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-rw-r--r--slice/slice.go74
-rw-r--r--slice/slice_test.go21
2 files changed, 95 insertions, 0 deletions
diff --git a/slice/slice.go b/slice/slice.go
new file mode 100644
index 0000000..15be5dd
--- /dev/null
+++ b/slice/slice.go
@@ -0,0 +1,74 @@
+package slice
+
+import "reflect"
+
+type Slice []interface{}
+
+type SliceDel int
+
+type SliceIns struct {
+ Idx int
+ Value []interface{}
+}
+
+type SlicePatch struct {
+ Del []SliceDel
+ Ins []SliceIns
+}
+
+func PatchSlice(source Slice, patch SlicePatch) (target Slice) {
+ // apply Del part from patch to source into temp
+ size := len(source) - len(patch.Del)
+ temp := make(Slice, size)
+ fill := 0
+ prev := 0
+ for _, del := range patch.Del {
+ di := int(del)
+ copy(temp[fill:], source[prev:di])
+ fill += di - prev
+ prev = di + 1
+ }
+ copy(temp[fill:], source[prev:])
+ // apply Ins part from patch to temp into target
+ for _, ins := range patch.Ins {
+ size += len(ins.Value)
+ }
+ target = make(Slice, size)
+ fill = 0
+ prev = 0
+ tpos := 0
+ for _, ins := range patch.Ins {
+ offset := ins.Idx - prev
+ copy(target[fill:], temp[tpos:tpos+offset])
+ fill += offset
+ tpos += offset
+ copy(target[fill:], ins.Value)
+ fill += len(ins.Value)
+ prev = ins.Idx + len(ins.Value)
+ }
+ return
+}
+
+func DiffSlice(source Slice, target Slice) (patch SlicePatch) {
+ var si, ti int
+ var found bool
+ for ; si < len(source); si++ {
+ for i := ti; i < len(target); i++ {
+ found = reflect.DeepEqual(target[i], source[si])
+ if found {
+ if i != ti {
+ patch.Ins = append(patch.Ins, SliceIns{ti, target[ti:i]})
+ }
+ ti = i + 1
+ break
+ }
+ }
+ if !found {
+ patch.Del = append(patch.Del, SliceDel(si))
+ }
+ }
+ if ti < len(target) {
+ patch.Ins = append(patch.Ins, SliceIns{ti, target[ti:]})
+ }
+ return
+}
diff --git a/slice/slice_test.go b/slice/slice_test.go
new file mode 100644
index 0000000..b73946e
--- /dev/null
+++ b/slice/slice_test.go
@@ -0,0 +1,21 @@
+package slice
+
+import (
+ "testing"
+
+ "github.com/n-peugnet/dna-backup/testutils"
+)
+
+func TestPatch(t *testing.T) {
+ source := Slice{1, 2, 3, 4}
+ target := Slice{2, 5, 3, 6, 4, 7, 8}
+ patch := DiffSlice(source, target)
+ testutils.AssertSame(t, []SliceDel{0}, patch.Del, "Patch del part")
+ testutils.AssertSame(t, []SliceIns{
+ {1, Slice{5}},
+ {3, Slice{6}},
+ {5, Slice{7, 8}},
+ }, patch.Ins, "Patch ins part")
+ actual := PatchSlice(source, patch)
+ testutils.AssertSame(t, target, actual, "Target obtained from patch application")
+}