package mp4

import "io"

type FreeBox struct {
    Box  BasicBox
    Data []byte
}

func NewFreeBox() *FreeBox {
    return &FreeBox{
        Box: BasicBox{
            Type: [4]byte{'f', 'r', 'e', 'e'},
        },
    }
}

func (free *FreeBox) Size() uint64 {
    return 8 + uint64(len(free.Data))
}

func (free *FreeBox) Decode(r io.Reader) (int, error) {
    if BasicBoxLen < free.Box.Size {
        free.Data = make([]byte, free.Box.Size-BasicBoxLen)
        if _, err := io.ReadFull(r, free.Data); err != nil {
            return 0, err
        }
    }
    return int(free.Box.Size - BasicBoxLen), nil
}

func (free *FreeBox) Encode() (int, []byte) {
    free.Box.Size = free.Size()
    offset, buf := free.Box.Encode()
    copy(buf[offset:], free.Data)
    return int(free.Box.Size), buf
}

func decodeFreeBox(demuxer *MovDemuxer, size uint32) (err error) {
    var free FreeBox
	free.Box.Size = uint64(size)
    _, err = free.Decode(demuxer.reader)
    return
}