Grand test fixup (#138)

* start fixing up tests

* fix up tests + automate with drone

* fiddle with linting

* messing about with drone.yml

* some more fiddling

* hmmm

* add cache

* add vendor directory

* verbose

* ci updates

* update some little things

* update sig

1 files changed, 1479 insertions, 0 deletions

diff --git a/vendor/github.com/ugorji/go/codec/encode.go b/vendor/github.com/ugorji/go/codec/encode.go
new file mode 100644
index 000000000..e411bdb81
--- /dev/null
+++ b/vendor/github.com/ugorji/go/codec/encode.go
@@ -0,0 +1,1479 @@
+// 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 (
+	"encoding"
+	"errors"
+	"io"
+	"reflect"
+	"sort"
+	"strconv"
+	"time"
+)
+
+// defEncByteBufSize is the default size of []byte used
+// for bufio buffer or []byte (when nil passed)
+const defEncByteBufSize = 1 << 10 // 4:16, 6:64, 8:256, 10:1024
+
+var errEncoderNotInitialized = errors.New("Encoder not initialized")
+
+// encDriver abstracts the actual codec (binc vs msgpack, etc)
+type encDriver interface {
+	EncodeNil()
+	EncodeInt(i int64)
+	EncodeUint(i uint64)
+	EncodeBool(b bool)
+	EncodeFloat32(f float32)
+	EncodeFloat64(f float64)
+	EncodeRawExt(re *RawExt)
+	EncodeExt(v interface{}, basetype reflect.Type, xtag uint64, ext Ext)
+	// EncodeString using cUTF8, honor'ing StringToRaw flag
+	EncodeString(v string)
+	EncodeStringBytesRaw(v []byte)
+	EncodeTime(time.Time)
+	WriteArrayStart(length int)
+	WriteArrayEnd()
+	WriteMapStart(length int)
+	WriteMapEnd()
+
+	// reset will reset current encoding runtime state, and cached information from the handle
+	reset()
+
+	encoder() *Encoder
+
+	driverStateManager
+}
+
+type encDriverContainerTracker interface {
+	WriteArrayElem()
+	WriteMapElemKey()
+	WriteMapElemValue()
+}
+
+type encDriverNoState struct{}
+
+func (encDriverNoState) captureState() interface{}  { return nil }
+func (encDriverNoState) reset()                     {}
+func (encDriverNoState) resetState()                {}
+func (encDriverNoState) restoreState(v interface{}) {}
+
+type encDriverNoopContainerWriter struct{}
+
+func (encDriverNoopContainerWriter) WriteArrayStart(length int) {}
+func (encDriverNoopContainerWriter) WriteArrayEnd()             {}
+func (encDriverNoopContainerWriter) WriteMapStart(length int)   {}
+func (encDriverNoopContainerWriter) WriteMapEnd()               {}
+
+// encStructFieldObj[Slice] is used for sorting when there are missing fields and canonical flag is set
+type encStructFieldObj struct {
+	key   string
+	rv    reflect.Value
+	intf  interface{}
+	ascii bool
+	isRv  bool
+}
+
+type encStructFieldObjSlice []encStructFieldObj
+
+func (p encStructFieldObjSlice) Len() int      { return len(p) }
+func (p encStructFieldObjSlice) Swap(i, j int) { p[uint(i)], p[uint(j)] = p[uint(j)], p[uint(i)] }
+func (p encStructFieldObjSlice) Less(i, j int) bool {
+	return p[uint(i)].key < p[uint(j)].key
+}
+
+// EncodeOptions captures configuration options during encode.
+type EncodeOptions struct {
+	// WriterBufferSize is the size of the buffer used when writing.
+	//
+	// if > 0, we use a smart buffer internally for performance purposes.
+	WriterBufferSize int
+
+	// ChanRecvTimeout is the timeout used when selecting from a chan.
+	//
+	// Configuring this controls how we receive from a chan during the encoding process.
+	//   - If ==0, we only consume the elements currently available in the chan.
+	//   - if  <0, we consume until the chan is closed.
+	//   - If  >0, we consume until this timeout.
+	ChanRecvTimeout time.Duration
+
+	// StructToArray specifies to encode a struct as an array, and not as a map
+	StructToArray bool
+
+	// Canonical representation means that encoding a value will always result in the same
+	// sequence of bytes.
+	//
+	// This only affects maps, as the iteration order for maps is random.
+	//
+	// The implementation MAY use the natural sort order for the map keys if possible:
+	//
+	//     - If there is a natural sort order (ie for number, bool, string or []byte keys),
+	//       then the map keys are first sorted in natural order and then written
+	//       with corresponding map values to the strema.
+	//     - If there is no natural sort order, then the map keys will first be
+	//       encoded into []byte, and then sorted,
+	//       before writing the sorted keys and the corresponding map values to the stream.
+	//
+	Canonical bool
+
+	// CheckCircularRef controls whether we check for circular references
+	// and error fast during an encode.
+	//
+	// If enabled, an error is received if a pointer to a struct
+	// references itself either directly or through one of its fields (iteratively).
+	//
+	// This is opt-in, as there may be a performance hit to checking circular references.
+	CheckCircularRef bool
+
+	// RecursiveEmptyCheck controls how we determine whether a value is empty.
+	//
+	// If true, we descend into interfaces and pointers to reursively check if value is empty.
+	//
+	// We *might* check struct fields one by one to see if empty
+	// (if we cannot directly check if a struct value is equal to its zero value).
+	// If so, we honor IsZero, Comparable, IsCodecEmpty(), etc.
+	// Note: This *may* make OmitEmpty more expensive due to the large number of reflect calls.
+	//
+	// If false, we check if the value is equal to its zero value (newly allocated state).
+	RecursiveEmptyCheck bool
+
+	// Raw controls whether we encode Raw values.
+	// This is a "dangerous" option and must be explicitly set.
+	// If set, we blindly encode Raw values as-is, without checking
+	// if they are a correct representation of a value in that format.
+	// If unset, we error out.
+	Raw bool
+
+	// StringToRaw controls how strings are encoded.
+	//
+	// As a go string is just an (immutable) sequence of bytes,
+	// it can be encoded either as raw bytes or as a UTF string.
+	//
+	// By default, strings are encoded as UTF-8.
+	// but can be treated as []byte during an encode.
+	//
+	// Note that things which we know (by definition) to be UTF-8
+	// are ALWAYS encoded as UTF-8 strings.
+	// These include encoding.TextMarshaler, time.Format calls, struct field names, etc.
+	StringToRaw bool
+
+	// OptimumSize controls whether we optimize for the smallest size.
+	//
+	// Some formats will use this flag to determine whether to encode
+	// in the smallest size possible, even if it takes slightly longer.
+	//
+	// For example, some formats that support half-floats might check if it is possible
+	// to store a float64 as a half float. Doing this check has a small performance cost,
+	// but the benefit is that the encoded message will be smaller.
+	OptimumSize bool
+
+	// NoAddressableReadonly controls whether we try to force a non-addressable value
+	// to be addressable so we can call a pointer method on it e.g. for types
+	// that support Selfer, json.Marshaler, etc.
+	//
+	// Use it in the very rare occurrence that your types modify a pointer value when calling
+	// an encode callback function e.g. JsonMarshal, TextMarshal, BinaryMarshal or CodecEncodeSelf.
+	NoAddressableReadonly bool
+}
+
+// ---------------------------------------------
+
+func (e *Encoder) rawExt(f *codecFnInfo, rv reflect.Value) {
+	e.e.EncodeRawExt(rv2i(rv).(*RawExt))
+}
+
+func (e *Encoder) ext(f *codecFnInfo, rv reflect.Value) {
+	e.e.EncodeExt(rv2i(rv), f.ti.rt, f.xfTag, f.xfFn)
+}
+
+func (e *Encoder) selferMarshal(f *codecFnInfo, rv reflect.Value) {
+	rv2i(rv).(Selfer).CodecEncodeSelf(e)
+}
+
+func (e *Encoder) binaryMarshal(f *codecFnInfo, rv reflect.Value) {
+	bs, fnerr := rv2i(rv).(encoding.BinaryMarshaler).MarshalBinary()
+	e.marshalRaw(bs, fnerr)
+}
+
+func (e *Encoder) textMarshal(f *codecFnInfo, rv reflect.Value) {
+	bs, fnerr := rv2i(rv).(encoding.TextMarshaler).MarshalText()
+	e.marshalUtf8(bs, fnerr)
+}
+
+func (e *Encoder) jsonMarshal(f *codecFnInfo, rv reflect.Value) {
+	bs, fnerr := rv2i(rv).(jsonMarshaler).MarshalJSON()
+	e.marshalAsis(bs, fnerr)
+}
+
+func (e *Encoder) raw(f *codecFnInfo, rv reflect.Value) {
+	e.rawBytes(rv2i(rv).(Raw))
+}
+
+func (e *Encoder) encodeComplex64(v complex64) {
+	if imag(v) != 0 {
+		e.errorf("cannot encode complex number: %v, with imaginary values: %v", v, imag(v))
+	}
+	e.e.EncodeFloat32(real(v))
+}
+
+func (e *Encoder) encodeComplex128(v complex128) {
+	if imag(v) != 0 {
+		e.errorf("cannot encode complex number: %v, with imaginary values: %v", v, imag(v))
+	}
+	e.e.EncodeFloat64(real(v))
+}
+
+func (e *Encoder) kBool(f *codecFnInfo, rv reflect.Value) {
+	e.e.EncodeBool(rvGetBool(rv))
+}
+
+func (e *Encoder) kTime(f *codecFnInfo, rv reflect.Value) {
+	e.e.EncodeTime(rvGetTime(rv))
+}
+
+func (e *Encoder) kString(f *codecFnInfo, rv reflect.Value) {
+	e.e.EncodeString(rvGetString(rv))
+}
+
+func (e *Encoder) kFloat32(f *codecFnInfo, rv reflect.Value) {
+	e.e.EncodeFloat32(rvGetFloat32(rv))
+}
+
+func (e *Encoder) kFloat64(f *codecFnInfo, rv reflect.Value) {
+	e.e.EncodeFloat64(rvGetFloat64(rv))
+}
+
+func (e *Encoder) kComplex64(f *codecFnInfo, rv reflect.Value) {
+	e.encodeComplex64(rvGetComplex64(rv))
+}
+
+func (e *Encoder) kComplex128(f *codecFnInfo, rv reflect.Value) {
+	e.encodeComplex128(rvGetComplex128(rv))
+}
+
+func (e *Encoder) kInt(f *codecFnInfo, rv reflect.Value) {
+	e.e.EncodeInt(int64(rvGetInt(rv)))
+}
+
+func (e *Encoder) kInt8(f *codecFnInfo, rv reflect.Value) {
+	e.e.EncodeInt(int64(rvGetInt8(rv)))
+}
+
+func (e *Encoder) kInt16(f *codecFnInfo, rv reflect.Value) {
+	e.e.EncodeInt(int64(rvGetInt16(rv)))
+}
+
+func (e *Encoder) kInt32(f *codecFnInfo, rv reflect.Value) {
+	e.e.EncodeInt(int64(rvGetInt32(rv)))
+}
+
+func (e *Encoder) kInt64(f *codecFnInfo, rv reflect.Value) {
+	e.e.EncodeInt(int64(rvGetInt64(rv)))
+}
+
+func (e *Encoder) kUint(f *codecFnInfo, rv reflect.Value) {
+	e.e.EncodeUint(uint64(rvGetUint(rv)))
+}
+
+func (e *Encoder) kUint8(f *codecFnInfo, rv reflect.Value) {
+	e.e.EncodeUint(uint64(rvGetUint8(rv)))
+}
+
+func (e *Encoder) kUint16(f *codecFnInfo, rv reflect.Value) {
+	e.e.EncodeUint(uint64(rvGetUint16(rv)))
+}
+
+func (e *Encoder) kUint32(f *codecFnInfo, rv reflect.Value) {
+	e.e.EncodeUint(uint64(rvGetUint32(rv)))
+}
+
+func (e *Encoder) kUint64(f *codecFnInfo, rv reflect.Value) {
+	e.e.EncodeUint(uint64(rvGetUint64(rv)))
+}
+
+func (e *Encoder) kUintptr(f *codecFnInfo, rv reflect.Value) {
+	e.e.EncodeUint(uint64(rvGetUintptr(rv)))
+}
+
+func (e *Encoder) kErr(f *codecFnInfo, rv reflect.Value) {
+	e.errorf("unsupported kind %s, for %#v", rv.Kind(), rv)
+}
+
+func chanToSlice(rv reflect.Value, rtslice reflect.Type, timeout time.Duration) (rvcs reflect.Value) {
+	rvcs = rvZeroK(rtslice, reflect.Slice)
+	if timeout < 0 { // consume until close
+		for {
+			recv, recvOk := rv.Recv()
+			if !recvOk {
+				break
+			}
+			rvcs = reflect.Append(rvcs, recv)
+		}
+	} else {
+		cases := make([]reflect.SelectCase, 2)
+		cases[0] = reflect.SelectCase{Dir: reflect.SelectRecv, Chan: rv}
+		if timeout == 0 {
+			cases[1] = reflect.SelectCase{Dir: reflect.SelectDefault}
+		} else {
+			tt := time.NewTimer(timeout)
+			cases[1] = reflect.SelectCase{Dir: reflect.SelectRecv, Chan: reflect.ValueOf(tt.C)}
+		}
+		for {
+			chosen, recv, recvOk := reflect.Select(cases)
+			if chosen == 1 || !recvOk {
+				break
+			}
+			rvcs = reflect.Append(rvcs, recv)
+		}
+	}
+	return
+}
+
+func (e *Encoder) kSeqFn(rtelem reflect.Type) (fn *codecFn) {
+	for rtelem.Kind() == reflect.Ptr {
+		rtelem = rtelem.Elem()
+	}
+	// if kind is reflect.Interface, do not pre-determine the encoding type,
+	// because preEncodeValue may break it down to a concrete type and kInterface will bomb.
+	if rtelem.Kind() != reflect.Interface {
+		fn = e.h.fn(rtelem)
+	}
+	return
+}
+
+func (e *Encoder) kSliceWMbs(rv reflect.Value, ti *typeInfo) {
+	var l = rvLenSlice(rv)
+	if l == 0 {
+		e.mapStart(0)
+	} else {
+		e.haltOnMbsOddLen(l)
+		e.mapStart(l >> 1) // e.mapStart(l / 2)
+		fn := e.kSeqFn(ti.elem)
+		for j := 0; j < l; j++ {
+			if j&1 == 0 { // j%2 == 0 {
+				e.mapElemKey()
+			} else {
+				e.mapElemValue()
+			}
+			e.encodeValue(rvSliceIndex(rv, j, ti), fn)
+		}
+	}
+	e.mapEnd()
+}
+
+func (e *Encoder) kSliceW(rv reflect.Value, ti *typeInfo) {
+	var l = rvLenSlice(rv)
+	e.arrayStart(l)
+	if l > 0 {
+		fn := e.kSeqFn(ti.elem)
+		for j := 0; j < l; j++ {
+			e.arrayElem()
+			e.encodeValue(rvSliceIndex(rv, j, ti), fn)
+		}
+	}
+	e.arrayEnd()
+}
+
+func (e *Encoder) kArrayWMbs(rv reflect.Value, ti *typeInfo) {
+	var l = rv.Len()
+	if l == 0 {
+		e.mapStart(0)
+	} else {
+		e.haltOnMbsOddLen(l)
+		e.mapStart(l >> 1) // e.mapStart(l / 2)
+		fn := e.kSeqFn(ti.elem)
+		for j := 0; j < l; j++ {
+			if j&1 == 0 { // j%2 == 0 {
+				e.mapElemKey()
+			} else {
+				e.mapElemValue()
+			}
+			e.encodeValue(rv.Index(j), fn)
+		}
+	}
+	e.mapEnd()
+}
+
+func (e *Encoder) kArrayW(rv reflect.Value, ti *typeInfo) {
+	var l = rv.Len()
+	e.arrayStart(l)
+	if l > 0 {
+		fn := e.kSeqFn(ti.elem)
+		for j := 0; j < l; j++ {
+			e.arrayElem()
+			e.encodeValue(rv.Index(j), fn)
+		}
+	}
+	e.arrayEnd()
+}
+
+func (e *Encoder) kChan(f *codecFnInfo, rv reflect.Value) {
+	if f.ti.chandir&uint8(reflect.RecvDir) == 0 {
+		e.errorf("send-only channel cannot be encoded")
+	}
+	if !f.ti.mbs && uint8TypId == rt2id(f.ti.elem) {
+		e.kSliceBytesChan(rv)
+		return
+	}
+	rtslice := reflect.SliceOf(f.ti.elem)
+	rv = chanToSlice(rv, rtslice, e.h.ChanRecvTimeout)
+	ti := e.h.getTypeInfo(rt2id(rtslice), rtslice)
+	if f.ti.mbs {
+		e.kSliceWMbs(rv, ti)
+	} else {
+		e.kSliceW(rv, ti)
+	}
+}
+
+func (e *Encoder) kSlice(f *codecFnInfo, rv reflect.Value) {
+	if f.ti.mbs {
+		e.kSliceWMbs(rv, f.ti)
+	} else if f.ti.rtid == uint8SliceTypId || uint8TypId == rt2id(f.ti.elem) {
+		e.e.EncodeStringBytesRaw(rvGetBytes(rv))
+	} else {
+		e.kSliceW(rv, f.ti)
+	}
+}
+
+func (e *Encoder) kArray(f *codecFnInfo, rv reflect.Value) {
+	if f.ti.mbs {
+		e.kArrayWMbs(rv, f.ti)
+	} else if handleBytesWithinKArray && uint8TypId == rt2id(f.ti.elem) {
+		e.e.EncodeStringBytesRaw(rvGetArrayBytes(rv, []byte{}))
+	} else {
+		e.kArrayW(rv, f.ti)
+	}
+}
+
+func (e *Encoder) kSliceBytesChan(rv reflect.Value) {
+	// do not use range, so that the number of elements encoded
+	// does not change, and encoding does not hang waiting on someone to close chan.
+
+	bs0 := e.blist.peek(32, true)
+	bs := bs0
+
+	irv := rv2i(rv)
+	ch, ok := irv.(<-chan byte)
+	if !ok {
+		ch = irv.(chan byte)
+	}
+
+L1:
+	switch timeout := e.h.ChanRecvTimeout; {
+	case timeout == 0: // only consume available
+		for {
+			select {
+			case b := <-ch:
+				bs = append(bs, b)
+			default:
+				break L1
+			}
+		}
+	case timeout > 0: // consume until timeout
+		tt := time.NewTimer(timeout)
+		for {
+			select {
+			case b := <-ch:
+				bs = append(bs, b)
+			case <-tt.C:
+				// close(tt.C)
+				break L1
+			}
+		}
+	default: // consume until close
+		for b := range ch {
+			bs = append(bs, b)
+		}
+	}
+
+	e.e.EncodeStringBytesRaw(bs)
+	e.blist.put(bs)
+	if !byteSliceSameData(bs0, bs) {
+		e.blist.put(bs0)
+	}
+}
+
+func (e *Encoder) kStructSfi(f *codecFnInfo) []*structFieldInfo {
+	if e.h.Canonical {
+		return f.ti.sfi.sorted()
+	}
+	return f.ti.sfi.source()
+}
+
+func (e *Encoder) kStructNoOmitempty(f *codecFnInfo, rv reflect.Value) {
+	var tisfi []*structFieldInfo
+	if f.ti.toArray || e.h.StructToArray { // toArray
+		tisfi = f.ti.sfi.source()
+		e.arrayStart(len(tisfi))
+		for _, si := range tisfi {
+			e.arrayElem()
+			e.encodeValue(si.path.field(rv), nil)
+		}
+		e.arrayEnd()
+	} else {
+		tisfi = e.kStructSfi(f)
+		e.mapStart(len(tisfi))
+		keytyp := f.ti.keyType
+		for _, si := range tisfi {
+			e.mapElemKey()
+			e.kStructFieldKey(keytyp, si.path.encNameAsciiAlphaNum, si.encName)
+			e.mapElemValue()
+			e.encodeValue(si.path.field(rv), nil)
+		}
+		e.mapEnd()
+	}
+}
+
+func (e *Encoder) kStructFieldKey(keyType valueType, encNameAsciiAlphaNum bool, encName string) {
+	encStructFieldKey(encName, e.e, e.w(), keyType, encNameAsciiAlphaNum, e.js)
+}
+
+func (e *Encoder) kStruct(f *codecFnInfo, rv reflect.Value) {
+	var newlen int
+	ti := f.ti
+	toMap := !(ti.toArray || e.h.StructToArray)
+	var mf map[string]interface{}
+	if ti.flagMissingFielder {
+		mf = rv2i(rv).(MissingFielder).CodecMissingFields()
+		toMap = true
+		newlen += len(mf)
+	} else if ti.flagMissingFielderPtr {
+		rv2 := e.addrRV(rv, ti.rt, ti.ptr)
+		mf = rv2i(rv2).(MissingFielder).CodecMissingFields()
+		toMap = true
+		newlen += len(mf)
+	}
+	tisfi := ti.sfi.source()
+	newlen += len(tisfi)
+
+	var fkvs = e.slist.get(newlen)[:newlen]
+
+	recur := e.h.RecursiveEmptyCheck
+
+	var kv sfiRv
+	var j int
+	if toMap {
+		newlen = 0
+		for _, si := range e.kStructSfi(f) {
+			kv.r = si.path.field(rv)
+			if si.path.omitEmpty && isEmptyValue(kv.r, e.h.TypeInfos, recur) {
+				continue
+			}
+			kv.v = si
+			fkvs[newlen] = kv
+			newlen++
+		}
+
+		var mf2s []stringIntf
+		if len(mf) > 0 {
+			mf2s = make([]stringIntf, 0, len(mf))
+			for k, v := range mf {
+				if k == "" {
+					continue
+				}
+				if ti.infoFieldOmitempty && isEmptyValue(reflect.ValueOf(v), e.h.TypeInfos, recur) {
+					continue
+				}
+				mf2s = append(mf2s, stringIntf{k, v})
+			}
+		}
+
+		e.mapStart(newlen + len(mf2s))
+
+		// When there are missing fields, and Canonical flag is set,
+		// we cannot have the missing fields and struct fields sorted independently.
+		// We have to capture them together and sort as a unit.
+
+		if len(mf2s) > 0 && e.h.Canonical {
+			mf2w := make([]encStructFieldObj, newlen+len(mf2s))
+			for j = 0; j < newlen; j++ {
+				kv = fkvs[j]
+				mf2w[j] = encStructFieldObj{kv.v.encName, kv.r, nil, kv.v.path.encNameAsciiAlphaNum, true}
+			}
+			for _, v := range mf2s {
+				mf2w[j] = encStructFieldObj{v.v, reflect.Value{}, v.i, false, false}
+				j++
+			}
+			sort.Sort((encStructFieldObjSlice)(mf2w))
+			for _, v := range mf2w {
+				e.mapElemKey()
+				e.kStructFieldKey(ti.keyType, v.ascii, v.key)
+				e.mapElemValue()
+				if v.isRv {
+					e.encodeValue(v.rv, nil)
+				} else {
+					e.encode(v.intf)
+				}
+			}
+		} else {
+			keytyp := ti.keyType
+			for j = 0; j < newlen; j++ {
+				kv = fkvs[j]
+				e.mapElemKey()
+				e.kStructFieldKey(keytyp, kv.v.path.encNameAsciiAlphaNum, kv.v.encName)
+				e.mapElemValue()
+				e.encodeValue(kv.r, nil)
+			}
+			for _, v := range mf2s {
+				e.mapElemKey()
+				e.kStructFieldKey(keytyp, false, v.v)
+				e.mapElemValue()
+				e.encode(v.i)
+			}
+		}
+
+		e.mapEnd()
+	} else {
+		newlen = len(tisfi)
+		for i, si := range tisfi { // use unsorted array (to match sequence in struct)
+			kv.r = si.path.field(rv)
+			// use the zero value.
+			// if a reference or struct, set to nil (so you do not output too much)
+			if si.path.omitEmpty && isEmptyValue(kv.r, e.h.TypeInfos, recur) {
+				switch kv.r.Kind() {
+				case reflect.Struct, reflect.Interface, reflect.Ptr, reflect.Array, reflect.Map, reflect.Slice:
+					kv.r = reflect.Value{} //encode as nil
+				}
+			}
+			fkvs[i] = kv
+		}
+		// encode it all
+		e.arrayStart(newlen)
+		for j = 0; j < newlen; j++ {
+			e.arrayElem()
+			e.encodeValue(fkvs[j].r, nil)
+		}
+		e.arrayEnd()
+	}
+
+	// do not use defer. Instead, use explicit pool return at end of function.
+	// defer has a cost we are trying to avoid.
+	// If there is a panic and these slices are not returned, it is ok.
+	e.slist.put(fkvs)
+}
+
+func (e *Encoder) kMap(f *codecFnInfo, rv reflect.Value) {
+	l := rvLenMap(rv)
+	e.mapStart(l)
+	if l == 0 {
+		e.mapEnd()
+		return
+	}
+
+	// determine the underlying key and val encFn's for the map.
+	// This eliminates some work which is done for each loop iteration i.e.
+	// rv.Type(), ref.ValueOf(rt).Pointer(), then check map/list for fn.
+	//
+	// However, if kind is reflect.Interface, do not pre-determine the
+	// encoding type, because preEncodeValue may break it down to
+	// a concrete type and kInterface will bomb.
+
+	var keyFn, valFn *codecFn
+
+	ktypeKind := reflect.Kind(f.ti.keykind)
+	vtypeKind := reflect.Kind(f.ti.elemkind)
+
+	rtval := f.ti.elem
+	rtvalkind := vtypeKind
+	for rtvalkind == reflect.Ptr {
+		rtval = rtval.Elem()
+		rtvalkind = rtval.Kind()
+	}
+	if rtvalkind != reflect.Interface {
+		valFn = e.h.fn(rtval)
+	}
+
+	var rvv = mapAddrLoopvarRV(f.ti.elem, vtypeKind)
+
+	if e.h.Canonical {
+		e.kMapCanonical(f.ti, rv, rvv, valFn)
+		e.mapEnd()
+		return
+	}
+
+	rtkey := f.ti.key
+	var keyTypeIsString = stringTypId == rt2id(rtkey) // rtkeyid
+	if !keyTypeIsString {
+		for rtkey.Kind() == reflect.Ptr {
+			rtkey = rtkey.Elem()
+		}
+		if rtkey.Kind() != reflect.Interface {
+			keyFn = e.h.fn(rtkey)
+		}
+	}
+
+	var rvk = mapAddrLoopvarRV(f.ti.key, ktypeKind)
+
+	var it mapIter
+	mapRange(&it, rv, rvk, rvv, true)
+
+	for it.Next() {
+		e.mapElemKey()
+		if keyTypeIsString {
+			e.e.EncodeString(it.Key().String())
+		} else {
+			e.encodeValue(it.Key(), keyFn)
+		}
+		e.mapElemValue()
+		e.encodeValue(it.Value(), valFn)
+	}
+	it.Done()
+
+	e.mapEnd()
+}
+
+func (e *Encoder) kMapCanonical(ti *typeInfo, rv, rvv reflect.Value, valFn *codecFn) {
+	// we previously did out-of-band if an extension was registered.
+	// This is not necessary, as the natural kind is sufficient for ordering.
+
+	rtkey := ti.key
+	mks := rv.MapKeys()
+	rtkeyKind := rtkey.Kind()
+	kfast := mapKeyFastKindFor(rtkeyKind)
+	visindirect := mapStoresElemIndirect(uintptr(ti.elemsize))
+	visref := refBitset.isset(ti.elemkind)
+
+	switch rtkeyKind {
+	case reflect.Bool:
+		mksv := make([]boolRv, len(mks))
+		for i, k := range mks {
+			v := &mksv[i]
+			v.r = k
+			v.v = k.Bool()
+		}
+		sort.Sort(boolRvSlice(mksv))
+		for i := range mksv {
+			e.mapElemKey()
+			e.e.EncodeBool(mksv[i].v)
+			e.mapElemValue()
+			e.encodeValue(mapGet(rv, mksv[i].r, rvv, kfast, visindirect, visref), valFn)
+		}
+	case reflect.String:
+		mksv := make([]stringRv, len(mks))
+		for i, k := range mks {
+			v := &mksv[i]
+			v.r = k
+			v.v = k.String()
+		}
+		sort.Sort(stringRvSlice(mksv))
+		for i := range mksv {
+			e.mapElemKey()
+			e.e.EncodeString(mksv[i].v)
+			e.mapElemValue()
+			e.encodeValue(mapGet(rv, mksv[i].r, rvv, kfast, visindirect, visref), valFn)
+		}
+	case reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uint, reflect.Uintptr:
+		mksv := make([]uint64Rv, len(mks))
+		for i, k := range mks {
+			v := &mksv[i]
+			v.r = k
+			v.v = k.Uint()
+		}
+		sort.Sort(uint64RvSlice(mksv))
+		for i := range mksv {
+			e.mapElemKey()
+			e.e.EncodeUint(mksv[i].v)
+			e.mapElemValue()
+			e.encodeValue(mapGet(rv, mksv[i].r, rvv, kfast, visindirect, visref), valFn)
+		}
+	case reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Int:
+		mksv := make([]int64Rv, len(mks))
+		for i, k := range mks {
+			v := &mksv[i]
+			v.r = k
+			v.v = k.Int()
+		}
+		sort.Sort(int64RvSlice(mksv))
+		for i := range mksv {
+			e.mapElemKey()
+			e.e.EncodeInt(mksv[i].v)
+			e.mapElemValue()
+			e.encodeValue(mapGet(rv, mksv[i].r, rvv, kfast, visindirect, visref), valFn)
+		}
+	case reflect.Float32:
+		mksv := make([]float64Rv, len(mks))
+		for i, k := range mks {
+			v := &mksv[i]
+			v.r = k
+			v.v = k.Float()
+		}
+		sort.Sort(float64RvSlice(mksv))
+		for i := range mksv {
+			e.mapElemKey()
+			e.e.EncodeFloat32(float32(mksv[i].v))
+			e.mapElemValue()
+			e.encodeValue(mapGet(rv, mksv[i].r, rvv, kfast, visindirect, visref), valFn)
+		}
+	case reflect.Float64:
+		mksv := make([]float64Rv, len(mks))
+		for i, k := range mks {
+			v := &mksv[i]
+			v.r = k
+			v.v = k.Float()
+		}
+		sort.Sort(float64RvSlice(mksv))
+		for i := range mksv {
+			e.mapElemKey()
+			e.e.EncodeFloat64(mksv[i].v)
+			e.mapElemValue()
+			e.encodeValue(mapGet(rv, mksv[i].r, rvv, kfast, visindirect, visref), valFn)
+		}
+	case reflect.Struct:
+		if rtkey == timeTyp {
+			mksv := make([]timeRv, len(mks))
+			for i, k := range mks {
+				v := &mksv[i]
+				v.r = k
+				v.v = rv2i(k).(time.Time)
+			}
+			sort.Sort(timeRvSlice(mksv))
+			for i := range mksv {
+				e.mapElemKey()
+				e.e.EncodeTime(mksv[i].v)
+				e.mapElemValue()
+				e.encodeValue(mapGet(rv, mksv[i].r, rvv, kfast, visindirect, visref), valFn)
+			}
+			break
+		}
+		fallthrough
+	default:
+		// out-of-band
+		// first encode each key to a []byte first, then sort them, then record
+		bs0 := e.blist.get(len(mks) * 16)
+		mksv := bs0
+		mksbv := make([]bytesRv, len(mks))
+
+		func() {
+			// replicate sideEncode logic
+			defer func(wb bytesEncAppender, bytes bool, c containerState, state interface{}) {
+				e.wb = wb
+				e.bytes = bytes
+				e.c = c
+				e.e.restoreState(state)
+			}(e.wb, e.bytes, e.c, e.e.captureState())
+
+			// e2 := NewEncoderBytes(&mksv, e.hh)
+			e.wb = bytesEncAppender{mksv[:0], &mksv}
+			e.bytes = true
+			e.c = 0
+			e.e.resetState()
+
+			for i, k := range mks {
+				v := &mksbv[i]
+				l := len(mksv)
+
+				e.encodeValue(k, nil)
+				e.atEndOfEncode()
+				e.w().end()
+
+				v.r = k
+				v.v = mksv[l:]
+			}
+		}()
+
+		sort.Sort(bytesRvSlice(mksbv))
+		for j := range mksbv {
+			e.mapElemKey()
+			e.encWr.writeb(mksbv[j].v)
+			e.mapElemValue()
+			e.encodeValue(mapGet(rv, mksbv[j].r, rvv, kfast, visindirect, visref), valFn)
+		}
+		e.blist.put(mksv)
+		if !byteSliceSameData(bs0, mksv) {
+			e.blist.put(bs0)
+		}
+	}
+}
+
+// Encoder writes an object to an output stream in a supported format.
+//
+// Encoder is NOT safe for concurrent use i.e. a Encoder cannot be used
+// concurrently in multiple goroutines.
+//
+// However, as Encoder could be allocation heavy to initialize, a Reset method is provided
+// so its state can be reused to decode new input streams repeatedly.
+// This is the idiomatic way to use.
+type Encoder struct {
+	panicHdl
+
+	e encDriver
+
+	h *BasicHandle
+
+	// hopefully, reduce derefencing cost by laying the encWriter inside the Encoder
+	encWr
+
+	// ---- cpu cache line boundary
+	hh Handle
+
+	blist bytesFreelist
+	err   error
+
+	// ---- cpu cache line boundary
+
+	// ---- writable fields during execution --- *try* to keep in sep cache line
+
+	// ci holds interfaces during an encoding (if CheckCircularRef=true)
+	//
+	// We considered using a []uintptr (slice of pointer addresses) retrievable via rv.UnsafeAddr.
+	// However, it is possible for the same pointer to point to 2 different types e.g.
+	//    type T struct { tHelper }
+	//    Here, for var v T; &v and &v.tHelper are the same pointer.
+	// Consequently, we need a tuple of type and pointer, which interface{} natively provides.
+	ci []interface{} // []uintptr
+
+	perType encPerType
+
+	slist sfiRvFreelist
+}
+
+// NewEncoder returns an Encoder for encoding into an io.Writer.
+//
+// For efficiency, Users are encouraged to configure WriterBufferSize on the handle
+// OR pass in a memory buffered writer (eg bufio.Writer, bytes.Buffer).
+func NewEncoder(w io.Writer, h Handle) *Encoder {
+	e := h.newEncDriver().encoder()
+	if w != nil {
+		e.Reset(w)
+	}
+	return e
+}
+
+// NewEncoderBytes returns an encoder for encoding directly and efficiently
+// into a byte slice, using zero-copying to temporary slices.
+//
+// It will potentially replace the output byte slice pointed to.
+// After encoding, the out parameter contains the encoded contents.
+func NewEncoderBytes(out *[]byte, h Handle) *Encoder {
+	e := h.newEncDriver().encoder()
+	if out != nil {
+		e.ResetBytes(out)
+	}
+	return e
+}
+
+func (e *Encoder) init(h Handle) {
+	initHandle(h)
+	e.err = errEncoderNotInitialized
+	e.bytes = true
+	e.hh = h
+	e.h = h.getBasicHandle()
+	e.be = e.hh.isBinary()
+}
+
+func (e *Encoder) w() *encWr {
+	return &e.encWr
+}
+
+func (e *Encoder) resetCommon() {
+	e.e.reset()
+	if e.ci != nil {
+		e.ci = e.ci[:0]
+	}
+	e.c = 0
+	e.calls = 0
+	e.seq = 0
+	e.err = nil
+}
+
+// Reset resets the Encoder with a new output stream.
+//
+// This accommodates using the state of the Encoder,
+// where it has "cached" information about sub-engines.
+func (e *Encoder) Reset(w io.Writer) {
+	e.bytes = false
+	if e.wf == nil {
+		e.wf = new(bufioEncWriter)
+	}
+	e.wf.reset(w, e.h.WriterBufferSize, &e.blist)
+	e.resetCommon()
+}
+
+// ResetBytes resets the Encoder with a new destination output []byte.
+func (e *Encoder) ResetBytes(out *[]byte) {
+	e.bytes = true
+	e.wb.reset(encInBytes(out), out)
+	e.resetCommon()
+}
+
+// Encode writes an object into a stream.
+//
+// Encoding can be configured via the struct tag for the fields.
+// The key (in the struct tags) that we look at is configurable.
+//
+// By default, we look up the "codec" key in the struct field's tags,
+// and fall bak to the "json" key if "codec" is absent.
+// That key in struct field's tag value is the key name,
+// followed by an optional comma and options.
+//
+// To set an option on all fields (e.g. omitempty on all fields), you
+// can create a field called _struct, and set flags on it. The options
+// which can be set on _struct are:
+//    - omitempty: so all fields are omitted if empty
+//    - toarray: so struct is encoded as an array
+//    - int: so struct key names are encoded as signed integers (instead of strings)
+//    - uint: so struct key names are encoded as unsigned integers (instead of strings)
+//    - float: so struct key names are encoded as floats (instead of strings)
+// More details on these below.
+//
+// Struct values "usually" encode as maps. Each exported struct field is encoded unless:
+//    - the field's tag is "-", OR
+//    - the field is empty (empty or the zero value) and its tag specifies the "omitempty" option.
+//
+// When encoding as a map, the first string in the tag (before the comma)
+// is the map key string to use when encoding.
+// ...
+// This key is typically encoded as a string.
+// However, there are instances where the encoded stream has mapping keys encoded as numbers.
+// For example, some cbor streams have keys as integer codes in the stream, but they should map
+// to fields in a structured object. Consequently, a struct is the natural representation in code.
+// For these, configure the struct to encode/decode the keys as numbers (instead of string).
+// This is done with the int,uint or float option on the _struct field (see above).
+//
+// However, struct values may encode as arrays. This happens when:
+//    - StructToArray Encode option is set, OR
+//    - the tag on the _struct field sets the "toarray" option
+// Note that omitempty is ignored when encoding struct values as arrays,
+// as an entry must be encoded for each field, to maintain its position.
+//
+// Values with types that implement MapBySlice are encoded as stream maps.
+//
+// The empty values (for omitempty option) are false, 0, any nil pointer
+// or interface value, and any array, slice, map, or string of length zero.
+//
+// Anonymous fields are encoded inline except:
+//    - the struct tag specifies a replacement name (first value)
+//    - the field is of an interface type
+//
+// Examples:
+//
+//      // NOTE: 'json:' can be used as struct tag key, in place 'codec:' below.
+//      type MyStruct struct {
+//          _struct bool    `codec:",omitempty"`   //set omitempty for every field
+//          Field1 string   `codec:"-"`            //skip this field
+//          Field2 int      `codec:"myName"`       //Use key "myName" in encode stream
+//          Field3 int32    `codec:",omitempty"`   //use key "Field3". Omit if empty.
+//          Field4 bool     `codec:"f4,omitempty"` //use key "f4". Omit if empty.
+//          io.Reader                              //use key "Reader".
+//          MyStruct        `codec:"my1"           //use key "my1".
+//          MyStruct                               //inline it
+//          ...
+//      }
+//
+//      type MyStruct struct {
+//          _struct bool    `codec:",toarray"`     //encode struct as an array
+//      }
+//
+//      type MyStruct struct {
+//          _struct bool    `codec:",uint"`        //encode struct with "unsigned integer" keys
+//          Field1 string   `codec:"1"`            //encode Field1 key using: EncodeInt(1)
+//          Field2 string   `codec:"2"`            //encode Field2 key using: EncodeInt(2)
+//      }
+//
+// The mode of encoding is based on the type of the value. When a value is seen:
+//   - If a Selfer, call its CodecEncodeSelf method
+//   - If an extension is registered for it, call that extension function
+//   - If implements encoding.(Binary|Text|JSON)Marshaler, call Marshal(Binary|Text|JSON) method
+//   - Else encode it based on its reflect.Kind
+//
+// Note that struct field names and keys in map[string]XXX will be treated as symbols.
+// Some formats support symbols (e.g. binc) and will properly encode the string
+// only once in the stream, and use a tag to refer to it thereafter.
+func (e *Encoder) Encode(v interface{}) (err error) {
+	// tried to use closure, as runtime optimizes defer with no params.
+	// This seemed to be causing weird issues (like circular reference found, unexpected panic, etc).
+	// Also, see https://github.com/golang/go/issues/14939#issuecomment-417836139
+	if !debugging {
+		defer func() {
+			// if error occurred during encoding, return that error;
+			// else if error occurred on end'ing (i.e. during flush), return that error.
+			if x := recover(); x != nil {
+				panicValToErr(e, x, &e.err)
+				err = e.err
+			}
+		}()
+	}
+
+	e.MustEncode(v)
+	return
+}
+
+// MustEncode is like Encode, but panics if unable to Encode.
+//
+// Note: This provides insight to the code location that triggered the error.
+func (e *Encoder) MustEncode(v interface{}) {
+	halt.onerror(e.err)
+	if e.hh == nil {
+		halt.onerror(errNoFormatHandle)
+	}
+
+	e.calls++
+	e.encode(v)
+	e.calls--
+	if e.calls == 0 {
+		e.atEndOfEncode()
+		e.w().end()
+	}
+}
+
+// Release releases shared (pooled) resources.
+//
+// It is important to call Release() when done with an Encoder, so those resources
+// are released instantly for use by subsequently created Encoders.
+//
+// Deprecated: Release is a no-op as pooled resources are not used with an Encoder.
+// This method is kept for compatibility reasons only.
+func (e *Encoder) Release() {
+}
+
+func (e *Encoder) encode(iv interface{}) {
+	// MARKER: a switch with only concrete types can be optimized.
+	// consequently, we deal with nil and interfaces outside the switch.
+
+	if iv == nil {
+		e.e.EncodeNil()
+		return
+	}
+
+	rv, ok := isNil(iv)
+	if ok {
+		e.e.EncodeNil()
+		return
+	}
+
+	switch v := iv.(type) {
+	// case nil:
+	// case Selfer:
+	case Raw:
+		e.rawBytes(v)
+	case reflect.Value:
+		e.encodeValue(v, nil)
+
+	case string:
+		e.e.EncodeString(v)
+	case bool:
+		e.e.EncodeBool(v)
+	case int:
+		e.e.EncodeInt(int64(v))
+	case int8:
+		e.e.EncodeInt(int64(v))
+	case int16:
+		e.e.EncodeInt(int64(v))
+	case int32:
+		e.e.EncodeInt(int64(v))
+	case int64:
+		e.e.EncodeInt(v)
+	case uint:
+		e.e.EncodeUint(uint64(v))
+	case uint8:
+		e.e.EncodeUint(uint64(v))
+	case uint16:
+		e.e.EncodeUint(uint64(v))
+	case uint32:
+		e.e.EncodeUint(uint64(v))
+	case uint64:
+		e.e.EncodeUint(v)
+	case uintptr:
+		e.e.EncodeUint(uint64(v))
+	case float32:
+		e.e.EncodeFloat32(v)
+	case float64:
+		e.e.EncodeFloat64(v)
+	case complex64:
+		e.encodeComplex64(v)
+	case complex128:
+		e.encodeComplex128(v)
+	case time.Time:
+		e.e.EncodeTime(v)
+	case []byte:
+		e.e.EncodeStringBytesRaw(v)
+	case *Raw:
+		e.rawBytes(*v)
+	case *string:
+		e.e.EncodeString(*v)
+	case *bool:
+		e.e.EncodeBool(*v)
+	case *int:
+		e.e.EncodeInt(int64(*v))
+	case *int8:
+		e.e.EncodeInt(int64(*v))
+	case *int16:
+		e.e.EncodeInt(int64(*v))
+	case *int32:
+		e.e.EncodeInt(int64(*v))
+	case *int64:
+		e.e.EncodeInt(*v)
+	case *uint:
+		e.e.EncodeUint(uint64(*v))
+	case *uint8:
+		e.e.EncodeUint(uint64(*v))
+	case *uint16:
+		e.e.EncodeUint(uint64(*v))
+	case *uint32:
+		e.e.EncodeUint(uint64(*v))
+	case *uint64:
+		e.e.EncodeUint(*v)
+	case *uintptr:
+		e.e.EncodeUint(uint64(*v))
+	case *float32:
+		e.e.EncodeFloat32(*v)
+	case *float64:
+		e.e.EncodeFloat64(*v)
+	case *complex64:
+		e.encodeComplex64(*v)
+	case *complex128:
+		e.encodeComplex128(*v)
+	case *time.Time:
+		e.e.EncodeTime(*v)
+	case *[]byte:
+		if *v == nil {
+			e.e.EncodeNil()
+		} else {
+			e.e.EncodeStringBytesRaw(*v)
+		}
+	default:
+		// we can't check non-predefined types, as they might be a Selfer or extension.
+		if skipFastpathTypeSwitchInDirectCall || !fastpathEncodeTypeSwitch(iv, e) {
+			e.encodeValue(rv, nil)
+		}
+	}
+}
+
+// encodeValue will encode a value.
+//
+// Note that encodeValue will handle nil in the stream early, so that the
+// subsequent calls i.e. kXXX methods, etc do not have to handle it themselves.
+func (e *Encoder) encodeValue(rv reflect.Value, fn *codecFn) {
+	// if a valid fn is passed, it MUST BE for the dereferenced type of rv
+
+	// MARKER: We check if value is nil here, so that the kXXX method do not have to.
+
+	var sptr interface{}
+	var rvp reflect.Value
+	var rvpValid bool
+TOP:
+	switch rv.Kind() {
+	case reflect.Ptr:
+		if rvIsNil(rv) {
+			e.e.EncodeNil()
+			return
+		}
+		rvpValid = true
+		rvp = rv
+		rv = rv.Elem()
+		goto TOP
+	case reflect.Interface:
+		if rvIsNil(rv) {
+			e.e.EncodeNil()
+			return
+		}
+		rvpValid = false
+		rvp = reflect.Value{}
+		rv = rv.Elem()
+		goto TOP
+	case reflect.Struct:
+		if rvpValid && e.h.CheckCircularRef {
+			sptr = rv2i(rvp)
+			for _, vv := range e.ci {
+				if eq4i(sptr, vv) { // error if sptr already seen
+					e.errorf("circular reference found: %p, %T", sptr, sptr)
+				}
+			}
+			e.ci = append(e.ci, sptr)
+		}
+	case reflect.Slice, reflect.Map, reflect.Chan:
+		if rvIsNil(rv) {
+			e.e.EncodeNil()
+			return
+		}
+	case reflect.Invalid, reflect.Func:
+		e.e.EncodeNil()
+		return
+	}
+
+	if fn == nil {
+		fn = e.h.fn(rvType(rv))
+	}
+
+	if !fn.i.addrE { // typically, addrE = false, so check it first
+		// keep rv same
+	} else if rvpValid {
+		rv = rvp
+	} else {
+		rv = e.addrRV(rv, fn.i.ti.rt, fn.i.ti.ptr)
+	}
+	fn.fe(e, &fn.i, rv)
+
+	if sptr != nil { // remove sptr
+		e.ci = e.ci[:len(e.ci)-1]
+	}
+}
+
+// addrRV returns a addressable value which may be readonly
+func (e *Encoder) addrRV(rv reflect.Value, typ, ptrType reflect.Type) (rva reflect.Value) {
+	if rv.CanAddr() {
+		return rvAddr(rv, ptrType)
+	}
+	if e.h.NoAddressableReadonly {
+		rva = reflect.New(typ)
+		rvSetDirect(rva.Elem(), rv)
+		return
+	}
+	return rvAddr(e.perType.AddressableRO(rv), ptrType)
+}
+
+func (e *Encoder) marshalUtf8(bs []byte, fnerr error) {
+	e.onerror(fnerr)
+	if bs == nil {
+		e.e.EncodeNil()
+	} else {
+		e.e.EncodeString(stringView(bs))
+	}
+}
+
+func (e *Encoder) marshalAsis(bs []byte, fnerr error) {
+	e.onerror(fnerr)
+	if bs == nil {
+		e.e.EncodeNil()
+	} else {
+		e.encWr.writeb(bs) // e.asis(bs)
+	}
+}
+
+func (e *Encoder) marshalRaw(bs []byte, fnerr error) {
+	e.onerror(fnerr)
+	if bs == nil {
+		e.e.EncodeNil()
+	} else {
+		e.e.EncodeStringBytesRaw(bs)
+	}
+}
+
+func (e *Encoder) rawBytes(vv Raw) {
+	v := []byte(vv)
+	if !e.h.Raw {
+		e.errorf("Raw values cannot be encoded: %v", v)
+	}
+	e.encWr.writeb(v)
+}
+
+func (e *Encoder) wrapErr(v error, err *error) {
+	*err = wrapCodecErr(v, e.hh.Name(), 0, true)
+}
+
+// ---- container tracker methods
+// Note: We update the .c after calling the callback.
+// This way, the callback can know what the last status was.
+
+func (e *Encoder) mapStart(length int) {
+	e.e.WriteMapStart(length)
+	e.c = containerMapStart
+}
+
+func (e *Encoder) mapElemKey() {
+	if e.js {
+		e.jsondriver().WriteMapElemKey()
+	}
+	e.c = containerMapKey
+}
+
+func (e *Encoder) mapElemValue() {
+	if e.js {
+		e.jsondriver().WriteMapElemValue()
+	}
+	e.c = containerMapValue
+}
+
+func (e *Encoder) mapEnd() {
+	e.e.WriteMapEnd()
+	e.c = 0
+}
+
+func (e *Encoder) arrayStart(length int) {
+	e.e.WriteArrayStart(length)
+	e.c = containerArrayStart
+}
+
+func (e *Encoder) arrayElem() {
+	if e.js {
+		e.jsondriver().WriteArrayElem()
+	}
+	e.c = containerArrayElem
+}
+
+func (e *Encoder) arrayEnd() {
+	e.e.WriteArrayEnd()
+	e.c = 0
+}
+
+// ----------
+
+func (e *Encoder) haltOnMbsOddLen(length int) {
+	if length&1 != 0 { // similar to &1==1 or %2 == 1
+		e.errorf("mapBySlice requires even slice length, but got %v", length)
+	}
+}
+
+func (e *Encoder) atEndOfEncode() {
+	// e.e.atEndOfEncode()
+	if e.js {
+		e.jsondriver().atEndOfEncode()
+	}
+}
+
+func (e *Encoder) sideEncode(v interface{}, basetype reflect.Type, bs *[]byte) {
+	// rv := baseRV(v)
+	// e2 := NewEncoderBytes(bs, e.hh)
+	// e2.encodeValue(rv, e2.h.fnNoExt(basetype))
+	// e2.atEndOfEncode()
+	// e2.w().end()
+
+	defer func(wb bytesEncAppender, bytes bool, c containerState, state interface{}) {
+		e.wb = wb
+		e.bytes = bytes
+		e.c = c
+		e.e.restoreState(state)
+	}(e.wb, e.bytes, e.c, e.e.captureState())
+
+	e.wb = bytesEncAppender{encInBytes(bs)[:0], bs}
+	e.bytes = true
+	e.c = 0
+	e.e.resetState()
+
+	// must call using fnNoExt
+	rv := baseRV(v)
+	e.encodeValue(rv, e.h.fnNoExt(basetype))
+	e.atEndOfEncode()
+	e.w().end()
+}
+
+func encInBytes(out *[]byte) (in []byte) {
+	in = *out
+	if in == nil {
+		in = make([]byte, defEncByteBufSize)
+	}
+	return
+}
+
+func encStructFieldKey(encName string, ee encDriver, w *encWr,
+	keyType valueType, encNameAsciiAlphaNum bool, js bool) {
+	// use if-else-if, not switch (which compiles to binary-search)
+	// since keyType is typically valueTypeString, branch prediction is pretty good.
+
+	if keyType == valueTypeString {
+		if js && encNameAsciiAlphaNum { // keyType == valueTypeString
+			w.writeqstr(encName)
+		} else { // keyType == valueTypeString
+			ee.EncodeString(encName)
+		}
+	} else if keyType == valueTypeInt {
+		ee.EncodeInt(must.Int(strconv.ParseInt(encName, 10, 64)))
+	} else if keyType == valueTypeUint {
+		ee.EncodeUint(must.Uint(strconv.ParseUint(encName, 10, 64)))
+	} else if keyType == valueTypeFloat {
+		ee.EncodeFloat64(must.Float(strconv.ParseFloat(encName, 64)))
+	} else {
+		halt.errorf("invalid struct key type: %v", keyType)
+	}
+}