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mgt.go
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mgt.go
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package psip
import (
"github.com/mh-orange/ts"
"github.com/mh-orange/ts/psi"
)
type TableInfo []byte
func (t TableInfo) Type() uint16 {
return ts.Uimsbf16(t[0:2], 16)
}
func (t TableInfo) PID() uint16 {
return ts.Uimsbf16(t[2:4], 16) & 0x1fff
}
func (t TableInfo) Version() uint8 {
return ts.Uimsbf8(t[4]) & 0x1f
}
func (t TableInfo) TableLength() int {
return int(ts.Uimsbf32(t[5:9], 32))
}
func (t TableInfo) DescriptorsLength() int {
return int(ts.Uimsbf16(t[9:11], 16) & 0x0fff)
}
func (t TableInfo) Descriptors() []psi.Descriptor {
return psi.Descriptors(t[11 : 11+t.DescriptorsLength()])
}
func (t TableInfo) Length() int {
return 11 + t.DescriptorsLength()
}
// Master Guide Table
type MGT interface {
NumTables() int
Tables() []TableInfo
Descriptors() []psi.Descriptor
}
type mgt struct {
*Table
}
func newMGT(payload []byte) MGT {
return &mgt{&Table{psi.CreateTable(0xc7, payload)}}
}
func (m *mgt) NumTables() int {
return int(ts.Uimsbf16(m.Data()[0:2], 2))
}
func (m *mgt) Tables() []TableInfo {
tables := make([]TableInfo, m.NumTables())
start := 2
for i := 0; i < len(tables); i++ {
tables[i] = TableInfo(m.Data()[start:])
start += tables[i].Length()
}
return tables
}
func (m *mgt) descriptorLengthOffset() int {
offset := 2
for _, tableInfo := range m.Tables() {
offset += tableInfo.Length()
}
return offset
}
func (m *mgt) DescriptorsLength() int {
offset := m.descriptorLengthOffset()
return int(ts.Uimsbf16(m.Data()[offset:offset+2], 16) & 0x0fff)
}
func (m *mgt) Descriptors() []psi.Descriptor {
start := m.descriptorLengthOffset() + 2
end := len(m.Data())
return psi.Descriptors(m.Data()[start:end])
}