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stream/mts/psi/psi.go: checking that we have enough space in psi before creating descriptor

This commit is contained in:
saxon 2019-02-07 15:23:41 +10:30
parent 21265303d7
commit b4393e5136
1 changed files with 10 additions and 3 deletions
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13
stream/mts/psi/psi.go
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@ -52,6 +52,8 @@ const (
pmtID = 0x02 pmtID = 0x02
) )
const TotalSyntaxSecLen = 180
// Consts relating to time description // Consts relating to time description
const ( const (
TimeDescTag = 234 TimeDescTag = 234
@ -251,8 +253,8 @@ func (p *PSIBytes) AddDescriptor(tag int, data []byte) error {
i, desc := p.HasDescriptor(tag) i, desc := p.HasDescriptor(tag)
if desc == nil { if desc == nil {
p.createDescriptor(tag, data) err := p.createDescriptor(tag, data)
return nil return err
} }
oldDescLen := desc.len() oldDescLen := desc.len()
@ -308,9 +310,12 @@ func (p *PSIBytes) HasDescriptor(tag int) (int, Descriptor) {
// createDescriptor creates a descriptor in a psi given a tag and data. It does so // createDescriptor creates a descriptor in a psi given a tag and data. It does so
// by resizing the psi, shifting existing data down and copying in new descriptor // by resizing the psi, shifting existing data down and copying in new descriptor
// in new space. // in new space.
func (p *PSIBytes) createDescriptor(tag int, data []byte) { func (p *PSIBytes) createDescriptor(tag int, data []byte) error {
curProgLen := p.ProgramInfoLen() curProgLen := p.ProgramInfoLen()
oldSyntaxSectionLen := SyntaxSecLenFrom(*p) oldSyntaxSectionLen := SyntaxSecLenFrom(*p)
if TotalSyntaxSecLen-(oldSyntaxSectionLen+2+len(data)) <= 0 {
return errors.New("Not enough space in psi to create descriptor.")
}
dataLen := len(data) dataLen := len(data)
newDescIdx := DescriptorsIdx + curProgLen newDescIdx := DescriptorsIdx + curProgLen
newDescLen := dataLen + 2 newDescLen := dataLen + 2
@ -332,6 +337,8 @@ func (p *PSIBytes) createDescriptor(tag int, data []byte) {
newSyntaxSectionLen := int(oldSyntaxSectionLen) + addedLen newSyntaxSectionLen := int(oldSyntaxSectionLen) + addedLen
p.setSectionLen(newSyntaxSectionLen) p.setSectionLen(newSyntaxSectionLen)
UpdateCrc((*p)[1:]) UpdateCrc((*p)[1:])
return nil
} }
// setProgInfoLen sets the program information length in a psi with a pmt. // setProgInfoLen sets the program information length in a psi with a pmt.