tesseract  5.0.0
validate_grapheme.h
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1 #ifndef TESSERACT_TRAINING_VALIDATE_GRAPHEME_H_
2 #define TESSERACT_TRAINING_VALIDATE_GRAPHEME_H_
3 
4 #include "validator.h"
5 
6 namespace tesseract {
7 
8 // Subclass of Validator that validates and segments generic unicode into
9 // grapheme clusters, including Latin with diacritics.
10 class ValidateGrapheme : public Validator {
11 public:
12  ValidateGrapheme(ViramaScript script, bool report_errors) : Validator(script, report_errors) {}
13  ~ValidateGrapheme() override = default;
14 
15 protected:
16  // Consumes the next Grapheme in codes_[codes_used_++...] and copies it to
17  // parts_ and output_. Returns true if a valid Grapheme was consumed,
18  // otherwise does not increment codes_used_.
19  bool ConsumeGraphemeIfValid() override;
20  // Returns the CharClass corresponding to the given Unicode ch.
21  CharClass UnicodeToCharClass(char32 ch) const override;
22 
23 private:
24  // Helper returns true if the sequence prev_ch,ch is invalid.
25  bool IsBadlyFormed(char32 prev_ch, char32 ch);
26  // Helper returns true if the sequence prev_ch,ch is an invalid Indic vowel.
27  static bool IsBadlyFormedIndicVowel(char32 prev_ch, char32 ch);
28  // Helper returns true if the sequence prev_ch,ch is invalid Thai.
29  static bool IsBadlyFormedThai(char32 prev_ch, char32 ch);
30 };
31 
32 } // namespace tesseract
33 
34 #endif // TESSERACT_TRAINING_VALIDATE_GRAPHEME_H_
signed int char32
Definition: unichar.h:51
~ValidateGrapheme() override=default
CharClass UnicodeToCharClass(char32 ch) const override
ValidateGrapheme(ViramaScript script, bool report_errors)
bool ConsumeGraphemeIfValid() override