// 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 (
"bytes"
"encoding"
"errors"
"fmt"
"io"
"reflect"
"sort"
"sync"
)
const (
defEncByteBufSize = 1 << 6 // 4:16, 6:64, 8:256, 10:1024
)
// AsSymbolFlag defines what should be encoded as symbols.
type AsSymbolFlag uint8
const (
// AsSymbolDefault is default.
// Currently, this means only encode struct field names as symbols.
// The default is subject to change.
AsSymbolDefault AsSymbolFlag = iota
// AsSymbolAll means encode anything which could be a symbol as a symbol.
AsSymbolAll = 0xfe
// AsSymbolNone means do not encode anything as a symbol.
AsSymbolNone = 1 << iota
// AsSymbolMapStringKeys means encode keys in map[string]XXX as symbols.
AsSymbolMapStringKeysFlag
// AsSymbolStructFieldName means encode struct field names as symbols.
AsSymbolStructFieldNameFlag
)
// encWriter abstracts writing to a byte array or to an io.Writer.
type encWriter interface {
writeb([]byte)
writestr(string)
writen1(byte)
writen2(byte, byte)
atEndOfEncode()
}
// encDriver abstracts the actual codec (binc vs msgpack, etc)
type encDriver interface {
IsBuiltinType(rt uintptr) bool
EncodeBuiltin(rt uintptr, v interface{})
EncodeNil()
EncodeInt(i int64)
EncodeUint(i uint64)
EncodeBool(b bool)
EncodeFloat32(f float32)
EncodeFloat64(f float64)
// encodeExtPreamble(xtag byte, length int)
EncodeRawExt(re *RawExt, e *Encoder)
EncodeExt(v interface{}, xtag uint64, ext Ext, e *Encoder)
EncodeArrayStart(length int)
EncodeArrayEnd()
EncodeArrayEntrySeparator()
EncodeMapStart(length int)
EncodeMapEnd()
EncodeMapEntrySeparator()
EncodeMapKVSeparator()
EncodeString(c charEncoding, v string)
EncodeSymbol(v string)
EncodeStringBytes(c charEncoding, v []byte)
//TODO
//encBignum(f *big.Int)
//encStringRunes(c charEncoding, v []rune)
}
type encNoSeparator struct{}
func (_ encNoSeparator) EncodeMapEnd() {}
func (_ encNoSeparator) EncodeArrayEnd() {}
func (_ encNoSeparator) EncodeArrayEntrySeparator() {}
func (_ encNoSeparator) EncodeMapEntrySeparator() {}
func (_ encNoSeparator) EncodeMapKVSeparator() {}
type encStructFieldBytesV struct {
b []byte
v reflect.Value
}
type encStructFieldBytesVslice []encStructFieldBytesV
func (p encStructFieldBytesVslice) Len() int { return len(p) }
func (p encStructFieldBytesVslice) Less(i, j int) bool { return bytes.Compare(p[i].b, p[j].b) == -1 }
func (p encStructFieldBytesVslice) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
type ioEncWriterWriter interface {
WriteByte(c byte) error
WriteString(s string) (n int, err error)
Write(p []byte) (n int, err error)
}
type ioEncStringWriter interface {
WriteString(s string) (n int, err error)
}
type EncodeOptions struct {
// 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 mostly will apply to maps. In this case, codec will do more work to encode the
// map keys out of band, and then sort them, before writing out the map to the stream.
Canonical bool
// 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.
//
// Sample values:
// AsSymbolNone
// AsSymbolAll
// AsSymbolMapStringKeys
// AsSymbolMapStringKeysFlag | AsSymbolStructFieldNameFlag
AsSymbols AsSymbolFlag
}
// ---------------------------------------------
type simpleIoEncWriterWriter struct {
w io.Writer
bw io.ByteWriter
sw ioEncStringWriter
}
func (o *simpleIoEncWriterWriter) WriteByte(c byte) (err error) {
if o.bw != nil {
return o.bw.WriteByte(c)
}
_, err = o.w.Write([]byte{c})
return
}
func (o *simpleIoEncWriterWriter) WriteString(s string) (n int, err error) {
if o.sw != nil {
return o.sw.WriteString(s)
}
// return o.w.Write([]byte(s))
return o.w.Write(bytesView(s))
}
func (o *simpleIoEncWriterWriter) Write(p []byte) (n int, err error) {
return o.w.Write(p)
}
// ----------------------------------------
// ioEncWriter implements encWriter and can write to an io.Writer implementation
type ioEncWriter struct {
w ioEncWriterWriter
// x [8]byte // temp byte array re-used internally for efficiency
}
func (z *ioEncWriter) writeb(bs []byte) {
if len(bs) == 0 {
return
}
n, err := z.w.Write(bs)
if err != nil {
panic(err)
}
if n != len(bs) {
panic(fmt.Errorf("incorrect num bytes written. Expecting: %v, Wrote: %v", len(bs), n))
}
}
func (z *ioEncWriter) writestr(s string) {
n, err := z.w.WriteString(s)
if err != nil {
panic(err)
}
if n != len(s) {
panic(fmt.Errorf("incorrect num bytes written. Expecting: %v, Wrote: %v", len(s), n))
}
}
func (z *ioEncWriter) writen1(b byte) {
if err := z.w.WriteByte(b); err != nil {
panic(err)
}
}
func (z *ioEncWriter) writen2(b1 byte, b2 byte) {
z.writen1(b1)
z.writen1(b2)
}
func (z *ioEncWriter) atEndOfEncode() {}
// ----------------------------------------
// bytesEncWriter implements encWriter and can write to an byte slice.
// It is used by Marshal function.
type bytesEncWriter struct {
b []byte
c int // cursor
out *[]byte // write out on atEndOfEncode
}
func (z *bytesEncWriter) writeb(s []byte) {
if len(s) > 0 {
c := z.grow(len(s))
copy(z.b[c:], s)
}
}
func (z *bytesEncWriter) writestr(s string) {
if len(s) > 0 {
c := z.grow(len(s))
copy(z.b[c:], s)
}
}
func (z *bytesEncWriter) writen1(b1 byte) {
c := z.grow(1)
z.b[c] = b1
}
func (z *bytesEncWriter) writen2(b1 byte, b2 byte) {
c := z.grow(2)
z.b[c] = b1
z.b[c+1] = b2
}
func (z *bytesEncWriter) atEndOfEncode() {
*(z.out) = z.b[:z.c]
}
func (z *bytesEncWriter) grow(n int) (oldcursor int) {
oldcursor = z.c
z.c = oldcursor + n
if z.c > len(z.b) {
if z.c > cap(z.b) {
// Tried using appendslice logic: (if cap < 1024, *2, else *1.25).
// However, it was too expensive, causing too many iterations of copy.
// Using bytes.Buffer model was much better (2*cap + n)
bs := make([]byte, 2*cap(z.b)+n)
copy(bs, z.b[:oldcursor])
z.b = bs
} else {
z.b = z.b[:cap(z.b)]
}
}
return
}
// ---------------------------------------------
type encFnInfoX struct {
e *Encoder
ti *typeInfo
xfFn Ext
xfTag uint64
seq seqType
}
type encFnInfo struct {
// use encFnInfo as a value receiver.
// keep most of it less-used variables accessible via a pointer (*encFnInfoX).
// As sweet spot for value-receiver is 3 words, keep everything except
// encDriver (which everyone needs) directly accessible.
// ensure encFnInfoX is set for everyone who needs it i.e.
// rawExt, ext, builtin, (selfer|binary|text)Marshal, kSlice, kStruct, kMap, kInterface, fastpath
ee encDriver
*encFnInfoX
}
func (f encFnInfo) builtin(rv reflect.Value) {
f.ee.EncodeBuiltin(f.ti.rtid, rv.Interface())
}
func (f encFnInfo) rawExt(rv reflect.Value) {
// rev := rv.Interface().(RawExt)
// f.ee.EncodeRawExt(&rev, f.e)
var re *RawExt
if rv.CanAddr() {
re = rv.Addr().Interface().(*RawExt)
} else {
rev := rv.Interface().(RawExt)
re = &rev
}
f.ee.EncodeRawExt(re, f.e)
}
func (f encFnInfo) ext(rv reflect.Value) {
// if this is a struct and it was addressable, then pass the address directly (not the value)
if rv.CanAddr() && rv.Kind() == reflect.Struct {
rv = rv.Addr()
}
f.ee.EncodeExt(rv.Interface(), f.xfTag, f.xfFn, f.e)
}
func (f encFnInfo) getValueForMarshalInterface(rv reflect.Value, indir int8) (v interface{}, proceed bool) {
if indir == 0 {
v = rv.Interface()
} else if indir == -1 {
v = rv.Addr().Interface()
} else {
for j := int8(0); j < indir; j++ {
if rv.IsNil() {
f.ee.EncodeNil()
return
}
rv = rv.Elem()
}
v = rv.Interface()
}
return v, true
}
func (f encFnInfo) selferMarshal(rv reflect.Value) {
if v, proceed := f.getValueForMarshalInterface(rv, f.ti.csIndir); proceed {
v.(Selfer).CodecEncodeSelf(f.e)
}
}
func (f encFnInfo) binaryMarshal(rv reflect.Value) {
if v, proceed := f.getValueForMarshalInterface(rv, f.ti.bmIndir); proceed {
bs, fnerr := v.(encoding.BinaryMarshaler).MarshalBinary()
if fnerr != nil {
panic(fnerr)
}
if bs == nil {
f.ee.EncodeNil()
} else {
f.ee.EncodeStringBytes(c_RAW, bs)
}
}
}
func (f encFnInfo) textMarshal(rv reflect.Value) {
if v, proceed := f.getValueForMarshalInterface(rv, f.ti.tmIndir); proceed {
// debugf(">>>> encoding.TextMarshaler: %T", rv.Interface())
bs, fnerr := v.(encoding.TextMarshaler).MarshalText()
if fnerr != nil {
panic(fnerr)
}
if bs == nil {
f.ee.EncodeNil()
} else {
f.ee.EncodeStringBytes(c_UTF8, bs)
}
}
}
func (f encFnInfo) kBool(rv reflect.Value) {
f.ee.EncodeBool(rv.Bool())
}
func (f encFnInfo) kString(rv reflect.Value) {
f.ee.EncodeString(c_UTF8, rv.String())
}
func (f encFnInfo) kFloat64(rv reflect.Value) {
f.ee.EncodeFloat64(rv.Float())
}
func (f encFnInfo) kFloat32(rv reflect.Value) {
f.ee.EncodeFloat32(float32(rv.Float()))
}
func (f encFnInfo) kInt(rv reflect.Value) {
f.ee.EncodeInt(rv.Int())
}
func (f encFnInfo) kUint(rv reflect.Value) {
f.ee.EncodeUint(rv.Uint())
}
func (f encFnInfo) kInvalid(rv reflect.Value) {
f.ee.EncodeNil()
}
func (f encFnInfo) kErr(rv reflect.Value) {
f.e.errorf("unsupported kind %s, for %#v", rv.Kind(), rv)
}
func (f encFnInfo) kSlice(rv reflect.Value) {
ti := f.ti
// array may be non-addressable, so we have to manage with care
// (don't call rv.Bytes, rv.Slice, etc).
// E.g. type struct S{B [2]byte};
// Encode(S{}) will bomb on "panic: slice of unaddressable array".
if f.seq != seqTypeArray {
if rv.IsNil() {
f.ee.EncodeNil()
return
}
// If in this method, then there was no extension function defined.
// So it's okay to treat as []byte.
if ti.rtid == uint8SliceTypId {
f.ee.EncodeStringBytes(c_RAW, rv.Bytes())
return
}
}
rtelem := ti.rt.Elem()
l := rv.Len()
if rtelem.Kind() == reflect.Uint8 {
switch f.seq {
case seqTypeArray:
// if l == 0 { f.ee.encodeStringBytes(c_RAW, nil) } else
if rv.CanAddr() {
f.ee.EncodeStringBytes(c_RAW, rv.Slice(0, l).Bytes())
} else {
var bs []byte
if l <= cap(f.e.b) {
bs = f.e.b[:l]
} else {
bs = make([]byte, l)
}
reflect.Copy(reflect.ValueOf(bs), rv)
// TODO: Test that reflect.Copy works instead of manual one-by-one
// for i := 0; i < l; i++ {
// bs[i] = byte(rv.Index(i).Uint())
// }
f.ee.EncodeStringBytes(c_RAW, bs)
}
case seqTypeSlice:
f.ee.EncodeStringBytes(c_RAW, rv.Bytes())
case seqTypeChan:
bs := f.e.b[:0]
// 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.
// for b := range rv.Interface().(<-chan byte) {
// bs = append(bs, b)
// }
ch := rv.Interface().(<-chan byte)
for i := 0; i < l; i++ {
bs = append(bs, <-ch)
}
f.ee.EncodeStringBytes(c_RAW, bs)
}
return
}
if ti.mbs {
if l%2 == 1 {
f.e.errorf("mapBySlice requires even slice length, but got %v", l)
return
}
f.ee.EncodeMapStart(l / 2)
} else {
f.ee.EncodeArrayStart(l)
}
e := f.e
sep := !e.be
if l > 0 {
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.
var fn encFn
if rtelem.Kind() != reflect.Interface {
rtelemid := reflect.ValueOf(rtelem).Pointer()
fn = e.getEncFn(rtelemid, rtelem, true, true)
}
// TODO: Consider perf implication of encoding odd index values as symbols if type is string
if sep {
for j := 0; j < l; j++ {
if j > 0 {
if ti.mbs {
if j%2 == 0 {
f.ee.EncodeMapEntrySeparator()
} else {
f.ee.EncodeMapKVSeparator()
}
} else {
f.ee.EncodeArrayEntrySeparator()
}
}
if f.seq == seqTypeChan {
if rv2, ok2 := rv.Recv(); ok2 {
e.encodeValue(rv2, fn)
}
} else {
e.encodeValue(rv.Index(j), fn)
}
}
} else {
for j := 0; j < l; j++ {
if f.seq == seqTypeChan {
if rv2, ok2 := rv.Recv(); ok2 {
e.encodeValue(rv2, fn)
}
} else {
e.encodeValue(rv.Index(j), fn)
}
}
}
}
if sep {
if ti.mbs {
f.ee.EncodeMapEnd()
} else {
f.ee.EncodeArrayEnd()
}
}
}
func (f encFnInfo) kStruct(rv reflect.Value) {
fti := f.ti
e := f.e
tisfi := fti.sfip
toMap := !(fti.toArray || e.h.StructToArray)
newlen := len(fti.sfi)
// Use sync.Pool to reduce allocating slices unnecessarily.
// The cost of the occasional locking is less than the cost of locking.
var fkvs []encStructFieldKV
var pool *sync.Pool
var poolv interface{}
idxpool := newlen / 8
if encStructPoolLen != 4 {
panic(errors.New("encStructPoolLen must be equal to 4")) // defensive, in case it is changed
}
if idxpool < encStructPoolLen {
pool = &encStructPool[idxpool]
poolv = pool.Get()
switch vv := poolv.(type) {
case *[8]encStructFieldKV:
fkvs = vv[:newlen]
case *[16]encStructFieldKV:
fkvs = vv[:newlen]
case *[32]encStructFieldKV:
fkvs = vv[:newlen]
case *[64]encStructFieldKV:
fkvs = vv[:newlen]
}
}
if fkvs == nil {
fkvs = make([]encStructFieldKV, newlen)
}
// if toMap, use the sorted array. If toArray, use unsorted array (to match sequence in struct)
if toMap {
tisfi = fti.sfi
}
newlen = 0
var kv encStructFieldKV
for _, si := range tisfi {
kv.v = si.field(rv, false)
// if si.i != -1 {
// rvals[newlen] = rv.Field(int(si.i))
// } else {
// rvals[newlen] = rv.FieldByIndex(si.is)
// }
if toMap {
if si.omitEmpty && isEmptyValue(kv.v) {
continue
}
kv.k = si.encName
} else {
// use the zero value.
// if a reference or struct, set to nil (so you do not output too much)
if si.omitEmpty && isEmptyValue(kv.v) {
switch kv.v.Kind() {
case reflect.Struct, reflect.Interface, reflect.Ptr, reflect.Array,
reflect.Map, reflect.Slice:
kv.v = reflect.Value{} //encode as nil
}
}
}
fkvs[newlen] = kv
newlen++
}
// debugf(">>>> kStruct: newlen: %v", newlen)
sep := !e.be
ee := f.ee //don't dereference everytime
if sep {
if toMap {
ee.EncodeMapStart(newlen)
// asSymbols := e.h.AsSymbols&AsSymbolStructFieldNameFlag != 0
asSymbols := e.h.AsSymbols == AsSymbolDefault || e.h.AsSymbols&AsSymbolStructFieldNameFlag != 0
for j := 0; j < newlen; j++ {
kv = fkvs[j]
if j > 0 {
ee.EncodeMapEntrySeparator()
}
if asSymbols {
ee.EncodeSymbol(kv.k)
} else {
ee.EncodeString(c_UTF8, kv.k)
}
ee.EncodeMapKVSeparator()
e.encodeValue(kv.v, encFn{})
}
ee.EncodeMapEnd()
} else {
ee.EncodeArrayStart(newlen)
for j := 0; j < newlen; j++ {
kv = fkvs[j]
if j > 0 {
ee.EncodeArrayEntrySeparator()
}
e.encodeValue(kv.v, encFn{})
}
ee.EncodeArrayEnd()
}
} else {
if toMap {
ee.EncodeMapStart(newlen)
// asSymbols := e.h.AsSymbols&AsSymbolStructFieldNameFlag != 0
asSymbols := e.h.AsSymbols == AsSymbolDefault || e.h.AsSymbols&AsSymbolStructFieldNameFlag != 0
for j := 0; j < newlen; j++ {
kv = fkvs[j]
if asSymbols {
ee.EncodeSymbol(kv.k)
} else {
ee.EncodeString(c_UTF8, kv.k)
}
e.encodeValue(kv.v, encFn{})
}
} else {
ee.EncodeArrayStart(newlen)
for j := 0; j < newlen; j++ {
kv = fkvs[j]
e.encodeValue(kv.v, encFn{})
}
}
}
// 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.
if pool != nil {
pool.Put(poolv)
}
}
// func (f encFnInfo) kPtr(rv reflect.Value) {
// debugf(">>>>>>> ??? encode kPtr called - shouldn't get called")
// if rv.IsNil() {
// f.ee.encodeNil()
// return
// }
// f.e.encodeValue(rv.Elem())
// }
func (f encFnInfo) kInterface(rv reflect.Value) {
if rv.IsNil() {
f.ee.EncodeNil()
return
}
f.e.encodeValue(rv.Elem(), encFn{})
}
func (f encFnInfo) kMap(rv reflect.Value) {
if rv.IsNil() {
f.ee.EncodeNil()
return
}
l := rv.Len()
f.ee.EncodeMapStart(l)
e := f.e
sep := !e.be
if l == 0 {
if sep {
f.ee.EncodeMapEnd()
}
return
}
var asSymbols bool
// 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 encFn
ti := f.ti
rtkey := ti.rt.Key()
rtval := ti.rt.Elem()
rtkeyid := reflect.ValueOf(rtkey).Pointer()
// keyTypeIsString := f.ti.rt.Key().Kind() == reflect.String
var keyTypeIsString = rtkeyid == stringTypId
if keyTypeIsString {
asSymbols = e.h.AsSymbols&AsSymbolMapStringKeysFlag != 0
} else {
for rtkey.Kind() == reflect.Ptr {
rtkey = rtkey.Elem()
}
if rtkey.Kind() != reflect.Interface {
rtkeyid = reflect.ValueOf(rtkey).Pointer()
keyFn = e.getEncFn(rtkeyid, rtkey, true, true)
}
}
for rtval.Kind() == reflect.Ptr {
rtval = rtval.Elem()
}
if rtval.Kind() != reflect.Interface {
rtvalid := reflect.ValueOf(rtval).Pointer()
valFn = e.getEncFn(rtvalid, rtval, true, true)
}
mks := rv.MapKeys()
// for j, lmks := 0, len(mks); j < lmks; j++ {
ee := f.ee //don't dereference everytime
if e.h.Canonical {
// first encode each key to a []byte first, then sort them, then record
// println(">>>>>>>> CANONICAL <<<<<<<<")
var mksv []byte // temporary byte slice for the encoding
e2 := NewEncoderBytes(&mksv, e.hh)
mksbv := make([]encStructFieldBytesV, len(mks))
for i, k := range mks {
l := len(mksv)
e2.MustEncode(k)
mksbv[i].v = k
mksbv[i].b = mksv[l:]
}
sort.Sort(encStructFieldBytesVslice(mksbv))
for j := range mksbv {
if j > 0 {
ee.EncodeMapEntrySeparator()
}
e.w.writeb(mksbv[j].b)
ee.EncodeMapKVSeparator()
e.encodeValue(rv.MapIndex(mksbv[j].v), valFn)
}
ee.EncodeMapEnd()
} else if sep {
for j := range mks {
if j > 0 {
ee.EncodeMapEntrySeparator()
}
if keyTypeIsString {
if asSymbols {
ee.EncodeSymbol(mks[j].String())
} else {
ee.EncodeString(c_UTF8, mks[j].String())
}
} else {
e.encodeValue(mks[j], keyFn)
}
ee.EncodeMapKVSeparator()
e.encodeValue(rv.MapIndex(mks[j]), valFn)
}
ee.EncodeMapEnd()
} else {
for j := range mks {
if keyTypeIsString {
if asSymbols {
ee.EncodeSymbol(mks[j].String())
} else {
ee.EncodeString(c_UTF8, mks[j].String())
}
} else {
e.encodeValue(mks[j], keyFn)
}
e.encodeValue(rv.MapIndex(mks[j]), valFn)
}
}
}
// --------------------------------------------------
// encFn encapsulates the captured variables and the encode function.
// This way, we only do some calculations one times, and pass to the
// code block that should be called (encapsulated in a function)
// instead of executing the checks every time.
type encFn struct {
i encFnInfo
f func(encFnInfo, reflect.Value)
}
// --------------------------------------------------
type rtidEncFn struct {
rtid uintptr
fn encFn
}
// An Encoder writes an object to an output stream in the codec format.
type Encoder struct {
// hopefully, reduce derefencing cost by laying the encWriter inside the Encoder
e encDriver
w encWriter
s []rtidEncFn
be bool // is binary encoding
wi ioEncWriter
wb bytesEncWriter
h *BasicHandle
hh Handle
f map[uintptr]encFn
b [scratchByteArrayLen]byte
}
// NewEncoder returns an Encoder for encoding into an io.Writer.
//
// For efficiency, Users are encouraged to pass in a memory buffered writer
// (eg bufio.Writer, bytes.Buffer).
func NewEncoder(w io.Writer, h Handle) *Encoder {
e := &Encoder{hh: h, h: h.getBasicHandle(), be: h.isBinary()}
ww, ok := w.(ioEncWriterWriter)
if !ok {
sww := simpleIoEncWriterWriter{w: w}
sww.bw, _ = w.(io.ByteWriter)
sww.sw, _ = w.(ioEncStringWriter)
ww = &sww
//ww = bufio.NewWriterSize(w, defEncByteBufSize)
}
e.wi.w = ww
e.w = &e.wi
e.e = h.newEncDriver(e)
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 := &Encoder{hh: h, h: h.getBasicHandle(), be: h.isBinary()}
in := *out
if in == nil {
in = make([]byte, defEncByteBufSize)
}
e.wb.b, e.wb.out = in, out
e.w = &e.wb
e.e = h.newEncDriver(e)
return e
}
// Encode writes an object into a stream.
//
// Encoding can be configured via the struct tag for the fields.
// The "codec" key in struct field's tag value is the key name,
// followed by an optional comma and options.
// Note that the "json" key is used in the absence of the "codec" key.
//
// 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.
//
// 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.
//
// 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
//
// 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 if no struct tag is present.
// Else they are encoded as regular fields.
//
// 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.
// ...
// }
//
// type MyStruct struct {
// _struct bool `codec:",omitempty,toarray"` //set omitempty for every field
// //and encode struct as an array
// }
//
// The mode of encoding is based on the type of the value. When a value is seen:
// - If an extension is registered for it, call that extension function
// - If it implements BinaryMarshaler, call its MarshalBinary() (data []byte, err error)
// - 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) {
defer panicToErr(&err)
e.encode(v)
e.w.atEndOfEncode()
return
}
// MustEncode is like Encode, but panics if unable to Encode.
// This provides insight to the code location that triggered the error.
func (e *Encoder) MustEncode(v interface{}) {
e.encode(v)
e.w.atEndOfEncode()
}
// comment out these (Must)Write methods. They were only put there to support cbor.
// However, users already have access to the streams, and can write directly.
//
// // Write allows users write to the Encoder stream directly.
// func (e *Encoder) Write(bs []byte) (err error) {
// defer panicToErr(&err)
// e.w.writeb(bs)
// return
// }
// // MustWrite is like write, but panics if unable to Write.
// func (e *Encoder) MustWrite(bs []byte) {
// e.w.writeb(bs)
// }
func (e *Encoder) encode(iv interface{}) {
// if ics, ok := iv.(Selfer); ok {
// ics.CodecEncodeSelf(e)
// return
// }
switch v := iv.(type) {
case nil:
e.e.EncodeNil()
case Selfer:
v.CodecEncodeSelf(e)
case reflect.Value:
e.encodeValue(v, encFn{})
case string:
e.e.EncodeString(c_UTF8, 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 float32:
e.e.EncodeFloat32(v)
case float64:
e.e.EncodeFloat64(v)
case []uint8:
e.e.EncodeStringBytes(c_RAW, v)
case *string:
e.e.EncodeString(c_UTF8, *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 *float32:
e.e.EncodeFloat32(*v)
case *float64:
e.e.EncodeFloat64(*v)
case *[]uint8:
e.e.EncodeStringBytes(c_RAW, *v)
default:
// canonical mode is not supported for fastpath of maps (but is fine for slices)
if e.h.Canonical {
if !fastpathEncodeTypeSwitchSlice(iv, e) {
e.encodeI(iv, false, false)
}
} else if !fastpathEncodeTypeSwitch(iv, e) {
e.encodeI(iv, false, false)
}
}
}
func (e *Encoder) encodeI(iv interface{}, checkFastpath, checkCodecSelfer bool) {
if rv, proceed := e.preEncodeValue(reflect.ValueOf(iv)); proceed {
rt := rv.Type()
rtid := reflect.ValueOf(rt).Pointer()
fn := e.getEncFn(rtid, rt, checkFastpath, checkCodecSelfer)
fn.f(fn.i, rv)
}
}
func (e *Encoder) preEncodeValue(rv reflect.Value) (rv2 reflect.Value, proceed bool) {
LOOP:
for {
switch rv.Kind() {
case reflect.Ptr, reflect.Interface:
if rv.IsNil() {
e.e.EncodeNil()
return
}
rv = rv.Elem()
continue LOOP
case reflect.Slice, reflect.Map:
if rv.IsNil() {
e.e.EncodeNil()
return
}
case reflect.Invalid, reflect.Func:
e.e.EncodeNil()
return
}
break
}
return rv, true
}
func (e *Encoder) encodeValue(rv reflect.Value, fn encFn) {
// if a valid fn is passed, it MUST BE for the dereferenced type of rv
if rv, proceed := e.preEncodeValue(rv); proceed {
if fn.f == nil {
rt := rv.Type()
rtid := reflect.ValueOf(rt).Pointer()
fn = e.getEncFn(rtid, rt, true, true)
}
fn.f(fn.i, rv)
}
}
func (e *Encoder) getEncFn(rtid uintptr, rt reflect.Type, checkFastpath, checkCodecSelfer bool) (fn encFn) {
// rtid := reflect.ValueOf(rt).Pointer()
var ok bool
if useMapForCodecCache {
fn, ok = e.f[rtid]
} else {
for _, v := range e.s {
if v.rtid == rtid {
fn, ok = v.fn, true
break
}
}
}
if ok {
return
}
// fi.encFnInfoX = new(encFnInfoX)
ti := getTypeInfo(rtid, rt)
var fi encFnInfo
fi.ee = e.e
if checkCodecSelfer && ti.cs {
fi.encFnInfoX = &encFnInfoX{e: e, ti: ti}
fn.f = (encFnInfo).selferMarshal
} else if rtid == rawExtTypId {
fi.encFnInfoX = &encFnInfoX{e: e, ti: ti}
fn.f = (encFnInfo).rawExt
} else if e.e.IsBuiltinType(rtid) {
fi.encFnInfoX = &encFnInfoX{e: e, ti: ti}
fn.f = (encFnInfo).builtin
} else if xfFn := e.h.getExt(rtid); xfFn != nil {
// fi.encFnInfoX = new(encFnInfoX)
fi.encFnInfoX = &encFnInfoX{e: e, ti: ti}
fi.xfTag, fi.xfFn = xfFn.tag, xfFn.ext
fn.f = (encFnInfo).ext
} else if supportMarshalInterfaces && e.be && ti.bm {
fi.encFnInfoX = &encFnInfoX{e: e, ti: ti}
fn.f = (encFnInfo).binaryMarshal
} else if supportMarshalInterfaces && !e.be && ti.tm {
fi.encFnInfoX = &encFnInfoX{e: e, ti: ti}
fn.f = (encFnInfo).textMarshal
} else {
rk := rt.Kind()
if fastpathEnabled && checkFastpath && (rk == reflect.Map || rk == reflect.Slice) {
if rt.PkgPath() == "" {
if idx := fastpathAV.index(rtid); idx != -1 {
fi.encFnInfoX = &encFnInfoX{e: e, ti: ti}
fn.f = fastpathAV[idx].encfn
}
} else {
ok = false
// use mapping for underlying type if there
var rtu reflect.Type
if rk == reflect.Map {
rtu = reflect.MapOf(rt.Key(), rt.Elem())
} else {
rtu = reflect.SliceOf(rt.Elem())
}
rtuid := reflect.ValueOf(rtu).Pointer()
if idx := fastpathAV.index(rtuid); idx != -1 {
xfnf := fastpathAV[idx].encfn
xrt := fastpathAV[idx].rt
fi.encFnInfoX = &encFnInfoX{e: e, ti: ti}
fn.f = func(xf encFnInfo, xrv reflect.Value) {
xfnf(xf, xrv.Convert(xrt))
}
}
}
}
if fn.f == nil {
switch rk {
case reflect.Bool:
fn.f = (encFnInfo).kBool
case reflect.String:
fn.f = (encFnInfo).kString
case reflect.Float64:
fn.f = (encFnInfo).kFloat64
case reflect.Float32:
fn.f = (encFnInfo).kFloat32
case reflect.Int, reflect.Int8, reflect.Int64, reflect.Int32, reflect.Int16:
fn.f = (encFnInfo).kInt
case reflect.Uint8, reflect.Uint64, reflect.Uint, reflect.Uint32, reflect.Uint16:
fn.f = (encFnInfo).kUint
case reflect.Invalid:
fn.f = (encFnInfo).kInvalid
case reflect.Chan:
fi.encFnInfoX = &encFnInfoX{e: e, ti: ti, seq: seqTypeChan}
fn.f = (encFnInfo).kSlice
case reflect.Slice:
fi.encFnInfoX = &encFnInfoX{e: e, ti: ti, seq: seqTypeSlice}
fn.f = (encFnInfo).kSlice
case reflect.Array:
fi.encFnInfoX = &encFnInfoX{e: e, ti: ti, seq: seqTypeArray}
fn.f = (encFnInfo).kSlice
case reflect.Struct:
fi.encFnInfoX = &encFnInfoX{e: e, ti: ti}
fn.f = (encFnInfo).kStruct
// case reflect.Ptr:
// fn.f = (encFnInfo).kPtr
case reflect.Interface:
fi.encFnInfoX = &encFnInfoX{e: e, ti: ti}
fn.f = (encFnInfo).kInterface
case reflect.Map:
fi.encFnInfoX = &encFnInfoX{e: e, ti: ti}
fn.f = (encFnInfo).kMap
default:
fn.f = (encFnInfo).kErr
}
}
}
fn.i = fi
if useMapForCodecCache {
if e.f == nil {
e.f = make(map[uintptr]encFn, 32)
}
e.f[rtid] = fn
} else {
if e.s == nil {
e.s = make([]rtidEncFn, 0, 32)
}
e.s = append(e.s, rtidEncFn{rtid, fn})
}
return
}
func (e *Encoder) errorf(format string, params ...interface{}) {
err := fmt.Errorf(format, params...)
panic(err)
}
// ----------------------------------------
type encStructFieldKV struct {
k string
v reflect.Value
}
const encStructPoolLen = 4
// encStructPool is an array of sync.Pool.
// Each element of the array pools one of encStructPool(8|16|32|64).
// It allows the re-use of slices up to 64 in length.
// A performance cost of encoding structs was collecting
// which values were empty and should be omitted.
// We needed slices of reflect.Value and string to collect them.
// This shared pool reduces the amount of unnecessary creation we do.
// The cost is that of locking sometimes, but sync.Pool is efficient
// enough to reduce thread contention.
var encStructPool [encStructPoolLen]sync.Pool
func init() {
encStructPool[0].New = func() interface{} { return new([8]encStructFieldKV) }
encStructPool[1].New = func() interface{} { return new([16]encStructFieldKV) }
encStructPool[2].New = func() interface{} { return new([32]encStructFieldKV) }
encStructPool[3].New = func() interface{} { return new([64]encStructFieldKV) }
}
// ----------------------------------------
// func encErr(format string, params ...interface{}) {
// doPanic(msgTagEnc, format, params...)
// }