From 2cf1c151161ca92142a820fb5ff63dd3ba160b57 Mon Sep 17 00:00:00 2001
From: kimikage <kimikage.ceo@gmail.com>
Date: Tue, 24 Dec 2019 02:57:18 +0900
Subject: [PATCH] Fix `isinteger` and Commonize predicates (e.g. `isnan`)

---
 src/FixedPointNumbers.jl |  5 ++++-
 src/normed.jl            |  4 ----
 test/fixed.jl            | 33 ++++++++++++++++++++++++++++++++-
 test/normed.jl           | 29 ++++++++++++++++++++++++++---
 4 files changed, 62 insertions(+), 9 deletions(-)

diff --git a/src/FixedPointNumbers.jl b/src/FixedPointNumbers.jl
index f59013a5..ffb9962f 100644
--- a/src/FixedPointNumbers.jl
+++ b/src/FixedPointNumbers.jl
@@ -62,7 +62,10 @@ function isapprox(x::FixedPoint, y::FixedPoint; rtol=0, atol=max(eps(x), eps(y))
 end
 
 # predicates
-isinteger(x::FixedPoint{T,f}) where {T,f} = (x.i&(1<<f-1)) == 0
+isinteger(x::FixedPoint) = x == trunc(x) # TODO: use floor(x) when dropping support for Fixed{Int8,8}
+isfinite(x::FixedPoint) = true
+isnan(x::FixedPoint) = false
+isinf(x::FixedPoint) = false
 
 # identities
 zero(::Type{X}) where {X <: FixedPoint} = X(zero(rawtype(X)), 0)
diff --git a/src/normed.jl b/src/normed.jl
index 4b89d3e3..51924ab1 100644
--- a/src/normed.jl
+++ b/src/normed.jl
@@ -268,10 +268,6 @@ function round(::Type{Ti}, x::Normed) where {Ti <: Integer}
     convert(Ti, r > (rawone(x) >> 0x1) ? d + oneunit(rawtype(x)) : d)
 end
 
-isfinite(x::Normed) = true
-isnan(x::Normed) = false
-isinf(x::Normed) = false
-
 # Iteration
 # The main subtlety here is that iterating over N0f8(0):N0f8(1) will wrap around
 # unless we iterate using a wider type
diff --git a/test/fixed.jl b/test/fixed.jl
index e0038088..63fb60cb 100644
--- a/test/fixed.jl
+++ b/test/fixed.jl
@@ -17,7 +17,6 @@ function test_fixed(::Type{T}, f) where {T}
         if !(typemin(T) < x <= typemax(T))
             continue
         end
-        # isinteger(x) && @show x
         fx = convert(T,x)
         @test convert(T,convert(Float64, fx)) == fx
         @test convert(T,convert(Float64, -fx)) == -fx
@@ -243,6 +242,38 @@ end
     @test isa(float(one(Fixed{Int32,25})), Float64)
 end
 
+@testset "predicates" begin
+    @test isfinite(1Q7f8)
+    @test !isnan(1Q7f8)
+    @test !isinf(1Q7f8)
+
+    @testset "isinteger" begin
+        for T in (Int8, Int16)
+            @testset "isinteger(::Fixed{$T,$f})" for f = 0:bitwidth(T)-1
+                F = Fixed{T,f}
+                xs = typemin(F):eps(F):typemax(F)
+                @test all(x -> isinteger(x) == isinteger(float(x)), xs)
+            end
+        end
+        for T in (Int32, Int64)
+            @testset "isinteger(::Fixed{$T,$f})" for f = 0:bitwidth(T)-1
+                F = Fixed{T,f}
+                fzero, fmax, fmin = zero(F), typemax(F), typemin(F)
+                if f == 0
+                    @test isinteger(fzero) & isinteger(fmax) & isinteger(fmin)
+                else
+                    @test isinteger(fzero) & !isinteger(fmax) & isinteger(fmin)
+                end
+            end
+        end
+        @testset "isinteger(::Fixed{Int8,8})" begin # TODO: remove this testset
+            @test !isinteger(Fixed{Int8,8}(-0.5))
+            @test isinteger(Fixed{Int8,8}(0.0))
+            @test !isinteger(Fixed{Int8,8}(127/256))
+        end
+    end
+end
+
 @testset "Show" begin
     x = Fixed{Int32,5}(0.25)
     iob = IOBuffer()
diff --git a/test/normed.jl b/test/normed.jl
index 80c5949c..0151ba14 100644
--- a/test/normed.jl
+++ b/test/normed.jl
@@ -80,9 +80,6 @@ end
 @testset "conversion" begin
     x = N0f8(0.5)
     @test convert(N0f8, x) === x
-    @test isfinite(x) == true
-    @test isnan(x) == false
-    @test isinf(x) == false
 
     @test convert(N0f8,  1.1/typemax(UInt8)) == eps(N0f8)
     @test convert(N6f10, 1.1/typemax(UInt16)*64) == eps(N6f10)
@@ -334,6 +331,32 @@ end
     @test_throws OverflowError length(NInt1(0):NInt1(1):typemax(NInt1))
 end
 
+@testset "predicates" begin
+    @test isfinite(1N8f8)
+    @test !isnan(1N8f8)
+    @test !isinf(1N8f8)
+
+    @testset "isinteger" begin
+        for T in (UInt8, UInt16)
+            @testset "isinteger(::Normed{$T,$f})" for f = 1:bitwidth(T)
+                N = Normed{T,f}
+                xs = typemin(N):eps(N):typemax(N)
+                @test all(x -> isinteger(x) == isinteger(float(x)), xs)
+            end
+        end
+        for T in (UInt32, UInt64)
+            @testset "isinteger(::Normed{$T,$f})" for f = 1:bitwidth(T)
+                N = Normed{T,f}
+                if f == 1
+                    @test isinteger(zero(N)) & isinteger(oneunit(N))
+                else
+                    @test !isinteger(oneunit(N) - eps(N)) & isinteger(oneunit(N))
+                end
+            end
+        end
+    end
+end
+
 @testset "Promotion within Normed" begin
     @test @inferred(promote(N0f8(0.2), N0f8(0.8))) ===
         (N0f8(0.2), N0f8(0.8))