gtsocial-umbx

binc.go (32313B)

---

 // Copyright (c) 2012-2020 Ugorji Nwoke. All rights reserved.
 // Use of this source code is governed by a MIT license found in the LICENSE file.
 
 package codec
 
 import (
 	"math"
 	"reflect"
 	"time"
 	"unicode/utf8"
 )
 
 // Symbol management:
 // - symbols are stored in a symbol map during encoding and decoding.
 // - the symbols persist until the (En|De)coder ResetXXX method is called.
 
 const bincDoPrune = true
 
 // vd as low 4 bits (there are 16 slots)
 const (
 	bincVdSpecial byte = iota
 	bincVdPosInt
 	bincVdNegInt
 	bincVdFloat
 
 	bincVdString
 	bincVdByteArray
 	bincVdArray
 	bincVdMap
 
 	bincVdTimestamp
 	bincVdSmallInt
 	_ // bincVdUnicodeOther
 	bincVdSymbol
 
 	_               // bincVdDecimal
 	_               // open slot
 	_               // open slot
 	bincVdCustomExt = 0x0f
 )
 
 const (
 	bincSpNil byte = iota
 	bincSpFalse
 	bincSpTrue
 	bincSpNan
 	bincSpPosInf
 	bincSpNegInf
 	bincSpZeroFloat
 	bincSpZero
 	bincSpNegOne
 )
 
 const (
 	_ byte = iota // bincFlBin16
 	bincFlBin32
 	_ // bincFlBin32e
 	bincFlBin64
 	_ // bincFlBin64e
 	// others not currently supported
 )
 
 const bincBdNil = 0 // bincVdSpecial<<4 | bincSpNil // staticcheck barfs on this (SA4016)
 
 var (
 	bincdescSpecialVsNames = map[byte]string{
 		bincSpNil:       "nil",
 		bincSpFalse:     "false",
 		bincSpTrue:      "true",
 		bincSpNan:       "float",
 		bincSpPosInf:    "float",
 		bincSpNegInf:    "float",
 		bincSpZeroFloat: "float",
 		bincSpZero:      "uint",
 		bincSpNegOne:    "int",
 	}
 	bincdescVdNames = map[byte]string{
 		bincVdSpecial:   "special",
 		bincVdSmallInt:  "uint",
 		bincVdPosInt:    "uint",
 		bincVdFloat:     "float",
 		bincVdSymbol:    "string",
 		bincVdString:    "string",
 		bincVdByteArray: "bytes",
 		bincVdTimestamp: "time",
 		bincVdCustomExt: "ext",
 		bincVdArray:     "array",
 		bincVdMap:       "map",
 	}
 )
 
 func bincdescbd(bd byte) (s string) {
 	return bincdesc(bd>>4, bd&0x0f)
 }
 
 func bincdesc(vd, vs byte) (s string) {
 	if vd == bincVdSpecial {
 		s = bincdescSpecialVsNames[vs]
 	} else {
 		s = bincdescVdNames[vd]
 	}
 	if s == "" {
 		s = "unknown"
 	}
 	return
 }
 
 type bincEncState struct {
 	m map[string]uint16 // symbols
 }
 
 func (e bincEncState) captureState() interface{}   { return e.m }
 func (e *bincEncState) resetState()                { e.m = nil }
 func (e *bincEncState) reset()                     { e.resetState() }
 func (e *bincEncState) restoreState(v interface{}) { e.m = v.(map[string]uint16) }
 
 type bincEncDriver struct {
 	noBuiltInTypes
 	encDriverNoopContainerWriter
 	h *BincHandle
 	bincEncState
 
 	e Encoder
 }
 
 func (e *bincEncDriver) encoder() *Encoder {
 	return &e.e
 }
 
 func (e *bincEncDriver) EncodeNil() {
 	e.e.encWr.writen1(bincBdNil)
 }
 
 func (e *bincEncDriver) EncodeTime(t time.Time) {
 	if t.IsZero() {
 		e.EncodeNil()
 	} else {
 		bs := bincEncodeTime(t)
 		e.e.encWr.writen1(bincVdTimestamp<<4 | uint8(len(bs)))
 		e.e.encWr.writeb(bs)
 	}
 }
 
 func (e *bincEncDriver) EncodeBool(b bool) {
 	if b {
 		e.e.encWr.writen1(bincVdSpecial<<4 | bincSpTrue)
 	} else {
 		e.e.encWr.writen1(bincVdSpecial<<4 | bincSpFalse)
 	}
 }
 
 func (e *bincEncDriver) encSpFloat(f float64) (done bool) {
 	if f == 0 {
 		e.e.encWr.writen1(bincVdSpecial<<4 | bincSpZeroFloat)
 	} else if math.IsNaN(float64(f)) {
 		e.e.encWr.writen1(bincVdSpecial<<4 | bincSpNan)
 	} else if math.IsInf(float64(f), +1) {
 		e.e.encWr.writen1(bincVdSpecial<<4 | bincSpPosInf)
 	} else if math.IsInf(float64(f), -1) {
 		e.e.encWr.writen1(bincVdSpecial<<4 | bincSpNegInf)
 	} else {
 		return
 	}
 	return true
 }
 
 func (e *bincEncDriver) EncodeFloat32(f float32) {
 	if !e.encSpFloat(float64(f)) {
 		e.e.encWr.writen1(bincVdFloat<<4 | bincFlBin32)
 		bigen.writeUint32(e.e.w(), math.Float32bits(f))
 	}
 }
 
 func (e *bincEncDriver) EncodeFloat64(f float64) {
 	if e.encSpFloat(f) {
 		return
 	}
 	b := bigen.PutUint64(math.Float64bits(f))
 	if bincDoPrune {
 		i := 7
 		for ; i >= 0 && (b[i] == 0); i-- {
 		}
 		i++
 		if i <= 6 {
 			e.e.encWr.writen1(bincVdFloat<<4 | 0x8 | bincFlBin64)
 			e.e.encWr.writen1(byte(i))
 			e.e.encWr.writeb(b[:i])
 			return
 		}
 	}
 	e.e.encWr.writen1(bincVdFloat<<4 | bincFlBin64)
 	e.e.encWr.writen8(b)
 }
 
 func (e *bincEncDriver) encIntegerPrune32(bd byte, pos bool, v uint64) {
 	b := bigen.PutUint32(uint32(v))
 	if bincDoPrune {
 		i := byte(pruneSignExt(b[:], pos))
 		e.e.encWr.writen1(bd | 3 - i)
 		e.e.encWr.writeb(b[i:])
 	} else {
 		e.e.encWr.writen1(bd | 3)
 		e.e.encWr.writen4(b)
 	}
 }
 
 func (e *bincEncDriver) encIntegerPrune64(bd byte, pos bool, v uint64) {
 	b := bigen.PutUint64(v)
 	if bincDoPrune {
 		i := byte(pruneSignExt(b[:], pos))
 		e.e.encWr.writen1(bd | 7 - i)
 		e.e.encWr.writeb(b[i:])
 	} else {
 		e.e.encWr.writen1(bd | 7)
 		e.e.encWr.writen8(b)
 	}
 }
 
 func (e *bincEncDriver) EncodeInt(v int64) {
 	if v >= 0 {
 		e.encUint(bincVdPosInt<<4, true, uint64(v))
 	} else if v == -1 {
 		e.e.encWr.writen1(bincVdSpecial<<4 | bincSpNegOne)
 	} else {
 		e.encUint(bincVdNegInt<<4, false, uint64(-v))
 	}
 }
 
 func (e *bincEncDriver) EncodeUint(v uint64) {
 	e.encUint(bincVdPosInt<<4, true, v)
 }
 
 func (e *bincEncDriver) encUint(bd byte, pos bool, v uint64) {
 	if v == 0 {
 		e.e.encWr.writen1(bincVdSpecial<<4 | bincSpZero)
 	} else if pos && v >= 1 && v <= 16 {
 		e.e.encWr.writen1(bincVdSmallInt<<4 | byte(v-1))
 	} else if v <= math.MaxUint8 {
 		e.e.encWr.writen2(bd|0x0, byte(v))
 	} else if v <= math.MaxUint16 {
 		e.e.encWr.writen1(bd | 0x01)
 		bigen.writeUint16(e.e.w(), uint16(v))
 	} else if v <= math.MaxUint32 {
 		e.encIntegerPrune32(bd, pos, v)
 	} else {
 		e.encIntegerPrune64(bd, pos, v)
 	}
 }
 
 func (e *bincEncDriver) EncodeExt(v interface{}, basetype reflect.Type, xtag uint64, ext Ext) {
 	var bs0, bs []byte
 	if ext == SelfExt {
 		bs0 = e.e.blist.get(1024)
 		bs = bs0
 		e.e.sideEncode(v, basetype, &bs)
 	} else {
 		bs = ext.WriteExt(v)
 	}
 	if bs == nil {
 		e.EncodeNil()
 		goto END
 	}
 	e.encodeExtPreamble(uint8(xtag), len(bs))
 	e.e.encWr.writeb(bs)
 END:
 	if ext == SelfExt {
 		e.e.blist.put(bs)
 		if !byteSliceSameData(bs0, bs) {
 			e.e.blist.put(bs0)
 		}
 	}
 }
 
 func (e *bincEncDriver) EncodeRawExt(re *RawExt) {
 	e.encodeExtPreamble(uint8(re.Tag), len(re.Data))
 	e.e.encWr.writeb(re.Data)
 }
 
 func (e *bincEncDriver) encodeExtPreamble(xtag byte, length int) {
 	e.encLen(bincVdCustomExt<<4, uint64(length))
 	e.e.encWr.writen1(xtag)
 }
 
 func (e *bincEncDriver) WriteArrayStart(length int) {
 	e.encLen(bincVdArray<<4, uint64(length))
 }
 
 func (e *bincEncDriver) WriteMapStart(length int) {
 	e.encLen(bincVdMap<<4, uint64(length))
 }
 
 func (e *bincEncDriver) EncodeSymbol(v string) {
 	//symbols only offer benefit when string length > 1.
 	//This is because strings with length 1 take only 2 bytes to store
 	//(bd with embedded length, and single byte for string val).
 
 	l := len(v)
 	if l == 0 {
 		e.encBytesLen(cUTF8, 0)
 		return
 	} else if l == 1 {
 		e.encBytesLen(cUTF8, 1)
 		e.e.encWr.writen1(v[0])
 		return
 	}
 	if e.m == nil {
 		e.m = make(map[string]uint16, 16)
 	}
 	ui, ok := e.m[v]
 	if ok {
 		if ui <= math.MaxUint8 {
 			e.e.encWr.writen2(bincVdSymbol<<4, byte(ui))
 		} else {
 			e.e.encWr.writen1(bincVdSymbol<<4 | 0x8)
 			bigen.writeUint16(e.e.w(), ui)
 		}
 	} else {
 		e.e.seq++
 		ui = e.e.seq
 		e.m[v] = ui
 		var lenprec uint8
 		if l <= math.MaxUint8 {
 			// lenprec = 0
 		} else if l <= math.MaxUint16 {
 			lenprec = 1
 		} else if int64(l) <= math.MaxUint32 {
 			lenprec = 2
 		} else {
 			lenprec = 3
 		}
 		if ui <= math.MaxUint8 {
 			e.e.encWr.writen2(bincVdSymbol<<4|0x0|0x4|lenprec, byte(ui))
 		} else {
 			e.e.encWr.writen1(bincVdSymbol<<4 | 0x8 | 0x4 | lenprec)
 			bigen.writeUint16(e.e.w(), ui)
 		}
 		if lenprec == 0 {
 			e.e.encWr.writen1(byte(l))
 		} else if lenprec == 1 {
 			bigen.writeUint16(e.e.w(), uint16(l))
 		} else if lenprec == 2 {
 			bigen.writeUint32(e.e.w(), uint32(l))
 		} else {
 			bigen.writeUint64(e.e.w(), uint64(l))
 		}
 		e.e.encWr.writestr(v)
 	}
 }
 
 func (e *bincEncDriver) EncodeString(v string) {
 	if e.h.StringToRaw {
 		e.encLen(bincVdByteArray<<4, uint64(len(v)))
 		if len(v) > 0 {
 			e.e.encWr.writestr(v)
 		}
 		return
 	}
 	e.EncodeStringEnc(cUTF8, v)
 }
 
 func (e *bincEncDriver) EncodeStringEnc(c charEncoding, v string) {
 	if e.e.c == containerMapKey && c == cUTF8 && (e.h.AsSymbols == 1) {
 		e.EncodeSymbol(v)
 		return
 	}
 	e.encLen(bincVdString<<4, uint64(len(v)))
 	if len(v) > 0 {
 		e.e.encWr.writestr(v)
 	}
 }
 
 func (e *bincEncDriver) EncodeStringBytesRaw(v []byte) {
 	if v == nil {
 		e.EncodeNil()
 		return
 	}
 	e.encLen(bincVdByteArray<<4, uint64(len(v)))
 	if len(v) > 0 {
 		e.e.encWr.writeb(v)
 	}
 }
 
 func (e *bincEncDriver) encBytesLen(c charEncoding, length uint64) {
 	// MARKER: we currently only support UTF-8 (string) and RAW (bytearray).
 	// We should consider supporting bincUnicodeOther.
 
 	if c == cRAW {
 		e.encLen(bincVdByteArray<<4, length)
 	} else {
 		e.encLen(bincVdString<<4, length)
 	}
 }
 
 func (e *bincEncDriver) encLen(bd byte, l uint64) {
 	if l < 12 {
 		e.e.encWr.writen1(bd | uint8(l+4))
 	} else {
 		e.encLenNumber(bd, l)
 	}
 }
 
 func (e *bincEncDriver) encLenNumber(bd byte, v uint64) {
 	if v <= math.MaxUint8 {
 		e.e.encWr.writen2(bd, byte(v))
 	} else if v <= math.MaxUint16 {
 		e.e.encWr.writen1(bd | 0x01)
 		bigen.writeUint16(e.e.w(), uint16(v))
 	} else if v <= math.MaxUint32 {
 		e.e.encWr.writen1(bd | 0x02)
 		bigen.writeUint32(e.e.w(), uint32(v))
 	} else {
 		e.e.encWr.writen1(bd | 0x03)
 		bigen.writeUint64(e.e.w(), uint64(v))
 	}
 }
 
 //------------------------------------
 
 type bincDecState struct {
 	bdRead bool
 	bd     byte
 	vd     byte
 	vs     byte
 
 	_ bool
 	// MARKER: consider using binary search here instead of a map (ie bincDecSymbol)
 	s map[uint16][]byte
 }
 
 func (x bincDecState) captureState() interface{}   { return x }
 func (x *bincDecState) resetState()                { *x = bincDecState{} }
 func (x *bincDecState) reset()                     { x.resetState() }
 func (x *bincDecState) restoreState(v interface{}) { *x = v.(bincDecState) }
 
 type bincDecDriver struct {
 	decDriverNoopContainerReader
 	decDriverNoopNumberHelper
 	noBuiltInTypes
 
 	h *BincHandle
 
 	bincDecState
 	d Decoder
 }
 
 func (d *bincDecDriver) decoder() *Decoder {
 	return &d.d
 }
 
 func (d *bincDecDriver) descBd() string {
 	return sprintf("%v (%s)", d.bd, bincdescbd(d.bd))
 }
 
 func (d *bincDecDriver) readNextBd() {
 	d.bd = d.d.decRd.readn1()
 	d.vd = d.bd >> 4
 	d.vs = d.bd & 0x0f
 	d.bdRead = true
 }
 
 func (d *bincDecDriver) advanceNil() (null bool) {
 	if !d.bdRead {
 		d.readNextBd()
 	}
 	if d.bd == bincBdNil {
 		d.bdRead = false
 		return true // null = true
 	}
 	return
 }
 
 func (d *bincDecDriver) TryNil() bool {
 	return d.advanceNil()
 }
 
 func (d *bincDecDriver) ContainerType() (vt valueType) {
 	if !d.bdRead {
 		d.readNextBd()
 	}
 	if d.bd == bincBdNil {
 		d.bdRead = false
 		return valueTypeNil
 	} else if d.vd == bincVdByteArray {
 		return valueTypeBytes
 	} else if d.vd == bincVdString {
 		return valueTypeString
 	} else if d.vd == bincVdArray {
 		return valueTypeArray
 	} else if d.vd == bincVdMap {
 		return valueTypeMap
 	}
 	return valueTypeUnset
 }
 
 func (d *bincDecDriver) DecodeTime() (t time.Time) {
 	if d.advanceNil() {
 		return
 	}
 	if d.vd != bincVdTimestamp {
 		d.d.errorf("cannot decode time - %s %x-%x/%s", msgBadDesc, d.vd, d.vs, bincdesc(d.vd, d.vs))
 	}
 	t, err := bincDecodeTime(d.d.decRd.readx(uint(d.vs)))
 	halt.onerror(err)
 	d.bdRead = false
 	return
 }
 
 func (d *bincDecDriver) decFloatPruned(maxlen uint8) {
 	l := d.d.decRd.readn1()
 	if l > maxlen {
 		d.d.errorf("cannot read float - at most %v bytes used to represent float - received %v bytes", maxlen, l)
 	}
 	for i := l; i < maxlen; i++ {
 		d.d.b[i] = 0
 	}
 	d.d.decRd.readb(d.d.b[0:l])
 }
 
 func (d *bincDecDriver) decFloatPre32() (b [4]byte) {
 	if d.vs&0x8 == 0 {
 		b = d.d.decRd.readn4()
 	} else {
 		d.decFloatPruned(4)
 		copy(b[:], d.d.b[:])
 	}
 	return
 }
 
 func (d *bincDecDriver) decFloatPre64() (b [8]byte) {
 	if d.vs&0x8 == 0 {
 		b = d.d.decRd.readn8()
 	} else {
 		d.decFloatPruned(8)
 		copy(b[:], d.d.b[:])
 	}
 	return
 }
 
 func (d *bincDecDriver) decFloatVal() (f float64) {
 	switch d.vs & 0x7 {
 	case bincFlBin32:
 		f = float64(math.Float32frombits(bigen.Uint32(d.decFloatPre32())))
 	case bincFlBin64:
 		f = math.Float64frombits(bigen.Uint64(d.decFloatPre64()))
 	default:
 		// ok = false
 		d.d.errorf("read float supports only float32/64 - %s %x-%x/%s", msgBadDesc, d.vd, d.vs, bincdesc(d.vd, d.vs))
 	}
 	return
 }
 
 func (d *bincDecDriver) decUint() (v uint64) {
 	switch d.vs {
 	case 0:
 		v = uint64(d.d.decRd.readn1())
 	case 1:
 		v = uint64(bigen.Uint16(d.d.decRd.readn2()))
 	case 2:
 		b3 := d.d.decRd.readn3()
 		var b [4]byte
 		copy(b[1:], b3[:])
 		v = uint64(bigen.Uint32(b))
 	case 3:
 		v = uint64(bigen.Uint32(d.d.decRd.readn4()))
 	case 4, 5, 6:
 		var b [8]byte
 		lim := 7 - d.vs
 		bs := d.d.b[lim:8]
 		d.d.decRd.readb(bs)
 		copy(b[lim:], bs)
 		v = bigen.Uint64(b)
 	case 7:
 		v = bigen.Uint64(d.d.decRd.readn8())
 	default:
 		d.d.errorf("unsigned integers with greater than 64 bits of precision not supported: d.vs: %v %x", d.vs, d.vs)
 	}
 	return
 }
 
 func (d *bincDecDriver) uintBytes() (bs []byte) {
 	switch d.vs {
 	case 0:
 		bs = d.d.b[:1]
 		bs[0] = d.d.decRd.readn1()
 	case 1:
 		bs = d.d.b[:2]
 		d.d.decRd.readb(bs)
 	case 2:
 		bs = d.d.b[:3]
 		d.d.decRd.readb(bs)
 	case 3:
 		bs = d.d.b[:4]
 		d.d.decRd.readb(bs)
 	case 4, 5, 6:
 		lim := 7 - d.vs
 		bs = d.d.b[lim:8]
 		d.d.decRd.readb(bs)
 	case 7:
 		bs = d.d.b[:8]
 		d.d.decRd.readb(bs)
 	default:
 		d.d.errorf("unsigned integers with greater than 64 bits of precision not supported: d.vs: %v %x", d.vs, d.vs)
 	}
 	return
 }
 
 func (d *bincDecDriver) decInteger() (ui uint64, neg, ok bool) {
 	ok = true
 	vd, vs := d.vd, d.vs
 	if vd == bincVdPosInt {
 		ui = d.decUint()
 	} else if vd == bincVdNegInt {
 		ui = d.decUint()
 		neg = true
 	} else if vd == bincVdSmallInt {
 		ui = uint64(d.vs) + 1
 	} else if vd == bincVdSpecial {
 		if vs == bincSpZero {
 			// i = 0
 		} else if vs == bincSpNegOne {
 			neg = true
 			ui = 1
 		} else {
 			ok = false
 			// d.d.errorf("integer decode has invalid special value %x-%x/%s", d.vd, d.vs, bincdesc(d.vd, d.vs))
 		}
 	} else {
 		ok = false
 		// d.d.errorf("integer can only be decoded from int/uint. d.bd: 0x%x, d.vd: 0x%x", d.bd, d.vd)
 	}
 	return
 }
 
 func (d *bincDecDriver) decFloat() (f float64, ok bool) {
 	ok = true
 	vd, vs := d.vd, d.vs
 	if vd == bincVdSpecial {
 		if vs == bincSpNan {
 			f = math.NaN()
 		} else if vs == bincSpPosInf {
 			f = math.Inf(1)
 		} else if vs == bincSpZeroFloat || vs == bincSpZero {
 
 		} else if vs == bincSpNegInf {
 			f = math.Inf(-1)
 		} else {
 			ok = false
 			// d.d.errorf("float - invalid special value %x-%x/%s", d.vd, d.vs, bincdesc(d.vd, d.vs))
 		}
 	} else if vd == bincVdFloat {
 		f = d.decFloatVal()
 	} else {
 		ok = false
 	}
 	return
 }
 
 func (d *bincDecDriver) DecodeInt64() (i int64) {
 	if d.advanceNil() {
 		return
 	}
 	i = decNegintPosintFloatNumberHelper{&d.d}.int64(d.decInteger())
 	d.bdRead = false
 	return
 }
 
 func (d *bincDecDriver) DecodeUint64() (ui uint64) {
 	if d.advanceNil() {
 		return
 	}
 	ui = decNegintPosintFloatNumberHelper{&d.d}.uint64(d.decInteger())
 	d.bdRead = false
 	return
 }
 
 func (d *bincDecDriver) DecodeFloat64() (f float64) {
 	if d.advanceNil() {
 		return
 	}
 	f = decNegintPosintFloatNumberHelper{&d.d}.float64(d.decFloat())
 	d.bdRead = false
 	return
 }
 
 func (d *bincDecDriver) DecodeBool() (b bool) {
 	if d.advanceNil() {
 		return
 	}
 	if d.bd == (bincVdSpecial | bincSpFalse) {
 		// b = false
 	} else if d.bd == (bincVdSpecial | bincSpTrue) {
 		b = true
 	} else {
 		d.d.errorf("bool - %s %x-%x/%s", msgBadDesc, d.vd, d.vs, bincdesc(d.vd, d.vs))
 	}
 	d.bdRead = false
 	return
 }
 
 func (d *bincDecDriver) ReadMapStart() (length int) {
 	if d.advanceNil() {
 		return containerLenNil
 	}
 	if d.vd != bincVdMap {
 		d.d.errorf("map - %s %x-%x/%s", msgBadDesc, d.vd, d.vs, bincdesc(d.vd, d.vs))
 	}
 	length = d.decLen()
 	d.bdRead = false
 	return
 }
 
 func (d *bincDecDriver) ReadArrayStart() (length int) {
 	if d.advanceNil() {
 		return containerLenNil
 	}
 	if d.vd != bincVdArray {
 		d.d.errorf("array - %s %x-%x/%s", msgBadDesc, d.vd, d.vs, bincdesc(d.vd, d.vs))
 	}
 	length = d.decLen()
 	d.bdRead = false
 	return
 }
 
 func (d *bincDecDriver) decLen() int {
 	if d.vs > 3 {
 		return int(d.vs - 4)
 	}
 	return int(d.decLenNumber())
 }
 
 func (d *bincDecDriver) decLenNumber() (v uint64) {
 	if x := d.vs; x == 0 {
 		v = uint64(d.d.decRd.readn1())
 	} else if x == 1 {
 		v = uint64(bigen.Uint16(d.d.decRd.readn2()))
 	} else if x == 2 {
 		v = uint64(bigen.Uint32(d.d.decRd.readn4()))
 	} else {
 		v = bigen.Uint64(d.d.decRd.readn8())
 	}
 	return
 }
 
 // func (d *bincDecDriver) decStringBytes(bs []byte, zerocopy bool) (bs2 []byte) {
 func (d *bincDecDriver) DecodeStringAsBytes() (bs2 []byte) {
 	d.d.decByteState = decByteStateNone
 	if d.advanceNil() {
 		return
 	}
 	var slen = -1
 	switch d.vd {
 	case bincVdString, bincVdByteArray:
 		slen = d.decLen()
 		if d.d.bytes {
 			d.d.decByteState = decByteStateZerocopy
 			bs2 = d.d.decRd.rb.readx(uint(slen))
 		} else {
 			d.d.decByteState = decByteStateReuseBuf
 			bs2 = decByteSlice(d.d.r(), slen, d.d.h.MaxInitLen, d.d.b[:])
 		}
 	case bincVdSymbol:
 		// zerocopy doesn't apply for symbols,
 		// as the values must be stored in a table for later use.
 		var symbol uint16
 		vs := d.vs
 		if vs&0x8 == 0 {
 			symbol = uint16(d.d.decRd.readn1())
 		} else {
 			symbol = uint16(bigen.Uint16(d.d.decRd.readn2()))
 		}
 		if d.s == nil {
 			d.s = make(map[uint16][]byte, 16)
 		}
 
 		if vs&0x4 == 0 {
 			bs2 = d.s[symbol]
 		} else {
 			switch vs & 0x3 {
 			case 0:
 				slen = int(d.d.decRd.readn1())
 			case 1:
 				slen = int(bigen.Uint16(d.d.decRd.readn2()))
 			case 2:
 				slen = int(bigen.Uint32(d.d.decRd.readn4()))
 			case 3:
 				slen = int(bigen.Uint64(d.d.decRd.readn8()))
 			}
 			// As we are using symbols, do not store any part of
 			// the parameter bs in the map, as it might be a shared buffer.
 			bs2 = decByteSlice(d.d.r(), slen, d.d.h.MaxInitLen, nil)
 			d.s[symbol] = bs2
 		}
 	default:
 		d.d.errorf("string/bytes - %s %x-%x/%s", msgBadDesc, d.vd, d.vs, bincdesc(d.vd, d.vs))
 	}
 
 	if d.h.ValidateUnicode && !utf8.Valid(bs2) {
 		d.d.errorf("DecodeStringAsBytes: invalid UTF-8: %s", bs2)
 	}
 
 	d.bdRead = false
 	return
 }
 
 func (d *bincDecDriver) DecodeBytes(bs []byte) (bsOut []byte) {
 	d.d.decByteState = decByteStateNone
 	if d.advanceNil() {
 		return
 	}
 	if d.vd == bincVdArray {
 		if bs == nil {
 			bs = d.d.b[:]
 			d.d.decByteState = decByteStateReuseBuf
 		}
 		slen := d.ReadArrayStart()
 		var changed bool
 		if bs, changed = usableByteSlice(bs, slen); changed {
 			d.d.decByteState = decByteStateNone
 		}
 		for i := 0; i < slen; i++ {
 			bs[i] = uint8(chkOvf.UintV(d.DecodeUint64(), 8))
 		}
 		for i := len(bs); i < slen; i++ {
 			bs = append(bs, uint8(chkOvf.UintV(d.DecodeUint64(), 8)))
 		}
 		return bs
 	}
 	var clen int
 	if d.vd == bincVdString || d.vd == bincVdByteArray {
 		clen = d.decLen()
 	} else {
 		d.d.errorf("bytes - %s %x-%x/%s", msgBadDesc, d.vd, d.vs, bincdesc(d.vd, d.vs))
 	}
 	d.bdRead = false
 	if d.d.zerocopy() {
 		d.d.decByteState = decByteStateZerocopy
 		return d.d.decRd.rb.readx(uint(clen))
 	}
 	if bs == nil {
 		bs = d.d.b[:]
 		d.d.decByteState = decByteStateReuseBuf
 	}
 	return decByteSlice(d.d.r(), clen, d.d.h.MaxInitLen, bs)
 }
 
 func (d *bincDecDriver) DecodeExt(rv interface{}, basetype reflect.Type, xtag uint64, ext Ext) {
 	if xtag > 0xff {
 		d.d.errorf("ext: tag must be <= 0xff; got: %v", xtag)
 	}
 	if d.advanceNil() {
 		return
 	}
 	xbs, realxtag1, zerocopy := d.decodeExtV(ext != nil, uint8(xtag))
 	realxtag := uint64(realxtag1)
 	if ext == nil {
 		re := rv.(*RawExt)
 		re.Tag = realxtag
 		re.setData(xbs, zerocopy)
 	} else if ext == SelfExt {
 		d.d.sideDecode(rv, basetype, xbs)
 	} else {
 		ext.ReadExt(rv, xbs)
 	}
 }
 
 func (d *bincDecDriver) decodeExtV(verifyTag bool, tag byte) (xbs []byte, xtag byte, zerocopy bool) {
 	if d.vd == bincVdCustomExt {
 		l := d.decLen()
 		xtag = d.d.decRd.readn1()
 		if verifyTag && xtag != tag {
 			d.d.errorf("wrong extension tag - got %b, expecting: %v", xtag, tag)
 		}
 		if d.d.bytes {
 			xbs = d.d.decRd.rb.readx(uint(l))
 			zerocopy = true
 		} else {
 			xbs = decByteSlice(d.d.r(), l, d.d.h.MaxInitLen, d.d.b[:])
 		}
 	} else if d.vd == bincVdByteArray {
 		xbs = d.DecodeBytes(nil)
 	} else {
 		d.d.errorf("ext expects extensions or byte array - %s %x-%x/%s", msgBadDesc, d.vd, d.vs, bincdesc(d.vd, d.vs))
 	}
 	d.bdRead = false
 	return
 }
 
 func (d *bincDecDriver) DecodeNaked() {
 	if !d.bdRead {
 		d.readNextBd()
 	}
 
 	n := d.d.naked()
 	var decodeFurther bool
 
 	switch d.vd {
 	case bincVdSpecial:
 		switch d.vs {
 		case bincSpNil:
 			n.v = valueTypeNil
 		case bincSpFalse:
 			n.v = valueTypeBool
 			n.b = false
 		case bincSpTrue:
 			n.v = valueTypeBool
 			n.b = true
 		case bincSpNan:
 			n.v = valueTypeFloat
 			n.f = math.NaN()
 		case bincSpPosInf:
 			n.v = valueTypeFloat
 			n.f = math.Inf(1)
 		case bincSpNegInf:
 			n.v = valueTypeFloat
 			n.f = math.Inf(-1)
 		case bincSpZeroFloat:
 			n.v = valueTypeFloat
 			n.f = float64(0)
 		case bincSpZero:
 			n.v = valueTypeUint
 			n.u = uint64(0) // int8(0)
 		case bincSpNegOne:
 			n.v = valueTypeInt
 			n.i = int64(-1) // int8(-1)
 		default:
 			d.d.errorf("cannot infer value - unrecognized special value %x-%x/%s", d.vd, d.vs, bincdesc(d.vd, d.vs))
 		}
 	case bincVdSmallInt:
 		n.v = valueTypeUint
 		n.u = uint64(int8(d.vs)) + 1 // int8(d.vs) + 1
 	case bincVdPosInt:
 		n.v = valueTypeUint
 		n.u = d.decUint()
 	case bincVdNegInt:
 		n.v = valueTypeInt
 		n.i = -(int64(d.decUint()))
 	case bincVdFloat:
 		n.v = valueTypeFloat
 		n.f = d.decFloatVal()
 	case bincVdString:
 		n.v = valueTypeString
 		n.s = d.d.stringZC(d.DecodeStringAsBytes())
 	case bincVdByteArray:
 		d.d.fauxUnionReadRawBytes(false)
 	case bincVdSymbol:
 		n.v = valueTypeSymbol
 		n.s = d.d.stringZC(d.DecodeStringAsBytes())
 	case bincVdTimestamp:
 		n.v = valueTypeTime
 		tt, err := bincDecodeTime(d.d.decRd.readx(uint(d.vs)))
 		halt.onerror(err)
 		n.t = tt
 	case bincVdCustomExt:
 		n.v = valueTypeExt
 		l := d.decLen()
 		n.u = uint64(d.d.decRd.readn1())
 		if d.d.bytes {
 			n.l = d.d.decRd.rb.readx(uint(l))
 		} else {
 			n.l = decByteSlice(d.d.r(), l, d.d.h.MaxInitLen, d.d.b[:])
 		}
 	case bincVdArray:
 		n.v = valueTypeArray
 		decodeFurther = true
 	case bincVdMap:
 		n.v = valueTypeMap
 		decodeFurther = true
 	default:
 		d.d.errorf("cannot infer value - %s %x-%x/%s", msgBadDesc, d.vd, d.vs, bincdesc(d.vd, d.vs))
 	}
 
 	if !decodeFurther {
 		d.bdRead = false
 	}
 	if n.v == valueTypeUint && d.h.SignedInteger {
 		n.v = valueTypeInt
 		n.i = int64(n.u)
 	}
 }
 
 func (d *bincDecDriver) nextValueBytes(v0 []byte) (v []byte) {
 	if !d.bdRead {
 		d.readNextBd()
 	}
 	v = v0
 	var h = decNextValueBytesHelper{d: &d.d}
 	var cursor = d.d.rb.c - 1
 	h.append1(&v, d.bd)
 	v = d.nextValueBytesBdReadR(v)
 	d.bdRead = false
 	h.bytesRdV(&v, cursor)
 	return
 }
 
 func (d *bincDecDriver) nextValueBytesR(v0 []byte) (v []byte) {
 	d.readNextBd()
 	v = v0
 	var h = decNextValueBytesHelper{d: &d.d}
 	h.append1(&v, d.bd)
 	return d.nextValueBytesBdReadR(v)
 }
 
 func (d *bincDecDriver) nextValueBytesBdReadR(v0 []byte) (v []byte) {
 	v = v0
 	var h = decNextValueBytesHelper{d: &d.d}
 
 	fnLen := func(vs byte) uint {
 		switch vs {
 		case 0:
 			x := d.d.decRd.readn1()
 			h.append1(&v, x)
 			return uint(x)
 		case 1:
 			x := d.d.decRd.readn2()
 			h.appendN(&v, x[:]...)
 			return uint(bigen.Uint16(x))
 		case 2:
 			x := d.d.decRd.readn4()
 			h.appendN(&v, x[:]...)
 			return uint(bigen.Uint32(x))
 		case 3:
 			x := d.d.decRd.readn8()
 			h.appendN(&v, x[:]...)
 			return uint(bigen.Uint64(x))
 		default:
 			return uint(vs - 4)
 		}
 	}
 
 	var clen uint
 
 	switch d.vd {
 	case bincVdSpecial:
 		switch d.vs {
 		case bincSpNil, bincSpFalse, bincSpTrue, bincSpNan, bincSpPosInf: // pass
 		case bincSpNegInf, bincSpZeroFloat, bincSpZero, bincSpNegOne: // pass
 		default:
 			d.d.errorf("cannot infer value - unrecognized special value %x-%x/%s", d.vd, d.vs, bincdesc(d.vd, d.vs))
 		}
 	case bincVdSmallInt: // pass
 	case bincVdPosInt, bincVdNegInt:
 		bs := d.uintBytes()
 		h.appendN(&v, bs...)
 	case bincVdFloat:
 		fn := func(xlen byte) {
 			if d.vs&0x8 != 0 {
 				xlen = d.d.decRd.readn1()
 				h.append1(&v, xlen)
 				if xlen > 8 {
 					d.d.errorf("cannot read float - at most 8 bytes used to represent float - received %v bytes", xlen)
 				}
 			}
 			d.d.decRd.readb(d.d.b[:xlen])
 			h.appendN(&v, d.d.b[:xlen]...)
 		}
 		switch d.vs & 0x7 {
 		case bincFlBin32:
 			fn(4)
 		case bincFlBin64:
 			fn(8)
 		default:
 			d.d.errorf("read float supports only float32/64 - %s %x-%x/%s", msgBadDesc, d.vd, d.vs, bincdesc(d.vd, d.vs))
 		}
 	case bincVdString, bincVdByteArray:
 		clen = fnLen(d.vs)
 		h.appendN(&v, d.d.decRd.readx(clen)...)
 	case bincVdSymbol:
 		if d.vs&0x8 == 0 {
 			h.append1(&v, d.d.decRd.readn1())
 		} else {
 			h.appendN(&v, d.d.decRd.rb.readx(2)...)
 		}
 		if d.vs&0x4 != 0 {
 			clen = fnLen(d.vs & 0x3)
 			h.appendN(&v, d.d.decRd.readx(clen)...)
 		}
 	case bincVdTimestamp:
 		h.appendN(&v, d.d.decRd.readx(uint(d.vs))...)
 	case bincVdCustomExt:
 		clen = fnLen(d.vs)
 		h.append1(&v, d.d.decRd.readn1()) // tag
 		h.appendN(&v, d.d.decRd.readx(clen)...)
 	case bincVdArray:
 		clen = fnLen(d.vs)
 		for i := uint(0); i < clen; i++ {
 			v = d.nextValueBytesR(v)
 		}
 	case bincVdMap:
 		clen = fnLen(d.vs)
 		for i := uint(0); i < clen; i++ {
 			v = d.nextValueBytesR(v)
 			v = d.nextValueBytesR(v)
 		}
 	default:
 		d.d.errorf("cannot infer value - %s %x-%x/%s", msgBadDesc, d.vd, d.vs, bincdesc(d.vd, d.vs))
 	}
 	return
 }
 
 //------------------------------------
 
 // BincHandle is a Handle for the Binc Schema-Free Encoding Format
 // defined at https://github.com/ugorji/binc .
 //
 // BincHandle currently supports all Binc features with the following EXCEPTIONS:
 //   - only integers up to 64 bits of precision are supported.
 //     big integers are unsupported.
 //   - Only IEEE 754 binary32 and binary64 floats are supported (ie Go float32 and float64 types).
 //     extended precision and decimal IEEE 754 floats are unsupported.
 //   - Only UTF-8 strings supported.
 //     Unicode_Other Binc types (UTF16, UTF32) are currently unsupported.
 //
 // Note that these EXCEPTIONS are temporary and full support is possible and may happen soon.
 type BincHandle struct {
 	BasicHandle
 	binaryEncodingType
 	// noElemSeparators
 
 	// AsSymbols defines what should be encoded as symbols.
 	//
 	// Encoding as symbols can reduce the encoded size significantly.
 	//
 	// However, during decoding, each string to be encoded as a symbol must
 	// be checked to see if it has been seen before. Consequently, encoding time
 	// will increase if using symbols, because string comparisons has a clear cost.
 	//
 	// Values:
 	// - 0: default: library uses best judgement
 	// - 1: use symbols
 	// - 2: do not use symbols
 	AsSymbols uint8
 
 	// AsSymbols: may later on introduce more options ...
 	// - m: map keys
 	// - s: struct fields
 	// - n: none
 	// - a: all: same as m, s, ...
 
 	// _ [7]uint64 // padding (cache-aligned)
 }
 
 // Name returns the name of the handle: binc
 func (h *BincHandle) Name() string { return "binc" }
 
 func (h *BincHandle) desc(bd byte) string { return bincdesc(bd>>4, bd&0x0f) }
 
 func (h *BincHandle) newEncDriver() encDriver {
 	var e = &bincEncDriver{h: h}
 	e.e.e = e
 	e.e.init(h)
 	e.reset()
 	return e
 }
 
 func (h *BincHandle) newDecDriver() decDriver {
 	d := &bincDecDriver{h: h}
 	d.d.d = d
 	d.d.init(h)
 	d.reset()
 	return d
 }
 
 // var timeDigits = [...]byte{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9'}
 
 // EncodeTime encodes a time.Time as a []byte, including
 // information on the instant in time and UTC offset.
 //
 // Format Description
 //
 //	A timestamp is composed of 3 components:
 //
 //	- secs: signed integer representing seconds since unix epoch
 //	- nsces: unsigned integer representing fractional seconds as a
 //	  nanosecond offset within secs, in the range 0 <= nsecs < 1e9
 //	- tz: signed integer representing timezone offset in minutes east of UTC,
 //	  and a dst (daylight savings time) flag
 //
 //	When encoding a timestamp, the first byte is the descriptor, which
 //	defines which components are encoded and how many bytes are used to
 //	encode secs and nsecs components. *If secs/nsecs is 0 or tz is UTC, it
 //	is not encoded in the byte array explicitly*.
 //
 //	    Descriptor 8 bits are of the form `A B C DDD EE`:
 //	        A:   Is secs component encoded? 1 = true
 //	        B:   Is nsecs component encoded? 1 = true
 //	        C:   Is tz component encoded? 1 = true
 //	        DDD: Number of extra bytes for secs (range 0-7).
 //	             If A = 1, secs encoded in DDD+1 bytes.
 //	                 If A = 0, secs is not encoded, and is assumed to be 0.
 //	                 If A = 1, then we need at least 1 byte to encode secs.
 //	                 DDD says the number of extra bytes beyond that 1.
 //	                 E.g. if DDD=0, then secs is represented in 1 byte.
 //	                      if DDD=2, then secs is represented in 3 bytes.
 //	        EE:  Number of extra bytes for nsecs (range 0-3).
 //	             If B = 1, nsecs encoded in EE+1 bytes (similar to secs/DDD above)
 //
 //	Following the descriptor bytes, subsequent bytes are:
 //
 //	    secs component encoded in `DDD + 1` bytes (if A == 1)
 //	    nsecs component encoded in `EE + 1` bytes (if B == 1)
 //	    tz component encoded in 2 bytes (if C == 1)
 //
 //	secs and nsecs components are integers encoded in a BigEndian
 //	2-complement encoding format.
 //
 //	tz component is encoded as 2 bytes (16 bits). Most significant bit 15 to
 //	Least significant bit 0 are described below:
 //
 //	    Timezone offset has a range of -12:00 to +14:00 (ie -720 to +840 minutes).
 //	    Bit 15 = have\_dst: set to 1 if we set the dst flag.
 //	    Bit 14 = dst\_on: set to 1 if dst is in effect at the time, or 0 if not.
 //	    Bits 13..0 = timezone offset in minutes. It is a signed integer in Big Endian format.
 func bincEncodeTime(t time.Time) []byte {
 	// t := rv2i(rv).(time.Time)
 	tsecs, tnsecs := t.Unix(), t.Nanosecond()
 	var (
 		bd byte
 		bs [16]byte
 		i  int = 1
 	)
 	l := t.Location()
 	if l == time.UTC {
 		l = nil
 	}
 	if tsecs != 0 {
 		bd = bd | 0x80
 		btmp := bigen.PutUint64(uint64(tsecs))
 		f := pruneSignExt(btmp[:], tsecs >= 0)
 		bd = bd | (byte(7-f) << 2)
 		copy(bs[i:], btmp[f:])
 		i = i + (8 - f)
 	}
 	if tnsecs != 0 {
 		bd = bd | 0x40
 		btmp := bigen.PutUint32(uint32(tnsecs))
 		f := pruneSignExt(btmp[:4], true)
 		bd = bd | byte(3-f)
 		copy(bs[i:], btmp[f:4])
 		i = i + (4 - f)
 	}
 	if l != nil {
 		bd = bd | 0x20
 		// Note that Go Libs do not give access to dst flag.
 		_, zoneOffset := t.Zone()
 		// zoneName, zoneOffset := t.Zone()
 		zoneOffset /= 60
 		z := uint16(zoneOffset)
 		btmp := bigen.PutUint16(z)
 		// clear dst flags
 		bs[i] = btmp[0] & 0x3f
 		bs[i+1] = btmp[1]
 		i = i + 2
 	}
 	bs[0] = bd
 	return bs[0:i]
 }
 
 // bincDecodeTime decodes a []byte into a time.Time.
 func bincDecodeTime(bs []byte) (tt time.Time, err error) {
 	bd := bs[0]
 	var (
 		tsec  int64
 		tnsec uint32
 		tz    uint16
 		i     byte = 1
 		i2    byte
 		n     byte
 	)
 	if bd&(1<<7) != 0 {
 		var btmp [8]byte
 		n = ((bd >> 2) & 0x7) + 1
 		i2 = i + n
 		copy(btmp[8-n:], bs[i:i2])
 		// if first bit of bs[i] is set, then fill btmp[0..8-n] with 0xff (ie sign extend it)
 		if bs[i]&(1<<7) != 0 {
 			copy(btmp[0:8-n], bsAll0xff)
 		}
 		i = i2
 		tsec = int64(bigen.Uint64(btmp))
 	}
 	if bd&(1<<6) != 0 {
 		var btmp [4]byte
 		n = (bd & 0x3) + 1
 		i2 = i + n
 		copy(btmp[4-n:], bs[i:i2])
 		i = i2
 		tnsec = bigen.Uint32(btmp)
 	}
 	if bd&(1<<5) == 0 {
 		tt = time.Unix(tsec, int64(tnsec)).UTC()
 		return
 	}
 	// In stdlib time.Parse, when a date is parsed without a zone name, it uses "" as zone name.
 	// However, we need name here, so it can be shown when time is printf.d.
 	// Zone name is in form: UTC-08:00.
 	// Note that Go Libs do not give access to dst flag, so we ignore dst bits
 
 	tz = bigen.Uint16([2]byte{bs[i], bs[i+1]})
 	// sign extend sign bit into top 2 MSB (which were dst bits):
 	if tz&(1<<13) == 0 { // positive
 		tz = tz & 0x3fff //clear 2 MSBs: dst bits
 	} else { // negative
 		tz = tz | 0xc000 //set 2 MSBs: dst bits
 	}
 	tzint := int16(tz)
 	if tzint == 0 {
 		tt = time.Unix(tsec, int64(tnsec)).UTC()
 	} else {
 		// For Go Time, do not use a descriptive timezone.
 		// It's unnecessary, and makes it harder to do a reflect.DeepEqual.
 		// The Offset already tells what the offset should be, if not on UTC and unknown zone name.
 		// var zoneName = timeLocUTCName(tzint)
 		tt = time.Unix(tsec, int64(tnsec)).In(time.FixedZone("", int(tzint)*60))
 	}
 	return
 }
 
 var _ decDriver = (*bincDecDriver)(nil)
 var _ encDriver = (*bincEncDriver)(nil)