gotosocial/vendor/github.com/abema/go-mp4/extract.go

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package mp4
import (
"errors"
"io"
)
type BoxInfoWithPayload struct {
Info BoxInfo
Payload IBox
}
func ExtractBoxWithPayload(r io.ReadSeeker, parent *BoxInfo, path BoxPath) ([]*BoxInfoWithPayload, error) {
return ExtractBoxesWithPayload(r, parent, []BoxPath{path})
}
func ExtractBoxesWithPayload(r io.ReadSeeker, parent *BoxInfo, paths []BoxPath) ([]*BoxInfoWithPayload, error) {
bis, err := ExtractBoxes(r, parent, paths)
if err != nil {
return nil, err
}
bs := make([]*BoxInfoWithPayload, 0, len(bis))
for _, bi := range bis {
if _, err := bi.SeekToPayload(r); err != nil {
return nil, err
}
var ctx Context
if parent != nil {
ctx = parent.Context
}
box, _, err := UnmarshalAny(r, bi.Type, bi.Size-bi.HeaderSize, ctx)
if err != nil {
return nil, err
}
bs = append(bs, &BoxInfoWithPayload{
Info: *bi,
Payload: box,
})
}
return bs, nil
}
func ExtractBox(r io.ReadSeeker, parent *BoxInfo, path BoxPath) ([]*BoxInfo, error) {
return ExtractBoxes(r, parent, []BoxPath{path})
}
func ExtractBoxes(r io.ReadSeeker, parent *BoxInfo, paths []BoxPath) ([]*BoxInfo, error) {
if len(paths) == 0 {
return nil, nil
}
for i := range paths {
if len(paths[i]) == 0 {
return nil, errors.New("box path must not be empty")
}
}
boxes := make([]*BoxInfo, 0, 8)
handler := func(handle *ReadHandle) (interface{}, error) {
path := handle.Path
if parent != nil {
path = path[1:]
}
if handle.BoxInfo.Type == BoxTypeAny() {
return nil, nil
}
fm, m := matchPath(paths, path)
if m {
boxes = append(boxes, &handle.BoxInfo)
}
if fm {
if _, err := handle.Expand(); err != nil {
return nil, err
}
}
return nil, nil
}
if parent != nil {
_, err := ReadBoxStructureFromInternal(r, parent, handler)
return boxes, err
}
_, err := ReadBoxStructure(r, handler)
return boxes, err
}
func matchPath(paths []BoxPath, path BoxPath) (forwardMatch bool, match bool) {
for i := range paths {
fm, m := path.compareWith(paths[i])
forwardMatch = forwardMatch || fm
match = match || m
}
return
}