Move TChar* -> std::u16string conversion to base.h

We're going to need it for VST3 events.

src/common/serialization/vst3/base.cpp

@@ -19,6 +19,16 @@
 
 #include "base.h"
 
+std::u16string tchar_string_to_u16string(const Steinberg::Vst::TChar* string) {
+#ifdef __WINE__
+    // This is great, thanks Steinberg
+    static_assert(sizeof(Steinberg::Vst::TChar) == sizeof(char16_t));
+    return std::u16string(reinterpret_cast<const char16_t*>(string));
+#else
+    return std::u16string(static_cast<const char16_t*>(string));
+#endif
+}
+
 UniversalTResult::UniversalTResult() : universal_result(Value::kResultFalse) {}
 
 UniversalTResult::UniversalTResult(tresult native_result)

src/common/serialization/vst3/base.h

@@ -23,6 +23,7 @@
 #include <pluginterfaces/base/ftypes.h>
 #include <pluginterfaces/base/funknown.h>
 #include <pluginterfaces/base/ibstream.h>
+#include <pluginterfaces/vst/vsttypes.h>
 
 // Yet Another layer of includes, but these are some VST3-specific typedefs that
 // we'll need for all of our interfaces
@@ -51,6 +52,12 @@ constexpr size_t max_num_speakers = 16384;
  */
 constexpr size_t max_vector_stream_size = 50 << 20;
 
+/**
+ * Convert a UTF-16 C-style string to an `std::u16string`. Who event invented
+ * UTF-16?
+ */
+std::u16string tchar_string_to_u16string(const Steinberg::Vst::TChar* string);
+
 /**
  * Empty struct for when we have send a response to some operation without any
  * result values.

src/common/serialization/vst3/host-application.cpp

@@ -24,13 +24,7 @@ YaHostApplication::ConstructArgs::ConstructArgs(
     : component_instance_id(component_instance_id) {
     Steinberg::Vst::String128 name_array;
     if (context->getName(name_array) == Steinberg::kResultOk) {
-#ifdef __WINE__
-        // Who even invented UTF-16
-        static_assert(sizeof(Steinberg::Vst::TChar) == sizeof(char16_t));
-        name = std::u16string(reinterpret_cast<const char16_t*>(name_array));
-#else
-        name = std::u16string(static_cast<const char16_t*>(name_array));
-#endif
+        name = tchar_string_to_u16string(name_array);
     }
 }