From e31832f5d1bfa64b1848e4adb148286934b488fb Mon Sep 17 00:00:00 2001
From: psi <ryo.hirafuji@link-u.co.jp>
Date: Sun, 3 Apr 2022 15:06:44 +0900
Subject: [PATCH] add

---
 src/avif/math/Fraction.hpp |  4 ++++
 test/math/FractionTest.cpp | 10 ++++++++++
 2 files changed, 14 insertions(+)

diff --git a/src/avif/math/Fraction.hpp b/src/avif/math/Fraction.hpp
index d8eefc0..1f3f24b 100644
--- a/src/avif/math/Fraction.hpp
+++ b/src/avif/math/Fraction.hpp
@@ -31,6 +31,10 @@ struct Fraction {
     int32_t const r = std::lcm(std::abs(denominator_), std::abs(b.denominator_));
     return Fraction((r / denominator_ * numerator_) - (r / b.denominator_ * b.numerator_), r).reduce();
   }
+  [[ nodiscard ]] constexpr Fraction add(Fraction const& b) const {
+    int32_t const r = std::lcm(std::abs(denominator_), std::abs(b.denominator_));
+    return Fraction((r / denominator_ * numerator_) + (r / b.denominator_ * b.numerator_), r).reduce();
+  }
   [[ nodiscard ]] constexpr int32_t numerator() const {
     return numerator_;
   }
diff --git a/test/math/FractionTest.cpp b/test/math/FractionTest.cpp
index bde2968..71c2ed8 100644
--- a/test/math/FractionTest.cpp
+++ b/test/math/FractionTest.cpp
@@ -48,3 +48,13 @@ TEST(FractionTest, Minus) {
   ASSERT_EQ(-1, v.numerator());
   ASSERT_EQ(2, v.denominator());
 }
+
+TEST(FractionTest, Add) {
+  using avif::math::Fraction;
+
+  auto const one = Fraction(1, 1);
+  auto const half = one.div(2);
+  auto const v = half.add(one);
+  ASSERT_EQ(3, v.numerator());
+  ASSERT_EQ(2, v.denominator());
+}