Function IsHex

extern/re2/re2/parse.cc:1428–1432

Is c a hex digit?

// Is c a hex digit?
static int IsHex(int c) {
  return ('0' <= c && c <= '9') ||
         ('A' <= c && c <= 'F') ||
         ('a' <= c && c <= 'f');
}

// Convert hex digit to value.
static int UnHex(int c) {