added to_string for rng

src/typed-geometry/common/random.hh

@@ -54,6 +54,8 @@ public:
     constexpr bool operator==(splitmix const& rhs) const { return m_seed == rhs.m_seed; }
     constexpr bool operator!=(splitmix const& rhs) const { return m_seed != rhs.m_seed; }
 
+    constexpr u64 state() const { return m_seed; }
+
 private:
     u64 m_seed;
 };
@@ -97,6 +99,8 @@ public:
     constexpr bool operator==(xorshift const& rhs) const { return m_seed == rhs.m_seed; }
     constexpr bool operator!=(xorshift const& rhs) const { return m_seed != rhs.m_seed; }
 
+    constexpr u64 state() const { return m_seed; }
+
 private:
     u64 m_seed;
 };

src/typed-geometry/std/io.hh

@@ -30,6 +30,18 @@ std::basic_ostringstream<CharT, Traits> temp_sstream(std::basic_ostream<CharT, T
 }
 }
 
+//
+// =============================== Random ===============================
+//
+
+template <class CharT, class Traits>
+std::basic_ostream<CharT, Traits>& operator<<(std::basic_ostream<CharT, Traits>& out, xorshift const& val)
+{
+    auto ss = detail::temp_sstream(out);
+    ss << "rng(" << std::hex << val.state() << ")";
+    return out << ss.str();
+}
+
 //
 // =============================== Scalars ===============================
 //