methods lcm, gcd, gcdx, rem, sign, signbit for periods (issue #60)

Author: Alexander-Barth

src/CFTime.jl

@@ -50,9 +50,12 @@ import Dates:
     len,
     monthday,
     yearmonth,
-    yearmonthday
+    yearmonthday,
+    value
 
-import Base: +, -, *, /, div, isless, string, show, convert, reinterpret, ==,
+import Base: +, -, *, /, div, rem, lcm, gcd, gcdx, isless,
+    abs, sign, signbit,
+    string, show, convert, reinterpret, ==,
     promote_rule, floor, mod, round, typemax, typemin
 
 include("constants.jl")

src/period.jl

@@ -24,6 +24,8 @@ _type(::Type{Period{T, Tfactor, Texponent}}) where {T, Tfactor, Texponent} = T
 _factor(::Type{Period{T, Tfactor, Texponent}}) where {T, Tfactor, Texponent} = unwrap(Tfactor)
 _exponent(::Type{Period{T, Tfactor, Texponent}}) where {T, Tfactor, Texponent} = unwrap(Texponent)
 
+Dates.value(p::Period) = p.duration
+
 function Base.zero(p::Period{T, Tfactor, Texponent}) where {T, Tfactor, Texponent}
     return Period{T, Tfactor, Texponent}(0)
 end
@@ -33,11 +35,11 @@ function Base.one(p::Period{T, Tfactor, Texponent}) where {T, Tfactor, Texponent
 end
 
 function Base.abs(p::Period{T, Tfactor, Texponent}) where {T, Tfactor, Texponent}
-    return Period{T, Tfactor, Texponent}(abs(Dates.value(p)))
+    return Period{T, Tfactor, Texponent}(abs(value(p)))
 end
 
-
-Dates.value(p::Period) = p.duration
+Base.sign(x::Period) = sign(value(x))
+Base.signbit(x::Period) = signbit(value(x))
 
 # helper functions for _timetuple
 @inline __tf(result, time) = result
@@ -228,16 +230,21 @@ end
 
 # operations between two CFTime.Periods (or Dates.Period)
 
-#   operators returning a CFTime.Period
-for op in (:+, :-, :mod)
+# operators returning a CFTime.Period
+for op in (:+, :-, :mod, :lcm, :gcd, :rem)
     @eval begin
         function $op(p1::Period{T, Tfactor, Texponent}, p2::Period{T, Tfactor, Texponent}) where {T, Tfactor, Texponent}
             return Period{T, Tfactor, Texponent}($op(p1.duration, p2.duration))
         end
     end
 end
 
-#   divisions and boolean functions
+function Base.gcdx(a::T, b::T) where {T <: Period}
+    (g, x, y) = gcdx(value(a), value(b))
+    return (T(g), x, y)
+end
+
+# operators not returning a CFTime.Period
 for op in (:/, :div, :(==), :isless)
     @eval begin
         function $op(p1::Period{T, Tfactor, Texponent}, p2::Period{T, Tfactor, Texponent}) where {T, Tfactor, Texponent}
@@ -247,7 +254,7 @@ for op in (:/, :div, :(==), :isless)
 end
 
 
-for op in (:+, :-, :/, :div, :mod, :(==), :isless)
+for op in (:+, :-, :/, :div, :mod, :(==), :isless, :lcm, :gcd, :gcdx, :rem)
     @eval begin
         $op(p1::Period, p2::Period) = $op(promote(p1, p2)...)
         $op(p1::Period, p2::Dates.Period) = $op(promote(p1, p2)...)
@@ -264,6 +271,7 @@ for op in (:*, :/, :div)
         end
     end
 end
+
 *(v::Number, p::Period) = p * v
 
 function -(p::Period{T, Tfactor, Texponent}) where {T, Tfactor, Texponent}

test/test_issues.jl

@@ -219,3 +219,26 @@ dt = DateTimeStandard(2021, 5, 7, 5, 4, 17, 9, 933)
 
 dt = DateTimeStandard(2021, 5, 7, 5, 4, 17, 9, 933)
 @test_throws InexactError convert(DateTime, dt)
+
+# issue #60
+
+@test sign(CFTime.Picosecond(-7)) == -1
+@test signbit(CFTime.Picosecond(-7)) == true
+@test abs(CFTime.Picosecond(-7)) == abs(CFTime.Picosecond(7))
+
+@test rem(CFTime.Picosecond(7), CFTime.Picosecond(3)) == CFTime.Picosecond(1)
+@test CFTime.Picosecond(7) % CFTime.Picosecond(3) == CFTime.Picosecond(1)
+
+@test lcm(CFTime.Picosecond(3), CFTime.Picosecond(4)) == CFTime.Picosecond(12)
+@test lcm(CFTime.Picosecond(3), Dates.Microsecond(4)) == CFTime.Picosecond(12_000_000)
+@test lcm(CFTime.Picosecond(3), CFTime.Femtosecond(4)) == CFTime.Femtosecond(3000)
+
+@test gcd(CFTime.Picosecond(12), CFTime.Picosecond(28)) == CFTime.Picosecond(4)
+
+a, b = CFTime.Picosecond(12), CFTime.Picosecond(28)
+(d, u, v) = gcdx(a, b)
+@test u * a + v * b == d
+
+a, b = CFTime.Picosecond(12), Dates.Microsecond(28)
+(d, u, v) = gcdx(a, b)
+@test u * a + v * b == d