1 files changed, 39 insertions, 0 deletions

diff --git a/gl/unicase/simple-mapping.h b/gl/unicase/simple-mapping.h
new file mode 100644
index 00000000..0c4c75b3
--- /dev/null
+++ b/gl/unicase/simple-mapping.h
@@ -0,0 +1,39 @@
+/* Simple case mapping for Unicode characters.
+   Copyright (C) 2002, 2006, 2009-2025 Free Software Foundation, Inc.
+   Written by Bruno Haible <bruno@clisp.org>, 2009.
+
+   This file is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   This file is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+ucs4_t
+FUNC (ucs4_t uc)
+{
+  unsigned int index1 = uc >> mapping_header_0;
+  if (index1 < mapping_header_1)
+    {
+      int lookup1 = u_mapping.level1[index1];
+      if (lookup1 >= 0)
+        {
+          unsigned int index2 = (uc >> mapping_header_2) & mapping_header_3;
+          int lookup2 = u_mapping.level2[lookup1 + index2];
+          if (lookup2 >= 0)
+            {
+              unsigned int index3 = (uc & mapping_header_4);
+              int lookup3 = u_mapping.level3[lookup2 + index3];
+
+              return uc + lookup3;
+            }
+        }
+    }
+  return uc;
+}