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-rw-r--r--vendor/gopkg.in/mgo.v2/internal/json/decode.go1685
1 files changed, 1685 insertions, 0 deletions
diff --git a/vendor/gopkg.in/mgo.v2/internal/json/decode.go b/vendor/gopkg.in/mgo.v2/internal/json/decode.go
new file mode 100644
index 0000000..ce7c7d2
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+++ b/vendor/gopkg.in/mgo.v2/internal/json/decode.go
@@ -0,0 +1,1685 @@
+// 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.
+
+// Represents JSON data structure using native Go types: booleans, floats,
+// strings, arrays, and maps.
+
+package json
+
+import (
+ "bytes"
+ "encoding"
+ "encoding/base64"
+ "errors"
+ "fmt"
+ "reflect"
+ "runtime"
+ "strconv"
+ "unicode"
+ "unicode/utf16"
+ "unicode/utf8"
+)
+
+// Unmarshal parses the JSON-encoded data and stores the result
+// in the value pointed to by v.
+//
+// Unmarshal uses the inverse of the encodings that
+// Marshal uses, allocating maps, slices, and pointers as necessary,
+// with the following additional rules:
+//
+// To unmarshal JSON into a pointer, Unmarshal first handles the case of
+// the JSON being the JSON literal null. In that case, Unmarshal sets
+// the pointer to nil. Otherwise, Unmarshal unmarshals the JSON into
+// the value pointed at by the pointer. If the pointer is nil, Unmarshal
+// allocates a new value for it to point to.
+//
+// To unmarshal JSON into a struct, Unmarshal matches incoming object
+// keys to the keys used by Marshal (either the struct field name or its tag),
+// preferring an exact match but also accepting a case-insensitive match.
+// Unmarshal will only set exported fields of the struct.
+//
+// To unmarshal JSON into an interface value,
+// Unmarshal stores one of these in the interface value:
+//
+// bool, for JSON booleans
+// float64, for JSON numbers
+// string, for JSON strings
+// []interface{}, for JSON arrays
+// map[string]interface{}, for JSON objects
+// nil for JSON null
+//
+// To unmarshal a JSON array into a slice, Unmarshal resets the slice length
+// to zero and then appends each element to the slice.
+// As a special case, to unmarshal an empty JSON array into a slice,
+// Unmarshal replaces the slice with a new empty slice.
+//
+// To unmarshal a JSON array into a Go array, Unmarshal decodes
+// JSON array elements into corresponding Go array elements.
+// If the Go array is smaller than the JSON array,
+// the additional JSON array elements are discarded.
+// If the JSON array is smaller than the Go array,
+// the additional Go array elements are set to zero values.
+//
+// To unmarshal a JSON object into a map, Unmarshal first establishes a map to
+// use, If the map is nil, Unmarshal allocates a new map. Otherwise Unmarshal
+// reuses the existing map, keeping existing entries. Unmarshal then stores key-
+// value pairs from the JSON object into the map. The map's key type must
+// either be a string or implement encoding.TextUnmarshaler.
+//
+// If a JSON value is not appropriate for a given target type,
+// or if a JSON number overflows the target type, Unmarshal
+// skips that field and completes the unmarshaling as best it can.
+// If no more serious errors are encountered, Unmarshal returns
+// an UnmarshalTypeError describing the earliest such error.
+//
+// The JSON null value unmarshals into an interface, map, pointer, or slice
+// by setting that Go value to nil. Because null is often used in JSON to mean
+// ``not present,'' unmarshaling a JSON null into any other Go type has no effect
+// on the value and produces no error.
+//
+// When unmarshaling quoted strings, invalid UTF-8 or
+// invalid UTF-16 surrogate pairs are not treated as an error.
+// Instead, they are replaced by the Unicode replacement
+// character U+FFFD.
+//
+func Unmarshal(data []byte, v interface{}) error {
+ // Check for well-formedness.
+ // Avoids filling out half a data structure
+ // before discovering a JSON syntax error.
+ var d decodeState
+ err := checkValid(data, &d.scan)
+ if err != nil {
+ return err
+ }
+
+ d.init(data)
+ return d.unmarshal(v)
+}
+
+// Unmarshaler is the interface implemented by types
+// that can unmarshal a JSON description of themselves.
+// The input can be assumed to be a valid encoding of
+// a JSON value. UnmarshalJSON must copy the JSON data
+// if it wishes to retain the data after returning.
+type Unmarshaler interface {
+ UnmarshalJSON([]byte) error
+}
+
+// An UnmarshalTypeError describes a JSON value that was
+// not appropriate for a value of a specific Go type.
+type UnmarshalTypeError struct {
+ Value string // description of JSON value - "bool", "array", "number -5"
+ Type reflect.Type // type of Go value it could not be assigned to
+ Offset int64 // error occurred after reading Offset bytes
+}
+
+func (e *UnmarshalTypeError) Error() string {
+ return "json: cannot unmarshal " + e.Value + " into Go value of type " + e.Type.String()
+}
+
+// An UnmarshalFieldError describes a JSON object key that
+// led to an unexported (and therefore unwritable) struct field.
+// (No longer used; kept for compatibility.)
+type UnmarshalFieldError struct {
+ Key string
+ Type reflect.Type
+ Field reflect.StructField
+}
+
+func (e *UnmarshalFieldError) Error() string {
+ return "json: cannot unmarshal object key " + strconv.Quote(e.Key) + " into unexported field " + e.Field.Name + " of type " + e.Type.String()
+}
+
+// An InvalidUnmarshalError describes an invalid argument passed to Unmarshal.
+// (The argument to Unmarshal must be a non-nil pointer.)
+type InvalidUnmarshalError struct {
+ Type reflect.Type
+}
+
+func (e *InvalidUnmarshalError) Error() string {
+ if e.Type == nil {
+ return "json: Unmarshal(nil)"
+ }
+
+ if e.Type.Kind() != reflect.Ptr {
+ return "json: Unmarshal(non-pointer " + e.Type.String() + ")"
+ }
+ return "json: Unmarshal(nil " + e.Type.String() + ")"
+}
+
+func (d *decodeState) unmarshal(v interface{}) (err error) {
+ defer func() {
+ if r := recover(); r != nil {
+ if _, ok := r.(runtime.Error); ok {
+ panic(r)
+ }
+ err = r.(error)
+ }
+ }()
+
+ rv := reflect.ValueOf(v)
+ if rv.Kind() != reflect.Ptr || rv.IsNil() {
+ return &InvalidUnmarshalError{reflect.TypeOf(v)}
+ }
+
+ d.scan.reset()
+ // We decode rv not rv.Elem because the Unmarshaler interface
+ // test must be applied at the top level of the value.
+ d.value(rv)
+ return d.savedError
+}
+
+// A Number represents a JSON number literal.
+type Number string
+
+// String returns the literal text of the number.
+func (n Number) String() string { return string(n) }
+
+// Float64 returns the number as a float64.
+func (n Number) Float64() (float64, error) {
+ return strconv.ParseFloat(string(n), 64)
+}
+
+// Int64 returns the number as an int64.
+func (n Number) Int64() (int64, error) {
+ return strconv.ParseInt(string(n), 10, 64)
+}
+
+// isValidNumber reports whether s is a valid JSON number literal.
+func isValidNumber(s string) bool {
+ // This function implements the JSON numbers grammar.
+ // See https://tools.ietf.org/html/rfc7159#section-6
+ // and http://json.org/number.gif
+
+ if s == "" {
+ return false
+ }
+
+ // Optional -
+ if s[0] == '-' {
+ s = s[1:]
+ if s == "" {
+ return false
+ }
+ }
+
+ // Digits
+ switch {
+ default:
+ return false
+
+ case s[0] == '0':
+ s = s[1:]
+
+ case '1' <= s[0] && s[0] <= '9':
+ s = s[1:]
+ for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
+ s = s[1:]
+ }
+ }
+
+ // . followed by 1 or more digits.
+ if len(s) >= 2 && s[0] == '.' && '0' <= s[1] && s[1] <= '9' {
+ s = s[2:]
+ for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
+ s = s[1:]
+ }
+ }
+
+ // e or E followed by an optional - or + and
+ // 1 or more digits.
+ if len(s) >= 2 && (s[0] == 'e' || s[0] == 'E') {
+ s = s[1:]
+ if s[0] == '+' || s[0] == '-' {
+ s = s[1:]
+ if s == "" {
+ return false
+ }
+ }
+ for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
+ s = s[1:]
+ }
+ }
+
+ // Make sure we are at the end.
+ return s == ""
+}
+
+// decodeState represents the state while decoding a JSON value.
+type decodeState struct {
+ data []byte
+ off int // read offset in data
+ scan scanner
+ nextscan scanner // for calls to nextValue
+ savedError error
+ useNumber bool
+ ext Extension
+}
+
+// errPhase is used for errors that should not happen unless
+// there is a bug in the JSON decoder or something is editing
+// the data slice while the decoder executes.
+var errPhase = errors.New("JSON decoder out of sync - data changing underfoot?")
+
+func (d *decodeState) init(data []byte) *decodeState {
+ d.data = data
+ d.off = 0
+ d.savedError = nil
+ return d
+}
+
+// error aborts the decoding by panicking with err.
+func (d *decodeState) error(err error) {
+ panic(err)
+}
+
+// saveError saves the first err it is called with,
+// for reporting at the end of the unmarshal.
+func (d *decodeState) saveError(err error) {
+ if d.savedError == nil {
+ d.savedError = err
+ }
+}
+
+// next cuts off and returns the next full JSON value in d.data[d.off:].
+// The next value is known to be an object or array, not a literal.
+func (d *decodeState) next() []byte {
+ c := d.data[d.off]
+ item, rest, err := nextValue(d.data[d.off:], &d.nextscan)
+ if err != nil {
+ d.error(err)
+ }
+ d.off = len(d.data) - len(rest)
+
+ // Our scanner has seen the opening brace/bracket
+ // and thinks we're still in the middle of the object.
+ // invent a closing brace/bracket to get it out.
+ if c == '{' {
+ d.scan.step(&d.scan, '}')
+ } else if c == '[' {
+ d.scan.step(&d.scan, ']')
+ } else {
+ // Was inside a function name. Get out of it.
+ d.scan.step(&d.scan, '(')
+ d.scan.step(&d.scan, ')')
+ }
+
+ return item
+}
+
+// scanWhile processes bytes in d.data[d.off:] until it
+// receives a scan code not equal to op.
+// It updates d.off and returns the new scan code.
+func (d *decodeState) scanWhile(op int) int {
+ var newOp int
+ for {
+ if d.off >= len(d.data) {
+ newOp = d.scan.eof()
+ d.off = len(d.data) + 1 // mark processed EOF with len+1
+ } else {
+ c := d.data[d.off]
+ d.off++
+ newOp = d.scan.step(&d.scan, c)
+ }
+ if newOp != op {
+ break
+ }
+ }
+ return newOp
+}
+
+// value decodes a JSON value from d.data[d.off:] into the value.
+// it updates d.off to point past the decoded value.
+func (d *decodeState) value(v reflect.Value) {
+ if !v.IsValid() {
+ _, rest, err := nextValue(d.data[d.off:], &d.nextscan)
+ if err != nil {
+ d.error(err)
+ }
+ d.off = len(d.data) - len(rest)
+
+ // d.scan thinks we're still at the beginning of the item.
+ // Feed in an empty string - the shortest, simplest value -
+ // so that it knows we got to the end of the value.
+ if d.scan.redo {
+ // rewind.
+ d.scan.redo = false
+ d.scan.step = stateBeginValue
+ }
+ d.scan.step(&d.scan, '"')
+ d.scan.step(&d.scan, '"')
+
+ n := len(d.scan.parseState)
+ if n > 0 && d.scan.parseState[n-1] == parseObjectKey {
+ // d.scan thinks we just read an object key; finish the object
+ d.scan.step(&d.scan, ':')
+ d.scan.step(&d.scan, '"')
+ d.scan.step(&d.scan, '"')
+ d.scan.step(&d.scan, '}')
+ }
+
+ return
+ }
+
+ switch op := d.scanWhile(scanSkipSpace); op {
+ default:
+ d.error(errPhase)
+
+ case scanBeginArray:
+ d.array(v)
+
+ case scanBeginObject:
+ d.object(v)
+
+ case scanBeginLiteral:
+ d.literal(v)
+
+ case scanBeginName:
+ d.name(v)
+ }
+}
+
+type unquotedValue struct{}
+
+// valueQuoted is like value but decodes a
+// quoted string literal or literal null into an interface value.
+// If it finds anything other than a quoted string literal or null,
+// valueQuoted returns unquotedValue{}.
+func (d *decodeState) valueQuoted() interface{} {
+ switch op := d.scanWhile(scanSkipSpace); op {
+ default:
+ d.error(errPhase)
+
+ case scanBeginArray:
+ d.array(reflect.Value{})
+
+ case scanBeginObject:
+ d.object(reflect.Value{})
+
+ case scanBeginName:
+ switch v := d.nameInterface().(type) {
+ case nil, string:
+ return v
+ }
+
+ case scanBeginLiteral:
+ switch v := d.literalInterface().(type) {
+ case nil, string:
+ return v
+ }
+ }
+ return unquotedValue{}
+}
+
+// indirect walks down v allocating pointers as needed,
+// until it gets to a non-pointer.
+// if it encounters an Unmarshaler, indirect stops and returns that.
+// if decodingNull is true, indirect stops at the last pointer so it can be set to nil.
+func (d *decodeState) indirect(v reflect.Value, decodingNull bool) (Unmarshaler, encoding.TextUnmarshaler, reflect.Value) {
+ // If v is a named type and is addressable,
+ // start with its address, so that if the type has pointer methods,
+ // we find them.
+ if v.Kind() != reflect.Ptr && v.Type().Name() != "" && v.CanAddr() {
+ v = v.Addr()
+ }
+ for {
+ // Load value from interface, but only if the result will be
+ // usefully addressable.
+ if v.Kind() == reflect.Interface && !v.IsNil() {
+ e := v.Elem()
+ if e.Kind() == reflect.Ptr && !e.IsNil() && (!decodingNull || e.Elem().Kind() == reflect.Ptr) {
+ v = e
+ continue
+ }
+ }
+
+ if v.Kind() != reflect.Ptr {
+ break
+ }
+
+ if v.Elem().Kind() != reflect.Ptr && decodingNull && v.CanSet() {
+ break
+ }
+ if v.IsNil() {
+ v.Set(reflect.New(v.Type().Elem()))
+ }
+ if v.Type().NumMethod() > 0 {
+ if u, ok := v.Interface().(Unmarshaler); ok {
+ return u, nil, v
+ }
+ if u, ok := v.Interface().(encoding.TextUnmarshaler); ok {
+ return nil, u, v
+ }
+ }
+ v = v.Elem()
+ }
+ return nil, nil, v
+}
+
+// array consumes an array from d.data[d.off-1:], decoding into the value v.
+// the first byte of the array ('[') has been read already.
+func (d *decodeState) array(v reflect.Value) {
+ // Check for unmarshaler.
+ u, ut, pv := d.indirect(v, false)
+ if u != nil {
+ d.off--
+ err := u.UnmarshalJSON(d.next())
+ if err != nil {
+ d.error(err)
+ }
+ return
+ }
+ if ut != nil {
+ d.saveError(&UnmarshalTypeError{"array", v.Type(), int64(d.off)})
+ d.off--
+ d.next()
+ return
+ }
+
+ v = pv
+
+ // Check type of target.
+ switch v.Kind() {
+ case reflect.Interface:
+ if v.NumMethod() == 0 {
+ // Decoding into nil interface? Switch to non-reflect code.
+ v.Set(reflect.ValueOf(d.arrayInterface()))
+ return
+ }
+ // Otherwise it's invalid.
+ fallthrough
+ default:
+ d.saveError(&UnmarshalTypeError{"array", v.Type(), int64(d.off)})
+ d.off--
+ d.next()
+ return
+ case reflect.Array:
+ case reflect.Slice:
+ break
+ }
+
+ i := 0
+ for {
+ // Look ahead for ] - can only happen on first iteration.
+ op := d.scanWhile(scanSkipSpace)
+ if op == scanEndArray {
+ break
+ }
+
+ // Back up so d.value can have the byte we just read.
+ d.off--
+ d.scan.undo(op)
+
+ // Get element of array, growing if necessary.
+ if v.Kind() == reflect.Slice {
+ // Grow slice if necessary
+ if i >= v.Cap() {
+ newcap := v.Cap() + v.Cap()/2
+ if newcap < 4 {
+ newcap = 4
+ }
+ newv := reflect.MakeSlice(v.Type(), v.Len(), newcap)
+ reflect.Copy(newv, v)
+ v.Set(newv)
+ }
+ if i >= v.Len() {
+ v.SetLen(i + 1)
+ }
+ }
+
+ if i < v.Len() {
+ // Decode into element.
+ d.value(v.Index(i))
+ } else {
+ // Ran out of fixed array: skip.
+ d.value(reflect.Value{})
+ }
+ i++
+
+ // Next token must be , or ].
+ op = d.scanWhile(scanSkipSpace)
+ if op == scanEndArray {
+ break
+ }
+ if op != scanArrayValue {
+ d.error(errPhase)
+ }
+ }
+
+ if i < v.Len() {
+ if v.Kind() == reflect.Array {
+ // Array. Zero the rest.
+ z := reflect.Zero(v.Type().Elem())
+ for ; i < v.Len(); i++ {
+ v.Index(i).Set(z)
+ }
+ } else {
+ v.SetLen(i)
+ }
+ }
+ if i == 0 && v.Kind() == reflect.Slice {
+ v.Set(reflect.MakeSlice(v.Type(), 0, 0))
+ }
+}
+
+var nullLiteral = []byte("null")
+var textUnmarshalerType = reflect.TypeOf(new(encoding.TextUnmarshaler)).Elem()
+
+// object consumes an object from d.data[d.off-1:], decoding into the value v.
+// the first byte ('{') of the object has been read already.
+func (d *decodeState) object(v reflect.Value) {
+ // Check for unmarshaler.
+ u, ut, pv := d.indirect(v, false)
+ if d.storeKeyed(pv) {
+ return
+ }
+ if u != nil {
+ d.off--
+ err := u.UnmarshalJSON(d.next())
+ if err != nil {
+ d.error(err)
+ }
+ return
+ }
+ if ut != nil {
+ d.saveError(&UnmarshalTypeError{"object", v.Type(), int64(d.off)})
+ d.off--
+ d.next() // skip over { } in input
+ return
+ }
+ v = pv
+
+ // Decoding into nil interface? Switch to non-reflect code.
+ if v.Kind() == reflect.Interface && v.NumMethod() == 0 {
+ v.Set(reflect.ValueOf(d.objectInterface()))
+ return
+ }
+
+ // Check type of target:
+ // struct or
+ // map[string]T or map[encoding.TextUnmarshaler]T
+ switch v.Kind() {
+ case reflect.Map:
+ // Map key must either have string kind or be an encoding.TextUnmarshaler.
+ t := v.Type()
+ if t.Key().Kind() != reflect.String &&
+ !reflect.PtrTo(t.Key()).Implements(textUnmarshalerType) {
+ d.saveError(&UnmarshalTypeError{"object", v.Type(), int64(d.off)})
+ d.off--
+ d.next() // skip over { } in input
+ return
+ }
+ if v.IsNil() {
+ v.Set(reflect.MakeMap(t))
+ }
+ case reflect.Struct:
+
+ default:
+ d.saveError(&UnmarshalTypeError{"object", v.Type(), int64(d.off)})
+ d.off--
+ d.next() // skip over { } in input
+ return
+ }
+
+ var mapElem reflect.Value
+
+ empty := true
+ for {
+ // Read opening " of string key or closing }.
+ op := d.scanWhile(scanSkipSpace)
+ if op == scanEndObject {
+ if !empty && !d.ext.trailingCommas {
+ d.syntaxError("beginning of object key string")
+ }
+ break
+ }
+ empty = false
+ if op == scanBeginName {
+ if !d.ext.unquotedKeys {
+ d.syntaxError("beginning of object key string")
+ }
+ } else if op != scanBeginLiteral {
+ d.error(errPhase)
+ }
+ unquotedKey := op == scanBeginName
+
+ // Read key.
+ start := d.off - 1
+ op = d.scanWhile(scanContinue)
+ item := d.data[start : d.off-1]
+ var key []byte
+ if unquotedKey {
+ key = item
+ // TODO Fix code below to quote item when necessary.
+ } else {
+ var ok bool
+ key, ok = unquoteBytes(item)
+ if !ok {
+ d.error(errPhase)
+ }
+ }
+
+ // Figure out field corresponding to key.
+ var subv reflect.Value
+ destring := false // whether the value is wrapped in a string to be decoded first
+
+ if v.Kind() == reflect.Map {
+ elemType := v.Type().Elem()
+ if !mapElem.IsValid() {
+ mapElem = reflect.New(elemType).Elem()
+ } else {
+ mapElem.Set(reflect.Zero(elemType))
+ }
+ subv = mapElem
+ } else {
+ var f *field
+ fields := cachedTypeFields(v.Type())
+ for i := range fields {
+ ff := &fields[i]
+ if bytes.Equal(ff.nameBytes, key) {
+ f = ff
+ break
+ }
+ if f == nil && ff.equalFold(ff.nameBytes, key) {
+ f = ff
+ }
+ }
+ if f != nil {
+ subv = v
+ destring = f.quoted
+ for _, i := range f.index {
+ if subv.Kind() == reflect.Ptr {
+ if subv.IsNil() {
+ subv.Set(reflect.New(subv.Type().Elem()))
+ }
+ subv = subv.Elem()
+ }
+ subv = subv.Field(i)
+ }
+ }
+ }
+
+ // Read : before value.
+ if op == scanSkipSpace {
+ op = d.scanWhile(scanSkipSpace)
+ }
+ if op != scanObjectKey {
+ d.error(errPhase)
+ }
+
+ // Read value.
+ if destring {
+ switch qv := d.valueQuoted().(type) {
+ case nil:
+ d.literalStore(nullLiteral, subv, false)
+ case string:
+ d.literalStore([]byte(qv), subv, true)
+ default:
+ d.saveError(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal unquoted value into %v", subv.Type()))
+ }
+ } else {
+ d.value(subv)
+ }
+
+ // Write value back to map;
+ // if using struct, subv points into struct already.
+ if v.Kind() == reflect.Map {
+ kt := v.Type().Key()
+ var kv reflect.Value
+ switch {
+ case kt.Kind() == reflect.String:
+ kv = reflect.ValueOf(key).Convert(v.Type().Key())
+ case reflect.PtrTo(kt).Implements(textUnmarshalerType):
+ kv = reflect.New(v.Type().Key())
+ d.literalStore(item, kv, true)
+ kv = kv.Elem()
+ default:
+ panic("json: Unexpected key type") // should never occur
+ }
+ v.SetMapIndex(kv, subv)
+ }
+
+ // Next token must be , or }.
+ op = d.scanWhile(scanSkipSpace)
+ if op == scanEndObject {
+ break
+ }
+ if op != scanObjectValue {
+ d.error(errPhase)
+ }
+ }
+}
+
+// isNull returns whether there's a null literal at the provided offset.
+func (d *decodeState) isNull(off int) bool {
+ if off+4 >= len(d.data) || d.data[off] != 'n' || d.data[off+1] != 'u' || d.data[off+2] != 'l' || d.data[off+3] != 'l' {
+ return false
+ }
+ d.nextscan.reset()
+ for i, c := range d.data[off:] {
+ if i > 4 {
+ return false
+ }
+ switch d.nextscan.step(&d.nextscan, c) {
+ case scanContinue, scanBeginName:
+ continue
+ }
+ break
+ }
+ return true
+}
+
+// name consumes a const or function from d.data[d.off-1:], decoding into the value v.
+// the first byte of the function name has been read already.
+func (d *decodeState) name(v reflect.Value) {
+ if d.isNull(d.off-1) {
+ d.literal(v)
+ return
+ }
+
+ // Check for unmarshaler.
+ u, ut, pv := d.indirect(v, false)
+ if d.storeKeyed(pv) {
+ return
+ }
+ if u != nil {
+ d.off--
+ err := u.UnmarshalJSON(d.next())
+ if err != nil {
+ d.error(err)
+ }
+ return
+ }
+ if ut != nil {
+ d.saveError(&UnmarshalTypeError{"object", v.Type(), int64(d.off)})
+ d.off--
+ d.next() // skip over function in input
+ return
+ }
+ v = pv
+
+ // Decoding into nil interface? Switch to non-reflect code.
+ if v.Kind() == reflect.Interface && v.NumMethod() == 0 {
+ out := d.nameInterface()
+ if out == nil {
+ v.Set(reflect.Zero(v.Type()))
+ } else {
+ v.Set(reflect.ValueOf(out))
+ }
+ return
+ }
+
+ nameStart := d.off - 1
+
+ op := d.scanWhile(scanContinue)
+
+ name := d.data[nameStart : d.off-1]
+ if op != scanParam {
+ // Back up so the byte just read is consumed next.
+ d.off--
+ d.scan.undo(op)
+ if l, ok := d.convertLiteral(name); ok {
+ d.storeValue(v, l)
+ return
+ }
+ d.error(&SyntaxError{fmt.Sprintf("json: unknown constant %q", name), int64(d.off)})
+ }
+
+ funcName := string(name)
+ funcData := d.ext.funcs[funcName]
+ if funcData.key == "" {
+ d.error(fmt.Errorf("json: unknown function %q", funcName))
+ }
+
+ // Check type of target:
+ // struct or
+ // map[string]T or map[encoding.TextUnmarshaler]T
+ switch v.Kind() {
+ case reflect.Map:
+ // Map key must either have string kind or be an encoding.TextUnmarshaler.
+ t := v.Type()
+ if t.Key().Kind() != reflect.String &&
+ !reflect.PtrTo(t.Key()).Implements(textUnmarshalerType) {
+ d.saveError(&UnmarshalTypeError{"object", v.Type(), int64(d.off)})
+ d.off--
+ d.next() // skip over { } in input
+ return
+ }
+ if v.IsNil() {
+ v.Set(reflect.MakeMap(t))
+ }
+ case reflect.Struct:
+
+ default:
+ d.saveError(&UnmarshalTypeError{"object", v.Type(), int64(d.off)})
+ d.off--
+ d.next() // skip over { } in input
+ return
+ }
+
+ // TODO Fix case of func field as map.
+ //topv := v
+
+ // Figure out field corresponding to function.
+ key := []byte(funcData.key)
+ if v.Kind() == reflect.Map {
+ elemType := v.Type().Elem()
+ v = reflect.New(elemType).Elem()
+ } else {
+ var f *field
+ fields := cachedTypeFields(v.Type())
+ for i := range fields {
+ ff := &fields[i]
+ if bytes.Equal(ff.nameBytes, key) {
+ f = ff
+ break
+ }
+ if f == nil && ff.equalFold(ff.nameBytes, key) {
+ f = ff
+ }
+ }
+ if f != nil {
+ for _, i := range f.index {
+ if v.Kind() == reflect.Ptr {
+ if v.IsNil() {
+ v.Set(reflect.New(v.Type().Elem()))
+ }
+ v = v.Elem()
+ }
+ v = v.Field(i)
+ }
+ if v.Kind() == reflect.Ptr {
+ if v.IsNil() {
+ v.Set(reflect.New(v.Type().Elem()))
+ }
+ v = v.Elem()
+ }
+ }
+ }
+
+ // Check for unmarshaler on func field itself.
+ u, ut, pv = d.indirect(v, false)
+ if u != nil {
+ d.off = nameStart
+ err := u.UnmarshalJSON(d.next())
+ if err != nil {
+ d.error(err)
+ }
+ return
+ }
+
+ var mapElem reflect.Value
+
+ // Parse function arguments.
+ for i := 0; ; i++ {
+ // closing ) - can only happen on first iteration.
+ op := d.scanWhile(scanSkipSpace)
+ if op == scanEndParams {
+ break
+ }
+
+ // Back up so d.value can have the byte we just read.
+ d.off--
+ d.scan.undo(op)
+
+ if i >= len(funcData.args) {
+ d.error(fmt.Errorf("json: too many arguments for function %s", funcName))
+ }
+ key := []byte(funcData.args[i])
+
+ // Figure out field corresponding to key.
+ var subv reflect.Value
+ destring := false // whether the value is wrapped in a string to be decoded first
+
+ if v.Kind() == reflect.Map {
+ elemType := v.Type().Elem()
+ if !mapElem.IsValid() {
+ mapElem = reflect.New(elemType).Elem()
+ } else {
+ mapElem.Set(reflect.Zero(elemType))
+ }
+ subv = mapElem
+ } else {
+ var f *field
+ fields := cachedTypeFields(v.Type())
+ for i := range fields {
+ ff := &fields[i]
+ if bytes.Equal(ff.nameBytes, key) {
+ f = ff
+ break
+ }
+ if f == nil && ff.equalFold(ff.nameBytes, key) {
+ f = ff
+ }
+ }
+ if f != nil {
+ subv = v
+ destring = f.quoted
+ for _, i := range f.index {
+ if subv.Kind() == reflect.Ptr {
+ if subv.IsNil() {
+ subv.Set(reflect.New(subv.Type().Elem()))
+ }
+ subv = subv.Elem()
+ }
+ subv = subv.Field(i)
+ }
+ }
+ }
+
+ // Read value.
+ if destring {
+ switch qv := d.valueQuoted().(type) {
+ case nil:
+ d.literalStore(nullLiteral, subv, false)
+ case string:
+ d.literalStore([]byte(qv), subv, true)
+ default:
+ d.saveError(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal unquoted value into %v", subv.Type()))
+ }
+ } else {
+ d.value(subv)
+ }
+
+ // Write value back to map;
+ // if using struct, subv points into struct already.
+ if v.Kind() == reflect.Map {
+ kt := v.Type().Key()
+ var kv reflect.Value
+ switch {
+ case kt.Kind() == reflect.String:
+ kv = reflect.ValueOf(key).Convert(v.Type().Key())
+ case reflect.PtrTo(kt).Implements(textUnmarshalerType):
+ kv = reflect.New(v.Type().Key())
+ d.literalStore(key, kv, true)
+ kv = kv.Elem()
+ default:
+ panic("json: Unexpected key type") // should never occur
+ }
+ v.SetMapIndex(kv, subv)
+ }
+
+ // Next token must be , or ).
+ op = d.scanWhile(scanSkipSpace)
+ if op == scanEndParams {
+ break
+ }
+ if op != scanParam {
+ d.error(errPhase)
+ }
+ }
+}
+
+// keyed attempts to decode an object or function using a keyed doc extension,
+// and returns the value and true on success, or nil and false otherwise.
+func (d *decodeState) keyed() (interface{}, bool) {
+ if len(d.ext.keyed) == 0 {
+ return nil, false
+ }
+
+ unquote := false
+
+ // Look-ahead first key to check for a keyed document extension.
+ d.nextscan.reset()
+ var start, end int
+ for i, c := range d.data[d.off-1:] {
+ switch op := d.nextscan.step(&d.nextscan, c); op {
+ case scanSkipSpace, scanContinue, scanBeginObject:
+ continue
+ case scanBeginLiteral, scanBeginName:
+ unquote = op == scanBeginLiteral
+ start = i
+ continue
+ }
+ end = i
+ break
+ }
+
+ name := d.data[d.off-1+start : d.off-1+end]
+
+ var key []byte
+ var ok bool
+ if unquote {
+ key, ok = unquoteBytes(name)
+ if !ok {
+ d.error(errPhase)
+ }
+ } else {
+ funcData, ok := d.ext.funcs[string(name)]
+ if !ok {
+ return nil, false
+ }
+ key = []byte(funcData.key)
+ }
+
+ decode, ok := d.ext.keyed[string(key)]
+ if !ok {
+ return nil, false
+ }
+
+ d.off--
+ out, err := decode(d.next())
+ if err != nil {
+ d.error(err)
+ }
+ return out, true
+}
+
+func (d *decodeState) storeKeyed(v reflect.Value) bool {
+ keyed, ok := d.keyed()
+ if !ok {
+ return false
+ }
+ d.storeValue(v, keyed)
+ return true
+}
+
+var (
+ trueBytes = []byte("true")
+ falseBytes = []byte("false")
+ nullBytes = []byte("null")
+)
+
+func (d *decodeState) storeValue(v reflect.Value, from interface{}) {
+ switch from {
+ case nil:
+ d.literalStore(nullBytes, v, false)
+ return
+ case true:
+ d.literalStore(trueBytes, v, false)
+ return
+ case false:
+ d.literalStore(falseBytes, v, false)
+ return
+ }
+ fromv := reflect.ValueOf(from)
+ for fromv.Kind() == reflect.Ptr && !fromv.IsNil() {
+ fromv = fromv.Elem()
+ }
+ fromt := fromv.Type()
+ for v.Kind() == reflect.Ptr && !v.IsNil() {
+ v = v.Elem()
+ }
+ vt := v.Type()
+ if fromt.AssignableTo(vt) {
+ v.Set(fromv)
+ } else if fromt.ConvertibleTo(vt) {
+ v.Set(fromv.Convert(vt))
+ } else {
+ d.saveError(&UnmarshalTypeError{"object", v.Type(), int64(d.off)})
+ }
+}
+
+func (d *decodeState) convertLiteral(name []byte) (interface{}, bool) {
+ if len(name) == 0 {
+ return nil, false
+ }
+ switch name[0] {
+ case 't':
+ if bytes.Equal(name, trueBytes) {
+ return true, true
+ }
+ case 'f':
+ if bytes.Equal(name, falseBytes) {
+ return false, true
+ }
+ case 'n':
+ if bytes.Equal(name, nullBytes) {
+ return nil, true
+ }
+ }
+ if l, ok := d.ext.consts[string(name)]; ok {
+ return l, true
+ }
+ return nil, false
+}
+
+// literal consumes a literal from d.data[d.off-1:], decoding into the value v.
+// The first byte of the literal has been read already
+// (that's how the caller knows it's a literal).
+func (d *decodeState) literal(v reflect.Value) {
+ // All bytes inside literal return scanContinue op code.
+ start := d.off - 1
+ op := d.scanWhile(scanContinue)
+
+ // Scan read one byte too far; back up.
+ d.off--
+ d.scan.undo(op)
+
+ d.literalStore(d.data[start:d.off], v, false)
+}
+
+// convertNumber converts the number literal s to a float64 or a Number
+// depending on the setting of d.useNumber.
+func (d *decodeState) convertNumber(s string) (interface{}, error) {
+ if d.useNumber {
+ return Number(s), nil
+ }
+ f, err := strconv.ParseFloat(s, 64)
+ if err != nil {
+ return nil, &UnmarshalTypeError{"number " + s, reflect.TypeOf(0.0), int64(d.off)}
+ }
+ return f, nil
+}
+
+var numberType = reflect.TypeOf(Number(""))
+
+// literalStore decodes a literal stored in item into v.
+//
+// fromQuoted indicates whether this literal came from unwrapping a
+// string from the ",string" struct tag option. this is used only to
+// produce more helpful error messages.
+func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool) {
+ // Check for unmarshaler.
+ if len(item) == 0 {
+ //Empty string given
+ d.saveError(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
+ return
+ }
+ wantptr := item[0] == 'n' // null
+ u, ut, pv := d.indirect(v, wantptr)
+ if u != nil {
+ err := u.UnmarshalJSON(item)
+ if err != nil {
+ d.error(err)
+ }
+ return
+ }
+ if ut != nil {
+ if item[0] != '"' {
+ if fromQuoted {
+ d.saveError(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
+ } else {
+ d.saveError(&UnmarshalTypeError{"string", v.Type(), int64(d.off)})
+ }
+ return
+ }
+ s, ok := unquoteBytes(item)
+ if !ok {
+ if fromQuoted {
+ d.error(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
+ } else {
+ d.error(errPhase)
+ }
+ }
+ err := ut.UnmarshalText(s)
+ if err != nil {
+ d.error(err)
+ }
+ return
+ }
+
+ v = pv
+
+ switch c := item[0]; c {
+ case 'n': // null
+ switch v.Kind() {
+ case reflect.Interface, reflect.Ptr, reflect.Map, reflect.Slice:
+ v.Set(reflect.Zero(v.Type()))
+ // otherwise, ignore null for primitives/string
+ }
+ case 't', 'f': // true, false
+ value := c == 't'
+ switch v.Kind() {
+ default:
+ if fromQuoted {
+ d.saveError(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
+ } else {
+ d.saveError(&UnmarshalTypeError{"bool", v.Type(), int64(d.off)})
+ }
+ case reflect.Bool:
+ v.SetBool(value)
+ case reflect.Interface:
+ if v.NumMethod() == 0 {
+ v.Set(reflect.ValueOf(value))
+ } else {
+ d.saveError(&UnmarshalTypeError{"bool", v.Type(), int64(d.off)})
+ }
+ }
+
+ case '"': // string
+ s, ok := unquoteBytes(item)
+ if !ok {
+ if fromQuoted {
+ d.error(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
+ } else {
+ d.error(errPhase)
+ }
+ }
+ switch v.Kind() {
+ default:
+ d.saveError(&UnmarshalTypeError{"string", v.Type(), int64(d.off)})
+ case reflect.Slice:
+ if v.Type().Elem().Kind() != reflect.Uint8 {
+ d.saveError(&UnmarshalTypeError{"string", v.Type(), int64(d.off)})
+ break
+ }
+ b := make([]byte, base64.StdEncoding.DecodedLen(len(s)))
+ n, err := base64.StdEncoding.Decode(b, s)
+ if err != nil {
+ d.saveError(err)
+ break
+ }
+ v.SetBytes(b[:n])
+ case reflect.String:
+ v.SetString(string(s))
+ case reflect.Interface:
+ if v.NumMethod() == 0 {
+ v.Set(reflect.ValueOf(string(s)))
+ } else {
+ d.saveError(&UnmarshalTypeError{"string", v.Type(), int64(d.off)})
+ }
+ }
+
+ default: // number
+ if c != '-' && (c < '0' || c > '9') {
+ if fromQuoted {
+ d.error(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
+ } else {
+ d.error(errPhase)
+ }
+ }
+ s := string(item)
+ switch v.Kind() {
+ default:
+ if v.Kind() == reflect.String && v.Type() == numberType {
+ v.SetString(s)
+ if !isValidNumber(s) {
+ d.error(fmt.Errorf("json: invalid number literal, trying to unmarshal %q into Number", item))
+ }
+ break
+ }
+ if fromQuoted {
+ d.error(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
+ } else {
+ d.error(&UnmarshalTypeError{"number", v.Type(), int64(d.off)})
+ }
+ case reflect.Interface:
+ n, err := d.convertNumber(s)
+ if err != nil {
+ d.saveError(err)
+ break
+ }
+ if v.NumMethod() != 0 {
+ d.saveError(&UnmarshalTypeError{"number", v.Type(), int64(d.off)})
+ break
+ }
+ v.Set(reflect.ValueOf(n))
+
+ case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+ n, err := strconv.ParseInt(s, 10, 64)
+ if err != nil || v.OverflowInt(n) {
+ d.saveError(&UnmarshalTypeError{"number " + s, v.Type(), int64(d.off)})
+ break
+ }
+ v.SetInt(n)
+
+ case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+ n, err := strconv.ParseUint(s, 10, 64)
+ if err != nil || v.OverflowUint(n) {
+ d.saveError(&UnmarshalTypeError{"number " + s, v.Type(), int64(d.off)})
+ break
+ }
+ v.SetUint(n)
+
+ case reflect.Float32, reflect.Float64:
+ n, err := strconv.ParseFloat(s, v.Type().Bits())
+ if err != nil || v.OverflowFloat(n) {
+ d.saveError(&UnmarshalTypeError{"number " + s, v.Type(), int64(d.off)})
+ break
+ }
+ v.SetFloat(n)
+ }
+ }
+}
+
+// The xxxInterface routines build up a value to be stored
+// in an empty interface. They are not strictly necessary,
+// but they avoid the weight of reflection in this common case.
+
+// valueInterface is like value but returns interface{}
+func (d *decodeState) valueInterface() interface{} {
+ switch d.scanWhile(scanSkipSpace) {
+ default:
+ d.error(errPhase)
+ panic("unreachable")
+ case scanBeginArray:
+ return d.arrayInterface()
+ case scanBeginObject:
+ return d.objectInterface()
+ case scanBeginLiteral:
+ return d.literalInterface()
+ case scanBeginName:
+ return d.nameInterface()
+ }
+}
+
+func (d *decodeState) syntaxError(expected string) {
+ msg := fmt.Sprintf("invalid character '%c' looking for %s", d.data[d.off-1], expected)
+ d.error(&SyntaxError{msg, int64(d.off)})
+}
+
+// arrayInterface is like array but returns []interface{}.
+func (d *decodeState) arrayInterface() []interface{} {
+ var v = make([]interface{}, 0)
+ for {
+ // Look ahead for ] - can only happen on first iteration.
+ op := d.scanWhile(scanSkipSpace)
+ if op == scanEndArray {
+ if len(v) > 0 && !d.ext.trailingCommas {
+ d.syntaxError("beginning of value")
+ }
+ break
+ }
+
+ // Back up so d.value can have the byte we just read.
+ d.off--
+ d.scan.undo(op)
+
+ v = append(v, d.valueInterface())
+
+ // Next token must be , or ].
+ op = d.scanWhile(scanSkipSpace)
+ if op == scanEndArray {
+ break
+ }
+ if op != scanArrayValue {
+ d.error(errPhase)
+ }
+ }
+ return v
+}
+
+// objectInterface is like object but returns map[string]interface{}.
+func (d *decodeState) objectInterface() interface{} {
+ v, ok := d.keyed()
+ if ok {
+ return v
+ }
+
+ m := make(map[string]interface{})
+ for {
+ // Read opening " of string key or closing }.
+ op := d.scanWhile(scanSkipSpace)
+ if op == scanEndObject {
+ if len(m) > 0 && !d.ext.trailingCommas {
+ d.syntaxError("beginning of object key string")
+ }
+ break
+ }
+ if op == scanBeginName {
+ if !d.ext.unquotedKeys {
+ d.syntaxError("beginning of object key string")
+ }
+ } else if op != scanBeginLiteral {
+ d.error(errPhase)
+ }
+ unquotedKey := op == scanBeginName
+
+ // Read string key.
+ start := d.off - 1
+ op = d.scanWhile(scanContinue)
+ item := d.data[start : d.off-1]
+ var key string
+ if unquotedKey {
+ key = string(item)
+ } else {
+ var ok bool
+ key, ok = unquote(item)
+ if !ok {
+ d.error(errPhase)
+ }
+ }
+
+ // Read : before value.
+ if op == scanSkipSpace {
+ op = d.scanWhile(scanSkipSpace)
+ }
+ if op != scanObjectKey {
+ d.error(errPhase)
+ }
+
+ // Read value.
+ m[key] = d.valueInterface()
+
+ // Next token must be , or }.
+ op = d.scanWhile(scanSkipSpace)
+ if op == scanEndObject {
+ break
+ }
+ if op != scanObjectValue {
+ d.error(errPhase)
+ }
+ }
+ return m
+}
+
+// literalInterface is like literal but returns an interface value.
+func (d *decodeState) literalInterface() interface{} {
+ // All bytes inside literal return scanContinue op code.
+ start := d.off - 1
+ op := d.scanWhile(scanContinue)
+
+ // Scan read one byte too far; back up.
+ d.off--
+ d.scan.undo(op)
+ item := d.data[start:d.off]
+
+ switch c := item[0]; c {
+ case 'n': // null
+ return nil
+
+ case 't', 'f': // true, false
+ return c == 't'
+
+ case '"': // string
+ s, ok := unquote(item)
+ if !ok {
+ d.error(errPhase)
+ }
+ return s
+
+ default: // number
+ if c != '-' && (c < '0' || c > '9') {
+ d.error(errPhase)
+ }
+ n, err := d.convertNumber(string(item))
+ if err != nil {
+ d.saveError(err)
+ }
+ return n
+ }
+}
+
+// nameInterface is like function but returns map[string]interface{}.
+func (d *decodeState) nameInterface() interface{} {
+ v, ok := d.keyed()
+ if ok {
+ return v
+ }
+
+ nameStart := d.off - 1
+
+ op := d.scanWhile(scanContinue)
+
+ name := d.data[nameStart : d.off-1]
+ if op != scanParam {
+ // Back up so the byte just read is consumed next.
+ d.off--
+ d.scan.undo(op)
+ if l, ok := d.convertLiteral(name); ok {
+ return l
+ }
+ d.error(&SyntaxError{fmt.Sprintf("json: unknown constant %q", name), int64(d.off)})
+ }
+
+ funcName := string(name)
+ funcData := d.ext.funcs[funcName]
+ if funcData.key == "" {
+ d.error(fmt.Errorf("json: unknown function %q", funcName))
+ }
+
+ m := make(map[string]interface{})
+ for i := 0; ; i++ {
+ // Look ahead for ) - can only happen on first iteration.
+ op := d.scanWhile(scanSkipSpace)
+ if op == scanEndParams {
+ break
+ }
+
+ // Back up so d.value can have the byte we just read.
+ d.off--
+ d.scan.undo(op)
+
+ if i >= len(funcData.args) {
+ d.error(fmt.Errorf("json: too many arguments for function %s", funcName))
+ }
+ m[funcData.args[i]] = d.valueInterface()
+
+ // Next token must be , or ).
+ op = d.scanWhile(scanSkipSpace)
+ if op == scanEndParams {
+ break
+ }
+ if op != scanParam {
+ d.error(errPhase)
+ }
+ }
+ return map[string]interface{}{funcData.key: m}
+}
+
+// getu4 decodes \uXXXX from the beginning of s, returning the hex value,
+// or it returns -1.
+func getu4(s []byte) rune {
+ if len(s) < 6 || s[0] != '\\' || s[1] != 'u' {
+ return -1
+ }
+ r, err := strconv.ParseUint(string(s[2:6]), 16, 64)
+ if err != nil {
+ return -1
+ }
+ return rune(r)
+}
+
+// unquote converts a quoted JSON string literal s into an actual string t.
+// The rules are different than for Go, so cannot use strconv.Unquote.
+func unquote(s []byte) (t string, ok bool) {
+ s, ok = unquoteBytes(s)
+ t = string(s)
+ return
+}
+
+func unquoteBytes(s []byte) (t []byte, ok bool) {
+ if len(s) < 2 || s[0] != '"' || s[len(s)-1] != '"' {
+ return
+ }
+ s = s[1 : len(s)-1]
+
+ // Check for unusual characters. If there are none,
+ // then no unquoting is needed, so return a slice of the
+ // original bytes.
+ r := 0
+ for r < len(s) {
+ c := s[r]
+ if c == '\\' || c == '"' || c < ' ' {
+ break
+ }
+ if c < utf8.RuneSelf {
+ r++
+ continue
+ }
+ rr, size := utf8.DecodeRune(s[r:])
+ if rr == utf8.RuneError && size == 1 {
+ break
+ }
+ r += size
+ }
+ if r == len(s) {
+ return s, true
+ }
+
+ b := make([]byte, len(s)+2*utf8.UTFMax)
+ w := copy(b, s[0:r])
+ for r < len(s) {
+ // Out of room? Can only happen if s is full of
+ // malformed UTF-8 and we're replacing each
+ // byte with RuneError.
+ if w >= len(b)-2*utf8.UTFMax {
+ nb := make([]byte, (len(b)+utf8.UTFMax)*2)
+ copy(nb, b[0:w])
+ b = nb
+ }
+ switch c := s[r]; {
+ case c == '\\':
+ r++
+ if r >= len(s) {
+ return
+ }
+ switch s[r] {
+ default:
+ return
+ case '"', '\\', '/', '\'':
+ b[w] = s[r]
+ r++
+ w++
+ case 'b':
+ b[w] = '\b'
+ r++
+ w++
+ case 'f':
+ b[w] = '\f'
+ r++
+ w++
+ case 'n':
+ b[w] = '\n'
+ r++
+ w++
+ case 'r':
+ b[w] = '\r'
+ r++
+ w++
+ case 't':
+ b[w] = '\t'
+ r++
+ w++
+ case 'u':
+ r--
+ rr := getu4(s[r:])
+ if rr < 0 {
+ return
+ }
+ r += 6
+ if utf16.IsSurrogate(rr) {
+ rr1 := getu4(s[r:])
+ if dec := utf16.DecodeRune(rr, rr1); dec != unicode.ReplacementChar {
+ // A valid pair; consume.
+ r += 6
+ w += utf8.EncodeRune(b[w:], dec)
+ break
+ }
+ // Invalid surrogate; fall back to replacement rune.
+ rr = unicode.ReplacementChar
+ }
+ w += utf8.EncodeRune(b[w:], rr)
+ }
+
+ // Quote, control characters are invalid.
+ case c == '"', c < ' ':
+ return
+
+ // ASCII
+ case c < utf8.RuneSelf:
+ b[w] = c
+ r++
+ w++
+
+ // Coerce to well-formed UTF-8.
+ default:
+ rr, size := utf8.DecodeRune(s[r:])
+ r += size
+ w += utf8.EncodeRune(b[w:], rr)
+ }
+ }
+ return b[0:w], true
+}