loader: don't pass a NULL src pointer to memcpy with zero length (asan)

1 files changed, 5 insertions, 3 deletions

diff --git a/loader/atlas.cpp b/loader/atlas.cpp
index 63025122..c893e633 100644
--- a/loader/atlas.cpp
+++ b/loader/atlas.cpp
@@ -22,9 +22,11 @@ StringView loader_::make_atlas_path(char(&buf)[fm_FILENAME_MAX], StringView dir,
     const auto dirsiz = dir.size(), namesiz = name.size(), extsiz = ext.size(),
                len = dirsiz + namesiz + extsiz;
     fm_soft_assert(len < fm_FILENAME_MAX);
-    std::memcpy(&buf[0],                   dir.data(),   dirsiz);
-    std::memcpy(&buf[dirsiz],           name.data(), namesiz);
-    std::memcpy(&buf[dirsiz + namesiz], ext.data(),   extsiz);
+    if (dir)
+        std::memcpy(&buf[0], dir.data(), dirsiz);
+    std::memcpy(&buf[dirsiz], name.data(), namesiz);
+    if (ext)
+        std::memcpy(&buf[dirsiz + namesiz], ext.data(), extsiz);
     buf[len] = '\0';
     return StringView{buf, len, StringViewFlag::NullTerminated};
 }