code: public static final StringBuilder sprintf0d(StringBuilder sb, int value, int width) {
          long d = value;
          if (d < 0) {
              sb.append('-');
              d = -d;
              --width;
          }
          int n = 10;
          for (int i = 2; i < width; i++) {
              n *= 10;
          }
          for (int i = 1; i < width && d < n; i++) {
              sb.append('0');
              n /= 10;
          }
          sb.append(d);
          return sb;
      }
docs: Mimics sprintf(buf, "%0*d", decaimal, width).