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// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package reflectlite
import (
"unsafe"
)
// Field returns the i'th field of the struct v.
// It panics if v's Kind is not Struct or i is out of range.
func Field(v Value, i int) Value {
if v.kind() != Struct {
panic(&ValueError{"reflect.Value.Field", v.kind()})
}
tt := (*structType)(unsafe.Pointer(v.typ))
if uint(i) >= uint(len(tt.fields)) {
panic("reflect: Field index out of range")
}
field := &tt.fields[i]
typ := field.typ
// Inherit permission bits from v, but clear flagEmbedRO.
fl := v.flag&(flagStickyRO|flagIndir|flagAddr) | flag(typ.Kind())
// Using an unexported field forces flagRO.
if field.pkgPath != nil {
if field.embedded() {
fl |= flagEmbedRO
} else {
fl |= flagStickyRO
}
}
// Either flagIndir is set and v.ptr points at struct,
// or flagIndir is not set and v.ptr is the actual struct data.
// In the former case, we want v.ptr + offset.
// In the latter case, we must have field.offset = 0,
// so v.ptr + field.offset is still the correct address.
ptr := add(v.ptr, field.offset(), "same as non-reflect &v.field")
return Value{typ, ptr, fl}
}
func TField(typ Type, i int) Type {
t := typ.(*rtype)
if t.Kind() != Struct {
panic("reflect: Field of non-struct type")
}
tt := (*structType)(unsafe.Pointer(t))
return StructFieldType(tt, i)
}
// Field returns the i'th struct field.
func StructFieldType(t *structType, i int) Type {
if i < 0 || i >= len(t.fields) {
panic("reflect: Field index out of bounds")
}
p := &t.fields[i]
return toType(p.typ)
}
// Zero returns a Value representing the zero value for the specified type.
// The result is different from the zero value of the Value struct,
// which represents no value at all.
// For example, Zero(TypeOf(42)) returns a Value with Kind Int and value 0.
// The returned value is neither addressable nor settable.
func Zero(typ Type) Value {
if typ == nil {
panic("reflect: Zero(nil)")
}
t := typ.(*rtype)
fl := flag(t.Kind())
if ifaceIndir(t) {
return Value{t, unsafe_New(t), fl | flagIndir}
}
return Value{t, nil, fl}
}
// ToInterface returns v's current value as an interface{}.
// It is equivalent to:
// var i interface{} = (v's underlying value)
// It panics if the Value was obtained by accessing
// unexported struct fields.
func ToInterface(v Value) (i interface{}) {
return valueInterface(v)
}
type EmbedWithUnexpMeth struct{}
func (EmbedWithUnexpMeth) f() {}
type pinUnexpMeth interface {
f()
}
var pinUnexpMethI = pinUnexpMeth(EmbedWithUnexpMeth{})
/*
func FirstMethodNameBytes(t Type) *byte {
_ = pinUnexpMethI
ut := t.uncommon()
if ut == nil {
panic("type has no methods")
}
m := ut.methods[0]
mname := t.(*rtype).nameOff(m.name)
if *mname.data(0, "name flag field")&(1<<2) == 0 {
panic("method name does not have pkgPath *string")
}
return mname.bytes
}
*/
type Buffer struct {
buf []byte
}
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