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path: root/plumbing/format/idxfile/decoder.go
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Diffstat (limited to 'plumbing/format/idxfile/decoder.go')
-rw-r--r--plumbing/format/idxfile/decoder.go109
1 files changed, 64 insertions, 45 deletions
diff --git a/plumbing/format/idxfile/decoder.go b/plumbing/format/idxfile/decoder.go
index 45afb1e..25ff88e 100644
--- a/plumbing/format/idxfile/decoder.go
+++ b/plumbing/format/idxfile/decoder.go
@@ -17,6 +17,11 @@ var (
ErrMalformedIdxFile = errors.New("Malformed IDX file")
)
+const (
+ fanout = 256
+ objectIDLength = 20
+)
+
// Decoder reads and decodes idx files from an input stream.
type Decoder struct {
*bufio.Reader
@@ -27,13 +32,13 @@ func NewDecoder(r io.Reader) *Decoder {
return &Decoder{bufio.NewReader(r)}
}
-// Decode reads from the stream and decode the content into the Idxfile struct.
-func (d *Decoder) Decode(idx *Idxfile) error {
+// Decode reads from the stream and decode the content into the MemoryIndex struct.
+func (d *Decoder) Decode(idx *MemoryIndex) error {
if err := validateHeader(d); err != nil {
return err
}
- flow := []func(*Idxfile, io.Reader) error{
+ flow := []func(*MemoryIndex, io.Reader) error{
readVersion,
readFanout,
readObjectNames,
@@ -48,10 +53,6 @@ func (d *Decoder) Decode(idx *Idxfile) error {
}
}
- if !idx.isValid() {
- return ErrMalformedIdxFile
- }
-
return nil
}
@@ -68,7 +69,7 @@ func validateHeader(r io.Reader) error {
return nil
}
-func readVersion(idx *Idxfile, r io.Reader) error {
+func readVersion(idx *MemoryIndex, r io.Reader) error {
v, err := binary.ReadUint32(r)
if err != nil {
return err
@@ -82,74 +83,92 @@ func readVersion(idx *Idxfile, r io.Reader) error {
return nil
}
-func readFanout(idx *Idxfile, r io.Reader) error {
- var err error
- for i := 0; i < 255; i++ {
- idx.Fanout[i], err = binary.ReadUint32(r)
+func readFanout(idx *MemoryIndex, r io.Reader) error {
+ for k := 0; k < fanout; k++ {
+ n, err := binary.ReadUint32(r)
if err != nil {
return err
}
+
+ idx.Fanout[k] = n
+ idx.FanoutMapping[k] = noMapping
}
- idx.ObjectCount, err = binary.ReadUint32(r)
- return err
+ return nil
}
-func readObjectNames(idx *Idxfile, r io.Reader) error {
- c := int(idx.ObjectCount)
- new := make([]Entry, c)
- for i := 0; i < c; i++ {
- e := &new[i]
- if _, err := io.ReadFull(r, e.Hash[:]); err != nil {
+func readObjectNames(idx *MemoryIndex, r io.Reader) error {
+ for k := 0; k < fanout; k++ {
+ var buckets uint32
+ if k == 0 {
+ buckets = idx.Fanout[k]
+ } else {
+ buckets = idx.Fanout[k] - idx.Fanout[k-1]
+ }
+
+ if buckets == 0 {
+ continue
+ }
+
+ if buckets < 0 {
+ return ErrMalformedIdxFile
+ }
+
+ idx.FanoutMapping[k] = len(idx.Names)
+
+ nameLen := int(buckets * objectIDLength)
+ bin := make([]byte, nameLen)
+ if _, err := io.ReadFull(r, bin); err != nil {
return err
}
- idx.Entries = append(idx.Entries, e)
+ idx.Names = append(idx.Names, bin)
+ idx.Offset32 = append(idx.Offset32, make([]byte, buckets*4))
+ idx.Crc32 = append(idx.Crc32, make([]byte, buckets*4))
}
return nil
}
-func readCRC32(idx *Idxfile, r io.Reader) error {
- c := int(idx.ObjectCount)
- for i := 0; i < c; i++ {
- if err := binary.Read(r, &idx.Entries[i].CRC32); err != nil {
- return err
+func readCRC32(idx *MemoryIndex, r io.Reader) error {
+ for k := 0; k < fanout; k++ {
+ if pos := idx.FanoutMapping[k]; pos != noMapping {
+ if _, err := io.ReadFull(r, idx.Crc32[pos]); err != nil {
+ return err
+ }
}
}
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
+func readOffsets(idx *MemoryIndex, r io.Reader) error {
+ var o64cnt int
+ for k := 0; k < fanout; k++ {
+ if pos := idx.FanoutMapping[k]; pos != noMapping {
+ if _, err := io.ReadFull(r, idx.Offset32[pos]); err != nil {
+ return err
+ }
+
+ for p := 0; p < len(idx.Offset32[pos]); p += 4 {
+ if idx.Offset32[pos][p]&(byte(1)<<7) > 0 {
+ o64cnt++
+ }
+ }
}
-
- idx.Entries[i].Offset = uint64(o)
}
- for i := 0; i < c; i++ {
- if idx.Entries[i].Offset <= offsetLimit {
- continue
- }
-
- o, err := binary.ReadUint64(r)
- if err != nil {
+ if o64cnt > 0 {
+ idx.Offset64 = make([]byte, o64cnt*8)
+ if _, err := io.ReadFull(r, idx.Offset64); err != nil {
return err
}
-
- idx.Entries[i].Offset = o
}
return nil
}
-func readChecksums(idx *Idxfile, r io.Reader) error {
+func readChecksums(idx *MemoryIndex, r io.Reader) error {
if _, err := io.ReadFull(r, idx.PackfileChecksum[:]); err != nil {
return err
}