mirror of https://github.com/stashapp/stash.git
125 lines
3.2 KiB
Go
125 lines
3.2 KiB
Go
package astits
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import (
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"fmt"
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"time"
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"github.com/asticode/go-astikit"
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)
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// EITData represents an EIT data
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// Page: 36 | Chapter: 5.2.4 | Link: https://www.dvb.org/resources/public/standards/a38_dvb-si_specification.pdf
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// (barbashov) the link above can be broken, alternative: https://dvb.org/wp-content/uploads/2019/12/a038_tm1217r37_en300468v1_17_1_-_rev-134_-_si_specification.pdf
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type EITData struct {
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Events []*EITDataEvent
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LastTableID uint8
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OriginalNetworkID uint16
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SegmentLastSectionNumber uint8
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ServiceID uint16
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TransportStreamID uint16
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}
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// EITDataEvent represents an EIT data event
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type EITDataEvent struct {
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Descriptors []*Descriptor
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Duration time.Duration
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EventID uint16
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HasFreeCSAMode bool // When true indicates that access to one or more streams may be controlled by a CA system.
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RunningStatus uint8
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StartTime time.Time
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}
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// parseEITSection parses an EIT section
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func parseEITSection(i *astikit.BytesIterator, offsetSectionsEnd int, tableIDExtension uint16) (d *EITData, err error) {
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// Create data
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d = &EITData{ServiceID: tableIDExtension}
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// Get next 2 bytes
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var bs []byte
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if bs, err = i.NextBytesNoCopy(2); err != nil {
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err = fmt.Errorf("astits: fetching next bytes failed: %w", err)
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return
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}
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// Transport stream ID
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d.TransportStreamID = uint16(bs[0])<<8 | uint16(bs[1])
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// Get next 2 bytes
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if bs, err = i.NextBytesNoCopy(2); err != nil {
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err = fmt.Errorf("astits: fetching next bytes failed: %w", err)
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return
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}
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// Original network ID
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d.OriginalNetworkID = uint16(bs[0])<<8 | uint16(bs[1])
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// Get next byte
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var b byte
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if b, err = i.NextByte(); err != nil {
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err = fmt.Errorf("astits: fetching next byte failed: %w", err)
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return
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}
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// Segment last section number
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d.SegmentLastSectionNumber = uint8(b)
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// Get next byte
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if b, err = i.NextByte(); err != nil {
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err = fmt.Errorf("astits: fetching next byte failed: %w", err)
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return
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}
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// Last table ID
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d.LastTableID = uint8(b)
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// Loop until end of section data is reached
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for i.Offset() < offsetSectionsEnd {
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// Get next 2 bytes
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if bs, err = i.NextBytesNoCopy(2); err != nil {
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err = fmt.Errorf("astits: fetching next bytes failed: %w", err)
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return
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}
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// Event ID
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var e = &EITDataEvent{}
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e.EventID = uint16(bs[0])<<8 | uint16(bs[1])
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// Start time
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if e.StartTime, err = parseDVBTime(i); err != nil {
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err = fmt.Errorf("astits: parsing DVB time")
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return
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}
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// Duration
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if e.Duration, err = parseDVBDurationSeconds(i); err != nil {
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err = fmt.Errorf("astits: parsing DVB duration seconds failed: %w", err)
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return
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}
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// Get next byte
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if b, err = i.NextByte(); err != nil {
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err = fmt.Errorf("astits: fetching next byte failed: %w", err)
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return
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}
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// Running status
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e.RunningStatus = uint8(b) >> 5
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// Free CA mode
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e.HasFreeCSAMode = uint8(b&0x10) > 0
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// We need to rewind since the current byte is used by the descriptor as well
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i.Skip(-1)
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// Descriptors
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if e.Descriptors, err = parseDescriptors(i); err != nil {
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err = fmt.Errorf("astits: parsing descriptors failed: %w", err)
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return
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}
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// Add event
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d.Events = append(d.Events, e)
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}
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return
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}
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