--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/tesseract/src/training/pango/ligature_table.h	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,80 @@
+/**********************************************************************
+ * File:        ligature_table.h
+ * Description: Class for adding and removing optional latin ligatures,
+ *              conditional on codepoint support by a specified font
+ *              (if specified).
+ * Author:      Ranjith Unnikrishnan
+ * Created:     Mon Nov 18 2013
+ *
+ * (C) Copyright 2013, Google Inc.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ **********************************************************************/
+
+#ifndef TRAININGDATA_LIGATURE_TABLE_H_
+#define TRAININGDATA_LIGATURE_TABLE_H_
+
+#include "export.h"
+
+#include <memory>
+#include <string>
+#include <unordered_map>
+
+namespace tesseract {
+
+class PangoFontInfo; // defined in pango_font_info.h
+
+// Map to substitute strings for ligatures.
+using LigHash = std::unordered_map<std::string, std::string>;
+
+class TESS_PANGO_TRAINING_API LigatureTable {
+public:
+  // Get a static instance of this class.
+  static LigatureTable *Get();
+
+  // Convert the utf8 string so that ligaturizable sequences, such as "fi" get
+  // replaced by the (utf8 code for) appropriate ligature characters. Only do so
+  // if the corresponding ligature character is renderable in the current font.
+  std::string AddLigatures(const std::string &str, const PangoFontInfo *font) const;
+  // Remove all ligatures.
+  std::string RemoveLigatures(const std::string &str) const;
+  // Remove only custom ligatures (eg. "ct") encoded in the private-use-area.
+  std::string RemoveCustomLigatures(const std::string &str) const;
+
+  const LigHash &norm_to_lig_table() const {
+    return norm_to_lig_table_;
+  }
+  const LigHash &lig_to_norm_table() const {
+    return lig_to_norm_table_;
+  }
+
+protected:
+  LigatureTable();
+  // Initialize the hash tables mapping between ligature strings and the
+  // corresponding ligature characters.
+  void Init();
+
+  static std::unique_ptr<LigatureTable> instance_;
+  LigHash norm_to_lig_table_;
+  LigHash lig_to_norm_table_;
+  int min_lig_length_;
+  int max_lig_length_;
+  int min_norm_length_;
+  int max_norm_length_;
+
+private:
+  LigatureTable(const LigatureTable &) = delete;
+  void operator=(const LigatureTable &) = delete;
+};
+
+} // namespace tesseract
+
+#endif // OCR_TRAININGDATA_TYPESETTING_LIGATURE_TABLE_H_