Function CycleFoldRune

extern/re2/re2/parse.cc:335–340

Returns the next Rune in r's folding cycle (see unicode_casefold.h). Examples: CycleFoldRune('A') = 'a' CycleFoldRune('a') = 'A' CycleFoldRune('K') = 'k' CycleFoldRune('k') = 0x212A (Kelvin) CycleFoldRune(0x212A) = 'K' CycleFoldRune('?') = '?'

//
//   CycleFoldRune('?') = '?'
Rune CycleFoldRune(Rune r) {
  const CaseFold* f = LookupCaseFold(unicode_casefold, num_unicode_casefold, r);
  if (f == NULL || r < f->lo)
    return r;
  return ApplyFold(f, r);
}

// Add lo-hi to the class, along with their fold-equivalent characters.
// If lo-hi is already in the class, assume that the fold-equivalent