Caleb Gardner
91 lines
1.7 KiB
Go
91 lines
1.7 KiB
Go
package directory
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import (
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"encoding/binary"
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"io"
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)
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type header struct {
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Count uint32
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BlockStart uint32
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Num uint32
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}
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func readHeader(r io.Reader) (h header, err error) {
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dat := make([]byte, 12)
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_, err = r.Read(dat)
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if err != nil {
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return
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}
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h.Count = binary.LittleEndian.Uint32(dat)
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h.BlockStart = binary.LittleEndian.Uint32(dat[4:])
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h.Num = binary.LittleEndian.Uint32(dat[8:])
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return
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}
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type dirEntry struct {
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Offset uint16
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NumOffset int16
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InodeType uint16
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NameSize uint16
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Name []byte
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}
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func readEntry(r io.Reader) (e dirEntry, err error) {
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dat := make([]byte, 8)
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_, err = r.Read(dat)
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if err != nil {
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return
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}
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e.Offset = binary.LittleEndian.Uint16(dat)
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_, err = binary.Decode(dat[2:], binary.LittleEndian, &e.NumOffset)
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if err != nil {
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return
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}
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e.InodeType = binary.LittleEndian.Uint16(dat[4:])
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e.NameSize = binary.LittleEndian.Uint16(dat[6:])
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e.Name = make([]byte, e.NameSize+1)
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_, err = r.Read(e.Name)
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if err != nil {
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return
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}
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return
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}
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type Entry struct {
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Name string
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BlockStart uint32
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Offset uint16
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InodeType uint16
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Num uint32
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}
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func ReadDirectory(r io.Reader, size uint32) (out []Entry, err error) {
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size -= 3
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var curRead uint32
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var h header
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var de dirEntry
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for curRead < size {
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h, err = readHeader(r)
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if err != nil {
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return
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}
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curRead += 12
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for i := uint32(0); i < h.Count+1 && curRead < size; i++ {
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de, err = readEntry(r)
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if err != nil {
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return
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}
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curRead += 8 + uint32(de.NameSize) + 1
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out = append(out, Entry{
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BlockStart: h.BlockStart,
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Offset: de.Offset,
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Name: string(de.Name),
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InodeType: de.InodeType,
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Num: h.Num + uint32(de.NumOffset),
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})
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}
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}
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return
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}
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