code: public static CodeRangeBuffer notCodeRangeBuff(ScanEnvironment env, CodeRangeBuffer bbuf) {
          CodeRangeBuffer pbuf = null;
  
          if (bbuf == null) return setAllMultiByteRange(env, pbuf);
  
          int[]p = bbuf.p;
          int n = p[0];
  
          if (n <= 0) return setAllMultiByteRange(env, pbuf);
  
          int pre = mbcodeStartPosition(env.enc);
  
          int from;
          int to = 0;
          for (int i=0; i<n; i++) {
              from = p[i * 2 + 1];
              to = p[i * 2 + 2];
              if (pre <= from - 1) {
                  pbuf = addCodeRangeToBuff(pbuf, env, pre, from - 1);
              }
              if (to == LAST_CODE_POINT) break;
              pre = to + 1;
          }
  
          if (to < LAST_CODE_POINT) pbuf = addCodeRangeToBuff(pbuf, env, to + 1, LAST_CODE_POINT);
          return pbuf;
      }
docs: not_code_range_buf