From c75ff7881fdb6e55d8bc9a9047526a4ba18106df Mon Sep 17 00:00:00 2001
From: Gary Talent <gary@drinkingtea.net>
Date: Fri, 3 Mar 2023 23:24:38 -0600
Subject: [PATCH] [ox/std] Add UUID::isNull()

---
 deps/ox/src/ox/std/uuid.cpp |  3 +++
 deps/ox/src/ox/std/uuid.hpp | 18 +++++++++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/deps/ox/src/ox/std/uuid.cpp b/deps/ox/src/ox/std/uuid.cpp
index 89f5be52..a406309a 100644
--- a/deps/ox/src/ox/std/uuid.cpp
+++ b/deps/ox/src/ox/std/uuid.cpp
@@ -34,4 +34,7 @@ Result<UUID> UUID::generate() noexcept {
 	return out;
 }
 
+static_assert(UUID{}.isNull());
+static_assert(!UUID::fromString("34AF4809-043D-4348-B720-2B454E5678C7").value.isNull());
+
 }
diff --git a/deps/ox/src/ox/std/uuid.hpp b/deps/ox/src/ox/std/uuid.hpp
index 0e227e63..833521aa 100644
--- a/deps/ox/src/ox/std/uuid.hpp
+++ b/deps/ox/src/ox/std/uuid.hpp
@@ -107,6 +107,22 @@ class UUID {
 			return m_value;
 		}
 
+		[[nodiscard]]
+		constexpr auto isNull() const noexcept {
+			if (std::is_constant_evaluated()) {
+				for (auto v : m_value) {
+					if (v) {
+						return false;
+					}
+				}
+				return true;
+			} else {
+				constexpr uint64_t zero = 0;
+				return ox::memcmp(&zero, m_value.data() + 0, 8) == 0
+				    && ox::memcmp(&zero, m_value.data() + 8, 8) == 0;
+			}
+		}
+
 		static constexpr ox::Result<ox::UUID> fromString(ox::CRStringView s) noexcept {
 			if (s.len() < 36) {
 				return OxError(1, "Insufficient data contain complete UUID");
@@ -135,7 +151,7 @@ class UUID {
 			UUIDStr out;
 			auto valueI = 0u;
 			constexpr auto printChars = [](
-					ox::BString<36> *out,
+					UUIDStr *out,
 					const Array<uint8_t, 16> &value,
 					std::size_t cnt,
 					unsigned valueI) {