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#ifndef MOZC_COMPOSER_TRANSLITERATORS_H_
#define MOZC_COMPOSER_TRANSLITERATORS_H_

#include <cstddef>
#include <string>

#include "absl/strings/string_view.h"

namespace mozc {
namespace composer {
namespace internal {
class TransliteratorInterface {
 public:
  virtual ~TransliteratorInterface() = default;

  // Return the transliterated string of either raw or converted.
  // Determination of which argument is used depends on the
  // implementation.
  //
  // Expected usage examples:
  // - HalfKatakanaTransliterator("a", "あ") => "ｱ"
  // - FullAsciiTransliterator("a", "あ") => "ａ"
  virtual std::string Transliterate(absl::string_view raw,
                                    absl::string_view converted) const = 0;

  // Split raw and converted strings based on the transliteration
  // rule.  If raw or converted could not be deterministically split,
  // fall back strings are fill and false is returned.  The first
  // argument, position, is in character (rather than byte).
  //
  // Expected usage examples:
  // - HiraganaTransliterator(1, "kk", "っk") => true
  //   (raw_lhs, raw_rhs) => ("k", "k")
  //   (conv_lhs, conv_rhs) => ("っ", "k")
  // - HalfKatakanaTransliterator(1, "zu", "ず") => false
  //   (raw_lhs, raw_rhs) => ("す", "゛")  fall back strings.
  //   (conv_lhs, conv_rhs) => ("す", "゛")
  virtual bool Split(size_t position, absl::string_view raw,
                     absl::string_view converted, std::string* raw_lhs,
                     std::string* raw_rhs, std::string* converted_lhs,
                     std::string* converted_rhs) const = 0;
};
}  // namespace internal

// Factory class providing basic TransliteratorInterface instances.
class Transliterators {
 public:
  enum Transliterator {
    // Always uses a converted string rather than a raw string.
    // This should be used as default value.
    CONVERSION_STRING,
    // Always uses a raw string rather than a converted string.
    RAW_STRING,
    // Returns hiragana.
    HIRAGANA,
    // Returns full katakana.
    FULL_KATAKANA,
    // Returns half katakana.
    HALF_KATAKANA,
    // Returns full ascii.
    FULL_ASCII,
    // Returns half ascii.
    HALF_ASCII,
    // Special transliterator.
    // Use locally assigned transliterator.
    // Many methods don't accept this value.
    LOCAL,

    NUM_OF_TRANSLITERATOR,
  };

  // Return a singleton instance of a TransliteratorInterface.
  // LOCAL transliterator is not accepted.
  static const internal::TransliteratorInterface* GetTransliterator(
      Transliterator transliterator);

  static bool SplitRaw(size_t position, absl::string_view raw,
                       absl::string_view converted, std::string* raw_lhs,
                       std::string* raw_rhs, std::string* converted_lhs,
                       std::string* converted_rhs);

  static bool SplitConverted(size_t position, absl::string_view raw,
                             absl::string_view converted, std::string* raw_lhs,
                             std::string* raw_rhs, std::string* converted_lhs,
                             std::string* converted_rhs);
};

}  // namespace composer
}  // namespace mozc

#endif  // MOZC_COMPOSER_TRANSLITERATORS_H_
