code: public static int getBytesToken(ParsingContext ctx) {
          String input = ctx.getInput().substring(ctx.getLocation());
          int tokenOffset = 0;
          int i = 0;
          char[] inputChars = input.toCharArray();
          for (; i < input.length(); i += 1) {
              char c = inputChars[i];
              if (c == ' ') {
                  continue;
              }
              if (c != BYTES_TOKEN_CHARS[tokenOffset]) {
                  return -1;
              } else {
                  tokenOffset += 1;
                  if (tokenOffset == BYTES_TOKEN_CHARS.length) {
                      // Found the token.
                      return i;
                  }
              }
          }
          return -1;
      }
docs: handle white spaces.