decode_test.go

//go:build (amd64 && go1.17 && !go1.26) || (arm64 && go1.20 && !go1.26)
// +build amd64,go1.17,!go1.26 arm64,go1.20,!go1.26

/*
 * Copyright 2021 ByteDance Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package sonic

import (
	"bytes"
	"encoding"
	"encoding/json"
	"errors"
	"fmt"
	"image"
	"math"
	"math/big"
	"math/rand"
	"net"
	"reflect"
	"runtime"
	"strconv"
	"strings"
	"testing"
	"time"
	"unsafe"

	"github.com/bytedance/sonic/decoder"
	"github.com/bytedance/sonic/internal/native/types"
	"github.com/bytedance/sonic/internal/utils"
	"github.com/davecgh/go-spew/spew"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

type T struct {
    X string
    Y int
    Z int `json:"-"`
}

type U struct {
    Alphabet string `json:"alpha"`
}

type V struct {
    F1 interface{}
    F2 int32
    F3 json.Number
    F4 *VOuter
}

type VOuter struct {
    V V
}

type W struct {
    S SS
}

type P struct {
    PP PP
}

type PP struct {
    T  T
    Ts []T
}

type SS string

func (*SS) UnmarshalJSON(_ []byte) error {
    return &json.UnmarshalTypeError{Value: "number", Type: reflect.TypeOf(SS(""))}
}

// ifaceNumAsFloat64/ifaceNumAsNumber are used to test unmarshaling with and
// without UseNumber
var ifaceNumAsFloat64 = map[string]interface{}{
    "k1": float64(1),
    "k2": "s",
    "k3": []interface{}{float64(1), 2.0, 3e-3},
    "k4": map[string]interface{}{"kk1": "s", "kk2": float64(2)},
}

var ifaceNumAsNumber = map[string]interface{}{
    "k1": json.Number("1"),
    "k2": "s",
    "k3": []interface{}{json.Number("1"), json.Number("2.0"), json.Number("3e-3")},
    "k4": map[string]interface{}{"kk1": "s", "kk2": json.Number("2")},
}

type tx struct {
    x int
}

type u8 uint8

// A type that can unmarshal itself.

type unmarshaler struct {
    T bool
}

func (u *unmarshaler) UnmarshalJSON(_ []byte) error {
    *u = unmarshaler{true} // All we need to see that UnmarshalJSON is called.
    return nil
}

type ustruct struct {
    M unmarshaler
}

type unmarshalerText struct {
    A, B string
}

// needed for re-marshaling tests
func (u unmarshalerText) MarshalText() ([]byte, error) {
    return []byte(u.A + ":" + u.B), nil
}

func (u *unmarshalerText) UnmarshalText(b []byte) error {
    pos := bytes.IndexByte(b, ':')
    if pos == -1 {
        return errors.New("missing separator")
    }
    u.A, u.B = string(b[:pos]), string(b[pos+1:])
    return nil
}

var _ encoding.TextUnmarshaler = (*unmarshalerText)(nil)

type ustructText struct {
    M unmarshalerText
}

// u8marshal is an integer type that can marshal/unmarshal itself.
type u8marshal uint8

func (u8 u8marshal) MarshalText() ([]byte, error) {
    return []byte(fmt.Sprintf("u%d", u8)), nil
}

var errMissingU8Prefix = errors.New("missing 'u' prefix")

func (u8 *u8marshal) UnmarshalText(b []byte) error {
    if !bytes.HasPrefix(b, []byte{'u'}) {
        return errMissingU8Prefix
    }
    n, err := strconv.Atoi(string(b[1:]))
    if err != nil {
        return err
    }
    *u8 = u8marshal(n)
    return nil
}

var _ encoding.TextUnmarshaler = (*u8marshal)(nil)

var (
    umtrue   = unmarshaler{true}
    umslice  = []unmarshaler{{true}}
    umstruct = ustruct{unmarshaler{true}}

    umtrueXY   = unmarshalerText{"x", "y"}
    umsliceXY  = []unmarshalerText{{"x", "y"}}
    umstructXY = ustructText{unmarshalerText{"x", "y"}}

    ummapXY = map[unmarshalerText]bool{{"x", "y"}: true}
)

// Test data structures for anonymous fields.

type Point struct {
    Z int
}

type Top struct {
    Level0 int
    Embed0
    *Embed0a
    *Embed0b `json:"e,omitempty"` // treated as named
    Embed0c  `json:"-"`           // ignored
    Loop
    Embed0p // has Point with X, Y, used
    Embed0q // has Point with Z, used
    embed   // contains exported field
}

type Embed0 struct {
    Level1a int // overridden by Embed0a's Level1a with json tag
    Level1b int // used because Embed0a's Level1b is renamed
    Level1c int // used because Embed0a's Level1c is ignored
    Level1d int // annihilated by Embed0a's Level1d
    Level1e int `json:"x"` // annihilated by Embed0a.Level1e
}

type Embed0a struct {
    Level1a int `json:"Level1a,omitempty"`
    Level1b int `json:"LEVEL1B,omitempty"`
    Level1c int `json:"-"`
    Level1d int // annihilated by Embed0's Level1d
    Level1f int `json:"x"` // annihilated by Embed0's Level1e
}

type Embed0b Embed0

type Embed0c Embed0

type Embed0p struct {
    image.Point
}

type Embed0q struct {
    Point
}

type embed struct {
    Q int
}

type Loop struct {
    Loop1 int `json:",omitempty"`
    Loop2 int `json:",omitempty"`
    *Loop
}

// From reflect test:
// The X in S6 and S7 annihilate, but they also block the X in S8.S9.
type S5 struct {
    S6
    S7
    S8
}

type S6 struct {
    X int
}

type S7 S6

type S8 struct {
    S9
}

type S9 struct {
    X int
    Y int
}

// From reflect test:
// The X in S11.S6 and S12.S6 annihilate, but they also block the X in S13.S8.S9.
type S10 struct {
    S11
    S12
    S13
}

type S11 struct {
    S6
}

type S12 struct {
    S6
}

type S13 struct {
    S8
}

type Ambig struct {
    // Given "hello", the first match should win.
    First  int `json:"HELLO"`
    Second int `json:"Hello"`
}

type XYZ struct {
    X interface{}
    Y interface{}
    Z interface{}
}

type byteWithMarshalJSON byte

func (b byteWithMarshalJSON) MarshalJSON() ([]byte, error) {
    return []byte(fmt.Sprintf(`"Z%.2x"`, byte(b))), nil
}

func (b *byteWithMarshalJSON) UnmarshalJSON(data []byte) error {
    if len(data) != 5 || data[0] != '"' || data[1] != 'Z' || data[4] != '"' {
        return fmt.Errorf("bad quoted string")
    }
    i, err := strconv.ParseInt(string(data[2:4]), 16, 8)
    if err != nil {
        return fmt.Errorf("bad hex")
    }
    *b = byteWithMarshalJSON(i)
    return nil
}

type byteWithPtrMarshalJSON byte

func (b *byteWithPtrMarshalJSON) MarshalJSON() ([]byte, error) {
    return byteWithMarshalJSON(*b).MarshalJSON()
}

func (b *byteWithPtrMarshalJSON) UnmarshalJSON(data []byte) error {
    return (*byteWithMarshalJSON)(b).UnmarshalJSON(data)
}

type byteWithMarshalText byte

func (b byteWithMarshalText) MarshalText() ([]byte, error) {
    return []byte(fmt.Sprintf(`Z%.2x`, byte(b))), nil
}

func (b *byteWithMarshalText) UnmarshalText(data []byte) error {
    if len(data) != 3 || data[0] != 'Z' {
        return fmt.Errorf("bad quoted string")
    }
    i, err := strconv.ParseInt(string(data[1:3]), 16, 8)
    if err != nil {
        return fmt.Errorf("bad hex")
    }
    *b = byteWithMarshalText(i)
    return nil
}

type byteWithPtrMarshalText byte

func (b *byteWithPtrMarshalText) MarshalText() ([]byte, error) {
    return byteWithMarshalText(*b).MarshalText()
}

func (b *byteWithPtrMarshalText) UnmarshalText(data []byte) error {
    return (*byteWithMarshalText)(b).UnmarshalText(data)
}

type intWithMarshalJSON int

func (b intWithMarshalJSON) MarshalJSON() ([]byte, error) {
    return []byte(fmt.Sprintf(`"Z%.2x"`, int(b))), nil
}

func (b *intWithMarshalJSON) UnmarshalJSON(data []byte) error {
    if len(data) != 5 || data[0] != '"' || data[1] != 'Z' || data[4] != '"' {
        return fmt.Errorf("bad quoted string")
    }
    i, err := strconv.ParseInt(string(data[2:4]), 16, 8)
    if err != nil {
        return fmt.Errorf("bad hex")
    }
    *b = intWithMarshalJSON(i)
    return nil
}

type intWithPtrMarshalJSON int

func (b *intWithPtrMarshalJSON) MarshalJSON() ([]byte, error) {
    return intWithMarshalJSON(*b).MarshalJSON()
}

func (b *intWithPtrMarshalJSON) UnmarshalJSON(data []byte) error {
    return (*intWithMarshalJSON)(b).UnmarshalJSON(data)
}

type intWithMarshalText int

func (b intWithMarshalText) MarshalText() ([]byte, error) {
    return []byte(fmt.Sprintf(`Z%.2x`, int(b))), nil
}

func (b *intWithMarshalText) UnmarshalText(data []byte) error {
    if len(data) != 3 || data[0] != 'Z' {
        return fmt.Errorf("bad quoted string")
    }
    i, err := strconv.ParseInt(string(data[1:3]), 16, 8)
    if err != nil {
        return fmt.Errorf("bad hex")
    }
    *b = intWithMarshalText(i)
    return nil
}

type intWithPtrMarshalText int

func (b *intWithPtrMarshalText) MarshalText() ([]byte, error) {
    return intWithMarshalText(*b).MarshalText()
}

func (b *intWithPtrMarshalText) UnmarshalText(data []byte) error {
    return (*intWithMarshalText)(b).UnmarshalText(data)
}

type mapStringToStringData struct {
    Data map[string]string `json:"data"`
}

type unmarshalTest struct {
    in                    string
    ptr                   interface{} // new(type)
    out                   interface{}
    err                   error
    useNumber             bool
    golden                bool
    disallowUnknownFields bool
    validateString           bool
}

type B struct {
    B bool `json:",string"`
}

type DoublePtr struct {
    I **int
    J **int
}

type JsonSyntaxError struct {
    Msg    string
    Offset int64
}

func (self *JsonSyntaxError) err() *json.SyntaxError {
    return (*json.SyntaxError)(unsafe.Pointer(self))
}

var unmarshalTests = []unmarshalTest{
    // basic types
    {in: `true`, ptr: new(bool), out: true},
    {in: `1`, ptr: new(int), out: 1},
    {in: `1.2`, ptr: new(float64), out: 1.2},
    {in: `-5`, ptr: new(int16), out: int16(-5)},
    {in: `2`, ptr: new(json.Number), out: json.Number("2"), useNumber: true},
    {in: `2`, ptr: new(json.Number), out: json.Number("2")},
    {in: `2`, ptr: new(interface{}), out: 2.0},
    {in: `2`, ptr: new(interface{}), out: json.Number("2"), useNumber: true},
    {in: `"a\u1234"`, ptr: new(string), out: "a\u1234"},
    {in: `"http:\/\/"`, ptr: new(string), out: "http://"},
    {in: `"g-clef: \uD834\uDD1E"`, ptr: new(string), out: "g-clef: \U0001D11E"},
    {in: `"invalid: \uD834x\uDD1E"`, ptr: new(string), out: "invalid: \uFFFDx\uFFFD"},
    {in: "null", ptr: new(interface{}), out: nil},
    {in: `{"X": [1,2,3], "Y": 4}`, ptr: new(T), out: T{Y: 4}, err: &json.UnmarshalTypeError{Value: "array", Type: reflect.TypeOf(""), Offset: 7, Struct: "T", Field: "X"}},
    {in: `{"X": 23}`, ptr: new(T), out: T{}, err: &json.UnmarshalTypeError{Value: "number", Type: reflect.TypeOf(""), Offset: 8, Struct: "T", Field: "X"}},
    {in: `{"x": 1}`, ptr: new(tx), out: tx{}},
    {in: `{"x": 1}`, ptr: new(tx), err: fmt.Errorf("json: unknown field \"x\""), disallowUnknownFields: true},
    {in: `{"S": 23}`, ptr: new(W), out: W{}, err: &json.UnmarshalTypeError{Value: "number", Type: reflect.TypeOf(SS("")), Struct: "W", Field: "S"}},
    {in: `{"F1":1,"F2":2,"F3":3}`, ptr: new(V), out: V{F1: float64(1), F2: int32(2), F3: json.Number("3")}},
    {in: `{"F1":1,"F2":2,"F3":3}`, ptr: new(V), out: V{F1: json.Number("1"), F2: int32(2), F3: json.Number("3")}, useNumber: true},
    {in: `{"k1":1,"k2":"s","k3":[1,2.0,3e-3],"k4":{"kk1":"s","kk2":2}}`, ptr: new(interface{}), out: ifaceNumAsFloat64},
    {in: `{"k1":1,"k2":"s","k3":[1,2.0,3e-3],"k4":{"kk1":"s","kk2":2}}`, ptr: new(interface{}), out: ifaceNumAsNumber, useNumber: true},
	{in: `{"":""}`, ptr: new(struct{}), out: struct{}{}},
	{in: `{"x":""}`, ptr: new(struct{ X json.Number }),  err: errors.New("empty string into json number")},

    // raw values with whitespace
    {in: "\n true ", ptr: new(bool), out: true},
    {in: "\t 1 ", ptr: new(int), out: 1},
    {in: "\r 1.2 ", ptr: new(float64), out: 1.2},
    {in: "\t -5 \n", ptr: new(int16), out: int16(-5)},
    {in: "\t \"a\\u1234\" \n", ptr: new(string), out: "a\u1234"},

    // Z has a "-" tag.
    {in: `{"Y": 1, "Z": 2}`, ptr: new(T), out: T{Y: 1}},
    {in: `{"Y": 1, "Z": 2}`, ptr: new(T), err: fmt.Errorf("json: unknown field \"Z\""), disallowUnknownFields: true},

    {in: `{"alpha": "abc", "alphabet": "xyz"}`, ptr: new(U), out: U{Alphabet: "abc"}},
    {in: `{"alpha": "abc", "alphabet": "xyz"}`, ptr: new(U), err: fmt.Errorf("json: unknown field \"alphabet\""), disallowUnknownFields: true},
    {in: `{"alpha": "abc"}`, ptr: new(U), out: U{Alphabet: "abc"}},
    {in: `{"alphabet": "xyz"}`, ptr: new(U), out: U{}},
    {in: `{"alphabet": "xyz"}`, ptr: new(U), err: fmt.Errorf("json: unknown field \"alphabet\""), disallowUnknownFields: true},

    // syntax errors
    {in: `{"X": "foo", "Y"}`, err: (&JsonSyntaxError{"invalid character '}' after object key", 17}).err()},
    {in: `[1, 2, 3+]`, err: (&JsonSyntaxError{"invalid character '+' after array element", 9}).err()},
    {in: `{"X":12x}`, err: (&JsonSyntaxError{"invalid character 'x' after object key:value pair", 8}).err(), useNumber: true},
    {in: `[2, 3`, err: (&JsonSyntaxError{Msg:  "unexpected end of JSON input", Offset: 5}).err()},
    {in: `{"F3": -}`, ptr: new(V), out: V{F3: json.Number("-")}, err: (&JsonSyntaxError{Msg:  "invalid character '}' in numeric literal", Offset: 9}).err()},

    // raw value errors
    {in: "\x01 42", err: (&JsonSyntaxError{"invalid character '\\x01' looking for beginning of value", 1}).err()},
    {in: " 42 \x01", err: (&JsonSyntaxError{"invalid character '\\x01' after top-level value", 5}).err()},
    {in: "\x01 true", err: (&JsonSyntaxError{"invalid character '\\x01' looking for beginning of value", 1}).err()},
    {in: " false \x01", err: (&JsonSyntaxError{"invalid character '\\x01' after top-level value", 8}).err()},
    {in: "\x01 1.2", err: (&JsonSyntaxError{"invalid character '\\x01' looking for beginning of value", 1}).err()},
    {in: " 3.4 \x01", err: (&JsonSyntaxError{"invalid character '\\x01' after top-level value", 6}).err()},
    {in: "\x01 \"string\"", err: (&JsonSyntaxError{"invalid character '\\x01' looking for beginning of value", 1}).err()},
    {in: " \"string\" \x01", err: (&JsonSyntaxError{"invalid character '\\x01' after top-level value", 11}).err()},

    // array tests
    {in: `[1, 2, 3]`, ptr: new([3]int), out: [3]int{1, 2, 3}},
    {in: `[1, 2, 3]`, ptr: new([1]int), out: [1]int{1}},
    {in: `[1, 2, 3]`, ptr: new([5]int), out: [5]int{1, 2, 3, 0, 0}},
    {in: `[1, 2, 3]`, ptr: new(MustNotUnmarshalJSON), err: errors.New("MustNotUnmarshalJSON was used")},

    // empty array to interface test
    {in: `[]`, ptr: new([]interface{}), out: []interface{}{}},
    {in: `null`, ptr: new([]interface{}), out: []interface{}(nil)},
    {in: `{"T":[]}`, ptr: new(map[string]interface{}), out: map[string]interface{}{"T": []interface{}{}}},
    {in: `{"T":null}`, ptr: new(map[string]interface{}), out: map[string]interface{}{"T": interface{}(nil)}},

    // composite tests
    {in: allValueIndent, ptr: new(All), out: allValue},
    {in: allValueCompact, ptr: new(All), out: allValue},
    {in: allValueIndent, ptr: new(*All), out: &allValue},
    {in: allValueCompact, ptr: new(*All), out: &allValue},
    {in: pallValueIndent, ptr: new(All), out: pallValue},
    {in: pallValueCompact, ptr: new(All), out: pallValue},
    {in: pallValueIndent, ptr: new(*All), out: &pallValue},
    {in: pallValueCompact, ptr: new(*All), out: &pallValue},

    // unmarshal interface test
    {in: `{"T":false}`, ptr: new(unmarshaler), out: umtrue}, // use "false" so test will fail if custom unmarshaler is not called
    {in: `{"T":false}`, ptr: new(*unmarshaler), out: &umtrue},
    {in: `[{"T":false}]`, ptr: new([]unmarshaler), out: umslice},
    {in: `[{"T":false}]`, ptr: new(*[]unmarshaler), out: &umslice},
    {in: `{"M":{"T":"x:y"}}`, ptr: new(ustruct), out: umstruct},

    // UnmarshalText interface test
    {in: `"x:y"`, ptr: new(unmarshalerText), out: umtrueXY},
    {in: `"x:y"`, ptr: new(*unmarshalerText), out: &umtrueXY},
    {in: `["x:y"]`, ptr: new([]unmarshalerText), out: umsliceXY},
    {in: `["x:y"]`, ptr: new(*[]unmarshalerText), out: &umsliceXY},
    {in: `{"M":"x:y"}`, ptr: new(ustructText), out: umstructXY},

    // integer-keyed map test
    {
        in:  `{"-1":"a","0":"b","1":"c"}`,
        ptr: new(map[int]string),
        out: map[int]string{-1: "a", 0: "b", 1: "c"},
    },
    {
        in:  `{"0":"a","10":"c","9":"b"}`,
        ptr: new(map[u8]string),
        out: map[u8]string{0: "a", 9: "b", 10: "c"},
    },
    {
        in:  `{"-9223372036854775808":"min","9223372036854775807":"max"}`,
        ptr: new(map[int64]string),
        out: map[int64]string{math.MinInt64: "min", math.MaxInt64: "max"},
    },
    {
        in:  `{"18446744073709551615":"max"}`,
        ptr: new(map[uint64]string),
        out: map[uint64]string{math.MaxUint64: "max"},
    },
    {
        in:  `{"0":false,"10":true}`,
        ptr: new(map[uintptr]bool),
        out: map[uintptr]bool{0: false, 10: true},
    },

    // Check that MarshalText and UnmarshalText take precedence
    // over default integer handling in map keys.
    {
        in:  `{"u2":4}`,
        ptr: new(map[u8marshal]int),
        out: map[u8marshal]int{2: 4},
    },
    {
        in:  `{"2":4}`,
        ptr: new(map[u8marshal]int),
        err: errMissingU8Prefix,
    },

    // integer-keyed map errors
    {
        in:  `{"abc":"abc"}`,
        ptr: new(map[int]string),
        err: &json.UnmarshalTypeError{Value: "number abc", Type: reflect.TypeOf(0), Offset: 2},
    },
    {
        in:  `{"256":"abc"}`,
        ptr: new(map[uint8]string),
        err: &json.UnmarshalTypeError{Value: "number 256", Type: reflect.TypeOf(uint8(0)), Offset: 2},
    },
    {
        in:  `{"128":"abc"}`,
        ptr: new(map[int8]string),
        err: &json.UnmarshalTypeError{Value: "number 128", Type: reflect.TypeOf(int8(0)), Offset: 2},
    },
    {
        in:  `{"-1":"abc"}`,
        ptr: new(map[uint8]string),
        err: &json.UnmarshalTypeError{Value: "number -1", Type: reflect.TypeOf(uint8(0)), Offset: 2},
    },
    {
        in:  `{"F":{"a":2,"3":4}}`,
        ptr: new(map[string]map[int]int),
        err: &json.UnmarshalTypeError{Value: "number a", Type: reflect.TypeOf(0), Offset: 7},
    },
    {
        in:  `{"F":{"a":2,"3":4}}`,
        ptr: new(map[string]map[uint]int),
        err: &json.UnmarshalTypeError{Value: "number a", Type: reflect.TypeOf(uint(0)), Offset: 7},
    },

    // Map keys can be encoding.TextUnmarshalers.
    {in: `{"x:y":true}`, ptr: new(map[unmarshalerText]bool), out: ummapXY},
    // If multiple values for the same key exists, only the most recent value is used.
    {in: `{"x:y":false,"x:y":true}`, ptr: new(map[unmarshalerText]bool), out: ummapXY},

    {
        in: `{
            "Level0": 1,
            "Level1b": 2,
            "Level1c": 3,
            "x": 4,
            "Level1a": 5,
            "LEVEL1B": 6,
            "e": {
                "Level1a": 8,
                "Level1b": 9,
                "Level1c": 10,
                "Level1d": 11,
                "x": 12
            },
            "Loop1": 13,
            "Loop2": 14,
            "X": 15,
            "Y": 16,
            "Z": 17,
            "Q": 18
        }`,
        ptr: new(Top),
        out: Top{
            Level0: 1,
            Embed0: Embed0{
                Level1b: 2,
                Level1c: 3,
            },
            Embed0a: &Embed0a{
                Level1a: 5,
                Level1b: 6,
            },
            Embed0b: &Embed0b{
                Level1a: 8,
                Level1b: 9,
                Level1c: 10,
                Level1d: 11,
                Level1e: 12,
            },
            Loop: Loop{
                Loop1: 13,
                Loop2: 14,
            },
            Embed0p: Embed0p{
                Point: image.Point{X: 15, Y: 16},
            },
            Embed0q: Embed0q{
                Point: Point{Z: 17},
            },
            embed: embed{
                Q: 18,
            },
        },
    },
    {
        in:  `{"hello": 1}`,
        ptr: new(Ambig),
        out: Ambig{First: 1},
    },

    {
        in:  `{"X": 1,"Y":2}`,
        ptr: new(S5),
        out: S5{S8: S8{S9: S9{Y: 2}}},
    },
    {
        in:                    `{"X": 1,"Y":2}`,
        ptr:                   new(S5),
        err:                   fmt.Errorf("json: unknown field \"X\""),
        disallowUnknownFields: true,
    },
    {
        in:  `{"X": 1,"Y":2}`,
        ptr: new(S10),
        out: S10{S13: S13{S8: S8{S9: S9{Y: 2}}}},
    },
    {
        in:                    `{"X": 1,"Y":2}`,
        ptr:                   new(S10),
        err:                   fmt.Errorf("json: unknown field \"X\""),
        disallowUnknownFields: true,
    },
    {
        in:  `{"I": 0, "I": null, "J": null}`,
        ptr: new(DoublePtr),
        out: DoublePtr{I: nil, J: nil},
    },

    // invalid UTF-8 is coerced to valid UTF-8.
    {
        in:  "\"hello\xffworld\"",
        ptr: new(string),
        out: "hello\xffworld",
        validateString: false,
    },
    {
        in:  "\"hello\xc2\xc2world\"",
        ptr: new(string),
        out: "hello\xc2\xc2world",
        validateString: false,
    },
    {
        in:  "\"hello\xc2\xffworld\"",
        ptr: new(string),
        out: "hello\xc2\xffworld",
    },
    {
        in:  "\"hello\\ud800world\"",
        ptr: new(string),
        out: "hello\ufffdworld",
    },
    {
        in:  "\"hello\\ud800\\ud800world\"",
        ptr: new(string),
        out: "hello\ufffd\ufffdworld",
    },
    {
        in:  "\"hello\xed\xa0\x80\xed\xb0\x80world\"",
        ptr: new(string),
        out: "hello\xed\xa0\x80\xed\xb0\x80world",
    },

    // Used to be issue 8305, but time.Time implements encoding.TextUnmarshaler so this works now.
    {
        in:  `{"2009-11-10T23:00:00Z": "hello world"}`,
        ptr: new(map[time.Time]string),
        out: map[time.Time]string{time.Date(2009, 11, 10, 23, 0, 0, 0, time.UTC): "hello world"},
    },

    // issue 8305
    {
        in:  `{"2009-11-10T23:00:00Z": "hello world"}`,
        ptr: new(map[Point]string),
        err: &json.UnmarshalTypeError{Value: "object", Type: reflect.TypeOf(map[Point]string{}), Offset: 1},
    },
    {
        in:  `{"asdf": "hello world"}`,
        ptr: new(map[unmarshaler]string),
        err: &json.UnmarshalTypeError{Value: "object", Type: reflect.TypeOf(map[unmarshaler]string{}), Offset: 1},
    },

    // related to issue 13783.
    // Go 1.7 changed marshaling a slice of typed byte to use the methods on the byte type,
    // similar to marshaling a slice of typed int.
    // These tests check that, assuming the byte type also has valid decoding methods,
    // either the old base64 string encoding or the new per-element encoding can be
    // successfully unmarshaled. The custom unmarshalers were accessible in earlier
    // versions of Go, even though the custom marshaler was not.
    {
        in:  `"AQID"`,
        ptr: new([]byteWithMarshalJSON),
        out: []byteWithMarshalJSON{1, 2, 3},
    },
    {
        in:     `["Z01","Z02","Z03"]`,
        ptr:    new([]byteWithMarshalJSON),
        out:    []byteWithMarshalJSON{1, 2, 3},
        golden: true,
    },
    {
        in:  `"AQID"`,
        ptr: new([]byteWithMarshalText),
        out: []byteWithMarshalText{1, 2, 3},
    },
    {
        in:     `["Z01","Z02","Z03"]`,
        ptr:    new([]byteWithMarshalText),
        out:    []byteWithMarshalText{1, 2, 3},
        golden: true,
    },
    {
        in:  `"AQID"`,
        ptr: new([]byteWithPtrMarshalJSON),
        out: []byteWithPtrMarshalJSON{1, 2, 3},
    },
    {
        in:     `["Z01","Z02","Z03"]`,
        ptr:    new([]byteWithPtrMarshalJSON),
        out:    []byteWithPtrMarshalJSON{1, 2, 3},
        golden: true,
    },
    {
        in:  `"AQID"`,
        ptr: new([]byteWithPtrMarshalText),
        out: []byteWithPtrMarshalText{1, 2, 3},
    },
    {
        in:     `["Z01","Z02","Z03"]`,
        ptr:    new([]byteWithPtrMarshalText),
        out:    []byteWithPtrMarshalText{1, 2, 3},
        golden: true,
    },

    // ints work with the marshaler but not the base64 []byte case
    {
        in:     `["Z01","Z02","Z03"]`,
        ptr:    new([]intWithMarshalJSON),
        out:    []intWithMarshalJSON{1, 2, 3},
        golden: true,
    },
    {
        in:     `["Z01","Z02","Z03"]`,
        ptr:    new([]intWithMarshalText),
        out:    []intWithMarshalText{1, 2, 3},
        golden: true,
    },
    {
        in:     `["Z01","Z02","Z03"]`,
        ptr:    new([]intWithPtrMarshalJSON),
        out:    []intWithPtrMarshalJSON{1, 2, 3},
        golden: true,
    },
    {
        in:     `["Z01","Z02","Z03"]`,
        ptr:    new([]intWithPtrMarshalText),
        out:    []intWithPtrMarshalText{1, 2, 3},
        golden: true,
    },

    {in: `0.000001`, ptr: new(float64), out: 0.000001, golden: true},
    {in: `1e-7`, ptr: new(float64), out: 1e-7, golden: true},
    {in: `100000000000000000000`, ptr: new(float64), out: 100000000000000000000.0, golden: true},
    {in: `1e+21`, ptr: new(float64), out: 1e21, golden: true},
    {in: `-0.000001`, ptr: new(float64), out: -0.000001, golden: true},
    {in: `-1e-7`, ptr: new(float64), out: -1e-7, golden: true},
    {in: `-100000000000000000000`, ptr: new(float64), out: -100000000000000000000.0, golden: true},
    {in: `-1e+21`, ptr: new(float64), out: -1e21, golden: true},
    {in: `999999999999999900000`, ptr: new(float64), out: 999999999999999900000.0, golden: true},
    {in: `9007199254740992`, ptr: new(float64), out: 9007199254740992.0, golden: true},
    {in: `9007199254740993`, ptr: new(float64), out: 9007199254740992.0, golden: false},

    {
        in:  `{"V": {"F2": "hello"}}`,
        ptr: new(VOuter),
        err: &json.UnmarshalTypeError{
            Value:  "string",
            Struct: "V",
            Field:  "V.F2",
            Type:   reflect.TypeOf(int32(0)),
            Offset: 20,
        },
    },
    {
        in:  `{"V": {"F4": {}, "F2": "hello"}}`,
        ptr: new(VOuter),
        err: &json.UnmarshalTypeError{
            Value:  "string",
            Struct: "V",
            Field:  "V.F2",
            Type:   reflect.TypeOf(int32(0)),
            Offset: 30,
        },
    },

    // issue 15146.
    // invalid inputs in wrongStringTests below.
    {in: `{"B":"true"}`, ptr: new(B), out: B{true}, golden: true},
    {in: `{"B":"false"}`, ptr: new(B), out: B{false}, golden: true},
    {in: `{"B": "maybe"}`, ptr: new(B), err: errors.New(`json: invalid use of ,string struct tag, trying to unmarshal "maybe" into bool`)},
    {in: `{"B": "tru"}`, ptr: new(B), err: errors.New(`json: invalid use of ,string struct tag, trying to unmarshal "tru" into bool`)},
    {in: `{"B": "False"}`, ptr: new(B), err: errors.New(`json: invalid use of ,string struct tag, trying to unmarshal "False" into bool`)},
    {in: `{"B": "null"}`, ptr: new(B), out: B{false}},
    {in: `{"B": "nul"}`, ptr: new(B), err: errors.New(`json: invalid use of ,string struct tag, trying to unmarshal "nul" into bool`)},
    {in: `{"B": [2, 3]}`, ptr: new(B), err: errors.New(`json: invalid use of ,string struct tag, trying to unmarshal unquoted value into bool`)},

    // additional tests for disallowUnknownFields
    {
        in: `{
            "Level0": 1,
            "Level1b": 2,
            "Level1c": 3,
            "x": 4,
            "Level1a": 5,
            "LEVEL1B": 6,
            "e": {
                "Level1a": 8,
                "Level1b": 9,
                "Level1c": 10,
                "Level1d": 11,
                "x": 12
            },
            "Loop1": 13,
            "Loop2": 14,
            "X": 15,
            "Y": 16,
            "Z": 17,
            "Q": 18,
            "extra": true
        }`,
        ptr:                   new(Top),
        err:                   fmt.Errorf("json: unknown field \"extra\""),
        disallowUnknownFields: true,
    },
    {
        in: `{
            "Level0": 1,
            "Level1b": 2,
            "Level1c": 3,
            "x": 4,
            "Level1a": 5,
            "LEVEL1B": 6,
            "e": {
                "Level1a": 8,
                "Level1b": 9,
                "Level1c": 10,
                "Level1d": 11,
                "x": 12,
                "extra": null
            },
            "Loop1": 13,
            "Loop2": 14,
            "X": 15,
            "Y": 16,
            "Z": 17,
            "Q": 18
        }`,
        ptr:                   new(Top),
        err:                   fmt.Errorf("json: unknown field \"extra\""),
        disallowUnknownFields: true,
    },
    // issue 26444
    // json.UnmarshalTypeError without field & struct values
    {
        in:  `{"data":{"test1": "bob", "test2": 123}}`,
        ptr: new(mapStringToStringData),
        err: &json.UnmarshalTypeError{Value: "number", Type: reflect.TypeOf(""), Offset: 37, Struct: "mapStringToStringData", Field: "data"},
    },
    {
        in:  `{"data":{"test1": 123, "test2": "bob"}}`,
        ptr: new(mapStringToStringData),
        err: &json.UnmarshalTypeError{Value: "number", Type: reflect.TypeOf(""), Offset: 21, Struct: "mapStringToStringData", Field: "data"},
    },

    // trying to decode JSON arrays or objects via TextUnmarshaler
    {
        in:  `[1, 2, 3]`,
        ptr: new(MustNotUnmarshalText),
        err: &json.UnmarshalTypeError{Value: "array", Type: reflect.TypeOf(&MustNotUnmarshalText{}), Offset: 1},
    },
    {
        in:  `{"foo": "bar"}`,
        ptr: new(MustNotUnmarshalText),
        err: &json.UnmarshalTypeError{Value: "object", Type: reflect.TypeOf(&MustNotUnmarshalText{}), Offset: 1},
    },
    // #22369
    {
        in:  `{"PP": {"T": {"Y": "bad-type"}}}`,
        ptr: new(P),
        err: &json.UnmarshalTypeError{
            Value:  "string",
            Struct: "T",
            Field:  "PP.T.Y",
            Type:   reflect.TypeOf(0),
            Offset: 29,
        },
    },
    {
        in:  `{"Ts": [{"Y": 1}, {"Y": 2}, {"Y": "bad-type"}]}`,
        ptr: new(PP),
        err: &json.UnmarshalTypeError{
            Value:  "string",
            Struct: "T",
            Field:  "Ts.Y",
            Type:   reflect.TypeOf(0),
            Offset: 29,
        },
    },
    // #14702
    {
        in:  `invalid`,
        ptr: new(json.Number),
        err: (&JsonSyntaxError{
            Msg:    "invalid character 'i' looking for beginning of value",
            Offset: 1,
        }).err(),
    },
    {
        in:  `"invalid"`,
        ptr: new(json.Number),
        err: fmt.Errorf("json: invalid number literal, trying to unmarshal %q into Number", `"invalid"`),
    },
    {
        in:  `{"A":"invalid"}`,
        ptr: new(struct{ A json.Number }),
        err: fmt.Errorf("json: invalid number literal, trying to unmarshal %q into Number", `"invalid"`),
    },
    {
        in: `{"A":"invalid"}`,
        ptr: new(struct {
            A json.Number `json:",string"`
        }),
        err: fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into json.Number", `invalid`),
    },
    {
        in:  `{"A":"invalid"}`,
        ptr: new(map[string]json.Number),
        err: fmt.Errorf("json: invalid number literal, trying to unmarshal %q into Number", `"invalid"`),
    },

    // UTF-8 and string validation tests
    {in: `\u`, ptr: new(interface{}), err: fmt.Errorf("json: invald char"), validateString: true},
    {in: `\u`, ptr: new(string), err: fmt.Errorf("json: invald char"), validateString: true},

    {in: "\"\x00\"", ptr: new(interface{}), err: fmt.Errorf("json: invald char"), validateString: true},
    {in: "\"\x00\"", ptr: new(string), err: fmt.Errorf("json: invald char"), validateString: true},
    {in: "\"\xff\"", ptr: new(interface{}), out: interface{}("\ufffd"), validateString: true},
    {in: "\"\xff\"", ptr: new(string), out: "\ufffd", validateString: true},
    {in: "\"\x00\"", ptr: new(interface{}), out: interface{}("\x00"), validateString: false},
    {in: "\"\x00\"", ptr: new(string), out: "\x00", validateString: false},
    {in: "\"\xff\"", ptr: new(interface{}), out: interface{}("\xff"), validateString: false},
    {in: "\"\xff\"", ptr: new(string), out: "\xff", validateString: false},

    // cases found by fuzz
    {   
        in: `{"H":{"A": {}}}`,
        ptr: new(struct {
            F0 struct {
                F1 json.Number "json:\"a,omitempty\""
            } "json:\"H,\""
        }),
        err: fmt.Errorf("Mismatch type json.Number with value object.."),
    },
}

func trim(b []byte) []byte {
    if len(b) > 20 {
        return b[0:20]
    }
    return b
}

func diff(t *testing.T, a, b []byte) {
    for i := 0; ; i++ {
        if i >= len(a) || i >= len(b) || a[i] != b[i] {
            j := i - 10
            if j < 0 {
                j = 0
            }
            t.Errorf("diverge at %d: «%s» vs «%s»", i, trim(a[j:]), trim(b[j:]))
            return
        }
    }
}

func TestMarshal(t *testing.T) {
    b, err := Marshal(allValue)
    if err != nil {
        t.Fatalf("Marshal allValue: %v", err)
    }
    if string(b) != allValueCompact {
        t.Errorf("Marshal allValueCompact")
        diff(t, b, []byte(allValueCompact))
        return
    }

    b, err = Marshal(pallValue)
    if err != nil {
        t.Fatalf("Marshal pallValue: %v", err)
    }
    if string(b) != pallValueCompact {
        t.Errorf("Marshal pallValueCompact")
        diff(t, b, []byte(pallValueCompact))
        return
    }
}

func TestMarshalNumberZeroVal(t *testing.T) {
    var n json.Number
    out, err := Marshal(n)
    if err != nil {
        t.Fatal(err)
    }
    outStr := string(out)
    if outStr != "0" {
        t.Fatalf("Invalid zero val for json.Number: %q", outStr)
    }
}

func TestMarshalEmbeds(t *testing.T) {
    top := &Top{
        Level0: 1,
        Embed0: Embed0{
            Level1b: 2,
            Level1c: 3,
        },
        Embed0a: &Embed0a{
            Level1a: 5,
            Level1b: 6,
        },
        Embed0b: &Embed0b{
            Level1a: 8,
            Level1b: 9,
            Level1c: 10,
            Level1d: 11,
            Level1e: 12,
        },
        Loop: Loop{
            Loop1: 13,
            Loop2: 14,
        },
        Embed0p: Embed0p{
            Point: image.Point{X: 15, Y: 16},
        },
        Embed0q: Embed0q{
            Point: Point{Z: 17},
        },
        embed: embed{
            Q: 18,
        },
    }
    b, err := Marshal(top)
    if err != nil {
        t.Fatal(err)
    }
    want := "{\"Level0\":1,\"Level1b\":2,\"Level1c\":3,\"Level1a\":5,\"LEVEL1B\":6,\"e\":{\"Level1a\":8,\"Level1b\":9,\"Level1c\":10,\"Level1d\":11,\"x\":12},\"Loop1\":13,\"Loop2\":14,\"X\":15,\"Y\":16,\"Z\":17,\"Q\":18}"
    if string(b) != want {
        t.Errorf("Wrong marshal result.\n got: %q\nwant: %q", b, want)
    }
}

func TestUnmarshal(t *testing.T) {
    for i, tt := range unmarshalTests {
        // construct decoder
        dec := decoder.NewDecoder(tt.in)
        if tt.useNumber {
            dec.UseNumber()
        }
        if tt.disallowUnknownFields {
            dec.DisallowUnknownFields()
        }
        if tt.validateString {
            dec.ValidateString()
        }

        // check decode result for invalid jsons
        if !json.Valid([]byte(tt.in)) || tt.ptr == nil {
            var sv interface{}
            err := dec.Decode(&sv)
            if err == nil && tt.err != nil {
                err = dec.CheckTrailings()
                if err == nil && tt.err != nil {
                    t.Errorf("test json #%d: %v, %v, want %v", i, tt.in, err, tt.err)
                }
            }
            continue
        }

        typ := reflect.TypeOf(tt.ptr)
        if typ.Kind() != reflect.Ptr {
            t.Errorf("#%d: unmarshalTest.ptr %T is not a pointer type", i, tt.ptr)
            continue
        }
        typ = typ.Elem()

        v := reflect.New(typ)

        if !reflect.DeepEqual(tt.ptr, v.Interface()) {
            // There's no reason for ptr to point to non-zero data,
            // as we decode into new(right-type), so the data is
            // discarded.
            // This can easily mean tests that silently don't test
            // what they should. To test decoding into existing
            // data, see TestPrefilled.
            t.Errorf("#%d: unmarshalTest.ptr %#v is not a pointer to a zero value", i, tt.ptr)
            continue
        }

        if err := dec.Decode(v.Interface()); (err == nil) != (tt.err == nil) {
            spew.Dump(tt)
            t.Fatalf("#%d: %v, want %v", i, err, tt.err)
            continue
        } else if err != nil {
            continue
        }
        if !reflect.DeepEqual(v.Elem().Interface(), tt.out) {
            require.Equal(t, v.Elem().Interface(), tt.out)
            t.Errorf("#%d: mismatch\nhave: %#+v\nwant: %#+v", i, v.Elem().Interface(), tt.out)
            data, _ := Marshal(v.Elem().Interface())
            println(string(data))
            data, _ = Marshal(tt.out)
            println(string(data))
            continue
        }

        // Check round trip also decodes correctly.
        if tt.err == nil {
            enc, err := Marshal(v.Interface())
            if err != nil {
                t.Errorf("#%d: error re-marshaling: %v", i, err)
                continue
            }
            if tt.golden && !bytes.Equal(enc, []byte(tt.in)) {
                t.Errorf("#%d: remarshal mismatch:\nhave: %s\nwant: %s", i, enc, []byte(tt.in))
            }
            vv := reflect.New(reflect.TypeOf(tt.ptr).Elem())
            dec = decoder.NewDecoder(string(enc))
            if tt.useNumber {
                dec.UseNumber()
            }
            if err := dec.Decode(vv.Interface()); err != nil {
                t.Errorf("#%d: error re-unmarshaling %#q: %v", i, enc, err)
                continue
            }
            if !reflect.DeepEqual(v.Elem().Interface(), vv.Elem().Interface()) {
                t.Errorf("#%d: mismatch\nhave: %#+v\nwant: %#+v", i, v.Elem().Interface(), vv.Elem().Interface())
                t.Errorf("     In: %q", strings.Map(noSpace, tt.in))
                t.Errorf("Marshal: %q", strings.Map(noSpace, string(enc)))
                continue
            }
        }
    }
}

var jsonBig []byte

func initBig() {
    n := 10000
    if testing.Short() {
        n = 100
    }
    b, err := Marshal(genValue(n))
    if err != nil {
        panic(err)
    }
    jsonBig = b
}

func genValue(n int) interface{} {
    if n > 1 {
        switch rand.Intn(2) {
        case 0:
            return genArray(n)
        case 1:
            return genMap(n)
        }
    }
    switch rand.Intn(3) {
    case 0:
        return rand.Intn(2) == 0
    case 1:
        return float64(rand.Uint64()) / 4294967296
    case 2:
        return genString(30)
    }
    panic("unreachable")
}

func genString(stddev float64) string {
    n := int(math.Abs(rand.NormFloat64()*stddev + stddev/2))
    c := make([]rune, n)
    for i := range c {
        f := math.Abs(rand.NormFloat64()*64 + 32)
        if f > 0x10ffff {
            f = 0x10ffff
        }
        c[i] = rune(f)
    }
    return string(c)
}

func genArray(n int) []interface{} {
    f := int(math.Abs(rand.NormFloat64()) * math.Min(10, float64(n/2)))
    if f > n {
        f = n
    }
    if f < 1 {
        f = 1
    }
    x := make([]interface{}, f)
    for i := range x {
        x[i] = genValue(((i+1)*n)/f - (i*n)/f)
    }
    return x
}

func genMap(n int) map[string]interface{} {
    f := int(math.Abs(rand.NormFloat64()) * math.Min(10, float64(n/2)))
    if f > n {
        f = n
    }
    if n > 0 && f == 0 {
        f = 1
    }
    x := make(map[string]interface{})
    x[genString(10)] = genValue(n/f)
    return x
}

func TestUnmarshalMarshal(t *testing.T) {
    initBig()
    var v interface{}
    if err := Unmarshal(jsonBig, &v); err != nil {
        if e, ok := err.(decoder.SyntaxError); ok {
            println(e.Description())
        }
        t.Fatalf("Unmarshal: %v", err)
    }
    b, err := Marshal(v)
    if err != nil {
        t.Fatalf("Marshal: %v", err)
    }
    if !bytes.Equal(jsonBig, b) {
        t.Errorf("Marshal jsonBig")
        diff(t, b, jsonBig)
        println(string(b))
        println(string(jsonBig))
        return
    }
}

var numberTests = []struct {
    in       string
    i        int64
    intErr   string
    f        float64
    floatErr string
}{
    {in: "-1.23e1", intErr: "strconv.ParseInt: parsing \"-1.23e1\": invalid syntax", f: -1.23e1},
    {in: "-12", i: -12, f: -12.0},
    {in: "1e1000", intErr: "strconv.ParseInt: parsing \"1e1000\": invalid syntax", floatErr: "strconv.ParseFloat: parsing \"1e1000\": value out of range"},
}

// Independent of Decode, basic coverage of the accessors in json.Number
func TestNumberAccessors(t *testing.T) {
    for _, tt := range numberTests {
        n := json.Number(tt.in)
        if s := n.String(); s != tt.in {
            t.Errorf("json.Number(%q).String() is %q", tt.in, s)
        }
        if i, err := n.Int64(); err == nil && tt.intErr == "" && i != tt.i {
            t.Errorf("json.Number(%q).Int64() is %d", tt.in, i)
        } else if (err == nil && tt.intErr != "") || (err != nil && err.Error() != tt.intErr) {
            t.Errorf("json.Number(%q).Int64() wanted error %q but got: %v", tt.in, tt.intErr, err)
        }
        if f, err := n.Float64(); err == nil && tt.floatErr == "" && f != tt.f {
            t.Errorf("json.Number(%q).Float64() is %g", tt.in, f)
        } else if (err == nil && tt.floatErr != "") || (err != nil && err.Error() != tt.floatErr) {
            t.Errorf("json.Number(%q).Float64() wanted error %q but got: %v", tt.in, tt.floatErr, err)
        }
    }
}

func TestLargeByteSlice(t *testing.T) {
    s0 := make([]byte, 2000)
    for i := range s0 {
        s0[i] = byte(i)
    }
    b, err := Marshal(s0)
    if err != nil {
        t.Fatalf("Marshal: %v", err)
    }
    var s1 []byte
    if err := Unmarshal(b, &s1); err != nil {
        t.Fatalf("Unmarshal: %v", err)
    }
    if !bytes.Equal(s0, s1) {
        t.Errorf("Marshal large byte slice")
        diff(t, s0, s1)
    }
}

type Xint struct {
    X int
}

func TestUnmarshalPtrPtr(t *testing.T) {
    var xint Xint
    pxint := &xint
    if err := Unmarshal([]byte(`{"X":1}`), &pxint); err != nil {
        t.Fatalf("Unmarshal: %v", err)
    }
    if xint.X != 1 {
        t.Fatalf("Did not write to xint")
    }
}


func noSpace(c rune) rune {
    if utils.IsSpace(byte(c)) { // only used for ascii
        return -1
    }
    return c
}

type All struct {
    Bool    bool
    Int     int
    Int8    int8
    Int16   int16
    Int32   int32
    Int64   int64
    Uint    uint
    Uint8   uint8
    Uint16  uint16
    Uint32  uint32
    Uint64  uint64
    Uintptr uintptr
    Float32 float32
    Float64 float64

    Foo  string `json:"bar"`
    Foo2 string `json:"bar2,dummyopt"`

    IntStr     int64   `json:",string"`
    UintptrStr uintptr `json:",string"`

    PBool    *bool
    PInt     *int
    PInt8    *int8
    PInt16   *int16
    PInt32   *int32
    PInt64   *int64
    PUint    *uint
    PUint8   *uint8
    PUint16  *uint16
    PUint32  *uint32
    PUint64  *uint64
    PUintptr *uintptr
    PFloat32 *float32
    PFloat64 *float64

    String  string
    PString *string

    Map      map[string]Small
    MapP     map[string]*Small
    MapPNil  map[string]*Small
    PMap     *map[string]Small
    PMapP    *map[string]*Small
    PMapPNil *map[string]*Small

    EmptyMap map[string]Small
    NilMap   map[string]Small

    Slice   []Small
    SliceP  []*Small
    PSlice  *[]Small
    PSliceP *[]*Small

    EmptySlice []Small
    NilSlice   []Small

    StringSlice []string
    ByteSlice   []byte

    Small   Small
    PSmall  *Small
    PPSmall **Small

    Interface  interface{}
    PInterface *interface{}

    unexported int
}

type Small struct {
    Tag string
}

var allValue = All{
    Bool:       true,
    Int:        2,
    Int8:       3,
    Int16:      4,
    Int32:      5,
    Int64:      6,
    Uint:       7,
    Uint8:      8,
    Uint16:     9,
    Uint32:     10,
    Uint64:     11,
    Uintptr:    12,
    Float32:    14.25,
    Float64:    15.25,
    Foo:        "foo",
    Foo2:       "foo2",
    IntStr:     42,
    UintptrStr: 44,
    String:     "16",
    Map: map[string]Small{
        "17": {Tag: "tag17"},
    },
    MapP: map[string]*Small{
        "18": {Tag: "tag19"},
    },
    MapPNil: map[string]*Small{
        "19": nil,
    },
    EmptyMap:    map[string]Small{},
    Slice:       []Small{{Tag: "tag20"}, {Tag: "tag21"}},
    SliceP:      []*Small{{Tag: "tag22"}, nil, {Tag: "tag23"}},
    EmptySlice:  []Small{},
    StringSlice: []string{"str24", "str25", "str26"},
    ByteSlice:   []byte{27, 28, 29},
    Small:       Small{Tag: "tag30"},
    PSmall:      &Small{Tag: "tag31"},
    Interface:   5.2,
}

var pallValue = All{
    PBool:      &allValue.Bool,
    PInt:       &allValue.Int,
    PInt8:      &allValue.Int8,
    PInt16:     &allValue.Int16,
    PInt32:     &allValue.Int32,
    PInt64:     &allValue.Int64,
    PUint:      &allValue.Uint,
    PUint8:     &allValue.Uint8,
    PUint16:    &allValue.Uint16,
    PUint32:    &allValue.Uint32,
    PUint64:    &allValue.Uint64,
    PUintptr:   &allValue.Uintptr,
    PFloat32:   &allValue.Float32,
    PFloat64:   &allValue.Float64,
    PString:    &allValue.String,
    PMap:       &allValue.Map,
    PMapP:      &allValue.MapP,
    PMapPNil:   &allValue.MapPNil,
    PSlice:     &allValue.Slice,
    PSliceP:    &allValue.SliceP,
    PPSmall:    &allValue.PSmall,
    PInterface: &allValue.Interface,
}

var allValueIndent = `{
    "Bool": true,
    "Int": 2,
    "Int8": 3,
    "Int16": 4,
    "Int32": 5,
    "Int64": 6,
    "Uint": 7,
    "Uint8": 8,
    "Uint16": 9,
    "Uint32": 10,
    "Uint64": 11,
    "Uintptr": 12,
    "Float32": 14.25,
    "Float64": 15.25,
    "bar": "foo",
    "bar2": "foo2",
    "IntStr": "42",
    "UintptrStr": "44",
    "PBool": null,
    "PInt": null,
    "PInt8": null,
    "PInt16": null,
    "PInt32": null,
    "PInt64": null,
    "PUint": null,
    "PUint8": null,
    "PUint16": null,
    "PUint32": null,
    "PUint64": null,
    "PUintptr": null,
    "PFloat32": null,
    "PFloat64": null,
    "String": "16",
    "PString": null,
    "Map": {
        "17": {
            "Tag": "tag17"
        }
    },
    "MapP": {
        "18": {
            "Tag": "tag19"
        }
    },
    "MapPNil": {
        "19": null
    },
    "PMap": null,
    "PMapP": null,
    "PMapPNil": null,
    "EmptyMap": {},
    "NilMap": null,
    "Slice": [
        {
            "Tag": "tag20"
        },
        {
            "Tag": "tag21"
        }
    ],
    "SliceP": [
        {
            "Tag": "tag22"
        },
        null,
        {
            "Tag": "tag23"
        }
    ],
    "PSlice": null,
    "PSliceP": null,
    "EmptySlice": [],
    "NilSlice": null,
    "StringSlice": [
        "str24",
        "str25",
        "str26"
    ],
    "ByteSlice": "Gxwd",
    "Small": {
        "Tag": "tag30"
    },
    "PSmall": {
        "Tag": "tag31"
    },
    "PPSmall": null,
    "Interface": 5.2,
    "PInterface": null
}`

var allValueCompact = strings.Map(noSpace, allValueIndent)

var pallValueIndent = `{
    "Bool": false,
    "Int": 0,
    "Int8": 0,
    "Int16": 0,
    "Int32": 0,
    "Int64": 0,
    "Uint": 0,
    "Uint8": 0,
    "Uint16": 0,
    "Uint32": 0,
    "Uint64": 0,
    "Uintptr": 0,
    "Float32": 0,
    "Float64": 0,
    "bar": "",
    "bar2": "",
    "IntStr": "0",
    "UintptrStr": "0",
    "PBool": true,
    "PInt": 2,
    "PInt8": 3,
    "PInt16": 4,
    "PInt32": 5,
    "PInt64": 6,
    "PUint": 7,
    "PUint8": 8,
    "PUint16": 9,
    "PUint32": 10,
    "PUint64": 11,
    "PUintptr": 12,
    "PFloat32": 14.25,
    "PFloat64": 15.25,
    "String": "",
    "PString": "16",
    "Map": null,
    "MapP": null,
    "MapPNil": null,
    "PMap": {
        "17": {
            "Tag": "tag17"
        }
    },
    "PMapP": {
        "18": {
            "Tag": "tag19"
        }
    },
    "PMapPNil": {
        "19": null
    },
    "EmptyMap": null,
    "NilMap": null,
    "Slice": null,
    "SliceP": null,
    "PSlice": [
        {
            "Tag": "tag20"
        },
        {
            "Tag": "tag21"
        }
    ],
    "PSliceP": [
        {
            "Tag": "tag22"
        },
        null,
        {
            "Tag": "tag23"
        }
    ],
    "EmptySlice": null,
    "NilSlice": null,
    "StringSlice": null,
    "ByteSlice": null,
    "Small": {
        "Tag": ""
    },
    "PSmall": null,
    "PPSmall": {
        "Tag": "tag31"
    },
    "Interface": null,
    "PInterface": 5.2
}`

var pallValueCompact = strings.Map(noSpace, pallValueIndent)

func TestRefUnmarshal(t *testing.T) {
    type S struct {
        // Ref is defined in encode_test.go.
        R0 Ref
        R1 *Ref
        R2 RefText
        R3 *RefText
    }
    want := S{
        R0: 12,
        R1: new(Ref),
        R2: 13,
        R3: new(RefText),
    }
    *want.R1 = 12
    *want.R3 = 13

    var got S
    if err := Unmarshal([]byte(`{"R0":"ref","R1":"ref","R2":"ref","R3":"ref"}`), &got); err != nil {
        t.Fatalf("Unmarshal: %v", err)
    }
    if !reflect.DeepEqual(got, want) {
        t.Errorf("got %+v, want %+v", got, want)
    }
}

// Test that the empty string doesn't panic decoding when ,string is specified
// Issue 3450
func TestEmptyString(t *testing.T) {
    type T2 struct {
        Number1 int `json:",string"`
        Number2 string `json:",string"`
        Pass bool `json:",string"`
    }
    data := `{"Number1":"1", "Number2":"","Pass":"true"}`
    var t2, t3 T2
    t2.Number2 = "a"
    t3.Number2 = "a"
    err := Unmarshal([]byte(data), &t2)
    if err == nil {
        t.Fatal("Decode: did not return error")
    }
    println(err.Error())
    err2 := json.Unmarshal([]byte(data), &t3)
    assert.Equal(t, err == nil, err2 == nil)
    assert.Equal(t, t3, t2)
}

// Test that a null for ,string is not replaced with the previous quoted string (issue 7046).
// It should also not be an error (issue 2540, issue 8587).
func TestNullString(t *testing.T) {
    type T struct {
        A int  `json:",string"`
        B int  `json:",string"`
        C *int `json:",string"`
    }
    data := []byte(`{"A": "1", "B": null, "C": null}`)
    var s T
    s.B = 1
    s.C = new(int)
    *s.C = 2
    err := Unmarshal(data, &s)
    if err != nil {
        t.Fatalf("Unmarshal: %v", err)
    }
    if s.B != 1 || s.C != nil {
        t.Fatalf("after Unmarshal, s.B=%d, s.C=%p, want 1, nil", s.B, s.C)
    }
}

type NullTest struct {
    Bool      bool
    Int       int
    Int8      int8
    Int16     int16
    Int32     int32
    Int64     int64
    Uint      uint
    Uint8     uint8
    Uint16    uint16
    Uint32    uint32
    Uint64    uint64
    Float32   float32
    Float64   float64
    String    string
    PBool     *bool
    Map       map[string]string
    Slice     []string
    Interface interface{}

    PRaw    *json.RawMessage
    PTime   *time.Time
    PBigInt *big.Int
    PText   *MustNotUnmarshalText
    PBuffer *bytes.Buffer // has methods, just not relevant ones
    PStruct *struct{}

    Raw    json.RawMessage
    Time   time.Time
    BigInt big.Int
    Text   MustNotUnmarshalText
    Buffer bytes.Buffer
    Struct struct{}
}

// JSON null values should be ignored for primitives and string values instead of resulting in an error.
// Issue 2540
func TestUnmarshalNulls(t *testing.T) {
    // Unmarshal docs:
    // 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.

    jsonData := []byte(`{
                "Bool"    : null,
                "Int"     : null,
                "Int8"    : null,
                "Int16"   : null,
                "Int32"   : null,
                "Int64"   : null,
                "Uint"    : null,
                "Uint8"   : null,
                "Uint16"  : null,
                "Uint32"  : null,
                "Uint64"  : null,
                "Float32" : null,
                "Float64" : null,
                "String"  : null,
                "PBool": null,
                "Map": null,
                "Slice": null,
                "Interface": null,
                "PRaw": null,
                "PTime": null,
                "PBigInt": null,
                "PText": null,
                "PBuffer": null,
                "PStruct": null,
                "Raw": null,
                "Time": null,
                "BigInt": null,
                "Text": null,
                "Buffer": null,
                "Struct": null
            }`)
    nulls := NullTest{
        Bool:      true,
        Int:       2,
        Int8:      3,
        Int16:     4,
        Int32:     5,
        Int64:     6,
        Uint:      7,
        Uint8:     8,
        Uint16:    9,
        Uint32:    10,
        Uint64:    11,
        Float32:   12.1,
        Float64:   13.1,
        String:    "14",
        PBool:     new(bool),
        Map:       map[string]string{},
        Slice:     []string{},
        Interface: new(MustNotUnmarshalJSON),
        PRaw:      new(json.RawMessage),
        PTime:     new(time.Time),
        PBigInt:   new(big.Int),
        PText:     new(MustNotUnmarshalText),
        PStruct:   new(struct{}),
        PBuffer:   new(bytes.Buffer),
        Raw:       json.RawMessage("123"),
        Time:      time.Unix(123456789, 0),
        BigInt:    *big.NewInt(123),
    }

    before := nulls.Time.String()

    err := Unmarshal(jsonData, &nulls)
    if err != nil {
        t.Errorf("Unmarshal of null values failed: %v", err)
    }
    if !nulls.Bool || nulls.Int != 2 || nulls.Int8 != 3 || nulls.Int16 != 4 || nulls.Int32 != 5 || nulls.Int64 != 6 ||
        nulls.Uint != 7 || nulls.Uint8 != 8 || nulls.Uint16 != 9 || nulls.Uint32 != 10 || nulls.Uint64 != 11 ||
        nulls.Float32 != 12.1 || nulls.Float64 != 13.1 || nulls.String != "14" {
        t.Errorf("Unmarshal of null values affected primitives")
    }

    if nulls.PBool != nil {
        t.Errorf("Unmarshal of null did not clear nulls.PBool")
    }
    if nulls.Map != nil {
        t.Errorf("Unmarshal of null did not clear nulls.Map")
    }
    if nulls.Slice != nil {
        t.Errorf("Unmarshal of null did not clear nulls.Slice")
    }
    if nulls.Interface != nil {
        t.Errorf("Unmarshal of null did not clear nulls.Interface")
    }
    if nulls.PRaw != nil {
        t.Errorf("Unmarshal of null did not clear nulls.PRaw")
    }
    if nulls.PTime != nil {
        t.Errorf("Unmarshal of null did not clear nulls.PTime")
    }
    if nulls.PBigInt != nil {
        t.Errorf("Unmarshal of null did not clear nulls.PBigInt")
    }
    if nulls.PText != nil {
        t.Errorf("Unmarshal of null did not clear nulls.PText")
    }
    if nulls.PBuffer != nil {
        t.Errorf("Unmarshal of null did not clear nulls.PBuffer")
    }
    if nulls.PStruct != nil {
        t.Errorf("Unmarshal of null did not clear nulls.PStruct")
    }

    if string(nulls.Raw) != "null" {
        t.Errorf("Unmarshal of json.RawMessage null did not record null: %v", string(nulls.Raw))
    }
    if nulls.Time.String() != before {
        t.Errorf("Unmarshal of time.Time null set time to %v", nulls.Time.String())
    }
    if nulls.BigInt.String() != "123" {
        t.Errorf("Unmarshal of big.Int null set int to %v", nulls.BigInt.String())
    }
}

type MustNotUnmarshalJSON struct{}

func (x MustNotUnmarshalJSON) UnmarshalJSON(_ []byte) error {
    return errors.New("MustNotUnmarshalJSON was used")
}

type MustNotUnmarshalText struct{}

func (x MustNotUnmarshalText) UnmarshalText(_ []byte) error {
    return errors.New("MustNotUnmarshalText was used")
}

func TestStringKind(t *testing.T) {
    type stringKind string

    var m1, m2 map[stringKind]int
    m1 = map[stringKind]int{
        "foo": 42,
    }

    data, err := Marshal(m1)
    if err != nil {
        t.Errorf("Unexpected error marshaling: %v", err)
    }

    err = Unmarshal(data, &m2)
    if err != nil {
        t.Errorf("Unexpected error unmarshaling: %v", err)
    }

    if !reflect.DeepEqual(m1, m2) {
        t.Error("Items should be equal after encoding and then decoding")
    }
}

// Custom types with []byte as underlying type could not be marshaled
// and then unmarshaled.
// Issue 8962.
func TestByteKind(t *testing.T) {
    type byteKind []byte

    a := byteKind("hello")

    data, err := Marshal(a)
    if err != nil {
        t.Error(err)
    }
    var b byteKind
    err = Unmarshal(data, &b)
    if err != nil {
        t.Fatal(err)
    }
    if !reflect.DeepEqual(a, b) {
        t.Errorf("expected %v == %v", a, b)
    }
}

// The fix for issue 8962 introduced a regression.
// Issue 12921.
func TestSliceOfCustomByte(t *testing.T) {
    type Uint8 uint8

    a := []Uint8("hello")

    data, err := Marshal(a)
    if err != nil {
        t.Fatal(err)
    }
    var b []Uint8
    err = Unmarshal(data, &b)
    if err != nil {
        t.Fatal(err)
    }
    if !reflect.DeepEqual(a, b) {
        t.Fatalf("expected %v == %v", a, b)
    }
}

var decodeTypeErrorTests = []struct {
    dest interface{}
    src  string
}{
    {new(error), `{}`},                // issue 4222
    {new(error), `[]`},
    {new(error), `""`},
    {new(error), `123`},
    {new(error), `true`},
}

func TestUnmarshalTypeError(t *testing.T) {
    for _, item := range decodeTypeErrorTests {
        err := Unmarshal([]byte(item.src), item.dest)
        if _, ok := err.(*json.UnmarshalTypeError); !ok {
            if _, ok := err.(*decoder.MismatchTypeError); !ok {
                if _, ok = err.(decoder.SyntaxError); !ok {
                    t.Errorf("expected type error for Unmarshal(%q, type %T): got %T",
                        item.src, item.dest, err)
                }
            }
        }
    }
}

var decodeMismatchErrorTests = []struct {
    dest interface{}
    src  string
}{
    {new(int), `{}`},               
    {new(string), `{}`},               
    {new(bool), `{}`},               
    {new([]byte), `{}`},               
}

func TestMismatchTypeError(t *testing.T) {
    for _, item := range decodeMismatchErrorTests {
        err := Unmarshal([]byte(item.src), item.dest)
        if _, ok := err.(*decoder.MismatchTypeError); !ok {
            if _, ok = err.(decoder.SyntaxError); !ok {
                t.Errorf("expected mismatch error for Unmarshal(%q, type %T): got %T",
                    item.src, item.dest, err)
            }
        }
    }
}

var unmarshalSyntaxTests = []string{
    "tru",
    "fals",
    "nul",
    "123e",
    `"hello`,
    `[1,2,3`,
    `{"key":1`,
    `{"key":1,`,
}

func TestUnmarshalSyntax(t *testing.T) {
    var x interface{}
    for _, src := range unmarshalSyntaxTests {
        err := Unmarshal([]byte(src), &x)
        if _, ok := err.(decoder.SyntaxError); !ok {
            t.Errorf("expected syntax error for Unmarshal(%q): got %T", src, err)
        }
    }
}

// Test handling of unexported fields that should be ignored.
// Issue 4660
//goland:noinspection GoVetStructTag
type unexportedFields struct {
    Name string
    m    map[string]interface{} `json:"-"`
    m2   map[string]interface{} `json:"abcd"`

    s []int `json:"-"`
}

func TestUnmarshalUnexported(t *testing.T) {
    input := `{"Name": "Bob", "m": {"x": 123}, "m2": {"y": 456}, "abcd": {"z": 789}, "s": [2, 3]}`
    want := &unexportedFields{Name: "Bob"}

    out := &unexportedFields{}
    err := Unmarshal([]byte(input), out)
    if err != nil {
        t.Errorf("got error %v, expected nil", err)
    }
    if !reflect.DeepEqual(out, want) {
        t.Errorf("got %q, want %q", out, want)
    }
}

// Time3339 is a time.Time which encodes to and from JSON
// as an RFC 3339 time in UTC.
type Time3339 time.Time

func (t *Time3339) UnmarshalJSON(b []byte) error {
    if len(b) < 2 || b[0] != '"' || b[len(b)-1] != '"' {
        return fmt.Errorf("types: failed to unmarshal non-string value %q as an RFC 3339 time", b)
    }
    tm, err := time.Parse(time.RFC3339, string(b[1:len(b)-1]))
    if err != nil {
        return err
    }
    *t = Time3339(tm)
    return nil
}

func TestUnmarshalJSONLiteralError(t *testing.T) {
    var t3 Time3339
    err := Unmarshal([]byte(`"0000-00-00T00:00:00Z"`), &t3)
    if err == nil {
        t.Fatalf("expected error; got time %v", time.Time(t3))
    }
    if !strings.Contains(err.Error(), "range") {
        t.Errorf("got err = %v; want out of range error", err)
    }
}

// Test that extra object elements in an array do not result in a
// "data changing underfoot" error.
// Issue 3717
func TestSkipArrayObjects(t *testing.T) {
    s := `[{}]`
    var dest [0]interface{}

    err := Unmarshal([]byte(s), &dest)
    if err != nil {
        t.Errorf("got error %q, want nil", err)
    }
}

// Test semantics of pre-filled data, such as struct fields, map elements,
// slices, and arrays.
// Issues 4900 and 8837, among others.
func TestPrefilled(t *testing.T) {
    var one int = 1
    var two int = 2
    // Values here change, cannot reuse table across runs.
    var prefillTests = []struct {
        in  string
        ptr interface{}
        out interface{}
    }{
        {
            in:  `{"X": 1, "Y": 2}`,
            ptr: &XYZ{X: float32(3), Y: int16(4), Z: 1.5},
            out: &XYZ{X: float64(1), Y: float64(2), Z: 1.5},
        },
        {
            in:  `{"X": 1, "Y": 2}`,
            ptr: &map[string]interface{}{"X": float32(3), "Y": int16(4), "Z": 1.5},
            out: &map[string]interface{}{"X": float64(1), "Y": float64(2), "Z": 1.5},
        },
        {
            in:  `[2]`,
            ptr: &[]int{1},
            out: &[]int{2},
        },
        {
            in:  `[2]`,
            ptr: &[]int{1, 3},
            out: &[]int{2},
        },
        {
            in:  `[2, 3]`,
            ptr: &[]int{1},
            out: &[]int{2, 3},
        },
        {
            in:  `[2, 3]`,
            ptr: &[...]int{1},
            out: &[...]int{2},
        },
        {
            in:  `[3]`,
            ptr: &[...]int{1, 2},
            out: &[...]int{3, 0},
        },
        {
            in:  `[2]`,
            ptr: &[]interface{}{&one, 2.0},
            out: &[]interface{}{&two},
        },
        // TODO(rfc): different with encoding/json
        // {
        //     in:  `{"a": 2}`,
        //     ptr: &map[string]interface{}{"a": &one, "b": int(2)},
        //     out: &map[string]interface{}{"a": 2.0, "b": int(2)},
        // },
    }

    for _, tt := range prefillTests {
        ptrstr := fmt.Sprintf("%v", tt.ptr)
        err := Unmarshal([]byte(tt.in), tt.ptr) // tt.ptr edited here
        if err != nil {
            t.Errorf("Unmarshal: %v", err)
        }
        if !reflect.DeepEqual(tt.ptr, tt.out) {
            t.Errorf("Unmarshal(%#q, %s): have %v, want %v", tt.in, ptrstr, tt.ptr, tt.out)
        }
    }
}

var invalidUnmarshalTests = []struct {
    v    interface{}
    want string
}{
    {nil, "json: Unmarshal(nil)"},
    {struct{}{}, "json: Unmarshal(non-pointer struct {})"},
    {(*int)(nil), "json: Unmarshal(nil *int)"},
}

func TestInvalidUnmarshal(t *testing.T) {
    buf := []byte(`{"a":"1"}`)
    for _, tt := range invalidUnmarshalTests {
        err := Unmarshal(buf, tt.v)
        if err == nil {
            t.Errorf("Unmarshal expecting error, got nil")
            continue
        }
        if got := err.Error(); got != tt.want {
            t.Errorf("Unmarshal = %q; want %q", got, tt.want)
        }
    }
}

var invalidUnmarshalTextTests = []struct {
    v    interface{}
    want string
}{
    {nil, "json: Unmarshal(nil)"},
    {struct{}{}, "json: Unmarshal(non-pointer struct {})"},
    {(*int)(nil), "json: Unmarshal(nil *int)"},
    {new(net.IP), "json: cannot unmarshal number into Go value of type *net.IP"},
}

func TestInvalidUnmarshalText(t *testing.T) {
    buf := []byte(`123`)
    for _, tt := range invalidUnmarshalTextTests {
        err := Unmarshal(buf, tt.v)
        if err == nil {
            t.Errorf("Unmarshal expecting error, got nil")
            continue
        }
    }
}

// Test that string option is ignored for invalid types.
// Issue 9812.
func TestInvalidStringOption(t *testing.T) {
    num := 0
    item := struct {
        T time.Time         `json:",string"`
        M map[string]string `json:",string"`
        S []string          `json:",string"`
        A [1]string         `json:",string"`
        I interface{}       `json:",string"`
        P *int              `json:",string"`
    }{M: make(map[string]string), S: make([]string, 0), I: num, P: &num}

    data, err := Marshal(item)
    if err != nil {
        t.Fatalf("Marshal: %v", err)
    }
    err = Unmarshal(data, &item)
    if err != nil {
        t.Fatalf("Unmarshal: %v", err)
    }
}

func TestUnmarshalErrorAfterMultipleJSON(t *testing.T) {
    tests := []struct {
        in  string
        err error
    }{{
        in:  `1 false null :`,
        err: (&JsonSyntaxError{"invalid character ':' looking for beginning of value", 13}).err(),
    }, {
        in:  `1 [] [,]`,
        err: (&JsonSyntaxError{"invalid character ',' looking for beginning of value", 6}).err(),
    }, {
        in:  `1 [] [true:]`,
        err: (&JsonSyntaxError{"invalid character ':' after array element", 10}).err(),
    }, {
        in:  `1  {}    {"x"=}`,
        err: (&JsonSyntaxError{"invalid character '=' after object key", 13}).err(),
    }, {
        in:  `falsetruenul#`,
        err: (&JsonSyntaxError{"invalid character '#' in literal null (expecting 'l')", 12}).err(),
    }}
    for i, tt := range tests {
        dec := decoder.NewDecoder(tt.in)
        var err error
        for {
            var v interface{}
            if err = dec.Decode(&v); err != nil {
                break
            }
        }
        if v, ok := err.(decoder.SyntaxError); !ok {
            t.Errorf("#%d: got %#v, want %#v", i, err, tt.err)
        } else if v.Pos != int(tt.err.(*json.SyntaxError).Offset) {
            t.Errorf("#%d: got %#v, want %#v", i, err, tt.err)
            println(v.Description())
        }
    }
}

type unmarshalPanic struct{}

func (unmarshalPanic) UnmarshalJSON([]byte) error { panic(0xdead) }

func TestUnmarshalPanic(t *testing.T) {
    defer func() {
        if got := recover(); !reflect.DeepEqual(got, 0xdead) {
            t.Errorf("panic() = (%T)(%v), want 0xdead", got, got)
        }
    }()
    _ = Unmarshal([]byte("{}"), &unmarshalPanic{})
    t.Fatalf("Unmarshal should have panicked")
}

// The decoder used to hang if decoding into an interface pointing to its own address.
// See golang.org/issues/31740.
func TestUnmarshalRecursivePointer(t *testing.T) {
    var v interface{}
    v = &v
    data := []byte(`{"a": "b"}`)

    if err := Unmarshal(data, v); err != nil {
        t.Fatal(err)
    }
}

type textUnmarshalerString string

func (m *textUnmarshalerString) UnmarshalText(text []byte) error {
    *m = textUnmarshalerString(strings.ToLower(string(text)))
    return nil
}

// Test unmarshal to a map, where the map key is a user defined type.
// See golang.org/issues/34437.
func TestUnmarshalMapWithTextUnmarshalerStringKey(t *testing.T) {
    var p map[textUnmarshalerString]string
    if err := Unmarshal([]byte(`{"FOO": "1"}`), &p); err != nil {
        t.Fatalf("Unmarshal unexpected error: %v", err)
    }

    if _, ok := p["foo"]; !ok {
        t.Errorf(`Key "foo" does not exist in map: %v`, p)
    }
}

func TestUnmarshalRescanLiteralMangledUnquote(t *testing.T) {
    // See golang.org/issues/38105.
    var p map[textUnmarshalerString]string
    if err := Unmarshal([]byte(`{"开源":"12345开源"}`), &p); err != nil {
        t.Fatalf("Unmarshal unexpected error: %v", err)
    }
    if _, ok := p["开源"]; !ok {
        t.Errorf(`Key "开源" does not exist in map: %v`, p)
    }

    // See golang.org/issues/38126.
    type T struct {
        F1 string `json:"F1,string"`
    }
    t1 := T{"aaa\tbbb"}

    b, err := Marshal(t1)
    if err != nil {
        t.Fatalf("Marshal unexpected error: %v", err)
    }
    var t2 T
    if err := Unmarshal(b, &t2); err != nil {
        t.Fatalf("Unmarshal unexpected error: %v", err)
    }
    if t1 != t2 {
        t.Errorf("Marshal and Unmarshal roundtrip mismatch: want %q got %q", t1, t2)
    }

    // See golang.org/issues/39555.
    input := map[textUnmarshalerString]string{"FOO": "", `"`: ""}

    encoded, err := Marshal(input)
    if err != nil {
        t.Fatalf("Marshal unexpected error: %v", err)
    }
    var got map[textUnmarshalerString]string
    if err := Unmarshal(encoded, &got); err != nil {
        t.Fatalf("Unmarshal unexpected error: %v", err)
    }
    want := map[textUnmarshalerString]string{"foo": "", `"`: ""}
    if !reflect.DeepEqual(want, got) {
        t.Fatalf("Unexpected roundtrip result:\nwant: %q\ngot:  %q", want, got)
    }
}

func TestUnmarshalMaxDepth(t *testing.T) {
    const (
        _MaxDepth = types.MAX_RECURSE
        _OverMaxDepth = types.MAX_RECURSE + 1
        _UnderMaxDepth = types.MAX_RECURSE - 2
    )
    testcases := []struct {
        name        string
        data        string
        errMaxDepth bool
    }{
        {
            name:        "ArrayUnderMaxNestingDepth",
            data:        `{"a":` + strings.Repeat(`[`, _UnderMaxDepth) + `0` + strings.Repeat(`]`, _UnderMaxDepth) + `}`,
            errMaxDepth: false,
        },
        {
            name:        "ArrayOverMaxNestingDepth",
            data:        `{"a":` + strings.Repeat(`[`, _OverMaxDepth) + `0` + strings.Repeat(`]`, _OverMaxDepth) + `}`,
            errMaxDepth: true,
        },
        {
            name:        "ArrayOverStackDepth",
            data:        `{"a":` + strings.Repeat(`[`, 3000000) + `0` + strings.Repeat(`]`, 3000000) + `}`,
            errMaxDepth: true,
        },
        {
            name:        "ObjectUnderMaxNestingDepth",
            data:        `{"a":` + strings.Repeat(`{"a":`, _UnderMaxDepth) + `0` + strings.Repeat(`}`, _UnderMaxDepth) + `}`,
            errMaxDepth: false,
        },
        {
            name:        "ObjectOverMaxNestingDepth",
            data:        `{"a":` + strings.Repeat(`{"a":`, _OverMaxDepth) + `0` + strings.Repeat(`}`, _OverMaxDepth) + `}`,
            errMaxDepth: true,
        },
        {
            name:        "ObjectOverStackDepth",
            data:        `{"a":` + strings.Repeat(`{"a":`, 3000000) + `0` + strings.Repeat(`}`, 3000000) + `}`,
            errMaxDepth: true,
        },
    }

    targets := []struct {
        name     string
        newValue func() interface{}
    }{
        {
            name: "unstructured",
            newValue: func() interface{} {
                var v interface{}
                return &v
            },
        },
        {
            name: "typed named field",
            newValue: func() interface{} {
                v := struct {
                    A interface{} `json:"a"`
                }{}
                return &v
            },
        },
        {
            name: "typed missing field",
            newValue: func() interface{} {
                v := struct {
                    B interface{} `json:"b"`
                }{}
                return &v
            },
        },
        {
            name: "custom unmarshaler",
            newValue: func() interface{} {
                v := unmarshaler{}
                return &v
            },
        },
    }

    for _, tc := range testcases {
        for _, target := range targets {
            t.Run(target.name+"-"+tc.name, func(t *testing.T) {
                err := Unmarshal([]byte(tc.data), target.newValue())
                if !tc.errMaxDepth {
                    if err != nil {
                        t.Errorf("unexpected error: %v", err)
                    }
                } else {
                    if err == nil {
                        t.Errorf("expected error containing 'exceeded max depth', got none")
                    } else if !strings.Contains(err.Error(), "exceeded max depth") {
                        t.Errorf("expected error containing 'exceeded max depth', got: %v", err)
                    }
                }
            })
        }
    }
}

// Issues: map value type larger than 128 bytes are stored by pointer
type ChargeToolPacingBucketItemTcc struct {
    _ [128]byte
    T string `json:"T"`
}

type ChargeToolPacingParamsForDataRead struct {
    Bucket2Item map[int64]ChargeToolPacingBucketItemTcc `json:"bucket_to_item"`
}

var panicStr = `
{
    "bucket_to_item": {
        "102" : {
            "T": "xxxx"
        }
    }
}
`

func TestChangeTool(t *testing.T) {
    dataForRaw := ChargeToolPacingParamsForDataRead{}

    err := Unmarshal([]byte(panicStr), &dataForRaw)
    if err != nil {
        t.Fatalf("err %+v\n", err)
    }
    t.Logf("%#v\n", dataForRaw)
    t.Logf("%#v\n", &dataForRaw.Bucket2Item)
    a := dataForRaw.Bucket2Item[102]
    if a.T != "xxxx" {
        t.Fatalf("exp:%v, got:%v", "xxxx", a.T)
    }

}

func TestDecoder_LongestInvalidUtf8(t *testing.T) {
    for _, data := range([]string{
        "\"" + strings.Repeat("\x80", 4096) + "\"",
        "\"" + strings.Repeat("\x80", 4095) + "\"",
        "\"" + strings.Repeat("\x80", 4097) + "\"",
        "\"" + strings.Repeat("\x80", 12345) + "\"",
    }) {
        testDecodeInvalidUtf8(t, []byte(data))
    }
}

func testDecodeInvalidUtf8(t *testing.T, data []byte) {
    var sgot, jgot string
    serr := ConfigStd.Unmarshal(data, &sgot)
    jerr := json.Unmarshal(data, &jgot)
    assert.Equal(t, serr != nil, jerr != nil)
    if jerr == nil {
        assert.Equal(t, sgot, jgot)
    }
}

func needEscape(b byte) bool {
    return b == '"' || b == '\\' || b < '\x20'
}

func genRandJsonBytes(length int) []byte {
    var buf bytes.Buffer
    buf.WriteByte('"')
    for j := 0; j < length; j++ {
        r := rand.Intn(0xff + 1)
        if needEscape(byte(r)) {
            buf.WriteByte('\\')
        }
        buf.WriteByte(byte(r))
    }
    buf.WriteByte('"')
    return buf.Bytes()
}

func genRandJsonRune(length int) []byte {
    var buf bytes.Buffer
    buf.WriteByte('"')
    for j := 0; j < length; j++ {
        r := rand.Intn(0x10FFFF + 1)
        if r < 0x80 && needEscape(byte(r)) {
            buf.WriteByte('\\')
            buf.WriteByte(byte(r))
        } else {
            buf.WriteRune(rune(r))
        }
    }
    buf.WriteByte('"')
    return buf.Bytes()
}

func TestDecoder_RandomInvalidUtf8(t *testing.T) {
    nums   := 1000
    maxLen := 1000
    for i := 0; i < nums; i++ {
        length := rand.Intn(maxLen)
        testDecodeInvalidUtf8(t, genRandJsonBytes(length))
        testDecodeInvalidUtf8(t, genRandJsonRune(length))
    }
}


type atofTest struct {
    in  string
    out string
    err error
}

// Tests from Go strconv package, https://github.com/golang/go/blob/master/src/strconv/atof_test.go
// All tests are passed in Go encoding/json.
var atoftests = []atofTest{
    {"1.234e", "", nil}, // error
    {"1i", "1", nil},    // pass
    {"1", "1", nil},
    {"1e23", "1e+23", nil},
    {"1E23", "1e+23", nil},
    {"100000000000000000000000", "1e+23", nil},
    {"1e-100", "1e-100", nil},
    {"123456700", "1.234567e+08", nil},
    {"99999999999999974834176", "9.999999999999997e+22", nil},
    {"100000000000000000000001", "1.0000000000000001e+23", nil},
    {"100000000000000008388608", "1.0000000000000001e+23", nil},
    {"100000000000000016777215", "1.0000000000000001e+23", nil},
    {"100000000000000016777216", "1.0000000000000003e+23", nil},
    {"-1", "-1", nil},
    {"-0.1", "-0.1", nil},
    {"-0", "-0", nil},
    {"1e-20", "1e-20", nil},
    {"625e-3", "0.625", nil},

    // zeros
    {"0", "0", nil},
    {"0e0", "0", nil},
    {"-0e0", "-0", nil},
    {"0e-0", "0", nil},
    {"-0e-0", "-0", nil},
    {"0e+0", "0", nil},
    {"-0e+0", "-0", nil},
    {"0e+01234567890123456789", "0", nil},
    {"0.00e-01234567890123456789", "0", nil},
    {"-0e+01234567890123456789", "-0", nil},
    {"-0.00e-01234567890123456789", "-0", nil},

    {"0e291", "0", nil}, // issue 15364
    {"0e292", "0", nil}, // issue 15364
    {"0e347", "0", nil}, // issue 15364
    {"0e348", "0", nil}, // issue 15364
    {"-0e291", "-0", nil},
    {"-0e292", "-0", nil},
    {"-0e347", "-0", nil},
    {"-0e348", "-0", nil},

    // largest float64
    {"1.7976931348623157e308", "1.7976931348623157e+308", nil},
    {"-1.7976931348623157e308", "-1.7976931348623157e+308", nil},

    // the border is ...158079
    // borderline - okay
    {"1.7976931348623158e308", "1.7976931348623157e+308", nil},
    {"-1.7976931348623158e308", "-1.7976931348623157e+308", nil},

    // a little too large
    {"1e308", "1e+308", nil},

    // denormalized
    {"1e-305", "1e-305", nil},
    {"1e-306", "1e-306", nil},
    {"1e-307", "1e-307", nil},
    {"1e-308", "1e-308", nil},
    {"1e-309", "1e-309", nil},
    {"1e-310", "1e-310", nil},
    {"1e-322", "1e-322", nil},
    // smallest denormal
    {"5e-324", "5e-324", nil},
    {"4e-324", "5e-324", nil},
    {"3e-324", "5e-324", nil},
    // too small
    {"2e-324", "0", nil},
    // way too small
    {"1e-350", "0", nil},
    {"1e-400000", "0", nil},

    // try to overflow exponent
    {"1e-4294967296", "0", nil},
    {"1e-18446744073709551616", "0", nil},

    // https://www.exploringbinary.com/java-hangs-when-converting-2-2250738585072012e-308/
    {"2.2250738585072012e-308", "2.2250738585072014e-308", nil},
    // https://www.exploringbinary.com/php-hangs-on-numeric-value-2-2250738585072011e-308/
    {"2.2250738585072011e-308", "2.225073858507201e-308", nil},

    // A very large number (initially wrongly parsed by the fast algorithm).
    {"4.630813248087435e+307", "4.630813248087435e+307", nil},

    // A different kind of very large number.
    {"22.222222222222222", "22.22222222222222", nil},
    {"2." + strings.Repeat("2", 800) + "e+1", "22.22222222222222", nil},

    // Exactly halfway between 1 and math.Nextafter(1, 2).
    // Round to even (down).
    {"1.00000000000000011102230246251565404236316680908203125", "1", nil},
    // Slightly lower; still round down.
    {"1.00000000000000011102230246251565404236316680908203124", "1", nil},
    // Slightly higher; round up.
    {"1.00000000000000011102230246251565404236316680908203126", "1.0000000000000002", nil},
    // Slightly higher, but you have to read all the way to the end.
    {"1.00000000000000011102230246251565404236316680908203125" + strings.Repeat("0", 10000) + "1", "1.0000000000000002", nil},

    // Halfway between x := math.Nextafter(1, 2) and math.Nextafter(x, 2)
    // Round to even (up).
    {"1.00000000000000033306690738754696212708950042724609375", "1.0000000000000004", nil},

    // Halfway between 1090544144181609278303144771584 and 1090544144181609419040633126912
    // (15497564393479157p+46, should round to even 15497564393479156p+46, issue 36657)
    {"1090544144181609348671888949248", "1.0905441441816093e+30", nil},

    // Corner case between int64 and float64 for the input
    {"9223372036854775807", "9223372036854775807", nil}, // max int64: (1 << 63) - 1
    {"9223372036854775808", "9223372036854775808", nil},
    {"-9223372036854775808", "-9223372036854775808", nil}, // min int64: 1 << 63
    {"-9223372036854775809", "-9223372036854775809", nil},
}

func TestDecodeFloat(t *testing.T) {
    for i, tt := range atoftests {
        // default float64
        var sonicout, stdout float64
        sonicerr := decoder.NewDecoder(tt.in).Decode(&sonicout)
        stderr := json.NewDecoder(strings.NewReader(tt.in)).Decode(&stdout)
        if !reflect.DeepEqual(sonicout, stdout) {
            t.Fatalf("Test %d, %#v\ngot:\n   %#v\nexp:\n   %#v\n", i, tt.in, sonicout, stdout)
        }
        if !reflect.DeepEqual(sonicerr == nil, stderr == nil) {
            t.Fatalf("Test %d, %#v\ngot:\n   %#v\nexp:\n   %#v\n", i, tt.in, sonicerr, stderr)
        }
    }
}


type useInt64Test struct {
    in  string
    out int64
}

type useFloatTest struct {
    in  string
    out float64
}

var useinttest = []useInt64Test{
    // int64
    {"0", 0},
    {"1", 1},
    {"-1", -1},
    {"100", 100},

    {"-9223372036854775807", -9223372036854775807},
    {"-9223372036854775808", -9223372036854775808}, //min int64
    {"9223372036854775807", 9223372036854775807},   //max int64
    {"9223372036854775806", 9223372036854775806},
}

var usefloattest = []useFloatTest{
    // float64
    {"-9223372036854775809", -9223372036854775809}, // int64 overflow
    {"9223372036854775808", 9223372036854775808},   // int64 overflow
    {"1e2", 1e2},
    {"1e-20", 1e-20},
    {"1.0", 1},
}

func TestUseInt64(t *testing.T) {
    for i, tt := range useinttest {
        var sout interface{}
        dc := decoder.NewDecoder(tt.in)
        dc.UseInt64()
        serr := dc.Decode(&sout)
        if !reflect.DeepEqual(sout, tt.out) {
            t.Errorf("Test %d, %#v\ngot:\n   %#v\nexp:\n   %#v\n", i, tt.in, sout, tt.in)
        }
        if serr != nil {
            t.Errorf("Test %d, %#v\ngot:\n   %#v\nexp:\n   nil\n", i, tt, serr)
        }
    }

    for i, tt := range usefloattest {
        var sout interface{}
        dc := decoder.NewDecoder(tt.in)
        dc.UseInt64()
        //the input string is not int64, still return float64
        serr := dc.Decode(&sout)
        if !reflect.DeepEqual(sout, tt.out) {
            t.Errorf("Test %d, %#v\ngot:\n   %#v\nexp:\n   %#v\n", i, tt.in, sout, tt.in)
        }
        if serr != nil {
            t.Errorf("Test %d, %#v\ngot:\n   %#v\nexp:\n   nil\n", i, tt, serr)
        }
    }
}

func TestUseNumber(t *testing.T) {
    for i, tt := range useinttest {
        var sout interface{}
        dc := decoder.NewDecoder(tt.in)
        dc.UseNumber()
        serr := dc.Decode(&sout)
        if !reflect.DeepEqual(sout, json.Number(tt.in)) {
            t.Errorf("Test %d, %#v\ngot:\n   %#v\nexp:\n   %#v\n", i, tt.in, sout, tt.out)
        }
        if serr != nil {
            t.Errorf("Test %d, %#v\ngot:\n   %#v\nexp:\n   nil\n", i, tt, serr)
        }
    }

    for i, tt := range usefloattest {
        var sout interface{}
        dc := decoder.NewDecoder(tt.in)
        dc.UseNumber()
        serr := dc.Decode(&sout)
        if !reflect.DeepEqual(sout, json.Number(tt.in)) {
            t.Errorf("Test %d, %#v\ngot:\n   %#v\nexp:\n   %#v\n", i, tt.in, sout, tt.out)
        }
        if serr != nil {
            t.Errorf("Test %d, %#v\ngot:\n   %#v\nexp:\n   nil\n", i, tt, serr)
        }
    }
}


func BenchmarkDecoderRawMessage(b *testing.B) {
    data := `    {
      "coordinates": null,
      "favorited": false,
      "truncated": false,
      "created_at": "Mon Sep 24 03:35:21 +0000 2012",
      "id_str": "250075927172759552",
      "entities": {
        "urls": [
 
        ],
        "hashtags": [
          {
            "text": "freebandnames",
            "indices": [
              20,
              34
            ]
          }
        ],
        "user_mentions": [
 
        ]
      },
      "in_reply_to_user_id_str": null,
      "contributors": null,
      "text": "Aggressive Ponytail #freebandnames",
      "metadata": {
        "iso_language_code": "en",
        "result_type": "recent"
      },
      "retweet_count": 0,
      "in_reply_to_status_id_str": null,
      "id": 250075927172759552,
      "geo": null,
      "retweeted": false,
      "in_reply_to_user_id": null,
      "place": null,
      "user": {
        "profile_sidebar_fill_color": "DDEEF6",
        "profile_sidebar_border_color": "C0DEED",
        "profile_background_tile": false,
        "name": "Sean Cummings",
        "profile_image_url": "https://a0.twimg.com/profile_images/2359746665/1v6zfgqo8g0d3mk7ii5s_normal.jpeg",
        "created_at": "Mon Apr 26 06:01:55 +0000 2010",
        "location": "LA, CA",
        "follow_request_sent": null,
        "profile_link_color": "0084B4",
        "is_translator": false,
        "id_str": "137238150",
        "entities": {
          "url": {
            "urls": [
              {
                "expanded_url": null,
                "url": "",
                "indices": [
                  0,
                  0
                ]
              }
            ]
          },
          "description": {
            "urls": [
 
            ]
          }
        },
        "default_profile": true,
        "contributors_enabled": false,
        "favourites_count": 0,
        "url": null,
        "profile_image_url_https": "https://si0.twimg.com/profile_images/2359746665/1v6zfgqo8g0d3mk7ii5s_normal.jpeg",
        "utc_offset": -28800,
        "id": 137238150,
        "profile_use_background_image": true,
        "listed_count": 2,
        "profile_text_color": "333333",
        "lang": "en",
        "followers_count": 70,
        "protected": false,
        "notifications": null,
        "profile_background_image_url_https": "https://si0.twimg.com/images/themes/theme1/bg.png",
        "profile_background_color": "C0DEED",
        "verified": false,
        "geo_enabled": true,
        "time_zone": "Pacific Time (US & Canada)",
        "description": "Born 330 Live 310",
        "default_profile_image": false,
        "profile_background_image_url": "https://a0.twimg.com/images/themes/theme1/bg.png",
        "statuses_count": 579,
        "friends_count": 110,
        "following": null,
        "show_all_inline_media": false,
        "screen_name": "sean_cummings"
      },
      "in_reply_to_screen_name": null,
      "source": "<a href=\"//itunes.apple.com/us/app/twitter/id409789998?mt=12%5C%22\" rel=\"\\\"nofollow\\\"\">Twitter for Mac</a>",
      "in_reply_to_status_id": null
    }`

    bench := func(b *testing.B, run func(b *testing.B) ) {
        b.ResetTimer()
        b.ReportAllocs()
        b.SetBytes(int64(len(data)))
        for i := 0; i < b.N; i++ {
            run(b)
        }
        runtime.GC()
    }

    b.Run("StdRawMessage", func(b *testing.B) {
        bench(b, func(b *testing.B) {
            var obj map[string]json.RawMessage
            dc := decoder.NewDecoder(data)
            dc.SetOptions(decoder.OptionUseNumber)
            if err := dc.Decode(&obj); err!= nil {
                b.Fatal(err.Error())
            }
            _ = obj
        })
    })

    b.Run("NocopyRawMessage", func(b *testing.B) {
        bench(b, func(b *testing.B) {
            var obj map[string]NoCopyRawMessage
            dc := decoder.NewDecoder(data)
            dc.SetOptions(decoder.OptionUseNumber)
            if err := dc.Decode(&obj); err!= nil {
                b.Fatal(err.Error())
            }
            _ = obj
        })
    })


    b.Run("NocopyRawMessageWithoutValidation", func(b *testing.B) {
        bench(b, func(b *testing.B) {
            var obj map[string]NoCopyRawMessage
            dc := decoder.NewDecoder(data)
            dc.SetOptions(decoder.OptionNoValidateJSON | decoder.OptionUseNumber)
            if err := dc.Decode(&obj); err!= nil {
                b.Fatal(err.Error())
            }
            _ = obj
        })
    })
}


func TestJsonNumber(t *testing.T) {
    api := Config {
        UseNumber: true,
    }.Froze()


    type Foo struct {
        A json.Number `json:"a"`
        B json.Number `json:"b"`
        C json.Number `json:"c"`
    }

    data := []byte(`{"a": 1 , "b": "123", "c": "0.4e+56"}`)
    var foo1, foo2 Foo
    serr := api.Unmarshal(data, &foo1)
    jerr := json.Unmarshal(data, &foo2)
    assert.Equal(t, jerr, serr)
    assert.Equal(t, foo2, foo1)
}