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reflect: add Type.Bits method, add tags to prohibit conversions

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gob: substitute slice for map

R=r
CC=golang-dev
https://golang.org/cl/1699045
This commit is contained in:
Russ Cox 2010-06-21 13:19:29 -07:00
parent 2fc0b4f01b
commit fc090a3a54
9 changed files with 112 additions and 144 deletions
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8
src/pkg/fmt/print.go
View File

@ -612,10 +612,10 @@ func (p *pp) fmtUintptrGetter(field interface{}, value reflect.Value, verb int,
}
var (
intBits = uintptr(reflect.Typeof(int(0)).Size() * 8)
floatBits = uintptr(reflect.Typeof(float(0)).Size() * 8)
complexBits = uintptr(reflect.Typeof(complex(0+0i)).Size() * 8)
uintptrBits = uintptr(reflect.Typeof(uintptr(0)).Size() * 8)
intBits = reflect.Typeof(0).Bits()
floatBits = reflect.Typeof(0.0).Bits()
complexBits = reflect.Typeof(1i).Bits()
uintptrBits = reflect.Typeof(uintptr(0)).Bits()
)
func (p *pp) printField(field interface{}, verb int, plus, sharp bool, depth int) (was_string bool) {

23
src/pkg/fmt/scan.go
View File

@ -456,9 +456,10 @@ func (s *ss) scanNumber(digits string) string {
}
// scanRune returns the next rune value in the input.
func (s *ss) scanRune(bitSize uintptr) int64 {
func (s *ss) scanRune(bitSize int) int64 {
rune := int64(s.mustGetRune())
x := (rune << (64 - bitSize)) >> (64 - bitSize)
n := uint(bitSize)
x := (rune << (64 - n)) >> (64 - n)
if x != rune {
s.errorString("overflow on character value " + string(rune))
}
@ -467,7 +468,7 @@ func (s *ss) scanRune(bitSize uintptr) int64 {
// scanInt returns the value of the integer represented by the next
// token, checking for overflow. Any error is stored in s.err.
func (s *ss) scanInt(verb int, bitSize uintptr) int64 {
func (s *ss) scanInt(verb int, bitSize int) int64 {
if verb == 'c' {
return s.scanRune(bitSize)
}
@ -479,7 +480,8 @@ func (s *ss) scanInt(verb int, bitSize uintptr) int64 {
if err != nil {
s.error(err)
}
x := (i << (64 - bitSize)) >> (64 - bitSize)
n := uint(bitSize)
x := (i << (64 - n)) >> (64 - n)
if x != i {
s.errorString("integer overflow on token " + tok)
}
@ -488,7 +490,7 @@ func (s *ss) scanInt(verb int, bitSize uintptr) int64 {
// scanUint returns the value of the unsigned integer represented
// by the next token, checking for overflow. Any error is stored in s.err.
func (s *ss) scanUint(verb int, bitSize uintptr) uint64 {
func (s *ss) scanUint(verb int, bitSize int) uint64 {
if verb == 'c' {
return uint64(s.scanRune(bitSize))
}
@ -499,7 +501,8 @@ func (s *ss) scanUint(verb int, bitSize uintptr) uint64 {
if err != nil {
s.error(err)
}
x := (i << (64 - bitSize)) >> (64 - bitSize)
n := uint(bitSize)
x := (i << (64 - n)) >> (64 - n)
if x != i {
s.errorString("unsigned integer overflow on token " + tok)
}
@ -766,9 +769,9 @@ func (s *ss) scanOne(verb int, field interface{}) {
case *reflect.BoolValue:
v.Set(s.scanBool(verb))
case *reflect.IntValue:
v.Set(s.scanInt(verb, v.Type().Size()*8))
v.Set(s.scanInt(verb, v.Type().Bits()))
case *reflect.UintValue:
v.Set(s.scanUint(verb, v.Type().Size()*8))
v.Set(s.scanUint(verb, v.Type().Bits()))
case *reflect.StringValue:
v.Set(s.convertString(verb))
case *reflect.SliceValue:
@ -784,9 +787,9 @@ func (s *ss) scanOne(verb int, field interface{}) {
}
case *reflect.FloatValue:
s.skipSpace()
v.Set(s.convertFloat(s.floatToken(), int(v.Type().Size()*8)))
v.Set(s.convertFloat(s.floatToken(), v.Type().Bits()))
case *reflect.ComplexValue:
v.Set(s.scanComplex(verb, int(v.Type().Size()*8)))
v.Set(s.scanComplex(verb, v.Type().Bits()))
default:
CantHandle:
s.errorString("Scan: can't handle type: " + val.Type().String())

10
src/pkg/gob/decode.go
View File

@ -540,7 +540,7 @@ func ignoreSlice(state *decodeState, elemOp decOp) os.Error {
return ignoreArrayHelper(state, elemOp, int(decodeUint(state)))
}
var decOpMap = map[reflect.Kind]decOp{
var decOpMap = []decOp{
reflect.Bool: decBool,
reflect.Int8: decInt8,
reflect.Int16: decInt16,
@ -568,8 +568,12 @@ var decIgnoreOpMap = map[typeId]decOp{
// the indirection count to reach it.
func (dec *Decoder) decOpFor(wireId typeId, rt reflect.Type, name string) (decOp, int, os.Error) {
typ, indir := indirect(rt)
op, ok := decOpMap[typ.Kind()]
if !ok {
var op decOp
k := typ.Kind()
if int(k) < len(decOpMap) {
op = decOpMap[k]
}
if op == nil {
// Special cases
switch t := typ.(type) {
case *reflect.ArrayType:

10
src/pkg/gob/encode.go
View File

@ -601,7 +601,7 @@ func encodeMap(b *bytes.Buffer, rt reflect.Type, p uintptr, keyOp, elemOp encOp,
return state.err
}
var encOpMap = map[reflect.Kind]encOp{
var encOpMap = []encOp{
reflect.Bool: encBool,
reflect.Int: encInt,
reflect.Int8: encInt8,
@ -624,8 +624,12 @@ var encOpMap = map[reflect.Kind]encOp{
// the indirection count to reach it.
func encOpFor(rt reflect.Type) (encOp, int, os.Error) {
typ, indir := indirect(rt)
op, ok := encOpMap[typ.Kind()]
if !ok {
var op encOp
k := typ.Kind()
if int(k) < len(encOpMap) {
op = encOpMap[k]
}
if op == nil {
// Special cases
switch t := typ.(type) {
case *reflect.SliceType:

2
src/pkg/json/decode.go
View File

@ -588,7 +588,7 @@ func (d *decodeState) literal(v reflect.Value) {
v.Set(n)
case *reflect.FloatValue:
n, err := strconv.AtofN(s, int(v.Type().Size()*8))
n, err := strconv.AtofN(s, v.Type().Bits())
if err != nil || v.Overflow(n) {
d.saveError(&UnmarshalTypeError{"number " + s, v.Type()})
break

2
src/pkg/json/encode.go
View File

@ -162,7 +162,7 @@ func (e *encodeState) reflectValue(v reflect.Value) {
e.WriteString(strconv.Uitoa64(v.Get()))
case *reflect.FloatValue:
e.WriteString(strconv.FtoaN(v.Get(), 'g', -1, int(v.Type().Size()*8)))
e.WriteString(strconv.FtoaN(v.Get(), 'g', -1, v.Type().Bits()))
case *reflect.StringValue:
e.string(v.Get())

44
src/pkg/reflect/type.go
View File

@ -34,6 +34,11 @@ import (
* copy in order to access the private fields.
*/
// commonType is the common implementation of most values.
// It is embedded in other, public struct types, but always
// with a unique tag like "uint" or "float" so that the client cannot
// convert from, say, *UintType to *FloatType.
type commonType struct {
size uintptr
hash uint32
@ -62,42 +67,42 @@ type uncommonType struct {
// BoolType represents a boolean type.
type BoolType struct {
commonType
commonType "bool"
}
// FloatType represents a float type.
type FloatType struct {
commonType
commonType "float"
}
// ComplexType represents a complex type.
type ComplexType struct {
commonType
commonType "complex"
}
// IntType represents a signed integer type.
type IntType struct {
commonType
commonType "int"
}
// UintType represents a uint type.
type UintType struct {
commonType
commonType "uint"
}
// StringType represents a string type.
type StringType struct {
commonType
commonType "string"
}
// UnsafePointerType represents an unsafe.Pointer type.
type UnsafePointerType struct {
commonType
commonType "unsafe.Pointer"
}
// ArrayType represents a fixed array type.
type ArrayType struct {
commonType
commonType "array"
elem *runtime.Type
len uintptr
}
@ -113,14 +118,14 @@ const (
// ChanType represents a channel type.
type ChanType struct {
commonType
commonType "chan"
elem *runtime.Type
dir uintptr
}
// FuncType represents a function type.
type FuncType struct {
commonType
commonType "func"
dotdotdot bool
in []*runtime.Type
out []*runtime.Type
@ -135,26 +140,26 @@ type imethod struct {
// InterfaceType represents an interface type.
type InterfaceType struct {
commonType
commonType "interface"
methods []imethod
}
// MapType represents a map type.
type MapType struct {
commonType
commonType "map"
key *runtime.Type
elem *runtime.Type
}
// PtrType represents a pointer type.
type PtrType struct {
commonType
commonType "ptr"
elem *runtime.Type
}
// SliceType represents a slice type.
type SliceType struct {
commonType
commonType "slice"
elem *runtime.Type
}
@ -169,7 +174,7 @@ type structField struct {
// StructType represents a struct type.
type StructType struct {
commonType
commonType "struct"
fields []structField
}
@ -214,6 +219,11 @@ type Type interface {
// a value of the given type; it is analogous to unsafe.Sizeof.
Size() uintptr
// Bits returns the size of the type in bits.
// It is intended for use with numeric types and may overflow
// when used for composite types.
Bits() int
// Align returns the alignment of a value of this type
// when allocated in memory.
Align() int
@ -333,6 +343,8 @@ func (t *commonType) String() string { return *t.string }
func (t *commonType) Size() uintptr { return t.size }
func (t *commonType) Bits() int { return int(t.size * 8) }
func (t *commonType) Align() int { return int(t.align) }
func (t *commonType) FieldAlign() int { return int(t.fieldAlign) }
@ -352,7 +364,7 @@ func (t *uncommonType) Method(i int) (m Method) {
}
m.Type = toType(*p.typ).(*FuncType)
fn := p.tfn
m.Func = newFuncValue(m.Type, addr(&fn), true)
m.Func = &FuncValue{value: value{m.Type, addr(&fn), true}}
return
}

128
src/pkg/reflect/value.go
View File

@ -75,6 +75,10 @@ type Value interface {
getAddr() addr
}
// value is the common implementation of most values.
// It is embedded in other, public struct types, but always
// with a unique tag like "uint" or "float" so that the client cannot
// convert from, say, *UintValue to *FloatValue.
type value struct {
typ Type
addr addr
@ -113,7 +117,7 @@ func (v *value) CanSet() bool { return v.canSet }
// BoolValue represents a bool value.
type BoolValue struct {
value
value "bool"
}
// Get returns the underlying bool value.
@ -132,7 +136,7 @@ func (v *BoolValue) SetValue(x Value) { v.Set(x.(*BoolValue).Get()) }
// FloatValue represents a float value.
type FloatValue struct {
value
value "float"
}
// Get returns the underlying int value.
@ -181,7 +185,7 @@ func (v *FloatValue) SetValue(x Value) { v.Set(x.(*FloatValue).Get()) }
// ComplexValue represents a complex value.
type ComplexValue struct {
value
value "complex"
}
// Get returns the underlying complex value.
@ -217,47 +221,9 @@ func (v *ComplexValue) Set(x complex128) {
// Set sets v to the value x.
func (v *ComplexValue) SetValue(x Value) { v.Set(x.(*ComplexValue).Get()) }
// Complex64Value represents a complex64 value.
type Complex64Value struct {
value
}
// Get returns the underlying complex64 value.
func (v *Complex64Value) Get() complex64 { return *(*complex64)(v.addr) }
// Set sets v to the value x.
func (v *Complex64Value) Set(x complex64) {
if !v.canSet {
panic(cannotSet)
}
*(*complex64)(v.addr) = x
}
// Set sets v to the value x.
func (v *Complex64Value) SetValue(x Value) { v.Set(x.(*Complex64Value).Get()) }
// Complex128Value represents a complex128 value.
type Complex128Value struct {
value
}
// Get returns the underlying complex128 value.
func (v *Complex128Value) Get() complex128 { return *(*complex128)(v.addr) }
// Set sets v to the value x.
func (v *Complex128Value) Set(x complex128) {
if !v.canSet {
panic(cannotSet)
}
*(*complex128)(v.addr) = x
}
// Set sets v to the value x.
func (v *Complex128Value) SetValue(x Value) { v.Set(x.(*Complex128Value).Get()) }
// IntValue represents an int value.
type IntValue struct {
value
value "int"
}
// Get returns the underlying int value.
@ -303,7 +269,7 @@ func (v *IntValue) SetValue(x Value) { v.Set(x.(*IntValue).Get()) }
// Overflow returns true if x cannot be represented by the type of v.
func (v *IntValue) Overflow(x int64) bool {
bitSize := v.typ.Size() * 8
bitSize := uint(v.typ.Bits())
trunc := (x << (64 - bitSize)) >> (64 - bitSize)
return x != trunc
}
@ -316,7 +282,7 @@ type StringHeader struct {
// StringValue represents a string value.
type StringValue struct {
value
value "string"
}
// Get returns the underlying string value.
@ -335,7 +301,7 @@ func (v *StringValue) SetValue(x Value) { v.Set(x.(*StringValue).Get()) }
// UintValue represents a uint value.
type UintValue struct {
value
value "uint"
}
// Get returns the underlying uuint value.
@ -382,7 +348,7 @@ func (v *UintValue) Set(x uint64) {
// Overflow returns true if x cannot be represented by the type of v.
func (v *UintValue) Overflow(x uint64) bool {
bitSize := v.typ.Size() * 8
bitSize := uint(v.typ.Bits())
trunc := (x << (64 - bitSize)) >> (64 - bitSize)
return x != trunc
}
@ -392,7 +358,7 @@ func (v *UintValue) SetValue(x Value) { v.Set(x.(*UintValue).Get()) }
// UnsafePointerValue represents an unsafe.Pointer value.
type UnsafePointerValue struct {
value
value "unsafe.Pointer"
}
// Get returns the underlying uintptr value.
@ -454,7 +420,7 @@ func ArrayCopy(dst, src ArrayOrSliceValue) int {
// An ArrayValue represents an array.
type ArrayValue struct {
value
value "array"
}
// Len returns the length of the array.
@ -503,7 +469,7 @@ type SliceHeader struct {
// A SliceValue represents a slice.
type SliceValue struct {
value
value "slice"
}
func (v *SliceValue) slice() *SliceHeader { return (*SliceHeader)(v.value.addr) }
@ -593,7 +559,7 @@ func MakeSlice(typ *SliceType, len, cap int) *SliceValue {
// A ChanValue represents a chan.
type ChanValue struct {
value
value "chan"
}
// IsNil returns whether v is a nil channel.
@ -714,7 +680,7 @@ func MakeChan(typ *ChanType, buffer int) *ChanValue {
// A FuncValue represents a function value.
type FuncValue struct {
value
value "func"
first *value
isInterface bool
}
@ -874,7 +840,7 @@ func (fv *FuncValue) Call(in []Value) []Value {
// An InterfaceValue represents an interface value.
type InterfaceValue struct {
value
value "interface"
}
// No Get because v.Interface() is available.
@ -939,7 +905,7 @@ func (v *InterfaceValue) Method(i int) *FuncValue {
// A MapValue represents a map value.
type MapValue struct {
value
value "map"
}
// IsNil returns whether v is a nil map value.
@ -1056,7 +1022,7 @@ func MakeMap(typ *MapType) *MapValue {
// A PtrValue represents a pointer.
type PtrValue struct {
value
value "ptr"
}
// IsNil returns whether v is a nil pointer.
@ -1127,7 +1093,7 @@ func Indirect(v Value) Value {
// A StructValue represents a struct value.
type StructValue struct {
value
value "struct"
}
// Set assigns x to v.
@ -1211,57 +1177,39 @@ func NewValue(i interface{}) Value {
return newValue(toType(t), addr(a), true)
}
func newFuncValue(typ Type, addr addr, canSet bool) *FuncValue {
return &FuncValue{value: value{typ, addr, canSet}}
}
func newValue(typ Type, addr addr, canSet bool) Value {
// FuncValue has a different layout;
// it needs a extra space for the fixed receivers.
if _, ok := typ.(*FuncType); ok {
return newFuncValue(typ, addr, canSet)
}
// All values have same memory layout;
// build once and convert.
v := &struct{ value }{value{typ, addr, canSet}}
v := value{typ, addr, canSet}
switch typ.(type) {
case *ArrayType:
// TODO(rsc): Something must prevent
// clients of the package from doing
// this same kind of cast.
// We should be allowed because
// they're our types.
// Something about implicit assignment
// to struct fields.
return (*ArrayValue)(v)
return &ArrayValue{v}
case *BoolType:
return (*BoolValue)(v)
return &BoolValue{v}
case *ChanType:
return (*ChanValue)(v)
return &ChanValue{v}
case *FloatType:
return (*FloatValue)(v)
return &FloatValue{v}
case *FuncType:
return &FuncValue{value: v}
case *ComplexType:
return (*ComplexValue)(v)
return &ComplexValue{v}
case *IntType:
return (*IntValue)(v)
return &IntValue{v}
case *InterfaceType:
return (*InterfaceValue)(v)
return &InterfaceValue{v}
case *MapType:
return (*MapValue)(v)
return &MapValue{v}
case *PtrType:
return (*PtrValue)(v)
return &PtrValue{v}
case *SliceType:
return (*SliceValue)(v)
return &SliceValue{v}
case *StringType:
return (*StringValue)(v)
return &StringValue{v}
case *StructType:
return (*StructValue)(v)
return &StructValue{v}
case *UintType:
return (*UintValue)(v)
return &UintValue{v}
case *UnsafePointerType:
return (*UnsafePointerValue)(v)
return &UnsafePointerValue{v}
}
panic("newValue" + typ.String())
}

3
test/ken/cplx3.go
View File

@ -30,9 +30,6 @@ func main() {
var a interface{}
switch c := reflect.NewValue(a).(type) {
case *reflect.Complex64Value:
v := c.Get()
_, _ = complex64(v), true
case *reflect.ComplexValue:
if complexBits == 64 {
v := c.Get()