diff --git a/src/openrct2/FileClassifier.cpp b/src/openrct2/FileClassifier.cpp
index eeb1a49b25..d4033d7b39 100644
--- a/src/openrct2/FileClassifier.cpp
+++ b/src/openrct2/FileClassifier.cpp
@@ -15,6 +15,7 @@
 #pragma endregion
 
 #include "core/FileStream.hpp"
+#include "core/Path.hpp"
 #include "FileClassifier.h"
 #include "rct12/SawyerChunkReader.h"
 
@@ -151,3 +152,19 @@ static bool TryClassifyAsTD4_TD6(IStream * stream, ClassifiedFile * result)
 
     return success;
 }
+
+extern "C"
+{
+    uint32 get_file_extension_type(const utf8 * path)
+    {
+        auto extension = Path::GetExtension(path);
+        if (String::Equals(extension, ".dat", true)) return FILE_EXTENSION_DAT;
+        if (String::Equals(extension, ".sc4", true)) return FILE_EXTENSION_SC4;
+        if (String::Equals(extension, ".sv4", true)) return FILE_EXTENSION_SV4;
+        if (String::Equals(extension, ".td4", true)) return FILE_EXTENSION_TD4;
+        if (String::Equals(extension, ".sc6", true)) return FILE_EXTENSION_SC6;
+        if (String::Equals(extension, ".sv6", true)) return FILE_EXTENSION_SV6;
+        if (String::Equals(extension, ".td6", true)) return FILE_EXTENSION_TD6;
+        return FILE_EXTENSION_UNKNOWN;
+    }
+}
diff --git a/src/openrct2/FileClassifier.h b/src/openrct2/FileClassifier.h
index ac9e29c600..4356bd4d19 100644
--- a/src/openrct2/FileClassifier.h
+++ b/src/openrct2/FileClassifier.h
@@ -16,9 +16,24 @@
 
 #pragma once
 
-#include <string>
 #include "common.h"
 
+enum
+{
+    FILE_EXTENSION_UNKNOWN,
+    FILE_EXTENSION_DAT,
+    FILE_EXTENSION_SC4,
+    FILE_EXTENSION_SV4,
+    FILE_EXTENSION_TD4,
+    FILE_EXTENSION_SC6,
+    FILE_EXTENSION_SV6,
+    FILE_EXTENSION_TD6,
+};
+
+#ifdef __cplusplus
+
+#include <string>
+
 interface IStream;
 
 enum class FILE_TYPE
@@ -38,3 +53,15 @@ struct ClassifiedFile
 
 bool TryClassifyFile(const std::string &path, ClassifiedFile * result);
 bool TryClassifyFile(IStream * stream, ClassifiedFile * result);
+
+#endif // __cplusplus
+
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+    uint32 get_file_extension_type(const utf8 * path);
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/openrct2/cmdline/ConvertCommand.cpp b/src/openrct2/cmdline/ConvertCommand.cpp
index 3548b21773..cbc441b283 100644
--- a/src/openrct2/cmdline/ConvertCommand.cpp
+++ b/src/openrct2/cmdline/ConvertCommand.cpp
@@ -20,6 +20,7 @@
 #include "../core/Exception.hpp"
 #include "../core/Guard.hpp"
 #include "../core/Path.hpp"
+#include "../FileClassifier.h"
 #include "../ParkImporter.h"
 #include "../rct2/S6Exporter.h"
 #include "CommandLine.hpp"
diff --git a/src/openrct2/editor.c b/src/openrct2/editor.c
index 61b3d6d2d5..438544406e 100644
--- a/src/openrct2/editor.c
+++ b/src/openrct2/editor.c
@@ -17,6 +17,7 @@
 #include "audio/audio.h"
 #include "drawing/drawing.h"
 #include "editor.h"
+#include "FileClassifier.h"
 #include "game.h"
 #include "interface/viewport.h"
 #include "interface/window.h"
diff --git a/src/openrct2/game.c b/src/openrct2/game.c
index 2b5d3bf9ec..ac27d68552 100644
--- a/src/openrct2/game.c
+++ b/src/openrct2/game.c
@@ -19,6 +19,7 @@
 #include "config/Config.h"
 #include "Context.h"
 #include "editor.h"
+#include "FileClassifier.h"
 #include "game.h"
 #include "input.h"
 #include "interface/Screenshot.h"
diff --git a/src/openrct2/rct2.c b/src/openrct2/rct2.c
index 5ba8aabfd6..c797a653ed 100644
--- a/src/openrct2/rct2.c
+++ b/src/openrct2/rct2.c
@@ -135,16 +135,3 @@ const utf8 *get_file_path(sint32 pathId)
     }
     return path;
 }
-
-uint32 get_file_extension_type(const utf8 *path)
-{
-    const utf8 *extension = path_get_extension(path);
-    if (strcicmp(extension, ".dat") == 0) return FILE_EXTENSION_DAT;
-    if (strcicmp(extension, ".sc4") == 0) return FILE_EXTENSION_SC4;
-    if (strcicmp(extension, ".sv4") == 0) return FILE_EXTENSION_SV4;
-    if (strcicmp(extension, ".td4") == 0) return FILE_EXTENSION_TD4;
-    if (strcicmp(extension, ".sc6") == 0) return FILE_EXTENSION_SC6;
-    if (strcicmp(extension, ".sv6") == 0) return FILE_EXTENSION_SV6;
-    if (strcicmp(extension, ".td6") == 0) return FILE_EXTENSION_TD6;
-    return FILE_EXTENSION_UNKNOWN;
-}
diff --git a/src/openrct2/rct2.h b/src/openrct2/rct2.h
index f8480ec3cd..9e6a18e9a0 100644
--- a/src/openrct2/rct2.h
+++ b/src/openrct2/rct2.h
@@ -143,17 +143,6 @@ enum {
     PATH_ID_END
 };
 
-enum {
-    FILE_EXTENSION_UNKNOWN,
-    FILE_EXTENSION_DAT,
-    FILE_EXTENSION_SC4,
-    FILE_EXTENSION_SV4,
-    FILE_EXTENSION_TD4,
-    FILE_EXTENSION_SC6,
-    FILE_EXTENSION_SV6,
-    FILE_EXTENSION_TD6,
-};
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -170,8 +159,6 @@ sint32 rct2_init_directories();
 const char *get_file_path(sint32 pathId);
 void rct2_quit();
 
-uint32 get_file_extension_type(const utf8 *path);
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/openrct2/scenario/scenario.c b/src/openrct2/scenario/scenario.c
index 8082a01191..7027918fd2 100644
--- a/src/openrct2/scenario/scenario.c
+++ b/src/openrct2/scenario/scenario.c
@@ -17,6 +17,7 @@
 #include "../audio/audio.h"
 #include "../cheats.h"
 #include "../config/Config.h"
+#include "../FileClassifier.h"
 #include "../game.h"
 #include "../interface/viewport.h"
 #include "../localisation/date.h"
diff --git a/src/openrct2/windows/title_editor.c b/src/openrct2/windows/title_editor.c
index b38daa18d1..79b831e4f5 100644
--- a/src/openrct2/windows/title_editor.c
+++ b/src/openrct2/windows/title_editor.c
@@ -16,6 +16,7 @@
 
 #include "../config/Config.h"
 #include "../drawing/drawing.h"
+#include "../FileClassifier.h"
 #include "../game.h"
 #include "../input.h"
 #include "../interface/viewport.h"