Function BuildLookupTable

be/src/gutil/strings/stringpiece.cc:118–125

For each character in characters_wanted, sets the index corresponding to the ASCII code of that character to 1 in table. This is used by the find_.*_of methods below to tell whether or not a character is in the lookup table in constant time. The argument `table' must be an array that is large enough to hold all the possible values of an unsigned char. Thus it should be be declared as follows: bo

// as follows:
//   bool table[UCHAR_MAX + 1]
static inline void BuildLookupTable(StringPiece characters_wanted,
                                    bool* table) {
  const int length = characters_wanted.length();
  const char* const data = characters_wanted.data();
  for (int i = 0; i < length; ++i) {
    table[static_cast<unsigned char>(data[i])] = true;
  }
}

int StringPiece::find_first_of(StringPiece s, size_type pos) const {
  if (length_ <= 0 || s.length_ <= 0) {