func readFanout(idx *Idxfile, r io.Reader) error {
var err error
for i := 0; i < 255; i++ {
idx.Fanout[i], err = binary.ReadUint32(r)
if err != nil {
return err
}
}
idx.ObjectCount, err = binary.ReadUint32(r)
return err
}
func (d *Decoder) getExtensionReader() (io.Reader, error) {
len, err := binary.ReadUint32(d.r)
if err != nil {
return nil, err
}
return &io.LimitedReader{R: d.r, N: int64(len)}, nil
}
func readVersion(idx *Idxfile, r io.Reader) error {
v, err := binary.ReadUint32(r)
if err != nil {
return err
}
if v > VersionSupported {
return ErrUnsupportedVersion
}
idx.Version = v
return nil
}
func readOffsets(idx *Idxfile, r io.Reader) error {
c := int(idx.ObjectCount)
for i := 0; i < c; i++ {
o, err := binary.ReadUint32(r)
if err != nil {
return err
}
idx.Entries[i].Offset = uint64(o)
}
return nil
}
// Decode reads the whole index object from its input and stores it in the
// value pointed to by idx.
func (d *Decoder) Decode(idx *Index) error {
var err error
idx.Version, err = validateHeader(d.r)
if err != nil {
return err
}
entryCount, err := binary.ReadUint32(d.r)
if err != nil {
return err
}
if err := d.readEntries(idx, int(entryCount)); err != nil {
return err
}
return d.readExtensions(idx)
}
func validateHeader(r io.Reader) (version uint32, err error) {
var s = make([]byte, 4)
if _, err := io.ReadFull(r, s); err != nil {
return 0, err
}
if !bytes.Equal(s, indexSignature) {
return 0, ErrMalformedSignature
}
version, err = binary.ReadUint32(r)
if err != nil {
return 0, err
}
if version < DecodeVersionSupported.Min || version > DecodeVersionSupported.Max {
return 0, ErrUnsupportedVersion
}
return
}
// readCount reads and returns the count of objects field of a packfile.
func (s *Scanner) readCount() (uint32, error) {
return binary.ReadUint32(s.r)
}
// readVersion reads and returns the version field of a packfile.
func (s *Scanner) readVersion() (uint32, error) {
return binary.ReadUint32(s.r)
}
