1 files changed, 25 insertions, 0 deletions
diff --git a/git.go b/git.go
index 387d81e..d8cacc4 100644
--- a/git.go
+++ b/git.go
@@ -8,6 +8,7 @@ package git
 import "C"
 import (
 	"bytes"
+	"errors"
 	"unsafe"
 	"strings"
 	"fmt"
@@ -19,6 +20,10 @@ const (
 	ENOTFOUND = C.GIT_ENOTFOUND
 )
 
+var (
+	ErrIterOver = errors.New("Iteration is over")
+)
+
 func init() {
 	C.git_threads_init()
 }
@@ -97,6 +102,26 @@ func (oid *Oid) NCmp(oid2 *Oid, n uint) int {
 	return bytes.Compare(oid.bytes[:n], oid2.bytes[:n])
 }
 
+func ShortenOids(ids []*Oid, minlen int) (int, error) {
+	shorten := C.git_oid_shorten_new(C.size_t(minlen))
+	if shorten == nil {
+		panic("Out of memory")
+	}
+	defer C.git_oid_shorten_free(shorten)
+
+	var ret C.int
+	for _, id := range ids {
+		buf := make([]byte, 41)
+		C.git_oid_fmt((*C.char)(unsafe.Pointer(&buf[0])), id.toC())
+		buf[40] = 0
+		ret = C.git_oid_shorten_add(shorten, (*C.char)(unsafe.Pointer(&buf[0])))
+		if ret < 0 {
+			return int(ret), LastError()
+		}
+	}
+	return int(ret), nil
+}
+
 type GitError struct {
 	Message string
 	Code int