From b9d7ec228b03e2978b0e1d9f21dadd56b2f405e3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Mon, 29 Aug 2022 23:33:48 +0200
Subject: Small improvments.

---
 c/util.h | 60 +++++++++++++++++++++++++++++++++++-------------------------
 1 file changed, 35 insertions(+), 25 deletions(-)

(limited to 'c/util.h')

diff --git a/c/util.h b/c/util.h
index ffc6b57..f9e3057 100644
--- a/c/util.h
+++ b/c/util.h
@@ -19,42 +19,49 @@
 		_Exit(1);						\
 	})
 
+/* Scope guard. */
 template <typename F>
 struct Finally
 {
 	F f;
-	inline Finally(F f) : f(f) {}
+	inline Finally(F f) noexcept : f(f) {}
 	inline ~Finally() { f(); }
 };
 #define FINALLY Finally _ = [=]()
 
 template <typename T>
-inline void Delete(T v)
+inline void Delete(T v) noexcept
 {
     delete v;
 }
 
+/* Unique is similar to unique_ptr, but it is designed for pointers
+ * and handles of type T, where T is not an RAII class. Further, the
+ * managed object is assumed to be in an invalid state until checked
+ * with Good or Bad. Upon destruction, the object, if valid, is passed
+ * to a given destructor function F. */
 template <typename T, auto F = Delete<T>>
 struct Unique
 {
-	T v;
-	bool ok = true;
-	Unique() : ok(false) {}
-	Unique(T v) : v(v) {}
-	Unique& operator =(T v_)
+	union { T v; };
+	bool ok = false;
+	Unique() noexcept {}
+	Unique(T v) noexcept : v(v) {}
+	Unique& operator =(T v_) noexcept
 	{
-		if (ok)
+		if (ok) {
 			F(v);
+			v.~T();
+		}
 		v = v_;
-		ok = true;
+		ok = false;
 		return *this;
 	}
-	Unique(Unique&& other)
+	Unique(Unique&& other) noexcept : v(std::move(other.v)), ok(other.ok)
 	{
-		v = std::move(other.v);
 		other.ok = false;
 	}
-	Unique& operator =(Unique&& other)
+	Unique& operator =(Unique&& other) noexcept
 	{
 		if (ok)
 			F(v);
@@ -63,17 +70,20 @@ struct Unique
 		other.ok = false;
 		return *this;
 	}
-	bool Not(T u)
+	bool Good(T u) noexcept
 	{
-		if (v == u)
-			return ok = false;
-		else
-			return true;
+		return ok = v == u;
+	}
+	bool Bad(T u) noexcept
+	{
+		return ok = v != u;
 	}
 	~Unique()
 	{
-		if (ok)
+		if (ok) {
 			F(v);
+			v.~T();
+		}
 	}
 };
 
@@ -83,13 +93,13 @@ struct Buf
 {
 	T* data;
 	size_t c;
-	Buf(T* data, size_t c) : data(data), c(c) {}
-	Buf(std::basic_string<T>& s) : data(s.data()), c(s.capacity()) {}
-	template <size_t N> Buf(T (&data)[N]) : data(data), c(N) {}
-	operator T*() { return data; }
-	T& operator *() { return *data; }
-	T& operator [](size_t i) { return data[i]; }
-	Buf<T> operator +(size_t i) { return {data+i, c-i}; }
+	Buf(T* data, size_t c) noexcept : data(data), c(c) {}
+	Buf(std::basic_string<T>& s) noexcept : data(s.data()), c(s.capacity()) {}
+	template <size_t N> Buf(T (&data)[N]) noexcept : data(data), c(N) {}
+	operator T*() noexcept { return data; }
+	T& operator *() noexcept { return *data; }
+	T& operator [](size_t i) noexcept { return data[i]; }
+	Buf<T> operator +(size_t i) noexcept { return {data+i, c-i}; }
 	//T operator -(size_t i) { return {data-i, c+i}; }
 };
 
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