git/odb/pack: rename, unexport index offset consts

This commit is contained in:
Taylor Blau 2017-07-24 12:05:41 -06:00
parent bdc9ff0d87
commit edd354eaa1
8 changed files with 65 additions and 63 deletions

@ -8,47 +8,49 @@ import (
)
const (
// MagicWidth is the width of the magic header of packfiles version 2
// and newer.
MagicWidth = 4
// VersionWidth is the width of the version following the magic header.
VersionWidth = 4
// V2Width is the total width of the header in V2.
V2Width = MagicWidth + VersionWidth
// V1Width is the total width of the header in V1.
V1Width = 0
// FanoutEntries is the number of entries in the fanout table.
FanoutEntries = 256
// FanoutEntryWidth is the width of each entry in the fanout table.
FanoutEntryWidth = 4
// FanoutWidth is the width of the entire fanout table.
FanoutWidth = FanoutEntries * FanoutEntryWidth
// OffsetV1Start is the location of the first object outside of the V1
// indexMagicWidth is the width of the magic header of packfiles version
// 2 and newer.
indexMagicWidth = 4
// indexVersionWidth is the width of the version following the magic
// header.
OffsetV1Start = V1Width + FanoutWidth
// OffsetV2Start is the location of the first object outside of the V2
// header.
OffsetV2Start = V2Width + FanoutWidth
indexVersionWidth = 4
// indexV2Width is the total width of the header in V2.
indexV2Width = indexMagicWidth + indexVersionWidth
// indexV1Width is the total width of the header in V1.
indexV1Width = 0
// ObjectNameWidth is the width of a SHA1 object name.
ObjectNameWidth = 20
// ObjectCRCWidth is the width of the CRC accompanying each object in
// V2.
ObjectCRCWidth = 4
// ObjectSmallOffsetWidth is the width of the small offset encoded into
// each object.
ObjectSmallOffsetWidth = 4
// ObjectLargeOffsetWidth is the width of the optional large offset
// indexFanoutEntries is the number of entries in the fanout table.
indexFanoutEntries = 256
// indexFanoutEntryWidth is the width of each entry in the fanout table.
indexFanoutEntryWidth = 4
// indexFanoutWidth is the width of the entire fanout table.
indexFanoutWidth = indexFanoutEntries * indexFanoutEntryWidth
// indexOffsetV1Start is the location of the first object outside of the
// V1 header.
indexOffsetV1Start = indexV1Width + indexFanoutWidth
// indexOffsetV2Start is the location of the first object outside of the
// V2 header.
indexOffsetV2Start = indexV2Width + indexFanoutWidth
// indexObjectNameWidth is the width of a SHA1 object name.
indexObjectNameWidth = 20
// indexObjectCRCWidth is the width of the CRC accompanying each object
// in V2.
indexObjectCRCWidth = 4
// indexObjectSmallOffsetWidth is the width of the small offset encoded
// into each object.
indexObjectSmallOffsetWidth = 4
// indexObjectLargeOffsetWidth is the width of the optional large offset
// encoded into the small offset.
ObjectLargeOffsetWidth = 8
indexObjectLargeOffsetWidth = 8
// ObjectEntryV1Width is the width of one contiguous object entry in V1.
ObjectEntryV1Width = ObjectNameWidth + ObjectSmallOffsetWidth
// ObjectEntryV2Width is the width of one non-contiguous object entry in
// V2.
ObjectEntryV2Width = ObjectNameWidth + ObjectCRCWidth + ObjectSmallOffsetWidth
// indexObjectEntryV1Width is the width of one contiguous object entry
// in V1.
indexObjectEntryV1Width = indexObjectNameWidth + indexObjectSmallOffsetWidth
// indexObjectEntryV2Width is the width of one non-contiguous object
// entry in V2.
indexObjectEntryV2Width = indexObjectNameWidth + indexObjectCRCWidth + indexObjectSmallOffsetWidth
)
var (

@ -10,17 +10,17 @@ import (
)
func TestDecodeIndexV1InvalidFanout(t *testing.T) {
idx, err := DecodeIndex(bytes.NewReader(make([]byte, FanoutWidth-1)))
idx, err := DecodeIndex(bytes.NewReader(make([]byte, indexFanoutWidth-1)))
assert.Equal(t, ErrShortFanout, err)
assert.Nil(t, idx)
}
func TestDecodeIndexV2(t *testing.T) {
buf := make([]byte, 0, V2Width+FanoutWidth)
buf := make([]byte, 0, indexV2Width+indexFanoutWidth)
buf = append(buf, 0xff, 0x74, 0x4f, 0x63)
buf = append(buf, 0x0, 0x0, 0x0, 0x2)
for i := 0; i < FanoutEntries; i++ {
for i := 0; i < indexFanoutEntries; i++ {
x := make([]byte, 4)
binary.BigEndian.PutUint32(x, uint32(3))
@ -36,10 +36,10 @@ func TestDecodeIndexV2(t *testing.T) {
}
func TestDecodeIndexV2InvalidFanout(t *testing.T) {
buf := make([]byte, 0, V2Width+FanoutWidth-FanoutEntryWidth)
buf := make([]byte, 0, indexV2Width+indexFanoutWidth-indexFanoutEntryWidth)
buf = append(buf, 0xff, 0x74, 0x4f, 0x63)
buf = append(buf, 0x0, 0x0, 0x0, 0x2)
buf = append(buf, make([]byte, FanoutWidth-1)...)
buf = append(buf, make([]byte, indexFanoutWidth-1)...)
idx, err := DecodeIndex(bytes.NewReader(buf))
@ -48,7 +48,7 @@ func TestDecodeIndexV2InvalidFanout(t *testing.T) {
}
func TestDecodeIndexV1(t *testing.T) {
idx, err := DecodeIndex(bytes.NewReader(make([]byte, FanoutWidth)))
idx, err := DecodeIndex(bytes.NewReader(make([]byte, indexFanoutWidth)))
assert.NoError(t, err)
assert.Equal(t, V1, idx.version)

@ -90,7 +90,7 @@ func init() {
// Since we have an even distribution of SHA1s in the generated index,
// each entry will increase by the number of entries per slot (see: eps
// above).
fanout := make([]uint32, FanoutEntries)
fanout := make([]uint32, indexFanoutEntries)
for i := 0; i < len(fanout); i++ {
// Begin the index at (i+1), since the fanout table mandates
// objects less than the value at index "i".

@ -39,14 +39,14 @@ func v1ShaOffset(at int64) int64 {
return v1EntryOffset(at) +
// Skip past the 4-byte object offset in the desired entry to
// the SHA1.
ObjectSmallOffsetWidth
indexObjectSmallOffsetWidth
}
// v1EntryOffset returns the location of the packfile offset for the object
// given at "at".
func v1EntryOffset(at int64) int64 {
// Skip the L1 fanout table
return OffsetV1Start +
return indexOffsetV1Start +
// Skip the object entries before the one located at "at"
(ObjectEntryV1Width * at)
(indexObjectEntryV1Width * at)
}

@ -9,7 +9,7 @@ import (
)
var (
V1IndexFanout = make([]uint32, FanoutEntries)
V1IndexFanout = make([]uint32, indexFanoutEntries)
V1IndexSmallEntry = []byte{
0x0, 0x0, 0x0, 0x1,
@ -82,12 +82,12 @@ func init() {
V1IndexFanout[i] = 3
}
fanout := make([]byte, FanoutWidth)
fanout := make([]byte, indexFanoutWidth)
for i, n := range V1IndexFanout {
binary.BigEndian.PutUint32(fanout[i*FanoutEntryWidth:], n)
binary.BigEndian.PutUint32(fanout[i*indexFanoutEntryWidth:], n)
}
buf := make([]byte, 0, OffsetV1Start+(3*ObjectEntryV1Width))
buf := make([]byte, 0, indexOffsetV1Start+(3*indexObjectEntryV1Width))
buf = append(buf, fanout...)
buf = append(buf, V1IndexSmallEntry...)

@ -48,20 +48,20 @@ func v2Search(idx *Index, name []byte, at int64) (*IndexEntry, int, error) {
// v2ShaOffset returns the offset of a SHA1 given at "at" in the V2 index file.
func v2ShaOffset(at int64) int64 {
// Skip the packfile index header and the L1 fanout table.
return OffsetV2Start +
return indexOffsetV2Start +
// Skip until the desired name in the sorted names table.
(ObjectNameWidth * at)
(indexObjectNameWidth * at)
}
// v2SmallOffsetOffset returns the offset of an object's small (4-byte) offset
// given by "at".
func v2SmallOffsetOffset(at, total int64) int64 {
// Skip the packfile index header and the L1 fanout table.
return OffsetV2Start +
return indexOffsetV2Start +
// Skip the name table.
(ObjectNameWidth * total) +
(indexObjectNameWidth * total) +
// Skip the CRC table.
(ObjectCRCWidth * total) +
(indexObjectCRCWidth * total) +
// Skip until the desired index in the small offsets table.
(ObjectSmallOffsetWidth * at)
(indexObjectSmallOffsetWidth * at)
}

@ -13,7 +13,7 @@ var (
0xff, 0x74, 0x4f, 0x63,
0x00, 0x00, 0x00, 0x02,
}
V2IndexFanout = make([]uint32, FanoutEntries)
V2IndexFanout = make([]uint32, indexFanoutEntries)
V2IndexNames = []byte{
0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1,
@ -90,12 +90,12 @@ func init() {
V2IndexFanout[i] = 3
}
fanout := make([]byte, FanoutWidth)
fanout := make([]byte, indexFanoutWidth)
for i, n := range V2IndexFanout {
binary.BigEndian.PutUint32(fanout[i*FanoutEntryWidth:], n)
binary.BigEndian.PutUint32(fanout[i*indexFanoutEntryWidth:], n)
}
buf := make([]byte, 0, OffsetV2Start+3*(ObjectEntryV2Width)+ObjectLargeOffsetWidth)
buf := make([]byte, 0, indexOffsetV2Start+3*(indexObjectEntryV2Width)+indexObjectLargeOffsetWidth)
buf = append(buf, V2IndexHeader...)
buf = append(buf, fanout...)
buf = append(buf, V2IndexNames...)

@ -19,9 +19,9 @@ const (
func (v IndexVersion) Width() int64 {
switch v {
case V2:
return V2Width
return indexV2Width
case V1:
return V1Width
return indexV1Width
}
panic(fmt.Sprintf("git/odb/pack: width unknown for pack version %d", v))
}