format: idxfile.Encoder fix fanout generator

Author: mcuadros

fixtures/data/pack-c544593473465e6315ad4182d04d366c4592b829.idx

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"encoding/binary"
 	"errors"
-	"fmt"
 	"io"
 
 	"gopkg.in/src-d/go-git.v4/core"
@@ -96,7 +95,6 @@ func readFanout(idx *Idxfile, r io.Reader) error {
 	}
 
 	idx.ObjectCount, err = readInt32(r)
-	fmt.Println(idx.ObjectCount)
 	return err
 }
 

formats/idxfile/decoder.go

@@ -41,11 +41,10 @@ func (s *IdxfileSuite) TestDecodeCRCs(c *C) {
 	storage := memory.NewStorage()
 
 	pd := packfile.NewDecoder(scanner, storage.ObjectStorage())
-	checksum, err := pd.Decode()
+	_, err := pd.Decode()
 	c.Assert(err, IsNil)
 
 	i := &Idxfile{Version: VersionSupported}
-	i.PackfileChecksum = checksum
 
 	offsets := pd.Offsets()
 	for h, crc := range pd.CRCs() {
@@ -63,5 +62,5 @@ func (s *IdxfileSuite) TestDecodeCRCs(c *C) {
 	err = d.Decode(idx)
 	c.Assert(err, IsNil)
 
-	c.Assert(idx, DeepEquals, i)
+	c.Assert(idx.Entries, DeepEquals, i.Entries)
 }

formats/idxfile/decoder_test.go

@@ -50,19 +50,12 @@ func (idx *Idxfile) isValid() bool {
 
 func (idx *Idxfile) calculateFanout() [256]uint32 {
 	fanout := [256]uint32{}
-	var c uint32
 	for _, e := range idx.Entries {
-		c++
-		fanout[e.Hash[0]] = c
+		fanout[e.Hash[0]]++
 	}
 
-	var i uint32
-	for k, c := range fanout {
-		if c != 0 {
-			i = c
-		}
-
-		fanout[k] = i
+	for i := 1; i < 256; i++ {
+		fanout[i] += fanout[i-1]
 	}
 
 	return fanout