From 0143b6e7148692d02bfa31bb7ed640b4f9a3f80e Mon Sep 17 00:00:00 2001
From: Ludovic 'Archivist' Lagouardette <ludovic@nekoit.xyz>
Date: Tue, 28 Nov 2023 13:01:56 +0100
Subject: [PATCH] fixed a buffer detail and added fail function

---
 include/gp/containers/buffer.hpp |  8 ++++----
 include/gp_config.hpp            | 24 +++++++++++++++++-------
 2 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/include/gp/containers/buffer.hpp b/include/gp/containers/buffer.hpp
index 1e093f6..130acc3 100644
--- a/include/gp/containers/buffer.hpp
+++ b/include/gp/containers/buffer.hpp
@@ -213,14 +213,14 @@ namespace gp{
 			return hold_same_data<T>(this->slice_start(oth.size()), oth);
 		}
 		
-		optional<T> front() {
+		optional<gp::reference_wrapper<T>> front() {
 			if(size() == 0) return nullopt;
-			return *begin();
+			return gp::ref(*slice_start(1).begin());
 		}
 		
-		optional<T> back() {
+		optional<gp::reference_wrapper<T>> back() {
 			if(size() == 0) return nullopt;
-			return *slice_end(1).begin();
+			return gp::ref(*slice_end(1).begin());
 		}
 	};
 	
diff --git a/include/gp_config.hpp b/include/gp_config.hpp
index 068f6b5..eab16b9 100644
--- a/include/gp_config.hpp
+++ b/include/gp_config.hpp
@@ -114,9 +114,6 @@ namespace gp_config{
 	 */
 	constexpr bool has_buffer_bounds = true;
 
-	// 
-	// 
-	// 
 	/**
 	 * @brief A value used to determine the strength used by random number generators
 	 * 
@@ -129,7 +126,7 @@ namespace gp_config{
 	/**
 	 * @brief an exception that represents an assertion failure
 	 */
-	struct assert_failure{
+	struct assert_failure : std::exception {
 		assert_failure(const char* reason)
 		: what_str{reason}
 		{}
@@ -141,15 +138,28 @@ namespace gp_config{
 	 * @brief UNUSED
 	 */
 	constexpr size_t assert_buffer_size = 0;
+	
+	constexpr auto fail =  [] [[noreturn]] (auto reason) noexcept(not has_exceptions) {
+		if constexpr (has_exceptions) {
+			throw assert_failure(reason);
+		} else {
+			volatile uint8_t n = 0;
+			{
+				failure_point:
+				n = n + 1;
+				goto failure_point;
+			}
+		}
+	};
 
 	/**
 	 * @brief an assertion function
 	 */
-	constexpr auto assertion = [](bool pred, const char* reason) -> void{
+	constexpr auto assertion = [](bool pred, const char* reason)
+		noexcept(std::is_nothrow_invocable_v<decltype(fail), decltype(reason)>) -> void {
 		if(!pred) {
 			log_failure(reason);
-			if constexpr (has_exceptions)
-				throw assert_failure(reason);
+			fail(reason);
 		}
 	};