Add srb2::ArchiveWrapper and srb2::UnArchiveWrapper, helper class to simplify p_saveg I/O

src/archive_wrapper.hpp

@@ -0,0 +1,133 @@
+// DR. ROBOTNIK'S RING RACERS
+//-----------------------------------------------------------------------------
+// Copyright (C) 2024 by James Robert Roman
+//
+// This program is free software distributed under the
+// terms of the GNU General Public License, version 2.
+// See the 'LICENSE' file for more details.
+//-----------------------------------------------------------------------------
+
+#ifndef archive_wrapper_hpp
+#define archive_wrapper_hpp
+
+#include <type_traits>
+
+#include "typedef.h"
+
+#include "cxxutil.hpp"
+#include "byteptr.h"
+#include "doomdef.h" // p_saveg.h
+#include "doomtype.h"
+#include "m_fixed.h"
+#include "p_mobj.h" // p_saveg.h
+#include "p_saveg.h"
+
+namespace srb2
+{
+
+struct ArchiveWrapperBase
+{
+	explicit ArchiveWrapperBase(savebuffer_t* save) : p_(save->p) {}
+
+protected:
+	template <typename T, typename U>
+	void read(U& n) = delete;
+
+	template <typename T, typename U>
+	void write(const U& n) = delete;
+
+private:
+	UINT8*& p_;
+};
+
+#define READ_SPEC(T, arg) \
+	template <> void ArchiveWrapperBase::read<T, T>(T& arg)
+
+#define WRITE_SPEC(T, arg) \
+	template <> void ArchiveWrapperBase::write<T, T>(const T& arg)
+
+#define MACRO_PAIR(T) \
+	READ_SPEC(T, n) { n = READ ## T(p_); } \
+	WRITE_SPEC(T, n) { WRITE ## T(p_, n); }
+
+MACRO_PAIR(UINT8)
+MACRO_PAIR(SINT8)
+MACRO_PAIR(UINT16)
+MACRO_PAIR(INT16)
+MACRO_PAIR(UINT32)
+MACRO_PAIR(INT32)
+
+READ_SPEC(vector2_t, n)
+{
+	read<fixed_t>(n.x);
+	read<fixed_t>(n.y);
+}
+
+WRITE_SPEC(vector2_t, n)
+{
+	write<fixed_t>(n.x);
+	write<fixed_t>(n.y);
+}
+
+READ_SPEC(vector3_t, n)
+{
+	read<fixed_t>(n.x);
+	read<fixed_t>(n.y);
+	read<fixed_t>(n.z);
+}
+
+WRITE_SPEC(vector3_t, n)
+{
+	write<fixed_t>(n.x);
+	write<fixed_t>(n.y);
+	write<fixed_t>(n.z);
+}
+
+// Specializations for boolean, so it can stored as char
+// instead of int.
+
+template <>
+void ArchiveWrapperBase::read<bool, boolean>(boolean& n)
+{
+	SRB2_ASSERT(n == true || n == false);
+	n = READUINT8(p_);
+}
+
+template <>
+void ArchiveWrapperBase::write<bool, boolean>(const boolean& n)
+{
+	SRB2_ASSERT(n == true || n == false);
+	WRITEUINT8(p_, n);
+}
+
+#undef MACRO_PAIR
+#undef WRITE_SPEC
+#undef READ_SPEC
+
+struct ArchiveWrapper : ArchiveWrapperBase
+{
+	using ArchiveWrapperBase::ArchiveWrapperBase;
+
+	template <typename T, typename U>
+	void operator()(const U& n) { write<T, U>(n); }
+};
+
+struct UnArchiveWrapper : ArchiveWrapperBase
+{
+	using ArchiveWrapperBase::ArchiveWrapperBase;
+
+	template <typename T, typename U>
+	void operator()(U& n) { read<T, U>(n); }
+};
+
+template <typename T>
+struct is_archive_wrapper : std::is_base_of<ArchiveWrapperBase, T> {};
+
+template <typename T>
+inline constexpr bool is_archive_wrapper_v = is_archive_wrapper<T>::value;
+
+#define SRB2_ARCHIVE_WRAPPER_CALL(ar, T, var) ((ar). template operator()<T>(var))
+
+}; // namespace
+
+#endif/*archive_wrapper_hpp*/