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make a description of the slice header public

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R=rsc
DELTA=18  (3 added, 0 deleted, 15 changed)
OCL=31086
CL=31094
This commit is contained in:
Rob Pike 2009-07-02 16:28:04 -07:00
parent c7a9d9818a
commit 29e6eb21ec
1 changed files with 18 additions and 15 deletions
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33
src/pkg/reflect/value.go
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@ -563,17 +563,20 @@ func copyArray(dst ArrayValue, src ArrayValue, n int);
uint32 cap;
};
*/
type runtimeSlice struct {
data Addr;
len uint32;
cap uint32;
// A published version of the Slice header so that clients don't have a separate copy of the definition.
// SliceHeader is not useful to clients unless they use unsafe.Pointer.
type SliceHeader struct {
Data uintptr;
Len uint32;
Cap uint32;
}
type sliceValueStruct struct {
commonValue;
elemtype Type;
elemsize int;
slice *runtimeSlice;
slice *SliceHeader;
}
func (v *sliceValueStruct) IsSlice() bool {
@ -581,18 +584,18 @@ func (v *sliceValueStruct) IsSlice() bool {
}
func (v *sliceValueStruct) Len() int {
return int(v.slice.len);
return int(v.slice.Len);
}
func (v *sliceValueStruct) Cap() int {
return int(v.slice.cap);
return int(v.slice.Cap);
}
func (v *sliceValueStruct) SetLen(len int) {
if len > v.Cap() {
panicln("reflect: sliceValueStruct.SetLen", len, v.Cap());
}
v.slice.len = uint32(len);
v.slice.Len = uint32(len);
}
func (v *sliceValueStruct) Set(src ArrayValue) {
@ -607,7 +610,7 @@ func (v *sliceValueStruct) Set(src ArrayValue) {
}
func (v *sliceValueStruct) Elem(i int) Value {
data_uint := uintptr(v.slice.data) + uintptr(i * v.elemsize);
data_uint := v.slice.Data + uintptr(i * v.elemsize);
return newValueAddr(v.elemtype, Addr(data_uint));
}
@ -616,7 +619,7 @@ func (v *sliceValueStruct) CopyFrom(src ArrayValue, n int) {
}
func (v *sliceValueStruct) IsNil() bool {
return uintptr(v.slice.data) == 0
return v.slice.Data == 0
}
type arrayValueStruct struct {
@ -668,7 +671,7 @@ func arrayCreator(typ Type, addr Addr) Value {
v.typ = typ;
v.elemtype = arraytype.Elem();
v.elemsize = v.elemtype.Size();
v.slice = (*runtimeSlice)(addr);
v.slice = (*SliceHeader)(addr);
return v;
}
v := new(arrayValueStruct);
@ -897,15 +900,15 @@ func NewSliceValue(typ ArrayType, len, cap int) ArrayValue {
return nil
}
array := new(runtimeSlice);
array := new(SliceHeader);
size := typ.Elem().Size() * cap;
if size == 0 {
size = 1;
}
data := make([]uint8, size);
array.data = Addr(&data[0]);
array.len = uint32(len);
array.cap = uint32(cap);
array.Data = uintptr(Addr(&data[0]));
array.Len = uint32(len);
array.Cap = uint32(cap);
return newValueAddr(typ, Addr(array)).(ArrayValue);
}