Add C++ runtime for MeloTTS (#1138)

sherpa-onnx/csrc/melo-tts-lexicon.h

@@ -0,0 +1,36 @@
+// sherpa-onnx/csrc/melo-tts-lexicon.h
+//
+// Copyright (c)  2022-2024  Xiaomi Corporation
+
+#ifndef SHERPA_ONNX_CSRC_MELO_TTS_LEXICON_H_
+#define SHERPA_ONNX_CSRC_MELO_TTS_LEXICON_H_
+
+#include <memory>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+#include "sherpa-onnx/csrc/offline-tts-frontend.h"
+#include "sherpa-onnx/csrc/offline-tts-vits-model-metadata.h"
+
+namespace sherpa_onnx {
+
+class MeloTtsLexicon : public OfflineTtsFrontend {
+ public:
+  ~MeloTtsLexicon() override;
+  MeloTtsLexicon(const std::string &lexicon, const std::string &tokens,
+                 const std::string &dict_dir,
+                 const OfflineTtsVitsModelMetaData &meta_data, bool debug);
+
+  std::vector<TokenIDs> ConvertTextToTokenIds(
+      const std::string &text,
+      const std::string &unused_voice = "") const override;
+
+ private:
+  class Impl;
+  std::unique_ptr<Impl> impl_;
+};
+
+}  // namespace sherpa_onnx
+
+#endif  // SHERPA_ONNX_CSRC_MELO_TTS_LEXICON_H_