tesseract  5.0.0
validate_indic.h
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1 #ifndef TESSERACT_TRAINING_VALIDATE_INDIC_H_
2 #define TESSERACT_TRAINING_VALIDATE_INDIC_H_
3 
4 #include "validator.h"
5 
6 namespace tesseract {
7 
8 // Subclass of Validator that validates and segments Indic scripts in the
9 // unicode range 0x900-0xdff (Devanagari-Sinhala).
10 class ValidateIndic : public Validator {
11 public:
12  ValidateIndic(ViramaScript script, bool report_errors) : Validator(script, report_errors) {}
13  ~ValidateIndic() override = default;
14 
15 protected:
16  // Returns whether codes matches the pattern for an Indic Grapheme.
17  // Consumes the next Grapheme in codes_[codes_used_++...] and copies it to
18  // parts_ and output_. Returns true if a valid Grapheme was consumed,
19  // otherwise does not increment codes_used_.
20  bool ConsumeGraphemeIfValid() override;
21  // Returns the CharClass corresponding to the given Unicode ch.
23 
24 private:
25  // Helper consumes/copies a virama and any associated post-virama joiners.
26  bool ConsumeViramaIfValid(IndicPair joiner, bool post_matra);
27  // Helper consumes/copies a series of consonants separated by viramas while
28  // valid, but not any vowel or other modifiers.
29  bool ConsumeConsonantHeadIfValid();
30  // Helper consumes/copies a tail part of a consonant, comprising optional
31  // matra/piece, vowel modifier, vedic mark, terminating virama.
32  bool ConsumeConsonantTailIfValid();
33  // Helper consumes/copies a vowel and optional modifiers.
34  bool ConsumeVowelIfValid();
35 
36  // Some special unicodes used only for Indic processing.
37  static const char32 kYayana = 0xdba; // Sinhala Ya
38  static const char32 kRayana = 0xdbb; // Sinhala Ra
39 };
40 
41 } // namespace tesseract
42 
43 #endif // TESSERACT_TRAINING_VALIDATE_INDIC_H_
signed int char32
Definition: unichar.h:51
~ValidateIndic() override=default
ValidateIndic(ViramaScript script, bool report_errors)
bool ConsumeGraphemeIfValid() override
Validator::CharClass UnicodeToCharClass(char32 ch) const override
std::pair< CharClass, char32 > IndicPair
Definition: validator.h:135