From 40a456e54a6d3a1ee496dc637132edbded36db9b Mon Sep 17 00:00:00 2001
From: Gary Talent <gary@drinkingtea.net>
Date: Wed, 1 Jan 2025 19:29:41 -0600
Subject: [PATCH] [ox/std] Add Vector::shrink_to_fit

---
 deps/ox/src/ox/std/test/CMakeLists.txt |  1 +
 deps/ox/src/ox/std/test/tests.cpp      | 30 ++++++++++++++++++++++++++
 deps/ox/src/ox/std/vector.hpp          | 20 +++++++++++++++++
 3 files changed, 51 insertions(+)

diff --git a/deps/ox/src/ox/std/test/CMakeLists.txt b/deps/ox/src/ox/std/test/CMakeLists.txt
index 9c395b9c..1ecad4ed 100644
--- a/deps/ox/src/ox/std/test/CMakeLists.txt
+++ b/deps/ox/src/ox/std/test/CMakeLists.txt
@@ -17,6 +17,7 @@ add_test("[ox/std] String" ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/StdTest "String")
 add_test("[ox/std] SmallMap" ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/StdTest "SmallMap")
 add_test("[ox/std] SmallMap2" ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/StdTest "SmallMap2")
 add_test("[ox/std] Vector" ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/StdTest "Vector")
+add_test("[ox/std] Vector::shrink_to_fit" ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/StdTest "Vector::shrink_to_fit")
 add_test("[ox/std] HashMap" ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/StdTest "HashMap")
 add_test("[ox/std] HeapMgr" ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/StdTest malloc)
 add_test("[ox/std] Serialize-Int" ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/StdTest "Serialize-Int")
diff --git a/deps/ox/src/ox/std/test/tests.cpp b/deps/ox/src/ox/std/test/tests.cpp
index ede7e60a..6325d151 100644
--- a/deps/ox/src/ox/std/test/tests.cpp
+++ b/deps/ox/src/ox/std/test/tests.cpp
@@ -237,6 +237,36 @@ OX_CLANG_NOWARN_END
 			return ox::Error(0);
 		}
 	},
+	{
+		"Vector::shrink_to_fit",
+		[] {
+			{
+				ox::Vector<ox::IString<8>> v;
+				v.reserve(50);
+				v.emplace_back("asdf");
+				v.emplace_back("aoeu");
+				auto const origData = v.data();
+				v.shrink_to_fit();
+				oxExpect(v[0], "asdf");
+				oxExpect(v[1], "aoeu");
+				oxExpect(v.capacity(), 2u);
+				oxAssert(origData != v.data(), "shrink_to_fit did not create a new allocation");
+			}
+			{
+				ox::Vector<ox::IString<8>> v;
+				v.reserve(2);
+				v.emplace_back("asdf");
+				v.emplace_back("aoeu");
+				auto const origData = v.data();
+				v.shrink_to_fit();
+				oxExpect(v[0], "asdf");
+				oxExpect(v[1], "aoeu");
+				oxExpect(v.capacity(), 2u);
+				oxAssert(origData == v.data(), "shrink_to_fit inappropriately created a new allocation");
+			}
+			return ox::Error{};
+		}
+	},
 	{
 		"SmallMap",
 		[] {
diff --git a/deps/ox/src/ox/std/vector.hpp b/deps/ox/src/ox/std/vector.hpp
index 7c8b5e33..c60c3bdd 100644
--- a/deps/ox/src/ox/std/vector.hpp
+++ b/deps/ox/src/ox/std/vector.hpp
@@ -313,6 +313,8 @@ class Vector: detail::VectorAllocator<T, Allocator, SmallVectorSize> {
 
 		constexpr void reserve(std::size_t cap) noexcept(useNoexcept);
 
+		constexpr void shrink_to_fit() noexcept(useNoexcept);
+
 	private:
 		constexpr void reserveInsert(
 				std::size_t cap, std::size_t pos, std::size_t offset = 1) noexcept(useNoexcept);
@@ -675,6 +677,24 @@ constexpr void Vector<T, SmallVectorSize, Allocator>::reserve(std::size_t cap) n
 	}
 }
 
+template<typename T, std::size_t SmallVectorSize, typename Allocator>
+constexpr void Vector<T, SmallVectorSize, Allocator>::shrink_to_fit() noexcept(useNoexcept)  {
+	if (m_size == m_cap) {
+		return;
+	}
+	const auto oldItems = m_items;
+	const auto oldCap = m_cap;
+	m_cap = m_size;
+	this->allocate(&m_items, m_size);
+	if (oldItems) { // move over old items
+		for (std::size_t i = 0; i < m_size; ++i) {
+			std::construct_at(&m_items[i], std::move(oldItems[i]));
+			oldItems[i].~T();
+		}
+		this->deallocate(oldItems, oldCap);
+	}
+}
+
 template<typename T, std::size_t SmallVectorSize, typename Allocator>
 constexpr void Vector<T, SmallVectorSize, Allocator>::reserveInsert(
 		std::size_t cap,