From 417c17a3f1e6cbd885dd28dc6f4757ac8c6bf50e Mon Sep 17 00:00:00 2001
From: shad0wshayd3 <shad0wshayd3@users.noreply.github.com>
Date: Tue, 19 Nov 2024 23:36:59 -0700
Subject: [PATCH] feat: improve `Relocation` & `Utilities` (#302)

changes:
* add second template arg to applicable `Relocation::write_` funcs for
address offset
* remove `AllocTrampoline` from `stl::write_*` funcs, this is bad
practice
* normalize `stl::write_*` support for structs with `std::uintptr_t`,
`REL::ID`, `REL::Offset`, `REL::Relocation<std::uintptr_t>` static
`address` members
---
 include/REL/Relocation.h | 16 ++++-----
 include/SFSE/Utilities.h | 77 +++++++++++++++++++++++++++++++---------
 2 files changed, 69 insertions(+), 24 deletions(-)

diff --git a/include/REL/Relocation.h b/include/REL/Relocation.h
index af3642dc..3c829e7a 100644
--- a/include/REL/Relocation.h
+++ b/include/REL/Relocation.h
@@ -337,32 +337,32 @@ namespace REL
 			safe_write(address(), a_data.data(), a_data.size_bytes());
 		}
 
-		template <std::size_t N>
+		template <std::size_t N, std::ptrdiff_t O = 0>
 		std::uintptr_t write_branch(const std::uintptr_t a_dst)
 			requires(std::same_as<value_type, std::uintptr_t>)
 		{
-			return SFSE::GetTrampoline().write_branch<N>(address(), a_dst);
+			return SFSE::GetTrampoline().write_branch<N>(address() + O, a_dst);
 		}
 
-		template <std::size_t N, class F>
+		template <std::size_t N, std::ptrdiff_t O = 0, class F>
 		std::uintptr_t write_branch(const F a_dst)
 			requires(std::same_as<value_type, std::uintptr_t>)
 		{
-			return SFSE::GetTrampoline().write_branch<N>(address(), stl::unrestricted_cast<std::uintptr_t>(a_dst));
+			return SFSE::GetTrampoline().write_branch<N>(address() + O, stl::unrestricted_cast<std::uintptr_t>(a_dst));
 		}
 
-		template <std::size_t N>
+		template <std::size_t N, std::ptrdiff_t O = 0>
 		std::uintptr_t write_call(const std::uintptr_t a_dst)
 			requires(std::same_as<value_type, std::uintptr_t>)
 		{
-			return SFSE::GetTrampoline().write_call<N>(address(), a_dst);
+			return SFSE::GetTrampoline().write_call<N>(address() + O, a_dst);
 		}
 
-		template <std::size_t N, class F>
+		template <std::size_t N, std::ptrdiff_t O = 0, class F>
 		std::uintptr_t write_call(const F a_dst)
 			requires(std::same_as<value_type, std::uintptr_t>)
 		{
-			return SFSE::GetTrampoline().write_call<N>(address(), stl::unrestricted_cast<std::uintptr_t>(a_dst));
+			return SFSE::GetTrampoline().write_call<N>(address() + O, stl::unrestricted_cast<std::uintptr_t>(a_dst));
 		}
 
 		void write_fill(const std::uint8_t a_value, const std::size_t a_count)
diff --git a/include/SFSE/Utilities.h b/include/SFSE/Utilities.h
index 2ff6cdd3..33d8dcaa 100644
--- a/include/SFSE/Utilities.h
+++ b/include/SFSE/Utilities.h
@@ -5,39 +5,84 @@
 
 namespace SFSE::stl
 {
-	template <class T, std::size_t Size = 5>
+	template <class T, std::size_t N = 5>
 	constexpr void write_thunk_call(const std::uintptr_t a_address) noexcept
 	{
-		AllocTrampoline(14);
-		auto& trampoline = GetTrampoline();
-		T::func = trampoline.write_call<Size>(a_address, T::thunk);
+		T::func = GetTrampoline().write_call<N>(a_address, T::thunk);
 	}
 
-	template <class T, std::size_t Size = 5>
+	template <class T, std::size_t N = 5, class U>
+	constexpr void write_thunk_call(const U a_id) noexcept
+		requires(std::is_same_v<U, REL::ID> || std::is_same_v<U, REL::Offset>)
+	{
+		T::func = GetTrampoline().write_call<N>(a_id.address(), T::thunk);
+	}
+
+	template <class T, std::size_t N = 5, class U>
+	constexpr void write_thunk_call(const REL::Relocation<U> a_id) noexcept
+		requires(std::is_same_v<typename REL::Relocation<U>::value_type, std::uintptr_t>)
+	{
+		T::func = GetTrampoline().write_call<N>(a_id.address(), T::thunk);
+	}
+
+	template <class T, std::size_t N = 5>
 	constexpr void write_thunk_call() noexcept
 	{
-		write_thunk_call<T, Size>(T::address);
+		write_thunk_call<T, N>(T::address);
+	}
+
+	template <class T, std::size_t N = 5>
+	constexpr void write_thunk_jump(const std::uintptr_t a_address) noexcept
+	{
+		T::func = GetTrampoline().write_branch<N>(a_address, T::thunk);
+	}
+
+	template <class T, std::size_t N = 5, class U>
+	constexpr void write_thunk_jump(const U a_id) noexcept
+		requires(std::is_same_v<U, REL::ID> || std::is_same_v<U, REL::Offset>)
+	{
+		T::func = GetTrampoline().write_branch<N>(a_id.address(), T::thunk);
+	}
+
+	template <class T, std::size_t N = 5, class U>
+	constexpr void write_thunk_jump(const REL::Relocation<U> a_id) noexcept
+		requires(std::is_same_v<typename REL::Relocation<U>::value_type, std::uintptr_t>)
+	{
+		T::func = GetTrampoline().write_branch<N>(a_id.address(), T::thunk);
+	}
+
+	template <class T, std::size_t N = 5>
+	constexpr void write_thunk_jump() noexcept
+	{
+		write_thunk_jump<T, N>(T::address);
 	}
 
 	template <class T>
-	constexpr void write_vfunc(const REL::ID a_id) noexcept
+	constexpr void write_vfunc(const std::uintptr_t a_address) noexcept
 	{
-		static REL::Relocation<std::uintptr_t> vtbl{ a_id };
+		static REL::Relocation vtbl{ REL::Offset(a_address) };
 		T::func = vtbl.write_vfunc(T::idx, T::thunk);
 	}
 
-	template <class To, class From>
-	constexpr void write_vfunc(const std::size_t a_vtableIdx = 0) noexcept
+	template <class T, class U>
+	constexpr void write_vfunc(const U a_id) noexcept
+		requires(std::is_same_v<U, REL::ID> || std::is_same_v<U, REL::Offset>)
 	{
-		write_vfunc<From>(To::VTABLE[a_vtableIdx]);
+		static REL::Relocation vtbl{ a_id };
+		T::func = vtbl.write_vfunc(T::idx, T::thunk);
 	}
 
-	template <class T, std::size_t Size = 5>
-	constexpr void write_thunk_jump(const std::uintptr_t a_src) noexcept
+	template <class T, class U>
+	constexpr void write_vfunc(const REL::Relocation<U> a_id) noexcept
+		requires(std::is_same_v<typename REL::Relocation<U>::value_type, std::uintptr_t>)
 	{
-		AllocTrampoline(14);
-		auto& trampoline = GetTrampoline();
-		T::func = trampoline.write_branch<Size>(a_src, T::thunk);
+		T::func = a_id.write_vfunc(T::idx, T::thunk);
+	}
+
+	template <class To, class From>
+	constexpr void write_vfunc(const std::size_t a_vtableIdx = 0) noexcept
+	{
+		write_vfunc<From>(To::VTABLE[a_vtableIdx]);
 	}
 
 	namespace detail