k3s/vendor/github.com/ugorji/go/codec/helper_unsafe.go

419 lines
13 KiB
Go

// +build !safe
// +build !appengine
// +build go1.7
// Copyright (c) 2012-2015 Ugorji Nwoke. All rights reserved.
// Use of this source code is governed by a MIT license found in the LICENSE file.
package codec
import (
"reflect"
"sync/atomic"
"unsafe"
)
// This file has unsafe variants of some helper methods.
// NOTE: See helper_not_unsafe.go for the usage information.
// var zeroRTv [4]uintptr
const unsafeFlagIndir = 1 << 7 // keep in sync with GO_ROOT/src/reflect/value.go
type unsafeString struct {
Data uintptr
Len int
}
type unsafeSlice struct {
Data uintptr
Len int
Cap int
}
type unsafeIntf struct {
typ unsafe.Pointer
word unsafe.Pointer
}
type unsafeReflectValue struct {
typ unsafe.Pointer
ptr unsafe.Pointer
flag uintptr
}
func stringView(v []byte) string {
if len(v) == 0 {
return ""
}
bx := (*unsafeSlice)(unsafe.Pointer(&v))
sx := unsafeString{bx.Data, bx.Len}
return *(*string)(unsafe.Pointer(&sx))
}
func bytesView(v string) []byte {
if len(v) == 0 {
return zeroByteSlice
}
sx := (*unsafeString)(unsafe.Pointer(&v))
bx := unsafeSlice{sx.Data, sx.Len, sx.Len}
return *(*[]byte)(unsafe.Pointer(&bx))
}
func definitelyNil(v interface{}) bool {
return (*unsafeIntf)(unsafe.Pointer(&v)).word == nil
}
// func keepAlive4BytesView(v string) {
// runtime.KeepAlive(v)
// }
// func keepAlive4StringView(v []byte) {
// runtime.KeepAlive(v)
// }
// TODO: consider a more generally-known optimization for reflect.Value ==> Interface
//
// Currently, we use this fragile method that taps into implememtation details from
// the source go stdlib reflect/value.go,
// and trims the implementation.
func rv2i(rv reflect.Value) interface{} {
if false {
return rv.Interface()
}
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
// references that are single-words (map, ptr) may be double-referenced as flagIndir
kk := urv.flag & (1<<5 - 1)
if (kk == uintptr(reflect.Map) || kk == uintptr(reflect.Ptr)) && urv.flag&unsafeFlagIndir != 0 {
return *(*interface{})(unsafe.Pointer(&unsafeIntf{word: *(*unsafe.Pointer)(urv.ptr), typ: urv.typ}))
}
return *(*interface{})(unsafe.Pointer(&unsafeIntf{word: urv.ptr, typ: urv.typ}))
}
func rt2id(rt reflect.Type) uintptr {
return uintptr(((*unsafeIntf)(unsafe.Pointer(&rt))).word)
}
func rv2rtid(rv reflect.Value) uintptr {
return uintptr((*unsafeReflectValue)(unsafe.Pointer(&rv)).typ)
}
// func rv0t(rt reflect.Type) reflect.Value {
// ut := (*unsafeIntf)(unsafe.Pointer(&rt))
// // we need to determine whether ifaceIndir, and then whether to just pass 0 as the ptr
// uv := unsafeReflectValue{ut.word, &zeroRTv, flag(rt.Kind())}
// return *(*reflect.Value)(unsafe.Pointer(&uv})
// }
// --------------------------
type atomicTypeInfoSlice struct {
v unsafe.Pointer
}
func (x *atomicTypeInfoSlice) load() *[]rtid2ti {
return (*[]rtid2ti)(atomic.LoadPointer(&x.v))
}
func (x *atomicTypeInfoSlice) store(p *[]rtid2ti) {
atomic.StorePointer(&x.v, unsafe.Pointer(p))
}
// --------------------------
func (d *Decoder) raw(f *codecFnInfo, rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
// if urv.flag&unsafeFlagIndir != 0 {
// urv.ptr = *(*unsafe.Pointer)(urv.ptr)
// }
*(*[]byte)(urv.ptr) = d.rawBytes()
}
func (d *Decoder) kString(f *codecFnInfo, rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*string)(urv.ptr) = d.d.DecodeString()
}
func (d *Decoder) kBool(f *codecFnInfo, rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*bool)(urv.ptr) = d.d.DecodeBool()
}
func (d *Decoder) kFloat32(f *codecFnInfo, rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*float32)(urv.ptr) = float32(d.d.DecodeFloat(true))
}
func (d *Decoder) kFloat64(f *codecFnInfo, rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*float64)(urv.ptr) = d.d.DecodeFloat(false)
}
func (d *Decoder) kInt(f *codecFnInfo, rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*int)(urv.ptr) = int(d.d.DecodeInt(intBitsize))
}
func (d *Decoder) kInt8(f *codecFnInfo, rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*int8)(urv.ptr) = int8(d.d.DecodeInt(8))
}
func (d *Decoder) kInt16(f *codecFnInfo, rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*int16)(urv.ptr) = int16(d.d.DecodeInt(16))
}
func (d *Decoder) kInt32(f *codecFnInfo, rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*int32)(urv.ptr) = int32(d.d.DecodeInt(32))
}
func (d *Decoder) kInt64(f *codecFnInfo, rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*int64)(urv.ptr) = d.d.DecodeInt(64)
}
func (d *Decoder) kUint(f *codecFnInfo, rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*uint)(urv.ptr) = uint(d.d.DecodeUint(uintBitsize))
}
func (d *Decoder) kUintptr(f *codecFnInfo, rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*uintptr)(urv.ptr) = uintptr(d.d.DecodeUint(uintBitsize))
}
func (d *Decoder) kUint8(f *codecFnInfo, rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*uint8)(urv.ptr) = uint8(d.d.DecodeUint(8))
}
func (d *Decoder) kUint16(f *codecFnInfo, rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*uint16)(urv.ptr) = uint16(d.d.DecodeUint(16))
}
func (d *Decoder) kUint32(f *codecFnInfo, rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*uint32)(urv.ptr) = uint32(d.d.DecodeUint(32))
}
func (d *Decoder) kUint64(f *codecFnInfo, rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*uint64)(urv.ptr) = d.d.DecodeUint(64)
}
// ------------
// func rt2id(rt reflect.Type) uintptr {
// return uintptr(((*unsafeIntf)(unsafe.Pointer(&rt))).word)
// // var i interface{} = rt
// // // ui := (*unsafeIntf)(unsafe.Pointer(&i))
// // return ((*unsafeIntf)(unsafe.Pointer(&i))).word
// }
// func rv2i(rv reflect.Value) interface{} {
// urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
// // non-reference type: already indir
// // reference type: depend on flagIndir property ('cos maybe was double-referenced)
// // const (unsafeRvFlagKindMask = 1<<5 - 1 , unsafeRvFlagIndir = 1 << 7 )
// // rvk := reflect.Kind(urv.flag & (1<<5 - 1))
// // if (rvk == reflect.Chan ||
// // rvk == reflect.Func ||
// // rvk == reflect.Interface ||
// // rvk == reflect.Map ||
// // rvk == reflect.Ptr ||
// // rvk == reflect.UnsafePointer) && urv.flag&(1<<8) != 0 {
// // fmt.Printf(">>>>> ---- double indirect reference: %v, %v\n", rvk, rv.Type())
// // return *(*interface{})(unsafe.Pointer(&unsafeIntf{word: *(*unsafe.Pointer)(urv.ptr), typ: urv.typ}))
// // }
// if urv.flag&(1<<5-1) == uintptr(reflect.Map) && urv.flag&(1<<7) != 0 {
// // fmt.Printf(">>>>> ---- double indirect reference: %v, %v\n", rvk, rv.Type())
// return *(*interface{})(unsafe.Pointer(&unsafeIntf{word: *(*unsafe.Pointer)(urv.ptr), typ: urv.typ}))
// }
// // fmt.Printf(">>>>> ++++ direct reference: %v, %v\n", rvk, rv.Type())
// return *(*interface{})(unsafe.Pointer(&unsafeIntf{word: urv.ptr, typ: urv.typ}))
// }
// const (
// unsafeRvFlagKindMask = 1<<5 - 1
// unsafeRvKindDirectIface = 1 << 5
// unsafeRvFlagIndir = 1 << 7
// unsafeRvFlagAddr = 1 << 8
// unsafeRvFlagMethod = 1 << 9
// _USE_RV_INTERFACE bool = false
// _UNSAFE_RV_DEBUG = true
// )
// type unsafeRtype struct {
// _ [2]uintptr
// _ uint32
// _ uint8
// _ uint8
// _ uint8
// kind uint8
// _ [2]uintptr
// _ int32
// }
// func _rv2i(rv reflect.Value) interface{} {
// // Note: From use,
// // - it's never an interface
// // - the only calls here are for ifaceIndir types.
// // (though that conditional is wrong)
// // To know for sure, we need the value of t.kind (which is not exposed).
// //
// // Need to validate the path: type is indirect ==> only value is indirect ==> default (value is direct)
// // - Type indirect, Value indirect: ==> numbers, boolean, slice, struct, array, string
// // - Type Direct, Value indirect: ==> map???
// // - Type Direct, Value direct: ==> pointers, unsafe.Pointer, func, chan, map
// //
// // TRANSLATES TO:
// // if typeIndirect { } else if valueIndirect { } else { }
// //
// // Since we don't deal with funcs, then "flagNethod" is unset, and can be ignored.
// if _USE_RV_INTERFACE {
// return rv.Interface()
// }
// urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
// // if urv.flag&unsafeRvFlagMethod != 0 || urv.flag&unsafeRvFlagKindMask == uintptr(reflect.Interface) {
// // println("***** IS flag method or interface: delegating to rv.Interface()")
// // return rv.Interface()
// // }
// // if urv.flag&unsafeRvFlagKindMask == uintptr(reflect.Interface) {
// // println("***** IS Interface: delegate to rv.Interface")
// // return rv.Interface()
// // }
// // if urv.flag&unsafeRvFlagKindMask&unsafeRvKindDirectIface == 0 {
// // if urv.flag&unsafeRvFlagAddr == 0 {
// // println("***** IS ifaceIndir typ")
// // // ui := unsafeIntf{word: urv.ptr, typ: urv.typ}
// // // return *(*interface{})(unsafe.Pointer(&ui))
// // // return *(*interface{})(unsafe.Pointer(&unsafeIntf{word: urv.ptr, typ: urv.typ}))
// // }
// // } else if urv.flag&unsafeRvFlagIndir != 0 {
// // println("***** IS flagindir")
// // // return *(*interface{})(unsafe.Pointer(&unsafeIntf{word: *(*unsafe.Pointer)(urv.ptr), typ: urv.typ}))
// // } else {
// // println("***** NOT flagindir")
// // return *(*interface{})(unsafe.Pointer(&unsafeIntf{word: urv.ptr, typ: urv.typ}))
// // }
// // println("***** default: delegate to rv.Interface")
// urt := (*unsafeRtype)(unsafe.Pointer(urv.typ))
// if _UNSAFE_RV_DEBUG {
// fmt.Printf(">>>> start: %v: ", rv.Type())
// fmt.Printf("%v - %v\n", *urv, *urt)
// }
// if urt.kind&unsafeRvKindDirectIface == 0 {
// if _UNSAFE_RV_DEBUG {
// fmt.Printf("**** +ifaceIndir type: %v\n", rv.Type())
// }
// // println("***** IS ifaceIndir typ")
// // if true || urv.flag&unsafeRvFlagAddr == 0 {
// // // println(" ***** IS NOT addr")
// return *(*interface{})(unsafe.Pointer(&unsafeIntf{word: urv.ptr, typ: urv.typ}))
// // }
// } else if urv.flag&unsafeRvFlagIndir != 0 {
// if _UNSAFE_RV_DEBUG {
// fmt.Printf("**** +flagIndir type: %v\n", rv.Type())
// }
// // println("***** IS flagindir")
// return *(*interface{})(unsafe.Pointer(&unsafeIntf{word: *(*unsafe.Pointer)(urv.ptr), typ: urv.typ}))
// } else {
// if _UNSAFE_RV_DEBUG {
// fmt.Printf("**** -flagIndir type: %v\n", rv.Type())
// }
// // println("***** NOT flagindir")
// return *(*interface{})(unsafe.Pointer(&unsafeIntf{word: urv.ptr, typ: urv.typ}))
// }
// // println("***** default: delegating to rv.Interface()")
// // return rv.Interface()
// }
// var staticM0 = make(map[string]uint64)
// var staticI0 = (int32)(-5)
// func staticRv2iTest() {
// i0 := (int32)(-5)
// m0 := make(map[string]uint16)
// m0["1"] = 1
// for _, i := range []interface{}{
// (int)(7),
// (uint)(8),
// (int16)(-9),
// (uint16)(19),
// (uintptr)(77),
// (bool)(true),
// float32(-32.7),
// float64(64.9),
// complex(float32(19), 5),
// complex(float64(-32), 7),
// [4]uint64{1, 2, 3, 4},
// (chan<- int)(nil), // chan,
// rv2i, // func
// io.Writer(ioutil.Discard),
// make(map[string]uint),
// (map[string]uint)(nil),
// staticM0,
// m0,
// &m0,
// i0,
// &i0,
// &staticI0,
// &staticM0,
// []uint32{6, 7, 8},
// "abc",
// Raw{},
// RawExt{},
// &Raw{},
// &RawExt{},
// unsafe.Pointer(&i0),
// } {
// i2 := rv2i(reflect.ValueOf(i))
// eq := reflect.DeepEqual(i, i2)
// fmt.Printf(">>>> %v == %v? %v\n", i, i2, eq)
// }
// // os.Exit(0)
// }
// func init() {
// staticRv2iTest()
// }
// func rv2i(rv reflect.Value) interface{} {
// if _USE_RV_INTERFACE || rv.Kind() == reflect.Interface || rv.CanAddr() {
// return rv.Interface()
// }
// // var i interface{}
// // ui := (*unsafeIntf)(unsafe.Pointer(&i))
// var ui unsafeIntf
// urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
// // fmt.Printf("urv: flag: %b, typ: %b, ptr: %b\n", urv.flag, uintptr(urv.typ), uintptr(urv.ptr))
// if (urv.flag&unsafeRvFlagKindMask)&unsafeRvKindDirectIface == 0 {
// if urv.flag&unsafeRvFlagAddr != 0 {
// println("***** indirect and addressable! Needs typed move - delegate to rv.Interface()")
// return rv.Interface()
// }
// println("****** indirect type/kind")
// ui.word = urv.ptr
// } else if urv.flag&unsafeRvFlagIndir != 0 {
// println("****** unsafe rv flag indir")
// ui.word = *(*unsafe.Pointer)(urv.ptr)
// } else {
// println("****** default: assign prt to word directly")
// ui.word = urv.ptr
// }
// // ui.word = urv.ptr
// ui.typ = urv.typ
// // fmt.Printf("(pointers) ui.typ: %p, word: %p\n", ui.typ, ui.word)
// // fmt.Printf("(binary) ui.typ: %b, word: %b\n", uintptr(ui.typ), uintptr(ui.word))
// return *(*interface{})(unsafe.Pointer(&ui))
// // return i
// }