rwcore: convert windows wide string to ACP (active code page)

rwcore/CMakeLists.txt

@@ -44,6 +44,14 @@ add_library(rwcore
     loaders/LoaderTXD.cpp
     )
 
+if(WIN32)
+    target_sources(rwcore
+        PRIVATE
+            platform/RWWindows.hpp
+            platform/RWWindows.cpp
+        )
+endif()
+
 target_include_directories(rwcore
     PUBLIC
         "${CMAKE_CURRENT_SOURCE_DIR}"

rwcore/platform/RWWindows.cpp

@@ -0,0 +1,30 @@
+#include "RWWindows.hpp"
+
+#include "rw/Debug.hpp"
+
+#define WIN32_LEAN_AND_MEAN
+#include <Windows.h>
+
+std::string wideStringToACP(const wchar_t* wString) {
+    std::string returnValue;
+    bool result = true;
+
+    int nbChars = WideCharToMultiByte(CP_ACP, WC_NO_BEST_FIT_CHARS, wString, -1,
+                                      nullptr, 0, nullptr, nullptr);
+    if (nbChars == 0) {
+        if (GetLastError() != ERROR_SUCCESS) {
+            RW_ERROR("Unable to calculate length of wide string");
+            return returnValue;
+        }
+    }
+    returnValue.resize(nbChars);
+    nbChars =
+        WideCharToMultiByte(CP_ACP, WC_NO_BEST_FIT_CHARS, wString, -1,
+                            &returnValue.front(), nbChars, nullptr, nullptr);
+    if (nbChars == 0) {
+        returnValue.resize(0);
+        return returnValue;
+    }
+    returnValue.resize(nbChars - 1);
+    return returnValue;
+}

rwcore/platform/RWWindows.hpp

@@ -0,0 +1,14 @@
+#ifndef _RWCORE_PLATFORM_RWWINDOWS_HPP_
+#define _RWCORE_PLATFORM_RWWINDOWS_HPP_
+
+#include <string>
+
+/**
+ * @brief Convert a wide string to a ACP string (=active code page)
+ * This function converts to the active code page instead of utf8
+ * because Windows functions need to understand the encoding.
+ * @param str The wide string to convert
+ */
+std::string wideStringToACP(const wchar_t* str);
+
+#endif