forked from mirrors/gotosocial
69 lines
1.4 KiB
Go
69 lines
1.4 KiB
Go
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package mp4
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import (
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"errors"
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"io"
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)
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type Writer struct {
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writer io.WriteSeeker
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biStack []*BoxInfo
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}
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func NewWriter(w io.WriteSeeker) *Writer {
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return &Writer{
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writer: w,
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}
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}
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func (w *Writer) Write(p []byte) (int, error) {
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return w.writer.Write(p)
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}
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func (w *Writer) Seek(offset int64, whence int) (int64, error) {
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return w.writer.Seek(offset, whence)
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}
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func (w *Writer) StartBox(bi *BoxInfo) (*BoxInfo, error) {
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bi, err := WriteBoxInfo(w.writer, bi)
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if err != nil {
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return nil, err
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}
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w.biStack = append(w.biStack, bi)
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return bi, nil
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}
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func (w *Writer) EndBox() (*BoxInfo, error) {
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bi := w.biStack[len(w.biStack)-1]
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w.biStack = w.biStack[:len(w.biStack)-1]
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end, err := w.writer.Seek(0, io.SeekCurrent)
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if err != nil {
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return nil, err
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}
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bi.Size = uint64(end) - bi.Offset
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if _, err = bi.SeekToStart(w.writer); err != nil {
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return nil, err
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}
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if bi2, err := WriteBoxInfo(w.writer, bi); err != nil {
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return nil, err
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} else if bi.HeaderSize != bi2.HeaderSize {
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return nil, errors.New("header size changed")
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}
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if _, err := w.writer.Seek(end, io.SeekStart); err != nil {
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return nil, err
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}
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return bi, nil
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}
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func (w *Writer) CopyBox(r io.ReadSeeker, bi *BoxInfo) error {
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if _, err := bi.SeekToStart(r); err != nil {
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return err
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}
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if n, err := io.CopyN(w, r, int64(bi.Size)); err != nil {
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return err
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} else if n != int64(bi.Size) {
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return errors.New("failed to copy box")
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}
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return nil
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}
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