0.635N0f8   == N0f8(0.635)
     @test 0.635N6f10 == N6f10(0.635)
     @test 0.635N4f12 == N4f12(0.635)