refactor(furvm): improve serialization

Refs: #12

furvm/src/module.cpp

@@ -1,3 +1,34 @@
 #include "furvm/module.hpp"
 
-namespace furvm {}
+#include "furvm/detail/serialization.hpp"
+#include "furvm/fwd.hpp"
+
+#include <ios>
+
+namespace furvm {
+
+std::ostream& mod::serialize(std::ostream& os) const {
+    os << MAGIC;
+    detail::serialize(os, std::uint32_t(0)); // version
+
+    detail::serialize(os, function_id(m_functionMap.size()));
+    for (const auto& [name, id] : m_functionMap) {
+        detail::serialize(os, name);
+        function_h func = m_functions.at(id);
+        detail::serialize(os, std::uint8_t(func->type()));
+        switch (func->type()) {
+        case function_t::Normal: {
+            detail::serialize(os, func->position());
+        } break;
+        case function_t::Native: break;
+        case function_t::Import: {
+            detail::serialize(os, func->imp().mod);
+            detail::serialize(os, func->imp().function);
+        } break;
+        }
+    }
+
+    detail::serialize(os, std::uint64_t(m_bytecode.size()));
+    return os.write(reinterpret_cast<const char*>(m_bytecode.data()), static_cast<std::streamsize>(m_bytecode.size()));
+}
+} // namespace furvm