reflect: add Value.Bytes, Value.SetBytes methods
This allows code that wants to handle
[]byte separately to get at the actual slice
instead of just at individual bytes.
It seems to come up often enough.
R=r
CC=golang-dev
https://golang.org/cl/4942051
diff --git a/src/pkg/reflect/all_test.go b/src/pkg/reflect/all_test.go
index d63e986..610ba4b 100644
--- a/src/pkg/reflect/all_test.go
+++ b/src/pkg/reflect/all_test.go
@@ -1562,3 +1562,28 @@
}
}
}
+
+func TestBytes(t *testing.T) {
+ type B []byte
+ x := B{1, 2, 3, 4}
+ y := ValueOf(x).Bytes()
+ if !bytes.Equal(x, y) {
+ t.Fatalf("ValueOf(%v).Bytes() = %v", x, y)
+ }
+ if &x[0] != &y[0] {
+ t.Errorf("ValueOf(%p).Bytes() = %p", &x[0], &y[0])
+ }
+}
+
+func TestSetBytes(t *testing.T) {
+ type B []byte
+ var x B
+ y := []byte{1, 2, 3, 4}
+ ValueOf(&x).Elem().SetBytes(y)
+ if !bytes.Equal(x, y) {
+ t.Fatalf("ValueOf(%v).Bytes() = %v", x, y)
+ }
+ if &x[0] != &y[0] {
+ t.Errorf("ValueOf(%p).Bytes() = %p", &x[0], &y[0])
+ }
+}
diff --git a/src/pkg/reflect/value.go b/src/pkg/reflect/value.go
index d3c510a..99b1f24 100644
--- a/src/pkg/reflect/value.go
+++ b/src/pkg/reflect/value.go
@@ -398,6 +398,18 @@
return *(*bool)(unsafe.Pointer(&iv.word))
}
+// Bytes returns v's underlying value.
+// It panics if v's underlying value is not a slice of bytes.
+func (v Value) Bytes() []byte {
+ iv := v.internal()
+ iv.mustBe(Slice)
+ typ := iv.typ.toType()
+ if typ.Elem().Kind() != Uint8 {
+ panic("reflect.Value.Bytes of non-byte slice")
+ }
+ return *(*[]byte)(iv.addr)
+}
+
// CanAddr returns true if the value's address can be obtained with Addr.
// Such values are called addressable. A value is addressable if it is
// an element of a slice, an element of an addressable array,
@@ -1224,6 +1236,19 @@
*(*bool)(iv.addr) = x
}
+// SetBytes sets v's underlying value.
+// It panics if v's underlying value is not a slice of bytes.
+func (v Value) SetBytes(x []byte) {
+ iv := v.internal()
+ iv.mustBeAssignable()
+ iv.mustBe(Slice)
+ typ := iv.typ.toType()
+ if typ.Elem().Kind() != Uint8 {
+ panic("reflect.Value.SetBytes of non-byte slice")
+ }
+ *(*[]byte)(iv.addr) = x
+}
+
// SetComplex sets v's underlying value to x.
// It panics if v's Kind is not Complex64 or Complex128, or if CanSet() is false.
func (v Value) SetComplex(x complex128) {
