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90 lines
1.7 KiB
90 lines
1.7 KiB
package headers
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import (
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"errors"
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"io"
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)
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const MaxFolderCount = 1 << 30
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// ErrInvalidCountExceeded is returned when the folder count is
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// < 0 || > MaxFolderCount
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var ErrInvalidCountExceeded = errors.New("invalid folder count")
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// UnpackInfo is a structure containing folders.
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type UnpackInfo struct {
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Folders []*Folder
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}
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// ReadUnpackInfo reads unpack info structures.
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func ReadUnpackInfo(r io.Reader) (*UnpackInfo, error) {
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err := ReadByteExpect(r, k7zFolder)
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if err != nil {
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return nil, err
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}
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numFolders, err := ReadNumberInt(r)
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if err != nil {
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return nil, err
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}
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if numFolders > MaxFolderCount {
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return nil, ErrInvalidCountExceeded
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}
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unpackInfo := &UnpackInfo{}
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external, err := ReadByte(r)
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if err != nil {
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return nil, err
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}
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switch external {
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case 0:
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unpackInfo.Folders = make([]*Folder, numFolders)
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for i := range unpackInfo.Folders {
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if unpackInfo.Folders[i], err = ReadFolder(r); err != nil {
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return nil, err
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}
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}
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default:
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return nil, ErrAdditionalStreamsNotImplemented
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}
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if err = ReadByteExpect(r, k7zCodersUnpackSize); err != nil {
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return nil, err
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}
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for _, folder := range unpackInfo.Folders {
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folder.UnpackSizes = make([]uint64, folder.NumOutStreamsTotal())
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for i := range folder.UnpackSizes {
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if folder.UnpackSizes[i], err = ReadNumber(r); err != nil {
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return nil, err
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}
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}
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}
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id, err := ReadByte(r)
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if err != nil {
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return nil, err
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}
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if id == k7zCRC {
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crcs, err := ReadDigests(r, len(unpackInfo.Folders))
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if err != nil {
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return nil, err
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}
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for i := range unpackInfo.Folders {
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unpackInfo.Folders[i].UnpackCRC = crcs[i]
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}
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id, err = ReadByte(r)
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if err != nil {
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return nil, err
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}
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}
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if id != k7zEnd {
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return nil, ErrUnexpectedPropertyID
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}
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return unpackInfo, nil
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}
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