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authorMiguel Molina <miguel@erizocosmi.co>2017-09-07 12:02:52 +0200
committerMiguel Molina <miguel@erizocosmi.co>2017-09-07 12:02:52 +0200
commit6d486b4f996c8abffd3206590303d38381a3dca8 (patch)
tree174a34ac3da35cf72633c514c1f67aa50dfb4af9 /plumbing/format/packfile/diff_delta.go
parent90418e6ab682d1888dd7658a8ebd72a7be8cf502 (diff)
downloadgo-git-6d486b4f996c8abffd3206590303d38381a3dca8.tar.gz
packfile: small optimizations for findMatch and matchLength
Signed-off-by: Miguel Molina <miguel@erizocosmi.co>
Diffstat (limited to 'plumbing/format/packfile/diff_delta.go')
-rw-r--r--plumbing/format/packfile/diff_delta.go31
1 files changed, 15 insertions, 16 deletions
diff --git a/plumbing/format/packfile/diff_delta.go b/plumbing/format/packfile/diff_delta.go
index 2e58ec6..d4b207a 100644
--- a/plumbing/format/packfile/diff_delta.go
+++ b/plumbing/format/packfile/diff_delta.go
@@ -81,8 +81,22 @@ func diffDelta(index *deltaIndex, src []byte, tgt []byte) []byte {
for i := 0; i < len(tgt); i++ {
offset, l := index.findMatch(src, tgt, i)
- if l < s {
+ if l == 0 {
+ // couldn't find a match, just write the current byte and continue
ibuf.WriteByte(tgt[i])
+ } else if l < 0 {
+ // src is less than blksz, copy the rest of the target to avoid
+ // calls to findMatch
+ for ; i < len(tgt); i++ {
+ ibuf.WriteByte(tgt[i])
+ }
+ } else if l < s {
+ // remaining target is less than blksz, copy what's left of it
+ // and avoid calls to findMatch
+ for j := i; j < i+l; j++ {
+ ibuf.WriteByte(tgt[j])
+ }
+ i += l - 1
} else {
encodeInsertOperation(ibuf, buf)
@@ -135,21 +149,6 @@ func encodeInsertOperation(ibuf, buf *bytes.Buffer) {
ibuf.Reset()
}
-func matchLength(src, tgt []byte, otgt, osrc int) int {
- l := 0
- for {
- if (osrc >= len(src) || otgt >= len(tgt)) || src[osrc] != tgt[otgt] {
- break
- }
-
- l++
- osrc++
- otgt++
- }
-
- return l
-}
-
func deltaEncodeSize(size int) []byte {
var ret []byte
c := size & 0x7f