if d.bits.m == 0 {
			d.bits.m = 1 << 7
		} else {
			d.bits.m <<= 8
		}
		if d.bits.n >= n {
			break
		}
	}
	return nil
}

// receiveExtend is the composition of RECEIVE and EXTEND, specified in section
// F.2.2.1.
func (d *decoder) receiveExtend(t uint8) (int32, error) {
	if d.bits.n < int32(t) {
		if err := d.ensureNBits(int32(t)); err != nil {
			return 0, err
		}
	}
	d.bits.n -= int32(t)

							if err != nil {
								return err
							}
							if value > 16 {
								return UnsupportedError("excessive DC component")
							}
							dcDelta, err := d.receiveExtend(value)
							if err != nil {
								return err
							}
							dc[compIndex] += dcDelta
							b[0] = dc[compIndex] << al
						}

						if zig <= zigEnd && d.eobRun > 0 {
							d.eobRun--