diff options
| -rw-r--r-- | src/pkg/reflect/all_test.go | 24 | ||||
| -rw-r--r-- | src/pkg/reflect/value.go | 28 |
2 files changed, 49 insertions, 3 deletions
diff --git a/src/pkg/reflect/all_test.go b/src/pkg/reflect/all_test.go index 5ddd6bef1..842b50750 100644 --- a/src/pkg/reflect/all_test.go +++ b/src/pkg/reflect/all_test.go @@ -2036,6 +2036,24 @@ func TestSmallNegativeInt(t *testing.T) { } } +func TestIndex(t *testing.T) { + xs := []byte{1, 2, 3, 4, 5, 6, 7, 8} + v := ValueOf(xs).Index(3).Interface().(byte) + if v != xs[3] { + t.Errorf("xs.Index(3) = %v; expected %v", v, xs[3]) + } + xa := [8]byte{10, 20, 30, 40, 50, 60, 70, 80} + v = ValueOf(xa).Index(2).Interface().(byte) + if v != xa[2] { + t.Errorf("xa.Index(2) = %v; expected %v", v, xa[2]) + } + s := "0123456789" + v = ValueOf(s).Index(3).Interface().(byte) + if v != s[3] { + t.Errorf("s.Index(3) = %v; expected %v", v, s[3]) + } +} + func TestSlice(t *testing.T) { xs := []int{1, 2, 3, 4, 5, 6, 7, 8} v := ValueOf(xs).Slice(3, 5).Interface().([]int) @@ -2048,7 +2066,6 @@ func TestSlice(t *testing.T) { if !DeepEqual(v[0:5], xs[3:]) { t.Errorf("xs.Slice(3, 5)[0:5] = %v", v[0:5]) } - xa := [8]int{10, 20, 30, 40, 50, 60, 70, 80} v = ValueOf(&xa).Elem().Slice(2, 5).Interface().([]int) if len(v) != 3 { @@ -2060,6 +2077,11 @@ func TestSlice(t *testing.T) { if !DeepEqual(v[0:6], xa[2:]) { t.Errorf("xs.Slice(2, 5)[0:6] = %v", v[0:6]) } + s := "0123456789" + vs := ValueOf(s).Slice(3, 5).Interface().(string) + if vs != s[3:5] { + t.Errorf("s.Slice(3, 5) = %q; expected %q", vs, s[3:5]) + } } func TestVariadic(t *testing.T) { diff --git a/src/pkg/reflect/value.go b/src/pkg/reflect/value.go index 74addd195..be5d03504 100644 --- a/src/pkg/reflect/value.go +++ b/src/pkg/reflect/value.go @@ -810,8 +810,10 @@ func (v Value) Float() float64 { panic(&ValueError{"reflect.Value.Float", k}) } +var uint8Type = TypeOf(uint8(0)).(*commonType) + // Index returns v's i'th element. -// It panics if v's Kind is not Array or Slice or i is out of range. +// It panics if v's Kind is not Array, Slice, or String or i is out of range. func (v Value) Index(i int) Value { k := v.kind() switch k { @@ -852,6 +854,15 @@ func (v Value) Index(i int) Value { fl |= flag(typ.Kind()) << flagKindShift val := unsafe.Pointer(s.Data + uintptr(i)*typ.size) return Value{typ, val, fl} + + case String: + fl := v.flag&flagRO | flag(Uint8<<flagKindShift) + s := (*StringHeader)(v.val) + if i < 0 || i >= s.Len { + panic("reflect: string index out of range") + } + val := *(*byte)(unsafe.Pointer(s.Data + uintptr(i))) + return Value{uint8Type, unsafe.Pointer(uintptr(val)), fl} } panic(&ValueError{"reflect.Value.Index", k}) } @@ -1437,7 +1448,7 @@ func (v Value) SetString(x string) { } // Slice returns a slice of v. -// It panics if v's Kind is not Array or Slice. +// It panics if v's Kind is not Array, Slice, or String. func (v Value) Slice(beg, end int) Value { var ( cap int @@ -1447,6 +1458,7 @@ func (v Value) Slice(beg, end int) Value { switch k := v.kind(); k { default: panic(&ValueError{"reflect.Value.Slice", k}) + case Array: if v.flag&flagAddr == 0 { panic("reflect.Value.Slice: slice of unaddressable array") @@ -1455,13 +1467,25 @@ func (v Value) Slice(beg, end int) Value { cap = int(tt.len) typ = (*sliceType)(unsafe.Pointer(toCommonType(tt.slice))) base = v.val + case Slice: typ = (*sliceType)(unsafe.Pointer(v.typ)) s := (*SliceHeader)(v.val) base = unsafe.Pointer(s.Data) cap = s.Cap + case String: + s := (*StringHeader)(v.val) + if beg < 0 || end < beg || end > s.Len { + panic("reflect.Value.Slice: string slice index out of bounds") + } + var x string + val := (*StringHeader)(unsafe.Pointer(&x)) + val.Data = s.Data + uintptr(beg) + val.Len = end - beg + return Value{v.typ, unsafe.Pointer(&x), v.flag} } + if beg < 0 || end < beg || end > cap { panic("reflect.Value.Slice: slice index out of bounds") } |