Golang Value.Index方法代码示例

func encodeValue(buf []byte, prefix, name string, fv reflect.Value, inArray, arrayTable bool) ([]byte, error) {
	switch t := fv.Interface().(type) {
	case Marshaler:
		b, err := t.MarshalTOML()
		if err != nil {
			return nil, err
		}
		return appendNewline(append(appendKey(buf, name, inArray, arrayTable), b...), inArray, arrayTable), nil
	case time.Time:
		return appendNewline(encodeTime(appendKey(buf, name, inArray, arrayTable), t), inArray, arrayTable), nil
	}
	switch fv.Kind() {
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		return appendNewline(encodeInt(appendKey(buf, name, inArray, arrayTable), fv.Int()), inArray, arrayTable), nil
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
		return appendNewline(encodeUint(appendKey(buf, name, inArray, arrayTable), fv.Uint()), inArray, arrayTable), nil
	case reflect.Float32, reflect.Float64:
		return appendNewline(encodeFloat(appendKey(buf, name, inArray, arrayTable), fv.Float()), inArray, arrayTable), nil
	case reflect.Bool:
		return appendNewline(encodeBool(appendKey(buf, name, inArray, arrayTable), fv.Bool()), inArray, arrayTable), nil
	case reflect.String:
		return appendNewline(encodeString(appendKey(buf, name, inArray, arrayTable), fv.String()), inArray, arrayTable), nil
	case reflect.Slice, reflect.Array:
		ft := fv.Type().Elem()
		for ft.Kind() == reflect.Ptr {
			ft = ft.Elem()
		}
		if ft.Kind() == reflect.Struct {
			name := tableName(prefix, name)
			var err error
			for i := 0; i < fv.Len(); i++ {
				if buf, err = marshal(append(append(append(buf, '[', '['), name...), ']', ']', '\n'), name, fv.Index(i), false, true); err != nil {
					return nil, err
				}
			}
			return buf, nil
		}
		buf = append(appendKey(buf, name, inArray, arrayTable), '[')
		var err error
		for i := 0; i < fv.Len(); i++ {
			if i != 0 {
				buf = append(buf, ',')
			}
			if buf, err = encodeValue(buf, prefix, name, fv.Index(i), true, false); err != nil {
				return nil, err
			}
		}
		return appendNewline(append(buf, ']'), inArray, arrayTable), nil
	case reflect.Struct:
		name := tableName(prefix, name)
		return marshal(append(append(append(buf, '['), name...), ']', '\n'), name, fv, inArray, arrayTable)
	case reflect.Interface:
		var err error
		if buf, err = encodeInterface(appendKey(buf, name, inArray, arrayTable), fv.Interface()); err != nil {
			return nil, err
		}
		return appendNewline(buf, inArray, arrayTable), nil
	}
	return nil, fmt.Errorf("toml: marshal: unsupported type %v", fv.Kind())
}

func (d *decoder) readArrayDocTo(out reflect.Value) {
	end := int(d.readInt32())
	end += d.i - 4
	if end <= d.i || end > len(d.in) || d.in[end-1] != '\x00' {
		corrupted()
	}
	i := 0
	l := out.Len()
	for d.in[d.i] != '\x00' {
		if i >= l {
			panic("Length mismatch on array field")
		}
		kind := d.readByte()
		for d.i < end && d.in[d.i] != '\x00' {
			d.i++
		}
		if d.i >= end {
			corrupted()
		}
		d.i++
		d.readElemTo(out.Index(i), kind)
		if d.i >= end {
			corrupted()
		}
		i++
	}
	if i != l {
		panic("Length mismatch on array field")
	}
	d.i++ // '\x00'
	if d.i != end {
		corrupted()
	}
}

func isZero(v reflect.Value) bool {
	switch v.Kind() {
	case reflect.Func, reflect.Map, reflect.Slice:
		return v.IsNil()
	case reflect.Array:
		z := true
		for i := 0; i < v.Len(); i++ {
			z = z && isZero(v.Index(i))
		}
		return z
	case reflect.Struct:
		if v.Type() == reflect.TypeOf(t) {
			if v.Interface().(time.Time).IsZero() {
				return true
			}
			return false
		}
		z := true
		for i := 0; i < v.NumField(); i++ {
			z = z && isZero(v.Field(i))
		}
		return z
	}
	// Compare other types directly:
	z := reflect.Zero(v.Type())
	return v.Interface() == z.Interface()
}

// callSliceRequired returns true if CallSlice is required instead of Call.
func callSliceRequired(param reflect.Type, val reflect.Value) bool {
	vt := val.Type()
	for param.Kind() == reflect.Slice {
		if val.Kind() == reflect.Interface {
			val = reflect.ValueOf(val.Interface())
			vt = val.Type()
		}

		if vt.Kind() != reflect.Slice {
			return false
		}

		vt = vt.Elem()
		if val.Kind() != reflect.Invalid {
			if val.Len() > 0 {
				val = val.Index(0)
			} else {
				val = reflect.Value{}
			}
		}
		param = param.Elem()
	}

	return true
}

func convertSliceToCFArrayHelper(slice reflect.Value, helper func(reflect.Value) (cfTypeRef, error)) (C.CFArrayRef, error) {
	if slice.Len() == 0 {
		// short-circuit 0, so we can assume plists[0] is valid later
		return C.CFArrayCreate(nil, nil, 0, nil), nil
	}
	// assume slice is a slice/array, because our caller already checked
	plists := make([]cfTypeRef, slice.Len())
	// defer the release
	defer func() {
		for _, cfObj := range plists {
			cfRelease(cfObj)
		}
	}()
	// convert the slice
	for i := 0; i < slice.Len(); i++ {
		cfType, err := helper(slice.Index(i))
		if err != nil {
			return nil, err
		}
		plists[i] = cfType
	}

	// create the array
	callbacks := (*C.CFArrayCallBacks)(&C.kCFTypeArrayCallBacks)
	return C.CFArrayCreate(nil, (*unsafe.Pointer)(&plists[0]), C.CFIndex(len(plists)), callbacks), nil
}

func normalizeArray(
	opts *options,
	tagOpts tagOptions,
	ctx context,
	v reflect.Value,
) (value, Error) {
	l := v.Len()
	out := make([]value, 0, l)

	cfg := New()
	cfg.metadata = opts.meta
	cfg.ctx = ctx
	val := cfgSub{cfg}

	for i := 0; i < l; i++ {
		idx := fmt.Sprintf("%v", i)
		ctx := context{
			parent: val,
			field:  idx,
		}
		tmp, err := normalizeValue(opts, tagOpts, ctx, v.Index(i))
		if err != nil {
			return nil, err
		}
		out = append(out, tmp)
	}

	cfg.fields.a = out
	return val, nil
}

func readSlice(in io.Reader, obj reflect.Value) {
	len := int(readUint(in))
	obj.Set(reflect.MakeSlice(obj.Type(), len, len))
	for i := 0; i < len; i++ {
		readAny(in, obj.Index(i))
	}
}

// checkWhereArray handles the where-matching logic when the seqv value is an
// Array or Slice.
func checkWhereArray(
	seqv, kv, mv reflect.Value,
	path []string, op string) (interface{}, error) {

	rv := reflect.MakeSlice(seqv.Type(), 0, 0)
	for i := 0; i < seqv.Len(); i++ {
		var vvv reflect.Value
		rvv := seqv.Index(i)
		if kv.Kind() == reflect.String {
			vvv = rvv
			for _, elemName := range path {
				var err error
				vvv, err = evaluateSubElem(vvv, elemName)
				if err != nil {
					return nil, err
				}
			}
		} else {
			vv, _ := indirect(rvv)
			if vv.Kind() == reflect.Map &&
				kv.Type().AssignableTo(vv.Type().Key()) {
				vvv = vv.MapIndex(kv)
			}
		}

		if ok, err := checkCondition(vvv, mv, op); ok {
			rv = reflect.Append(rv, rvv)
		} else if err != nil {
			return nil, err
		}
	}
	return rv.Interface(), nil
}

// isZero reports whether the value is the zero of its type.
func isZero(val reflect.Value) bool {
	switch val.Kind() {
	case reflect.Array:
		for i := 0; i < val.Len(); i++ {
			if !isZero(val.Index(i)) {
				return false
			}
		}
		return true
	case reflect.Map, reflect.Slice, reflect.String:
		return val.Len() == 0
	case reflect.Bool:
		return !val.Bool()
	case reflect.Complex64, reflect.Complex128:
		return val.Complex() == 0
	case reflect.Chan, reflect.Func, reflect.Ptr:
		return val.IsNil()
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		return val.Int() == 0
	case reflect.Float32, reflect.Float64:
		return val.Float() == 0
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
		return val.Uint() == 0
	case reflect.Struct:
		for i := 0; i < val.NumField(); i++ {
			if !isZero(val.Field(i)) {
				return false
			}
		}
		return true
	}
	panic("unknown type in isZero " + val.Type().String())
}

// visit calls the visitor function for each string it finds, and will descend
// recursively into structures and slices. If any visitor returns an error then
// the search will stop and that error will be returned.
func visit(path string, v reflect.Value, t reflect.Type, fn visitor) error {
	switch v.Kind() {
	case reflect.String:
		return fn(path, v)
	case reflect.Struct:
		for i := 0; i < v.NumField(); i++ {
			vf := v.Field(i)
			tf := t.Field(i)
			newPath := fmt.Sprintf("%s.%s", path, tf.Name)
			if err := visit(newPath, vf, tf.Type, fn); err != nil {
				return err
			}
		}
	case reflect.Slice:
		for i := 0; i < v.Len(); i++ {
			vi := v.Index(i)
			ti := vi.Type()
			newPath := fmt.Sprintf("%s[%d]", path, i)
			if err := visit(newPath, vi, ti, fn); err != nil {
				return err
			}
		}
	}
	return nil
}

func (e *encoder) slicev(tag string, in reflect.Value) {
	var ctag *C.yaml_char_t
	var free func()
	var cimplicit C.int
	if tag != "" {
		ctag, free = ystr(tag)
		defer free()
		cimplicit = 0
	} else {
		cimplicit = 1
	}

	cstyle := C.yaml_sequence_style_t(C.YAML_BLOCK_SEQUENCE_STYLE)
	if e.flow {
		e.flow = false
		cstyle = C.YAML_FLOW_SEQUENCE_STYLE
	}
	C.yaml_sequence_start_event_initialize(&e.event, nil, ctag, cimplicit,
		cstyle)
	e.emit()
	n := in.Len()
	for i := 0; i < n; i++ {
		e.marshal("", in.Index(i))
	}
	C.yaml_sequence_end_event_initialize(&e.event)
	e.emit()
}

func encodeArray(v reflect.Value) interface{} {
	n := node{}
	for i := 0; i < v.Len(); i++ {
		n[strconv.Itoa(i)] = encodeValue(v.Index(i))
	}
	return n
}

func (f *Field) Size(val reflect.Value, options *Options) int {
	typ := f.Type.Resolve(options)
	size := 0
	if typ == Struct {
		vals := []reflect.Value{val}
		if f.Slice {
			vals = make([]reflect.Value, val.Len())
			for i := 0; i < val.Len(); i++ {
				vals[i] = val.Index(i)
			}
		}
		for _, val := range vals {
			size += f.Fields.Sizeof(val, options)
		}
	} else if typ == Pad {
		size = f.Len
	} else if f.Slice || f.kind == reflect.String {
		length := val.Len()
		if f.Len > 1 {
			length = f.Len
		}
		size = length * typ.Size()
	} else if typ == CustomType {
		return val.Addr().Interface().(Custom).Size(options)
	} else {
		size = typ.Size()
	}
	align := options.ByteAlign
	if align > 0 && size < align {
		size = align
	}
	return size
}

func (f *Field) Unpack(buf []byte, val reflect.Value, length int, options *Options) error {
	typ := f.Type.Resolve(options)
	if typ == Pad || f.kind == reflect.String {
		if typ == Pad {
			return nil
		} else {
			val.SetString(string(buf))
			return nil
		}
	} else if f.Slice {
		if val.Cap() < length {
			val.Set(reflect.MakeSlice(val.Type(), length, length))
		} else if val.Len() < length {
			val.Set(val.Slice(0, length))
		}
		// special case byte slices for performance
		if !f.Array && typ == Uint8 && f.defType == Uint8 {
			copy(val.Bytes(), buf[:length])
			return nil
		}
		pos := 0
		size := typ.Size()
		for i := 0; i < length; i++ {
			if err := f.unpackVal(buf[pos:pos+size], val.Index(i), 1, options); err != nil {
				return err
			}
			pos += size
		}
		return nil
	} else {
		return f.unpackVal(buf, val, length, options)
	}
}

func convertToFloat64(depth int, v reflect.Value) (float64, bool) {
	if v.Kind() == reflect.Interface {
		v = v.Elem()
	}
	switch v.Kind() {
	case reflect.Float32, reflect.Float64:
		return v.Float(), true
	case reflect.Int16, reflect.Int8, reflect.Int, reflect.Int32, reflect.Int64:
		return float64(v.Int()), true
	case reflect.String:
		s := v.String()
		var f float64
		var err error
		if strings.HasPrefix(s, "0x") {
			f, err = strconv.ParseFloat(s, 64)
		} else {
			f, err = strconv.ParseFloat(s, 64)
		}
		if err == nil {
			return float64(f), true
		}
		if depth == 0 {
			s = intStrReplacer.Replace(s)
			rv := reflect.ValueOf(s)
			return convertToFloat64(1, rv)
		}
	case reflect.Slice:
		// Should we grab first one?  Or Error?
		//u.Warnf("ToFloat() but is slice?: %T first=%v", v, v.Index(0))
		return convertToFloat64(0, v.Index(0))
	default:
		//u.Warnf("Cannot convert type?  %v", v.Kind())
	}
	return math.NaN(), false
}