loader: add atlas path maker function

2 files changed, 17 insertions, 0 deletions

diff --git a/loader/atlas.cpp b/loader/atlas.cpp
index cf3d310e..50645579 100644
--- a/loader/atlas.cpp
+++ b/loader/atlas.cpp
@@ -13,6 +13,22 @@
 #include <Corrade/Utility/Path.h>
 #include <Magnum/Trade/ImageData.h>
 
+namespace floormat {
+
+StringView loader_::make_atlas_path(char(&buf)[FILENAME_MAX], StringView dir, StringView name)
+{
+    fm_soft_assert(!dir || dir[dir.size()-1] == '/');
+    auto name_noext = Path::splitExtension(name).first();
+    const auto dirsiz = dir.size(), namesiz = name_noext.size();
+    fm_soft_assert(dirsiz + namesiz + 1 < FILENAME_MAX);
+    std::memcpy(buf, dir.data(), dirsiz);
+    std::memcpy(&buf[dirsiz], name_noext.data(), namesiz);
+    buf[dirsiz + namesiz] = '\0';
+    return StringView{buf};
+}
+
+} // namespace floormat
+
 namespace floormat::loader_detail {
 
 std::shared_ptr<tile_atlas> loader_impl::tile_atlas(StringView name, Vector2ub size, Optional<pass_mode> pass) noexcept(false)
diff --git a/loader/loader.hpp b/loader/loader.hpp
index 3ed519e9..937ef828 100644
--- a/loader/loader.hpp
+++ b/loader/loader.hpp
@@ -35,6 +35,7 @@ struct loader_
     static StringView strip_prefix(StringView name);
     virtual const vobj_info& vobj(StringView name) = 0;
     virtual ArrayView<struct vobj_info> vobj_list() = 0;
+    static StringView make_atlas_path(char(&buf)[FILENAME_MAX], StringView dir, StringView name);
 
     loader_(const loader_&) = delete;
     loader_& operator=(const loader_&) = delete;