From f154da9e12608589e8d5f0508f908a0c3e88a1bb Mon Sep 17 00:00:00 2001
From: Tianon Gravi <admwiggin@gmail.com>
Date: Thu, 15 Jan 2015 11:54:00 -0700
Subject: Imported Upstream version 1.4

---
 src/pkg/encoding/json/encode.go | 1175 ---------------------------------------
 1 file changed, 1175 deletions(-)
 delete mode 100644 src/pkg/encoding/json/encode.go

(limited to 'src/pkg/encoding/json/encode.go')

diff --git a/src/pkg/encoding/json/encode.go b/src/pkg/encoding/json/encode.go
deleted file mode 100644
index 741ddd89c..000000000
--- a/src/pkg/encoding/json/encode.go
+++ /dev/null
@@ -1,1175 +0,0 @@
-// Copyright 2010 The Go Authors.  All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package json implements encoding and decoding of JSON objects as defined in
-// RFC 4627. The mapping between JSON objects and Go values is described
-// in the documentation for the Marshal and Unmarshal functions.
-//
-// See "JSON and Go" for an introduction to this package:
-// http://golang.org/doc/articles/json_and_go.html
-package json
-
-import (
-	"bytes"
-	"encoding"
-	"encoding/base64"
-	"math"
-	"reflect"
-	"runtime"
-	"sort"
-	"strconv"
-	"strings"
-	"sync"
-	"unicode"
-	"unicode/utf8"
-)
-
-// Marshal returns the JSON encoding of v.
-//
-// Marshal traverses the value v recursively.
-// If an encountered value implements the Marshaler interface
-// and is not a nil pointer, Marshal calls its MarshalJSON method
-// to produce JSON.  The nil pointer exception is not strictly necessary
-// but mimics a similar, necessary exception in the behavior of
-// UnmarshalJSON.
-//
-// Otherwise, Marshal uses the following type-dependent default encodings:
-//
-// Boolean values encode as JSON booleans.
-//
-// Floating point, integer, and Number values encode as JSON numbers.
-//
-// String values encode as JSON strings. InvalidUTF8Error will be returned
-// if an invalid UTF-8 sequence is encountered.
-// The angle brackets "<" and ">" are escaped to "\u003c" and "\u003e"
-// to keep some browsers from misinterpreting JSON output as HTML.
-// Ampersand "&" is also escaped to "\u0026" for the same reason.
-//
-// Array and slice values encode as JSON arrays, except that
-// []byte encodes as a base64-encoded string, and a nil slice
-// encodes as the null JSON object.
-//
-// Struct values encode as JSON objects. Each exported struct field
-// becomes a member of the object unless
-//   - the field's tag is "-", or
-//   - the field is empty and its tag specifies the "omitempty" option.
-// The empty values are false, 0, any
-// nil pointer or interface value, and any array, slice, map, or string of
-// length zero. The object's default key string is the struct field name
-// but can be specified in the struct field's tag value. The "json" key in
-// the struct field's tag value is the key name, followed by an optional comma
-// and options. Examples:
-//
-//   // Field is ignored by this package.
-//   Field int `json:"-"`
-//
-//   // Field appears in JSON as key "myName".
-//   Field int `json:"myName"`
-//
-//   // Field appears in JSON as key "myName" and
-//   // the field is omitted from the object if its value is empty,
-//   // as defined above.
-//   Field int `json:"myName,omitempty"`
-//
-//   // Field appears in JSON as key "Field" (the default), but
-//   // the field is skipped if empty.
-//   // Note the leading comma.
-//   Field int `json:",omitempty"`
-//
-// The "string" option signals that a field is stored as JSON inside a
-// JSON-encoded string. It applies only to fields of string, floating point,
-// or integer types. This extra level of encoding is sometimes used when
-// communicating with JavaScript programs:
-//
-//    Int64String int64 `json:",string"`
-//
-// The key name will be used if it's a non-empty string consisting of
-// only Unicode letters, digits, dollar signs, percent signs, hyphens,
-// underscores and slashes.
-//
-// Anonymous struct fields are usually marshaled as if their inner exported fields
-// were fields in the outer struct, subject to the usual Go visibility rules amended
-// as described in the next paragraph.
-// An anonymous struct field with a name given in its JSON tag is treated as
-// having that name, rather than being anonymous.
-//
-// The Go visibility rules for struct fields are amended for JSON when
-// deciding which field to marshal or unmarshal. If there are
-// multiple fields at the same level, and that level is the least
-// nested (and would therefore be the nesting level selected by the
-// usual Go rules), the following extra rules apply:
-//
-// 1) Of those fields, if any are JSON-tagged, only tagged fields are considered,
-// even if there are multiple untagged fields that would otherwise conflict.
-// 2) If there is exactly one field (tagged or not according to the first rule), that is selected.
-// 3) Otherwise there are multiple fields, and all are ignored; no error occurs.
-//
-// Handling of anonymous struct fields is new in Go 1.1.
-// Prior to Go 1.1, anonymous struct fields were ignored. To force ignoring of
-// an anonymous struct field in both current and earlier versions, give the field
-// a JSON tag of "-".
-//
-// Map values encode as JSON objects.
-// The map's key type must be string; the object keys are used directly
-// as map keys.
-//
-// Pointer values encode as the value pointed to.
-// A nil pointer encodes as the null JSON object.
-//
-// Interface values encode as the value contained in the interface.
-// A nil interface value encodes as the null JSON object.
-//
-// Channel, complex, and function values cannot be encoded in JSON.
-// Attempting to encode such a value causes Marshal to return
-// an UnsupportedTypeError.
-//
-// JSON cannot represent cyclic data structures and Marshal does not
-// handle them.  Passing cyclic structures to Marshal will result in
-// an infinite recursion.
-//
-func Marshal(v interface{}) ([]byte, error) {
-	e := &encodeState{}
-	err := e.marshal(v)
-	if err != nil {
-		return nil, err
-	}
-	return e.Bytes(), nil
-}
-
-// MarshalIndent is like Marshal but applies Indent to format the output.
-func MarshalIndent(v interface{}, prefix, indent string) ([]byte, error) {
-	b, err := Marshal(v)
-	if err != nil {
-		return nil, err
-	}
-	var buf bytes.Buffer
-	err = Indent(&buf, b, prefix, indent)
-	if err != nil {
-		return nil, err
-	}
-	return buf.Bytes(), nil
-}
-
-// HTMLEscape appends to dst the JSON-encoded src with <, >, &, U+2028 and U+2029
-// characters inside string literals changed to \u003c, \u003e, \u0026, \u2028, \u2029
-// so that the JSON will be safe to embed inside HTML <script> tags.
-// For historical reasons, web browsers don't honor standard HTML
-// escaping within <script> tags, so an alternative JSON encoding must
-// be used.
-func HTMLEscape(dst *bytes.Buffer, src []byte) {
-	// The characters can only appear in string literals,
-	// so just scan the string one byte at a time.
-	start := 0
-	for i, c := range src {
-		if c == '<' || c == '>' || c == '&' {
-			if start < i {
-				dst.Write(src[start:i])
-			}
-			dst.WriteString(`\u00`)
-			dst.WriteByte(hex[c>>4])
-			dst.WriteByte(hex[c&0xF])
-			start = i + 1
-		}
-		// Convert U+2028 and U+2029 (E2 80 A8 and E2 80 A9).
-		if c == 0xE2 && i+2 < len(src) && src[i+1] == 0x80 && src[i+2]&^1 == 0xA8 {
-			if start < i {
-				dst.Write(src[start:i])
-			}
-			dst.WriteString(`\u202`)
-			dst.WriteByte(hex[src[i+2]&0xF])
-			start = i + 3
-		}
-	}
-	if start < len(src) {
-		dst.Write(src[start:])
-	}
-}
-
-// Marshaler is the interface implemented by objects that
-// can marshal themselves into valid JSON.
-type Marshaler interface {
-	MarshalJSON() ([]byte, error)
-}
-
-// An UnsupportedTypeError is returned by Marshal when attempting
-// to encode an unsupported value type.
-type UnsupportedTypeError struct {
-	Type reflect.Type
-}
-
-func (e *UnsupportedTypeError) Error() string {
-	return "json: unsupported type: " + e.Type.String()
-}
-
-type UnsupportedValueError struct {
-	Value reflect.Value
-	Str   string
-}
-
-func (e *UnsupportedValueError) Error() string {
-	return "json: unsupported value: " + e.Str
-}
-
-// Before Go 1.2, an InvalidUTF8Error was returned by Marshal when
-// attempting to encode a string value with invalid UTF-8 sequences.
-// As of Go 1.2, Marshal instead coerces the string to valid UTF-8 by
-// replacing invalid bytes with the Unicode replacement rune U+FFFD.
-// This error is no longer generated but is kept for backwards compatibility
-// with programs that might mention it.
-type InvalidUTF8Error struct {
-	S string // the whole string value that caused the error
-}
-
-func (e *InvalidUTF8Error) Error() string {
-	return "json: invalid UTF-8 in string: " + strconv.Quote(e.S)
-}
-
-type MarshalerError struct {
-	Type reflect.Type
-	Err  error
-}
-
-func (e *MarshalerError) Error() string {
-	return "json: error calling MarshalJSON for type " + e.Type.String() + ": " + e.Err.Error()
-}
-
-var hex = "0123456789abcdef"
-
-// An encodeState encodes JSON into a bytes.Buffer.
-type encodeState struct {
-	bytes.Buffer // accumulated output
-	scratch      [64]byte
-}
-
-var encodeStatePool sync.Pool
-
-func newEncodeState() *encodeState {
-	if v := encodeStatePool.Get(); v != nil {
-		e := v.(*encodeState)
-		e.Reset()
-		return e
-	}
-	return new(encodeState)
-}
-
-func (e *encodeState) marshal(v interface{}) (err error) {
-	defer func() {
-		if r := recover(); r != nil {
-			if _, ok := r.(runtime.Error); ok {
-				panic(r)
-			}
-			if s, ok := r.(string); ok {
-				panic(s)
-			}
-			err = r.(error)
-		}
-	}()
-	e.reflectValue(reflect.ValueOf(v))
-	return nil
-}
-
-func (e *encodeState) error(err error) {
-	panic(err)
-}
-
-var byteSliceType = reflect.TypeOf([]byte(nil))
-
-func isEmptyValue(v reflect.Value) bool {
-	switch v.Kind() {
-	case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
-		return v.Len() == 0
-	case reflect.Bool:
-		return !v.Bool()
-	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-		return v.Int() == 0
-	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
-		return v.Uint() == 0
-	case reflect.Float32, reflect.Float64:
-		return v.Float() == 0
-	case reflect.Interface, reflect.Ptr:
-		return v.IsNil()
-	}
-	return false
-}
-
-func (e *encodeState) reflectValue(v reflect.Value) {
-	valueEncoder(v)(e, v, false)
-}
-
-type encoderFunc func(e *encodeState, v reflect.Value, quoted bool)
-
-var encoderCache struct {
-	sync.RWMutex
-	m map[reflect.Type]encoderFunc
-}
-
-func valueEncoder(v reflect.Value) encoderFunc {
-	if !v.IsValid() {
-		return invalidValueEncoder
-	}
-	return typeEncoder(v.Type())
-}
-
-func typeEncoder(t reflect.Type) encoderFunc {
-	encoderCache.RLock()
-	f := encoderCache.m[t]
-	encoderCache.RUnlock()
-	if f != nil {
-		return f
-	}
-
-	// To deal with recursive types, populate the map with an
-	// indirect func before we build it. This type waits on the
-	// real func (f) to be ready and then calls it.  This indirect
-	// func is only used for recursive types.
-	encoderCache.Lock()
-	if encoderCache.m == nil {
-		encoderCache.m = make(map[reflect.Type]encoderFunc)
-	}
-	var wg sync.WaitGroup
-	wg.Add(1)
-	encoderCache.m[t] = func(e *encodeState, v reflect.Value, quoted bool) {
-		wg.Wait()
-		f(e, v, quoted)
-	}
-	encoderCache.Unlock()
-
-	// Compute fields without lock.
-	// Might duplicate effort but won't hold other computations back.
-	f = newTypeEncoder(t, true)
-	wg.Done()
-	encoderCache.Lock()
-	encoderCache.m[t] = f
-	encoderCache.Unlock()
-	return f
-}
-
-var (
-	marshalerType     = reflect.TypeOf(new(Marshaler)).Elem()
-	textMarshalerType = reflect.TypeOf(new(encoding.TextMarshaler)).Elem()
-)
-
-// newTypeEncoder constructs an encoderFunc for a type.
-// The returned encoder only checks CanAddr when allowAddr is true.
-func newTypeEncoder(t reflect.Type, allowAddr bool) encoderFunc {
-	if t.Implements(marshalerType) {
-		return marshalerEncoder
-	}
-	if t.Kind() != reflect.Ptr && allowAddr {
-		if reflect.PtrTo(t).Implements(marshalerType) {
-			return newCondAddrEncoder(addrMarshalerEncoder, newTypeEncoder(t, false))
-		}
-	}
-
-	if t.Implements(textMarshalerType) {
-		return textMarshalerEncoder
-	}
-	if t.Kind() != reflect.Ptr && allowAddr {
-		if reflect.PtrTo(t).Implements(textMarshalerType) {
-			return newCondAddrEncoder(addrTextMarshalerEncoder, newTypeEncoder(t, false))
-		}
-	}
-
-	switch t.Kind() {
-	case reflect.Bool:
-		return boolEncoder
-	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-		return intEncoder
-	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
-		return uintEncoder
-	case reflect.Float32:
-		return float32Encoder
-	case reflect.Float64:
-		return float64Encoder
-	case reflect.String:
-		return stringEncoder
-	case reflect.Interface:
-		return interfaceEncoder
-	case reflect.Struct:
-		return newStructEncoder(t)
-	case reflect.Map:
-		return newMapEncoder(t)
-	case reflect.Slice:
-		return newSliceEncoder(t)
-	case reflect.Array:
-		return newArrayEncoder(t)
-	case reflect.Ptr:
-		return newPtrEncoder(t)
-	default:
-		return unsupportedTypeEncoder
-	}
-}
-
-func invalidValueEncoder(e *encodeState, v reflect.Value, quoted bool) {
-	e.WriteString("null")
-}
-
-func marshalerEncoder(e *encodeState, v reflect.Value, quoted bool) {
-	if v.Kind() == reflect.Ptr && v.IsNil() {
-		e.WriteString("null")
-		return
-	}
-	m := v.Interface().(Marshaler)
-	b, err := m.MarshalJSON()
-	if err == nil {
-		// copy JSON into buffer, checking validity.
-		err = compact(&e.Buffer, b, true)
-	}
-	if err != nil {
-		e.error(&MarshalerError{v.Type(), err})
-	}
-}
-
-func addrMarshalerEncoder(e *encodeState, v reflect.Value, quoted bool) {
-	va := v.Addr()
-	if va.IsNil() {
-		e.WriteString("null")
-		return
-	}
-	m := va.Interface().(Marshaler)
-	b, err := m.MarshalJSON()
-	if err == nil {
-		// copy JSON into buffer, checking validity.
-		err = compact(&e.Buffer, b, true)
-	}
-	if err != nil {
-		e.error(&MarshalerError{v.Type(), err})
-	}
-}
-
-func textMarshalerEncoder(e *encodeState, v reflect.Value, quoted bool) {
-	if v.Kind() == reflect.Ptr && v.IsNil() {
-		e.WriteString("null")
-		return
-	}
-	m := v.Interface().(encoding.TextMarshaler)
-	b, err := m.MarshalText()
-	if err == nil {
-		_, err = e.stringBytes(b)
-	}
-	if err != nil {
-		e.error(&MarshalerError{v.Type(), err})
-	}
-}
-
-func addrTextMarshalerEncoder(e *encodeState, v reflect.Value, quoted bool) {
-	va := v.Addr()
-	if va.IsNil() {
-		e.WriteString("null")
-		return
-	}
-	m := va.Interface().(encoding.TextMarshaler)
-	b, err := m.MarshalText()
-	if err == nil {
-		_, err = e.stringBytes(b)
-	}
-	if err != nil {
-		e.error(&MarshalerError{v.Type(), err})
-	}
-}
-
-func boolEncoder(e *encodeState, v reflect.Value, quoted bool) {
-	if quoted {
-		e.WriteByte('"')
-	}
-	if v.Bool() {
-		e.WriteString("true")
-	} else {
-		e.WriteString("false")
-	}
-	if quoted {
-		e.WriteByte('"')
-	}
-}
-
-func intEncoder(e *encodeState, v reflect.Value, quoted bool) {
-	b := strconv.AppendInt(e.scratch[:0], v.Int(), 10)
-	if quoted {
-		e.WriteByte('"')
-	}
-	e.Write(b)
-	if quoted {
-		e.WriteByte('"')
-	}
-}
-
-func uintEncoder(e *encodeState, v reflect.Value, quoted bool) {
-	b := strconv.AppendUint(e.scratch[:0], v.Uint(), 10)
-	if quoted {
-		e.WriteByte('"')
-	}
-	e.Write(b)
-	if quoted {
-		e.WriteByte('"')
-	}
-}
-
-type floatEncoder int // number of bits
-
-func (bits floatEncoder) encode(e *encodeState, v reflect.Value, quoted bool) {
-	f := v.Float()
-	if math.IsInf(f, 0) || math.IsNaN(f) {
-		e.error(&UnsupportedValueError{v, strconv.FormatFloat(f, 'g', -1, int(bits))})
-	}
-	b := strconv.AppendFloat(e.scratch[:0], f, 'g', -1, int(bits))
-	if quoted {
-		e.WriteByte('"')
-	}
-	e.Write(b)
-	if quoted {
-		e.WriteByte('"')
-	}
-}
-
-var (
-	float32Encoder = (floatEncoder(32)).encode
-	float64Encoder = (floatEncoder(64)).encode
-)
-
-func stringEncoder(e *encodeState, v reflect.Value, quoted bool) {
-	if v.Type() == numberType {
-		numStr := v.String()
-		if numStr == "" {
-			numStr = "0" // Number's zero-val
-		}
-		e.WriteString(numStr)
-		return
-	}
-	if quoted {
-		sb, err := Marshal(v.String())
-		if err != nil {
-			e.error(err)
-		}
-		e.string(string(sb))
-	} else {
-		e.string(v.String())
-	}
-}
-
-func interfaceEncoder(e *encodeState, v reflect.Value, quoted bool) {
-	if v.IsNil() {
-		e.WriteString("null")
-		return
-	}
-	e.reflectValue(v.Elem())
-}
-
-func unsupportedTypeEncoder(e *encodeState, v reflect.Value, quoted bool) {
-	e.error(&UnsupportedTypeError{v.Type()})
-}
-
-type structEncoder struct {
-	fields    []field
-	fieldEncs []encoderFunc
-}
-
-func (se *structEncoder) encode(e *encodeState, v reflect.Value, quoted bool) {
-	e.WriteByte('{')
-	first := true
-	for i, f := range se.fields {
-		fv := fieldByIndex(v, f.index)
-		if !fv.IsValid() || f.omitEmpty && isEmptyValue(fv) {
-			continue
-		}
-		if first {
-			first = false
-		} else {
-			e.WriteByte(',')
-		}
-		e.string(f.name)
-		e.WriteByte(':')
-		se.fieldEncs[i](e, fv, f.quoted)
-	}
-	e.WriteByte('}')
-}
-
-func newStructEncoder(t reflect.Type) encoderFunc {
-	fields := cachedTypeFields(t)
-	se := &structEncoder{
-		fields:    fields,
-		fieldEncs: make([]encoderFunc, len(fields)),
-	}
-	for i, f := range fields {
-		se.fieldEncs[i] = typeEncoder(typeByIndex(t, f.index))
-	}
-	return se.encode
-}
-
-type mapEncoder struct {
-	elemEnc encoderFunc
-}
-
-func (me *mapEncoder) encode(e *encodeState, v reflect.Value, _ bool) {
-	if v.IsNil() {
-		e.WriteString("null")
-		return
-	}
-	e.WriteByte('{')
-	var sv stringValues = v.MapKeys()
-	sort.Sort(sv)
-	for i, k := range sv {
-		if i > 0 {
-			e.WriteByte(',')
-		}
-		e.string(k.String())
-		e.WriteByte(':')
-		me.elemEnc(e, v.MapIndex(k), false)
-	}
-	e.WriteByte('}')
-}
-
-func newMapEncoder(t reflect.Type) encoderFunc {
-	if t.Key().Kind() != reflect.String {
-		return unsupportedTypeEncoder
-	}
-	me := &mapEncoder{typeEncoder(t.Elem())}
-	return me.encode
-}
-
-func encodeByteSlice(e *encodeState, v reflect.Value, _ bool) {
-	if v.IsNil() {
-		e.WriteString("null")
-		return
-	}
-	s := v.Bytes()
-	e.WriteByte('"')
-	if len(s) < 1024 {
-		// for small buffers, using Encode directly is much faster.
-		dst := make([]byte, base64.StdEncoding.EncodedLen(len(s)))
-		base64.StdEncoding.Encode(dst, s)
-		e.Write(dst)
-	} else {
-		// for large buffers, avoid unnecessary extra temporary
-		// buffer space.
-		enc := base64.NewEncoder(base64.StdEncoding, e)
-		enc.Write(s)
-		enc.Close()
-	}
-	e.WriteByte('"')
-}
-
-// sliceEncoder just wraps an arrayEncoder, checking to make sure the value isn't nil.
-type sliceEncoder struct {
-	arrayEnc encoderFunc
-}
-
-func (se *sliceEncoder) encode(e *encodeState, v reflect.Value, _ bool) {
-	if v.IsNil() {
-		e.WriteString("null")
-		return
-	}
-	se.arrayEnc(e, v, false)
-}
-
-func newSliceEncoder(t reflect.Type) encoderFunc {
-	// Byte slices get special treatment; arrays don't.
-	if t.Elem().Kind() == reflect.Uint8 {
-		return encodeByteSlice
-	}
-	enc := &sliceEncoder{newArrayEncoder(t)}
-	return enc.encode
-}
-
-type arrayEncoder struct {
-	elemEnc encoderFunc
-}
-
-func (ae *arrayEncoder) encode(e *encodeState, v reflect.Value, _ bool) {
-	e.WriteByte('[')
-	n := v.Len()
-	for i := 0; i < n; i++ {
-		if i > 0 {
-			e.WriteByte(',')
-		}
-		ae.elemEnc(e, v.Index(i), false)
-	}
-	e.WriteByte(']')
-}
-
-func newArrayEncoder(t reflect.Type) encoderFunc {
-	enc := &arrayEncoder{typeEncoder(t.Elem())}
-	return enc.encode
-}
-
-type ptrEncoder struct {
-	elemEnc encoderFunc
-}
-
-func (pe *ptrEncoder) encode(e *encodeState, v reflect.Value, _ bool) {
-	if v.IsNil() {
-		e.WriteString("null")
-		return
-	}
-	pe.elemEnc(e, v.Elem(), false)
-}
-
-func newPtrEncoder(t reflect.Type) encoderFunc {
-	enc := &ptrEncoder{typeEncoder(t.Elem())}
-	return enc.encode
-}
-
-type condAddrEncoder struct {
-	canAddrEnc, elseEnc encoderFunc
-}
-
-func (ce *condAddrEncoder) encode(e *encodeState, v reflect.Value, quoted bool) {
-	if v.CanAddr() {
-		ce.canAddrEnc(e, v, quoted)
-	} else {
-		ce.elseEnc(e, v, quoted)
-	}
-}
-
-// newCondAddrEncoder returns an encoder that checks whether its value
-// CanAddr and delegates to canAddrEnc if so, else to elseEnc.
-func newCondAddrEncoder(canAddrEnc, elseEnc encoderFunc) encoderFunc {
-	enc := &condAddrEncoder{canAddrEnc: canAddrEnc, elseEnc: elseEnc}
-	return enc.encode
-}
-
-func isValidTag(s string) bool {
-	if s == "" {
-		return false
-	}
-	for _, c := range s {
-		switch {
-		case strings.ContainsRune("!#$%&()*+-./:<=>?@[]^_{|}~ ", c):
-			// Backslash and quote chars are reserved, but
-			// otherwise any punctuation chars are allowed
-			// in a tag name.
-		default:
-			if !unicode.IsLetter(c) && !unicode.IsDigit(c) {
-				return false
-			}
-		}
-	}
-	return true
-}
-
-func fieldByIndex(v reflect.Value, index []int) reflect.Value {
-	for _, i := range index {
-		if v.Kind() == reflect.Ptr {
-			if v.IsNil() {
-				return reflect.Value{}
-			}
-			v = v.Elem()
-		}
-		v = v.Field(i)
-	}
-	return v
-}
-
-func typeByIndex(t reflect.Type, index []int) reflect.Type {
-	for _, i := range index {
-		if t.Kind() == reflect.Ptr {
-			t = t.Elem()
-		}
-		t = t.Field(i).Type
-	}
-	return t
-}
-
-// stringValues is a slice of reflect.Value holding *reflect.StringValue.
-// It implements the methods to sort by string.
-type stringValues []reflect.Value
-
-func (sv stringValues) Len() int           { return len(sv) }
-func (sv stringValues) Swap(i, j int)      { sv[i], sv[j] = sv[j], sv[i] }
-func (sv stringValues) Less(i, j int) bool { return sv.get(i) < sv.get(j) }
-func (sv stringValues) get(i int) string   { return sv[i].String() }
-
-// NOTE: keep in sync with stringBytes below.
-func (e *encodeState) string(s string) (int, error) {
-	len0 := e.Len()
-	e.WriteByte('"')
-	start := 0
-	for i := 0; i < len(s); {
-		if b := s[i]; b < utf8.RuneSelf {
-			if 0x20 <= b && b != '\\' && b != '"' && b != '<' && b != '>' && b != '&' {
-				i++
-				continue
-			}
-			if start < i {
-				e.WriteString(s[start:i])
-			}
-			switch b {
-			case '\\', '"':
-				e.WriteByte('\\')
-				e.WriteByte(b)
-			case '\n':
-				e.WriteByte('\\')
-				e.WriteByte('n')
-			case '\r':
-				e.WriteByte('\\')
-				e.WriteByte('r')
-			default:
-				// This encodes bytes < 0x20 except for \n and \r,
-				// as well as <, > and &. The latter are escaped because they
-				// can lead to security holes when user-controlled strings
-				// are rendered into JSON and served to some browsers.
-				e.WriteString(`\u00`)
-				e.WriteByte(hex[b>>4])
-				e.WriteByte(hex[b&0xF])
-			}
-			i++
-			start = i
-			continue
-		}
-		c, size := utf8.DecodeRuneInString(s[i:])
-		if c == utf8.RuneError && size == 1 {
-			if start < i {
-				e.WriteString(s[start:i])
-			}
-			e.WriteString(`\ufffd`)
-			i += size
-			start = i
-			continue
-		}
-		// U+2028 is LINE SEPARATOR.
-		// U+2029 is PARAGRAPH SEPARATOR.
-		// They are both technically valid characters in JSON strings,
-		// but don't work in JSONP, which has to be evaluated as JavaScript,
-		// and can lead to security holes there. It is valid JSON to
-		// escape them, so we do so unconditionally.
-		// See http://timelessrepo.com/json-isnt-a-javascript-subset for discussion.
-		if c == '\u2028' || c == '\u2029' {
-			if start < i {
-				e.WriteString(s[start:i])
-			}
-			e.WriteString(`\u202`)
-			e.WriteByte(hex[c&0xF])
-			i += size
-			start = i
-			continue
-		}
-		i += size
-	}
-	if start < len(s) {
-		e.WriteString(s[start:])
-	}
-	e.WriteByte('"')
-	return e.Len() - len0, nil
-}
-
-// NOTE: keep in sync with string above.
-func (e *encodeState) stringBytes(s []byte) (int, error) {
-	len0 := e.Len()
-	e.WriteByte('"')
-	start := 0
-	for i := 0; i < len(s); {
-		if b := s[i]; b < utf8.RuneSelf {
-			if 0x20 <= b && b != '\\' && b != '"' && b != '<' && b != '>' && b != '&' {
-				i++
-				continue
-			}
-			if start < i {
-				e.Write(s[start:i])
-			}
-			switch b {
-			case '\\', '"':
-				e.WriteByte('\\')
-				e.WriteByte(b)
-			case '\n':
-				e.WriteByte('\\')
-				e.WriteByte('n')
-			case '\r':
-				e.WriteByte('\\')
-				e.WriteByte('r')
-			default:
-				// This encodes bytes < 0x20 except for \n and \r,
-				// as well as < and >. The latter are escaped because they
-				// can lead to security holes when user-controlled strings
-				// are rendered into JSON and served to some browsers.
-				e.WriteString(`\u00`)
-				e.WriteByte(hex[b>>4])
-				e.WriteByte(hex[b&0xF])
-			}
-			i++
-			start = i
-			continue
-		}
-		c, size := utf8.DecodeRune(s[i:])
-		if c == utf8.RuneError && size == 1 {
-			if start < i {
-				e.Write(s[start:i])
-			}
-			e.WriteString(`\ufffd`)
-			i += size
-			start = i
-			continue
-		}
-		// U+2028 is LINE SEPARATOR.
-		// U+2029 is PARAGRAPH SEPARATOR.
-		// They are both technically valid characters in JSON strings,
-		// but don't work in JSONP, which has to be evaluated as JavaScript,
-		// and can lead to security holes there. It is valid JSON to
-		// escape them, so we do so unconditionally.
-		// See http://timelessrepo.com/json-isnt-a-javascript-subset for discussion.
-		if c == '\u2028' || c == '\u2029' {
-			if start < i {
-				e.Write(s[start:i])
-			}
-			e.WriteString(`\u202`)
-			e.WriteByte(hex[c&0xF])
-			i += size
-			start = i
-			continue
-		}
-		i += size
-	}
-	if start < len(s) {
-		e.Write(s[start:])
-	}
-	e.WriteByte('"')
-	return e.Len() - len0, nil
-}
-
-// A field represents a single field found in a struct.
-type field struct {
-	name      string
-	nameBytes []byte                 // []byte(name)
-	equalFold func(s, t []byte) bool // bytes.EqualFold or equivalent
-
-	tag       bool
-	index     []int
-	typ       reflect.Type
-	omitEmpty bool
-	quoted    bool
-}
-
-func fillField(f field) field {
-	f.nameBytes = []byte(f.name)
-	f.equalFold = foldFunc(f.nameBytes)
-	return f
-}
-
-// byName sorts field by name, breaking ties with depth,
-// then breaking ties with "name came from json tag", then
-// breaking ties with index sequence.
-type byName []field
-
-func (x byName) Len() int { return len(x) }
-
-func (x byName) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
-
-func (x byName) Less(i, j int) bool {
-	if x[i].name != x[j].name {
-		return x[i].name < x[j].name
-	}
-	if len(x[i].index) != len(x[j].index) {
-		return len(x[i].index) < len(x[j].index)
-	}
-	if x[i].tag != x[j].tag {
-		return x[i].tag
-	}
-	return byIndex(x).Less(i, j)
-}
-
-// byIndex sorts field by index sequence.
-type byIndex []field
-
-func (x byIndex) Len() int { return len(x) }
-
-func (x byIndex) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
-
-func (x byIndex) Less(i, j int) bool {
-	for k, xik := range x[i].index {
-		if k >= len(x[j].index) {
-			return false
-		}
-		if xik != x[j].index[k] {
-			return xik < x[j].index[k]
-		}
-	}
-	return len(x[i].index) < len(x[j].index)
-}
-
-// typeFields returns a list of fields that JSON should recognize for the given type.
-// The algorithm is breadth-first search over the set of structs to include - the top struct
-// and then any reachable anonymous structs.
-func typeFields(t reflect.Type) []field {
-	// Anonymous fields to explore at the current level and the next.
-	current := []field{}
-	next := []field{{typ: t}}
-
-	// Count of queued names for current level and the next.
-	count := map[reflect.Type]int{}
-	nextCount := map[reflect.Type]int{}
-
-	// Types already visited at an earlier level.
-	visited := map[reflect.Type]bool{}
-
-	// Fields found.
-	var fields []field
-
-	for len(next) > 0 {
-		current, next = next, current[:0]
-		count, nextCount = nextCount, map[reflect.Type]int{}
-
-		for _, f := range current {
-			if visited[f.typ] {
-				continue
-			}
-			visited[f.typ] = true
-
-			// Scan f.typ for fields to include.
-			for i := 0; i < f.typ.NumField(); i++ {
-				sf := f.typ.Field(i)
-				if sf.PkgPath != "" { // unexported
-					continue
-				}
-				tag := sf.Tag.Get("json")
-				if tag == "-" {
-					continue
-				}
-				name, opts := parseTag(tag)
-				if !isValidTag(name) {
-					name = ""
-				}
-				index := make([]int, len(f.index)+1)
-				copy(index, f.index)
-				index[len(f.index)] = i
-
-				ft := sf.Type
-				if ft.Name() == "" && ft.Kind() == reflect.Ptr {
-					// Follow pointer.
-					ft = ft.Elem()
-				}
-
-				// Record found field and index sequence.
-				if name != "" || !sf.Anonymous || ft.Kind() != reflect.Struct {
-					tagged := name != ""
-					if name == "" {
-						name = sf.Name
-					}
-					fields = append(fields, fillField(field{
-						name:      name,
-						tag:       tagged,
-						index:     index,
-						typ:       ft,
-						omitEmpty: opts.Contains("omitempty"),
-						quoted:    opts.Contains("string"),
-					}))
-					if count[f.typ] > 1 {
-						// If there were multiple instances, add a second,
-						// so that the annihilation code will see a duplicate.
-						// It only cares about the distinction between 1 or 2,
-						// so don't bother generating any more copies.
-						fields = append(fields, fields[len(fields)-1])
-					}
-					continue
-				}
-
-				// Record new anonymous struct to explore in next round.
-				nextCount[ft]++
-				if nextCount[ft] == 1 {
-					next = append(next, fillField(field{name: ft.Name(), index: index, typ: ft}))
-				}
-			}
-		}
-	}
-
-	sort.Sort(byName(fields))
-
-	// Delete all fields that are hidden by the Go rules for embedded fields,
-	// except that fields with JSON tags are promoted.
-
-	// The fields are sorted in primary order of name, secondary order
-	// of field index length. Loop over names; for each name, delete
-	// hidden fields by choosing the one dominant field that survives.
-	out := fields[:0]
-	for advance, i := 0, 0; i < len(fields); i += advance {
-		// One iteration per name.
-		// Find the sequence of fields with the name of this first field.
-		fi := fields[i]
-		name := fi.name
-		for advance = 1; i+advance < len(fields); advance++ {
-			fj := fields[i+advance]
-			if fj.name != name {
-				break
-			}
-		}
-		if advance == 1 { // Only one field with this name
-			out = append(out, fi)
-			continue
-		}
-		dominant, ok := dominantField(fields[i : i+advance])
-		if ok {
-			out = append(out, dominant)
-		}
-	}
-
-	fields = out
-	sort.Sort(byIndex(fields))
-
-	return fields
-}
-
-// dominantField looks through the fields, all of which are known to
-// have the same name, to find the single field that dominates the
-// others using Go's embedding rules, modified by the presence of
-// JSON tags. If there are multiple top-level fields, the boolean
-// will be false: This condition is an error in Go and we skip all
-// the fields.
-func dominantField(fields []field) (field, bool) {
-	// The fields are sorted in increasing index-length order. The winner
-	// must therefore be one with the shortest index length. Drop all
-	// longer entries, which is easy: just truncate the slice.
-	length := len(fields[0].index)
-	tagged := -1 // Index of first tagged field.
-	for i, f := range fields {
-		if len(f.index) > length {
-			fields = fields[:i]
-			break
-		}
-		if f.tag {
-			if tagged >= 0 {
-				// Multiple tagged fields at the same level: conflict.
-				// Return no field.
-				return field{}, false
-			}
-			tagged = i
-		}
-	}
-	if tagged >= 0 {
-		return fields[tagged], true
-	}
-	// All remaining fields have the same length. If there's more than one,
-	// we have a conflict (two fields named "X" at the same level) and we
-	// return no field.
-	if len(fields) > 1 {
-		return field{}, false
-	}
-	return fields[0], true
-}
-
-var fieldCache struct {
-	sync.RWMutex
-	m map[reflect.Type][]field
-}
-
-// cachedTypeFields is like typeFields but uses a cache to avoid repeated work.
-func cachedTypeFields(t reflect.Type) []field {
-	fieldCache.RLock()
-	f := fieldCache.m[t]
-	fieldCache.RUnlock()
-	if f != nil {
-		return f
-	}
-
-	// Compute fields without lock.
-	// Might duplicate effort but won't hold other computations back.
-	f = typeFields(t)
-	if f == nil {
-		f = []field{}
-	}
-
-	fieldCache.Lock()
-	if fieldCache.m == nil {
-		fieldCache.m = map[reflect.Type][]field{}
-	}
-	fieldCache.m[t] = f
-	fieldCache.Unlock()
-	return f
-}
-- 
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