forked from mirror/go-json
480 lines
12 KiB
Go
480 lines
12 KiB
Go
package json
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import (
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"fmt"
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"io"
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"reflect"
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"strconv"
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"strings"
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"sync"
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"unsafe"
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"golang.org/x/xerrors"
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)
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// An Encoder writes JSON values to an output stream.
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type Encoder struct {
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w io.Writer
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buf []byte
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pool sync.Pool
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}
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type EncodeOp func(*Encoder, uintptr)
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const (
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bufSize = 1024
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)
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var (
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encPool sync.Pool
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cachedEncodeOp map[string]EncodeOp
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)
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func init() {
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encPool = sync.Pool{
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New: func() interface{} {
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return &Encoder{
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buf: make([]byte, 0, bufSize),
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pool: encPool,
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}
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},
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}
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cachedEncodeOp = map[string]EncodeOp{}
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}
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// NewEncoder returns a new encoder that writes to w.
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func NewEncoder(w io.Writer) *Encoder {
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enc := encPool.Get().(*Encoder)
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enc.w = w
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enc.reset()
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return enc
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}
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// Encode writes the JSON encoding of v to the stream, followed by a newline character.
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//
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// See the documentation for Marshal for details about the conversion of Go values to JSON.
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func (e *Encoder) Encode(v interface{}) error {
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header := (*interfaceHeader)(unsafe.Pointer(&v))
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if err := e.encode(reflect.ValueOf(v), header.ptr); err != nil {
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return err
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}
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if _, err := e.w.Write(e.buf); err != nil {
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return err
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}
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return nil
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}
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func (e *Encoder) encodeForMarshal(v interface{}) ([]byte, error) {
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header := (*interfaceHeader)(unsafe.Pointer(&v))
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if err := e.encode(reflect.ValueOf(v), header.ptr); err != nil {
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return nil, err
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}
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copied := make([]byte, len(e.buf))
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copy(copied, e.buf)
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return copied, nil
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}
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// SetEscapeHTML specifies whether problematic HTML characters should be escaped inside JSON quoted strings.
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// The default behavior is to escape &, <, and > to \u0026, \u003c, and \u003e to avoid certain safety problems that can arise when embedding JSON in HTML.
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//
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// In non-HTML settings where the escaping interferes with the readability of the output, SetEscapeHTML(false) disables this behavior.
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func (e *Encoder) SetEscapeHTML(on bool) {
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}
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// SetIndent instructs the encoder to format each subsequent encoded value as if indented by the package-level function Indent(dst, src, prefix, indent).
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// Calling SetIndent("", "") disables indentation.
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func (e *Encoder) SetIndent(prefix, indent string) {
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}
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func (e *Encoder) release() {
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e.w = nil
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e.pool.Put(e)
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}
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func (e *Encoder) reset() {
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e.buf = e.buf[:0]
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}
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func (e *Encoder) encodeInt(v int) {
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e.encodeInt64(int64(v))
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}
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func (e *Encoder) encodeInt8(v int8) {
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e.encodeInt64(int64(v))
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}
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func (e *Encoder) encodeInt16(v int16) {
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e.encodeInt64(int64(v))
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}
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func (e *Encoder) encodeInt32(v int32) {
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e.encodeInt64(int64(v))
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}
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func (e *Encoder) encodeInt64(v int64) {
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e.buf = strconv.AppendInt(e.buf, v, 10)
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}
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func (e *Encoder) encodeUint(v uint) {
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e.encodeUint64(uint64(v))
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}
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func (e *Encoder) encodeUint8(v uint8) {
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e.encodeUint64(uint64(v))
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}
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func (e *Encoder) encodeUint16(v uint16) {
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e.encodeUint64(uint64(v))
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}
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func (e *Encoder) encodeUint32(v uint32) {
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e.encodeUint64(uint64(v))
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}
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func (e *Encoder) encodeUint64(v uint64) {
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e.buf = strconv.AppendUint(e.buf, v, 10)
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}
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func (e *Encoder) encodeFloat32(v float32) {
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e.buf = strconv.AppendFloat(e.buf, float64(v), 'f', -1, 32)
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}
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func (e *Encoder) encodeFloat64(v float64) {
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e.buf = strconv.AppendFloat(e.buf, v, 'f', -1, 64)
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}
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func (e *Encoder) encodeBool(v bool) {
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e.buf = strconv.AppendBool(e.buf, v)
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}
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func (e *Encoder) encodeString(s string) {
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b := *(*[]byte)(unsafe.Pointer(&s))
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e.buf = append(e.buf, b...)
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}
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func (e *Encoder) encodeByte(b byte) {
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e.buf = append(e.buf, b)
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}
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type rtype struct{}
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type interfaceHeader struct {
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typ *rtype
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ptr unsafe.Pointer
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}
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func (e *Encoder) encode(v reflect.Value, ptr unsafe.Pointer) error {
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typ := v.Type()
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name := typ.String()
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if op, exists := cachedEncodeOp[name]; exists {
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op(e, uintptr(ptr))
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return nil
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}
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if typ.Kind() == reflect.Ptr {
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typ = typ.Elem()
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}
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op, err := e.compile(typ)
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if err != nil {
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return err
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}
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if name != "" {
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cachedEncodeOp[name] = op
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}
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op(e, uintptr(ptr))
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return nil
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}
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func (e *Encoder) compile(typ reflect.Type) (EncodeOp, error) {
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switch typ.Kind() {
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case reflect.Ptr:
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return e.compilePtr(typ)
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case reflect.Slice:
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return e.compileSlice(typ)
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case reflect.Struct:
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return e.compileStruct(typ)
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case reflect.Map:
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return e.compileMap(typ)
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case reflect.Array:
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return e.compileArray(typ)
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case reflect.Int:
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return e.compileInt()
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case reflect.Int8:
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return e.compileInt8()
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case reflect.Int16:
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return e.compileInt16()
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case reflect.Int32:
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return e.compileInt32()
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case reflect.Int64:
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return e.compileInt64()
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case reflect.Uint:
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return e.compileUint()
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case reflect.Uint8:
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return e.compileUint8()
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case reflect.Uint16:
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return e.compileUint16()
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case reflect.Uint32:
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return e.compileUint32()
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case reflect.Uint64:
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return e.compileUint64()
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case reflect.Uintptr:
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return e.compileUint()
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case reflect.Float32:
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return e.compileFloat32()
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case reflect.Float64:
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return e.compileFloat64()
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case reflect.String:
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return e.compileString()
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case reflect.Bool:
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return e.compileBool()
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case reflect.Interface:
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return nil, ErrCompileSlowPath
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}
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return nil, xerrors.Errorf("failed to encode type %s: %w", typ, ErrUnsupportedType)
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}
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func (e *Encoder) compilePtr(typ reflect.Type) (EncodeOp, error) {
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op, err := e.compile(typ.Elem())
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if err != nil {
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return nil, err
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}
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return func(enc *Encoder, p uintptr) {
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op(enc, e.ptrToPtr(p))
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}, nil
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}
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func (e *Encoder) compileInt() (EncodeOp, error) {
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return func(enc *Encoder, p uintptr) { enc.encodeInt(e.ptrToInt(p)) }, nil
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}
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func (e *Encoder) compileInt8() (EncodeOp, error) {
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return func(enc *Encoder, p uintptr) { enc.encodeInt8(e.ptrToInt8(p)) }, nil
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}
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func (e *Encoder) compileInt16() (EncodeOp, error) {
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return func(enc *Encoder, p uintptr) { enc.encodeInt16(e.ptrToInt16(p)) }, nil
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}
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func (e *Encoder) compileInt32() (EncodeOp, error) {
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return func(enc *Encoder, p uintptr) { enc.encodeInt32(e.ptrToInt32(p)) }, nil
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}
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func (e *Encoder) compileInt64() (EncodeOp, error) {
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return func(enc *Encoder, p uintptr) { enc.encodeInt64(e.ptrToInt64(p)) }, nil
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}
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func (e *Encoder) compileUint() (EncodeOp, error) {
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return func(enc *Encoder, p uintptr) { enc.encodeUint(e.ptrToUint(p)) }, nil
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}
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func (e *Encoder) compileUint8() (EncodeOp, error) {
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return func(enc *Encoder, p uintptr) { enc.encodeUint8(e.ptrToUint8(p)) }, nil
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}
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func (e *Encoder) compileUint16() (EncodeOp, error) {
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return func(enc *Encoder, p uintptr) { enc.encodeUint16(e.ptrToUint16(p)) }, nil
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}
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func (e *Encoder) compileUint32() (EncodeOp, error) {
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return func(enc *Encoder, p uintptr) { enc.encodeUint32(e.ptrToUint32(p)) }, nil
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}
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func (e *Encoder) compileUint64() (EncodeOp, error) {
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return func(enc *Encoder, p uintptr) { enc.encodeUint64(e.ptrToUint64(p)) }, nil
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}
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func (e *Encoder) compileFloat32() (EncodeOp, error) {
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return func(enc *Encoder, p uintptr) { enc.encodeFloat32(e.ptrToFloat32(p)) }, nil
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}
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func (e *Encoder) compileFloat64() (EncodeOp, error) {
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return func(enc *Encoder, p uintptr) { enc.encodeFloat64(e.ptrToFloat64(p)) }, nil
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}
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func (e *Encoder) compileString() (EncodeOp, error) {
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return func(enc *Encoder, p uintptr) { enc.encodeEscapedString(e.ptrToString(p)) }, nil
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}
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func (e *Encoder) compileBool() (EncodeOp, error) {
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return func(enc *Encoder, p uintptr) { enc.encodeBool(e.ptrToBool(p)) }, nil
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}
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func (e *Encoder) compileSlice(typ reflect.Type) (EncodeOp, error) {
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size := typ.Elem().Size()
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op, err := e.compile(typ.Elem())
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if err != nil {
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return nil, err
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}
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return func(enc *Encoder, base uintptr) {
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if base == 0 {
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enc.encodeString("null")
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return
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}
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enc.encodeByte('[')
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slice := (*reflect.SliceHeader)(unsafe.Pointer(base))
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num := slice.Len
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for i := 0; i < num; i++ {
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op(enc, slice.Data+uintptr(i)*size)
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if i != num-1 {
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enc.encodeByte(',')
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}
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}
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enc.encodeByte(']')
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}, nil
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}
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func (e *Encoder) compileArray(typ reflect.Type) (EncodeOp, error) {
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alen := typ.Len()
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size := typ.Elem().Size()
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op, err := e.compile(typ.Elem())
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if err != nil {
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return nil, err
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}
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return func(enc *Encoder, base uintptr) {
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if base == 0 {
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enc.encodeString("null")
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return
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}
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enc.encodeByte('[')
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for i := 0; i < alen; i++ {
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if i != 0 {
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enc.encodeByte(',')
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}
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op(enc, base+uintptr(i)*size)
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}
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enc.encodeByte(']')
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}, nil
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}
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func (e *Encoder) getTag(field reflect.StructField) string {
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return field.Tag.Get("json")
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}
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func (e *Encoder) isIgnoredStructField(field reflect.StructField) bool {
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if field.PkgPath != "" && !field.Anonymous {
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// private field
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return true
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}
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tag := e.getTag(field)
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if tag == "-" {
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return true
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}
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return false
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}
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func (e *Encoder) compileStruct(typ reflect.Type) (EncodeOp, error) {
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fieldNum := typ.NumField()
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opQueue := make([]EncodeOp, 0, fieldNum)
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for i := 0; i < fieldNum; i++ {
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field := typ.Field(i)
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if e.isIgnoredStructField(field) {
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continue
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}
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keyName := field.Name
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tag := e.getTag(field)
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opts := strings.Split(tag, ",")
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if len(opts) > 0 {
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if opts[0] != "" {
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keyName = opts[0]
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}
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}
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op, err := e.compile(field.Type)
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if err != nil {
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return nil, err
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}
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key := fmt.Sprintf(`"%s":`, keyName)
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opQueue = append(opQueue, func(enc *Encoder, base uintptr) {
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enc.encodeString(key)
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op(enc, base+field.Offset)
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})
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}
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queueNum := len(opQueue)
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return func(enc *Encoder, base uintptr) {
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if base == 0 {
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enc.encodeString("null")
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return
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}
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enc.encodeByte('{')
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for i := 0; i < queueNum; i++ {
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opQueue[i](enc, base)
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if i != queueNum-1 {
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enc.encodeByte(',')
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}
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}
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enc.encodeByte('}')
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}, nil
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}
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//go:linkname mapiterinit reflect.mapiterinit
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func mapiterinit(mapType unsafe.Pointer, m unsafe.Pointer) unsafe.Pointer
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//go:linkname mapiterkey reflect.mapiterkey
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func mapiterkey(it unsafe.Pointer) unsafe.Pointer
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//go:linkname mapitervalue reflect.mapitervalue
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func mapitervalue(it unsafe.Pointer) unsafe.Pointer
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//go:linkname mapiternext reflect.mapiternext
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func mapiternext(it unsafe.Pointer)
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//go:linkname maplen reflect.maplen
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func maplen(m unsafe.Pointer) int
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type valueType struct {
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typ unsafe.Pointer
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ptr unsafe.Pointer
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}
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func (e *Encoder) compileMap(typ reflect.Type) (EncodeOp, error) {
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v := reflect.New(typ).Elem()
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mapType := (*valueType)(unsafe.Pointer(&v)).typ
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keyOp, err := e.compile(typ.Key())
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if err != nil {
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return nil, err
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}
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valueOp, err := e.compile(typ.Elem())
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if err != nil {
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return nil, err
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}
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return func(enc *Encoder, base uintptr) {
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if base == 0 {
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enc.encodeString("null")
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return
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}
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enc.encodeByte('{')
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mlen := maplen(unsafe.Pointer(base))
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iter := mapiterinit(mapType, unsafe.Pointer(base))
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for i := 0; i < mlen; i++ {
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key := mapiterkey(iter)
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if i != 0 {
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enc.encodeByte(',')
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}
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value := mapitervalue(iter)
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keyOp(enc, uintptr(key))
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enc.encodeByte(':')
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valueOp(enc, uintptr(value))
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mapiternext(iter)
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}
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enc.encodeByte('}')
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}, nil
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}
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func (e *Encoder) ptrToPtr(p uintptr) uintptr { return *(*uintptr)(unsafe.Pointer(p)) }
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func (e *Encoder) ptrToInt(p uintptr) int { return *(*int)(unsafe.Pointer(p)) }
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func (e *Encoder) ptrToInt8(p uintptr) int8 { return *(*int8)(unsafe.Pointer(p)) }
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func (e *Encoder) ptrToInt16(p uintptr) int16 { return *(*int16)(unsafe.Pointer(p)) }
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func (e *Encoder) ptrToInt32(p uintptr) int32 { return *(*int32)(unsafe.Pointer(p)) }
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func (e *Encoder) ptrToInt64(p uintptr) int64 { return *(*int64)(unsafe.Pointer(p)) }
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func (e *Encoder) ptrToUint(p uintptr) uint { return *(*uint)(unsafe.Pointer(p)) }
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func (e *Encoder) ptrToUint8(p uintptr) uint8 { return *(*uint8)(unsafe.Pointer(p)) }
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func (e *Encoder) ptrToUint16(p uintptr) uint16 { return *(*uint16)(unsafe.Pointer(p)) }
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func (e *Encoder) ptrToUint32(p uintptr) uint32 { return *(*uint32)(unsafe.Pointer(p)) }
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func (e *Encoder) ptrToUint64(p uintptr) uint64 { return *(*uint64)(unsafe.Pointer(p)) }
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func (e *Encoder) ptrToFloat32(p uintptr) float32 { return *(*float32)(unsafe.Pointer(p)) }
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func (e *Encoder) ptrToFloat64(p uintptr) float64 { return *(*float64)(unsafe.Pointer(p)) }
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func (e *Encoder) ptrToBool(p uintptr) bool { return *(*bool)(unsafe.Pointer(p)) }
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func (e *Encoder) ptrToByte(p uintptr) byte { return *(*byte)(unsafe.Pointer(p)) }
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func (e *Encoder) ptrToBytes(p uintptr) []byte { return *(*[]byte)(unsafe.Pointer(p)) }
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func (e *Encoder) ptrToString(p uintptr) string { return *(*string)(unsafe.Pointer(p)) }
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