git subrepo clone https://github.com/Atmosphere-NX/Atmosphere-libs libraries

subrepo:
  subdir:   "libraries"
  merged:   "07af583b"
upstream:
  origin:   "https://github.com/Atmosphere-NX/Atmosphere-libs"
  branch:   "master"
  commit:   "07af583b"
git-subrepo:
  version:  "0.4.0"
  origin:   "https://github.com/ingydotnet/git-subrepo"
  commit:   "5d6aba9"

libraries/libstratosphere/source/fs/fs_path_utils.cpp

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2018-2019 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stratosphere.hpp>
+
+namespace ams::fs {
+
+    Result VerifyPath(const char *path, size_t max_path_len, size_t max_name_len) {
+        const char *cur = path;
+        size_t name_len = 0;
+
+        for (size_t path_len = 0; path_len <= max_path_len && name_len <= max_name_len; path_len++) {
+            const char c = *(cur++);
+
+            /* If terminated, we're done. */
+            R_UNLESS(c != StringTraits::NullTerminator, ResultSuccess());
+
+            /* TODO: Nintendo converts the path from utf-8 to utf-32, one character at a time. */
+            /* We should do this. */
+
+            /* Banned characters: :*?<>| */
+            R_UNLESS((c != ':' && c != '*' && c != '?' && c != '<' && c != '>' && c != '|'), fs::ResultInvalidCharacter());
+
+            name_len++;
+            /* Check for separator. */
+            if (c == '\\' || c == '/') {
+                name_len = 0;
+            }
+
+        }
+
+        return fs::ResultTooLongPath();
+    }
+
+}