Core (LV::Video): Account for wide-character paths on Windows.

Author: kaixiong

libvisual/libvisual/lv_video.cpp

@@ -77,11 +77,12 @@ namespace LV {
     }
 
     // TODO: Factor this out into a string utility library
-    std::string to_lower_ascii (std::string const& s)
+    template <typename CharT>
+    auto to_lower (std::basic_string<CharT> const& s, std::locale const& locale) -> std::basic_string<CharT>
     {
-        std::string result {s};
+        auto result {s};
         std::transform (result.begin (), result.end (), result.begin (),
-                        [=] (unsigned char c) { return std::tolower (c); });
+                        [=] (auto c) { return std::tolower(c, locale); });
         return result;
     }
 
@@ -295,9 +296,10 @@ namespace LV {
 
   bool Video::save_to_file (std::string const& path) const
   {
-      std::string extension {to_lower_ascii (fs::path {path}.extension ())};
+      auto extension {fs::path {path}.extension ()};
+      auto extension_lower (to_lower (extension.native (), std::locale ()));
 
-      auto entry {bitmap_format_extension_map.find (extension)};
+      auto entry {bitmap_format_extension_map.find (extension_lower)};
       if (entry == bitmap_format_extension_map.end ()) {
           visual_log (VISUAL_LOG_ERROR, "Could not deduce format from filename (%s)", path.c_str ());
           return false;