Support replacing homonphonic phrases (#2153)

sherpa-onnx/csrc/homophone-replacer.h

@@ -0,0 +1,58 @@
+// sherpa-onnx/csrc/homophone-replacer.h
+//
+// Copyright (c)  2025  Xiaomi Corporation
+
+#ifndef SHERPA_ONNX_CSRC_HOMOPHONE_REPLACER_H_
+#define SHERPA_ONNX_CSRC_HOMOPHONE_REPLACER_H_
+
+#include <memory>
+#include <string>
+
+#include "sherpa-onnx/csrc/parse-options.h"
+
+namespace sherpa_onnx {
+
+struct HomophoneReplacerConfig {
+  std::string dict_dir;
+  std::string lexicon;
+
+  // comma separated fst files, e.g. a.fst,b.fst,c.fst
+  std::string rule_fsts;
+
+  bool debug;
+
+  HomophoneReplacerConfig() = default;
+
+  HomophoneReplacerConfig(const std::string &dict_dir,
+                          const std::string &lexicon,
+                          const std::string &rule_fsts, bool debug)
+      : dict_dir(dict_dir),
+        lexicon(lexicon),
+        rule_fsts(rule_fsts),
+        debug(debug) {}
+
+  void Register(ParseOptions *po);
+  bool Validate() const;
+
+  std::string ToString() const;
+};
+
+class HomophoneReplacer {
+ public:
+  explicit HomophoneReplacer(const HomophoneReplacerConfig &config);
+
+  template <typename Manager>
+  HomophoneReplacer(Manager *mgr, const HomophoneReplacerConfig &config);
+
+  ~HomophoneReplacer();
+
+  std::string Apply(const std::string &text) const;
+
+ private:
+  class Impl;
+  std::unique_ptr<Impl> impl_;
+};
+
+}  // namespace sherpa_onnx
+
+#endif  // SHERPA_ONNX_CSRC_HOMOPHONE_REPLACER_H_