reflect: add Value.Slice3 and Value.SetCap methods, to match x[i:j:k]
Design doc at golang.org/s/go12slice.
R=golang-dev, r, nightlyone
CC=golang-dev
https://golang.org/cl/10761045
diff --git a/src/pkg/reflect/all_test.go b/src/pkg/reflect/all_test.go
index a61f663..93df4d1 100644
--- a/src/pkg/reflect/all_test.go
+++ b/src/pkg/reflect/all_test.go
@@ -2368,6 +2368,74 @@
}
}
+func TestSlice3(t *testing.T) {
+ xs := []int{1, 2, 3, 4, 5, 6, 7, 8}
+ v := ValueOf(xs).Slice3(3, 5, 7).Interface().([]int)
+ if len(v) != 2 {
+ t.Errorf("len(xs.Slice3(3, 5, 7)) = %d", len(v))
+ }
+ if cap(v) != 4 {
+ t.Errorf("cap(xs.Slice3(3, 5, 7)) = %d", cap(v))
+ }
+ if !DeepEqual(v[0:4], xs[3:7:7]) {
+ t.Errorf("xs.Slice3(3, 5, 7)[0:4] = %v", v[0:4])
+ }
+ rv := ValueOf(&xs).Elem()
+ shouldPanic(func() { rv.Slice3(1, 2, 1) })
+ shouldPanic(func() { rv.Slice3(1, 1, 11) })
+ shouldPanic(func() { rv.Slice3(2, 2, 1) })
+
+ xa := [8]int{10, 20, 30, 40, 50, 60, 70, 80}
+ v = ValueOf(&xa).Elem().Slice3(2, 5, 6).Interface().([]int)
+ if len(v) != 3 {
+ t.Errorf("len(xa.Slice(2, 5, 6)) = %d", len(v))
+ }
+ if cap(v) != 4 {
+ t.Errorf("cap(xa.Slice(2, 5, 6)) = %d", cap(v))
+ }
+ if !DeepEqual(v[0:4], xa[2:6:6]) {
+ t.Errorf("xs.Slice(2, 5, 6)[0:4] = %v", v[0:4])
+ }
+ rv = ValueOf(&xa).Elem()
+ shouldPanic(func() { rv.Slice3(1, 2, 1) })
+ shouldPanic(func() { rv.Slice3(1, 1, 11) })
+ shouldPanic(func() { rv.Slice3(2, 2, 1) })
+
+ s := "hello world"
+ rv = ValueOf(&s).Elem()
+ shouldPanic(func() { rv.Slice3(1, 2, 3) })
+}
+
+func TestSetLenCap(t *testing.T) {
+ xs := []int{1, 2, 3, 4, 5, 6, 7, 8}
+ xa := [8]int{10, 20, 30, 40, 50, 60, 70, 80}
+
+ vs := ValueOf(&xs).Elem()
+ shouldPanic(func() { vs.SetLen(10) })
+ shouldPanic(func() { vs.SetCap(10) })
+ shouldPanic(func() { vs.SetLen(-1) })
+ shouldPanic(func() { vs.SetCap(-1) })
+ shouldPanic(func() { vs.SetCap(6) }) // smaller than len
+ vs.SetLen(5)
+ if len(xs) != 5 || cap(xs) != 8 {
+ t.Errorf("after SetLen(5), len, cap = %d, %d, want 5, 8", len(xs), cap(xs))
+ }
+ vs.SetCap(6)
+ if len(xs) != 5 || cap(xs) != 6 {
+ t.Errorf("after SetCap(6), len, cap = %d, %d, want 5, 6", len(xs), cap(xs))
+ }
+ vs.SetCap(5)
+ if len(xs) != 5 || cap(xs) != 5 {
+ t.Errorf("after SetCap(5), len, cap = %d, %d, want 5, 5", len(xs), cap(xs))
+ }
+ shouldPanic(func() { vs.SetCap(4) }) // smaller than len
+ shouldPanic(func() { vs.SetLen(6) }) // bigger than cap
+
+ va := ValueOf(&xa).Elem()
+ shouldPanic(func() { va.SetLen(8) })
+ shouldPanic(func() { va.SetCap(8) })
+}
+
func TestVariadic(t *testing.T) {
var b bytes.Buffer
V := ValueOf
