Merge pull request #1 from swift-nav/in-range-fixup

Implement `inRange` for floating-point types

include/rapidcheck/shrink/Shrink.hpp

@@ -10,7 +10,7 @@ namespace rc {
 namespace shrink {
 namespace detail {
 
-template <typename T>
+template <typename T, typename Enable = void>
 class TowardsSeq {
 public:
   using UInt = typename std::make_unsigned<T>::type;
@@ -36,6 +36,35 @@ class TowardsSeq {
   bool m_down;
 };
 
+template <typename T>
+class TowardsSeq<
+    T,
+    typename std::enable_if<std::is_floating_point<T>::value>::type> {
+public:
+  TowardsSeq(T value, T target)
+      : m_value(value)
+      , m_target(target) {}
+
+  Maybe<T> operator()() {
+    if (m_value == m_target) {
+      return Nothing;
+    }
+
+    T new_value = (m_value / 2) + (m_target / 2);
+
+    if (new_value == m_value) {
+      new_value = m_target;
+    }
+
+    m_value = new_value;
+    return m_value;
+  }
+
+private:
+  T m_value;
+  T m_target;
+};
+
 template <typename Container>
 class RemoveChunksSeq {
 public: