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arrays, not slices, and only with non-pointer elements.

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(actually slices encode but do not decode yet)

R=rsc
DELTA=221  (82 added, 65 deleted, 74 changed)
OCL=31095
CL=31095
This commit is contained in:
Rob Pike 2009-07-02 16:43:46 -07:00
parent 29e6eb21ec
commit 0c33d4353e
3 changed files with 146 additions and 129 deletions
Download patch file Download diff file Expand all files Collapse all files

104
src/pkg/gob/encode.go
View file

@ -20,7 +20,6 @@ import (
// 0 terminates the structure.
type EncState struct {
w io.Writer;
base uintptr; // the base address of the data structure being written
err os.Error; // error encountered during encoding;
fieldnum int; // the last field number written.
buf [16]byte; // buffer used by the encoder; here to avoid allocation.
@ -71,6 +70,15 @@ type encInstr struct {
offset uintptr; // offset in the structure of the field to encode
}
// Emit a field number and update the state to record its value for delta encoding.
// If the instruction pointer is nil, do nothing
func (state *EncState) update(instr *encInstr) {
if instr != nil {
EncodeUint(state, uint64(instr.field - state.fieldnum));
state.fieldnum = instr.field;
}
}
// Each encoder is responsible for handling any indirections associated
// with the data structure. If any pointer so reached is nil, no bytes are written.
// If the data item is zero, no bytes are written.
@ -90,99 +98,88 @@ func encIndirect(p unsafe.Pointer, indir int) unsafe.Pointer {
func encBool(i *encInstr, state *EncState, p unsafe.Pointer) {
b := *(*bool)(p);
if b {
EncodeUint(state, uint64(i.field - state.fieldnum));
state.update(i);
EncodeUint(state, 1);
state.fieldnum = i.field;
}
}
func encInt(i *encInstr, state *EncState, p unsafe.Pointer) {
v := int64(*(*int)(p));
if v != 0 {
EncodeUint(state, uint64(i.field - state.fieldnum));
state.update(i);
EncodeInt(state, v);
state.fieldnum = i.field;
}
}
func encUint(i *encInstr, state *EncState, p unsafe.Pointer) {
v := uint64(*(*uint)(p));
if v != 0 {
EncodeUint(state, uint64(i.field - state.fieldnum));
state.update(i);
EncodeUint(state, v);
state.fieldnum = i.field;
}
}
func encInt8(i *encInstr, state *EncState, p unsafe.Pointer) {
v := int64(*(*int8)(p));
if v != 0 {
EncodeUint(state, uint64(i.field - state.fieldnum));
state.update(i);
EncodeInt(state, v);
state.fieldnum = i.field;
}
}
func encUint8(i *encInstr, state *EncState, p unsafe.Pointer) {
v := uint64(*(*uint8)(p));
if v != 0 {
EncodeUint(state, uint64(i.field - state.fieldnum));
state.update(i);
EncodeUint(state, v);
state.fieldnum = i.field;
}
}
func encInt16(i *encInstr, state *EncState, p unsafe.Pointer) {
v := int64(*(*int16)(p));
if v != 0 {
EncodeUint(state, uint64(i.field - state.fieldnum));
state.update(i);
EncodeInt(state, v);
state.fieldnum = i.field;
}
}
func encUint16(i *encInstr, state *EncState, p unsafe.Pointer) {
v := uint64(*(*uint16)(p));
if v != 0 {
EncodeUint(state, uint64(i.field - state.fieldnum));
state.update(i);
EncodeUint(state, v);
state.fieldnum = i.field;
}
}
func encInt32(i *encInstr, state *EncState, p unsafe.Pointer) {
v := int64(*(*int32)(p));
if v != 0 {
EncodeUint(state, uint64(i.field - state.fieldnum));
state.update(i);
EncodeInt(state, v);
state.fieldnum = i.field;
}
}
func encUint32(i *encInstr, state *EncState, p unsafe.Pointer) {
v := uint64(*(*uint32)(p));
if v != 0 {
EncodeUint(state, uint64(i.field - state.fieldnum));
state.update(i);
EncodeUint(state, v);
state.fieldnum = i.field;
}
}
func encInt64(i *encInstr, state *EncState, p unsafe.Pointer) {
v := *(*int64)(p);
if v != 0 {
EncodeUint(state, uint64(i.field - state.fieldnum));
state.update(i);
EncodeInt(state, v);
state.fieldnum = i.field;
}
}
func encUint64(i *encInstr, state *EncState, p unsafe.Pointer) {
v := *(*uint64)(p);
if v != 0 {
EncodeUint(state, uint64(i.field - state.fieldnum));
state.update(i);
EncodeUint(state, v);
state.fieldnum = i.field;
}
}
@ -206,9 +203,8 @@ func encFloat(i *encInstr, state *EncState, p unsafe.Pointer) {
f := float(*(*float)(p));
if f != 0 {
v := floatBits(float64(f));
EncodeUint(state, uint64(i.field - state.fieldnum));
state.update(i);
EncodeUint(state, v);
state.fieldnum = i.field;
}
}
@ -216,19 +212,17 @@ func encFloat32(i *encInstr, state *EncState, p unsafe.Pointer) {
f := float32(*(*float32)(p));
if f != 0 {
v := floatBits(float64(f));
EncodeUint(state, uint64(i.field - state.fieldnum));
state.update(i);
EncodeUint(state, v);
state.fieldnum = i.field;
}
}
func encFloat64(i *encInstr, state *EncState, p unsafe.Pointer) {
f := *(*float64)(p);
if f != 0 {
state.update(i);
v := floatBits(f);
EncodeUint(state, uint64(i.field - state.fieldnum));
EncodeUint(state, v);
state.fieldnum = i.field;
}
}
@ -236,10 +230,9 @@ func encFloat64(i *encInstr, state *EncState, p unsafe.Pointer) {
func encUint8Array(i *encInstr, state *EncState, p unsafe.Pointer) {
b := *(*[]byte)(p);
if len(b) > 0 {
EncodeUint(state, uint64(i.field - state.fieldnum));
state.update(i);
EncodeUint(state, uint64(len(b)));
state.w.Write(b);
state.fieldnum = i.field;
}
}
@ -247,10 +240,9 @@ func encUint8Array(i *encInstr, state *EncState, p unsafe.Pointer) {
func encString(i *encInstr, state *EncState, p unsafe.Pointer) {
s := *(*string)(p);
if len(s) > 0 {
EncodeUint(state, uint64(i.field - state.fieldnum));
state.update(i);
EncodeUint(state, uint64(len(s)));
io.WriteString(state.w, s);
state.fieldnum = i.field;
}
}
@ -267,14 +259,13 @@ type encEngine struct {
instr []encInstr
}
func (engine *encEngine) encodeStruct(w io.Writer, p uintptr) os.Error {
func encodeStruct(engine *encEngine, w io.Writer, basep uintptr) os.Error {
state := new(EncState);
state.w = w;
state.base = p;
state.fieldnum = -1;
for i := 0; i < len(engine.instr); i++ {
instr := &engine.instr[i];
p := unsafe.Pointer(state.base+instr.offset);
p := unsafe.Pointer(basep+instr.offset);
if instr.indir > 0 {
if p = encIndirect(p, instr.indir); p == nil {
state.fieldnum = i;
@ -289,6 +280,18 @@ func (engine *encEngine) encodeStruct(w io.Writer, p uintptr) os.Error {
return state.err
}
func encodeArray(w io.Writer, p uintptr, op encOp, elemWid int, length int) os.Error {
state := new(EncState);
state.w = w;
state.fieldnum = -1;
EncodeUint(state, uint64(length));
for i := 0; i < length && state.err == nil; i++ {
op(nil, state, unsafe.Pointer(p)); // TODO(r): indir on elements
p += uintptr(elemWid);
}
return state.err
}
var encEngineMap = make(map[reflect.Type] *encEngine)
var encOpMap = map[int] encOp {
reflect.BoolKind: encBool,
@ -316,18 +319,35 @@ func encOpFor(typ reflect.Type) encOp {
// Special cases
if typ.Kind() == reflect.ArrayKind {
atyp := typ.(reflect.ArrayType);
switch atyp.Elem().Kind() {
case reflect.Uint8Kind:
switch {
case atyp.Elem().Kind() == reflect.Uint8Kind:
op = encUint8Array
case atyp.IsSlice():
// Slices have a header; we decode it to find the underlying array.
elemOp := encOpFor(atyp.Elem());
op = func(i *encInstr, state *EncState, p unsafe.Pointer) {
slice := *(*reflect.SliceHeader)(p);
if slice.Len == 0 {
return
}
state.update(i);
state.err = encodeArray(state.w, slice.Data, elemOp, atyp.Elem().Size(), int(slice.Len));
};
case !atyp.IsSlice():
// True arrays have size in the type.
elemOp := encOpFor(atyp.Elem());
op = func(i *encInstr, state *EncState, p unsafe.Pointer) {
state.update(i);
state.err = encodeArray(state.w, uintptr(p), elemOp, atyp.Elem().Size(), atyp.Len());
};
}
}
if typ.Kind() == reflect.StructKind {
// Generate a closure that calls out to the engine for the nested type.
engine := getEncEngine(typ);
op = func(i *encInstr, state *EncState, p unsafe.Pointer) {
EncodeUint(state, uint64(i.field - state.fieldnum));
state.err = engine.encodeStruct(state.w, uintptr(p));
state.fieldnum = i.field;
state.update(i);
state.err = encodeStruct(engine, state.w, uintptr(p));
};
}
}
@ -394,5 +414,5 @@ func Encode(w io.Writer, e interface{}) os.Error {
typeLock.Lock();
engine := getEncEngine(rt);
typeLock.Unlock();
return engine.encodeStruct(w, uintptr(v.(reflect.StructValue).Addr()));
return encodeStruct(engine, w, uintptr(v.(reflect.StructValue).Addr()));
}