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7b27e506f1
PSSH decoding probably got broken in some refactoring. system id is 16 bytes, also scalar mapper should use cloned reader to not affect reader which in the case broke reading system id bytes. Add test with playread and widevine pssh boxes Related to #282
103 lines
2.3 KiB
Go
103 lines
2.3 KiB
Go
package bitio
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import (
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"errors"
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"io"
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)
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// IOBitReadSeeker is a bitio.ReadAtSeeker reading from a io.ReadSeeker.
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type IOBitReadSeeker struct {
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bitPos int64
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rs io.ReadSeeker
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buf []byte
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}
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// NewIOBitReadSeeker returns a new bitio.IOBitReadSeeker
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func NewIOBitReadSeeker(rs io.ReadSeeker) *IOBitReadSeeker {
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return &IOBitReadSeeker{
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bitPos: 0,
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rs: rs,
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}
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}
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func (r *IOBitReadSeeker) ReadBitsAt(p []byte, nBits int64, bitOffset int64) (int64, error) {
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if nBits < 0 {
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return 0, ErrNegativeNBits
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}
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readBytePos := bitOffset / 8
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readSkipBits := bitOffset % 8
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wantReadBits := readSkipBits + nBits
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wantReadBytes := int(BitsByteCount(wantReadBits))
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if wantReadBytes > len(r.buf) {
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// TODO: use append somehow?
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r.buf = make([]byte, wantReadBytes)
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}
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_, err := r.rs.Seek(readBytePos, io.SeekStart)
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if err != nil {
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return 0, err
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}
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// TODO: nBits should be available
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readBytes, err := io.ReadFull(r.rs, r.buf[0:wantReadBytes])
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if err != nil && !errors.Is(err, io.ErrUnexpectedEOF) {
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return 0, err
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} else if errors.Is(err, io.ErrUnexpectedEOF) {
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nBits = int64(readBytes) * 8
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err = io.EOF
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}
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if readSkipBits == 0 && nBits%8 == 0 {
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copy(p[0:readBytes], r.buf[0:readBytes])
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return nBits, err
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}
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nBytes := nBits / 8
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restBits := nBits % 8
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// TODO: copy smartness if many bytes
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for i := int64(0); i < nBytes; i++ {
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p[i] = byte(Read64(r.buf, readSkipBits+i*8, 8))
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}
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if restBits != 0 {
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p[nBytes] = byte(Read64(r.buf, readSkipBits+nBytes*8, restBits)) << (8 - restBits)
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}
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return nBits, err
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}
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func (r *IOBitReadSeeker) ReadBits(p []byte, nBits int64) (n int64, err error) {
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rBits, err := r.ReadBitsAt(p, nBits, r.bitPos)
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r.bitPos += rBits
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return rBits, err
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}
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func (r *IOBitReadSeeker) SeekBits(bitOff int64, whence int) (int64, error) {
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seekBytesPos, err := r.rs.Seek(bitOff/8, whence)
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if err != nil {
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return 0, err
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}
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seekBitPos := seekBytesPos*8 + bitOff%8
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r.bitPos = seekBitPos
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return seekBitPos, nil
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}
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func (r *IOBitReadSeeker) CloneReader() (Reader, error) {
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return r.CloneReaderAtSeeker()
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}
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func (r *IOBitReadSeeker) CloneReadSeeker() (ReadSeeker, error) {
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return r.CloneReaderAtSeeker()
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}
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func (r *IOBitReadSeeker) CloneReadAtSeeker() (ReadAtSeeker, error) {
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return r.CloneReaderAtSeeker()
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}
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func (r *IOBitReadSeeker) CloneReaderAtSeeker() (ReaderAtSeeker, error) {
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return NewIOBitReadSeeker(r.rs), nil
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}
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