Add decoder

This commit is contained in:
Masaaki Goshima 2020-04-22 13:06:52 +09:00
parent 39812b172b
commit 2c11838fe3
7 changed files with 614 additions and 8 deletions

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@ -1,6 +1,11 @@
# go-json
Fast JSON encoder/decoder compatible with encoding/json for Go
# Status
WIP
# Benchmarks
```
@ -8,9 +13,16 @@ $ go test -bench .
goos: darwin
goarch: amd64
pkg: github.com/goccy/go-json
Benchmark_jsoniter-12 5000000 377 ns/op 56 B/op 2 allocs/op
Benchmark_gojay-12 5000000 273 ns/op 512 B/op 1 allocs/op
Benchmark_gojson-12 5000000 242 ns/op 48 B/op 1 allocs/op
Benchmark_Encode_jsoniter-12 5000000 379 ns/op 56 B/op 2 allocs/op
Benchmark_Encode_gojay-12 5000000 273 ns/op 512 B/op 1 allocs/op
Benchmark_Encode_gojson-12 5000000 257 ns/op 48 B/op 1 allocs/op
Benchmark_Decode_jsoniter-12 2000000 846 ns/op 208 B/op 13 allocs/op
Benchmark_Decode_gojay-12 3000000 545 ns/op 256 B/op 2 allocs/op
Benchmark_Decode_gojson-12 3000000 506 ns/op 256 B/op 2 allocs/op
PASS
ok github.com/goccy/go-json 5.392s
ok github.com/goccy/go-json 12.258s
```
# License
MIT

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@ -28,7 +28,7 @@ func newT() *T {
return &T{A: 1, B: 3.14, C: `hello"world`}
}
func Benchmark_jsoniter(b *testing.B) {
func Benchmark_Encode_jsoniter(b *testing.B) {
v := newT()
var json = jsoniter.ConfigCompatibleWithStandardLibrary
b.ReportAllocs()
@ -39,7 +39,7 @@ func Benchmark_jsoniter(b *testing.B) {
}
}
func Benchmark_gojay(b *testing.B) {
func Benchmark_Encode_gojay(b *testing.B) {
v := newT()
b.ReportAllocs()
for i := 0; i < b.N; i++ {
@ -49,7 +49,7 @@ func Benchmark_gojay(b *testing.B) {
}
}
func Benchmark_gojson(b *testing.B) {
func Benchmark_Encode_gojson(b *testing.B) {
v := newT()
b.ReportAllocs()
for i := 0; i < b.N; i++ {
@ -58,3 +58,76 @@ func Benchmark_gojson(b *testing.B) {
}
}
}
var fixture = []byte(`{"st": 1,"sid": 486,"tt": "active","gr": 0,"uuid": "de305d54-75b4-431b-adb2-eb6b9e546014","ip": "127.0.0.1","ua": "user_agent","tz": -6,"v": 1}`)
type SmallPayload struct {
St int
Sid int
Tt string
Gr int
Uuid string
Ip string
Ua string
Tz int
V int
}
func (t *SmallPayload) UnmarshalJSONObject(dec *gojay.Decoder, key string) error {
switch key {
case "st":
return dec.AddInt(&t.St)
case "sid":
return dec.AddInt(&t.Sid)
case "gr":
return dec.AddInt(&t.Gr)
case "tz":
return dec.AddInt(&t.Tz)
case "v":
return dec.AddInt(&t.V)
case "tt":
return dec.AddString(&t.Tt)
case "uuid":
return dec.AddString(&t.Uuid)
case "ip":
return dec.AddString(&t.Ip)
case "ua":
return dec.AddString(&t.Ua)
}
return nil
}
func (t *SmallPayload) NKeys() int {
return 9
}
func Benchmark_Decode_jsoniter(b *testing.B) {
var json = jsoniter.ConfigCompatibleWithStandardLibrary
b.ReportAllocs()
for i := 0; i < b.N; i++ {
var v SmallPayload
if err := json.Unmarshal(fixture, &v); err != nil {
b.Fatal(err)
}
}
}
func Benchmark_Decode_gojay(b *testing.B) {
b.ReportAllocs()
for i := 0; i < b.N; i++ {
var v SmallPayload
if err := gojay.UnmarshalJSONObject(fixture, &v); err != nil {
b.Fatal(err)
}
}
}
func Benchmark_Decode_gojson(b *testing.B) {
b.ReportAllocs()
for i := 0; i < b.N; i++ {
var v SmallPayload
if err := gojson.Unmarshal(fixture, &v); err != nil {
b.Fatal(err)
}
}
}

496
decode.go Normal file
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@ -0,0 +1,496 @@
package json
import (
"errors"
"io"
"math"
"reflect"
"strings"
"sync"
"unsafe"
)
type Token interface{}
type Delim rune
const (
stateNone int = iota
stateLiteral
stateObject
stateArray
)
type Decoder struct {
r io.Reader
state int
literal []byte
}
type context struct {
idx int
keys [][]byte
literals [][]byte
start int
stack int
}
func newContext() *context {
return &context{
keys: make([][]byte, 64),
literals: make([][]byte, 64),
}
}
func (c *context) pushStack() {
if len(c.keys) <= c.stack {
c.keys = append(c.keys, nil)
c.literals = append(c.literals, nil)
}
c.stack++
}
func (c *context) popStack() {
c.stack--
}
func (c *context) setKey(key []byte) {
c.keys[c.stack] = key
}
func (c *context) setLiteral(literal []byte) {
c.literals[c.stack] = literal
}
func (c *context) key() ([]byte, error) {
if len(c.keys) <= c.stack {
return nil, errors.New("unexpected error")
}
key := c.keys[c.stack]
if len(key) == 0 {
return nil, errors.New("unexpected error")
}
return key, nil
}
func (c *context) literal() ([]byte, error) {
if len(c.literals) <= c.stack {
return nil, errors.New("unexpected error")
}
return c.literals[c.stack], nil
}
var (
ctxPool sync.Pool
cachedDecodeOp map[string]DecodeOp
)
func init() {
cachedDecodeOp = map[string]DecodeOp{}
ctxPool = sync.Pool{
New: func() interface{} {
return newContext()
},
}
}
func NewDecoder(r io.Reader) *Decoder {
return &Decoder{
r: r,
}
}
func (d *Decoder) Buffered() io.Reader {
return d.r
}
func (d *Decoder) decodeForUnmarshal(src []byte, v interface{}) error {
rv := reflect.ValueOf(v)
typ := rv.Type()
if typ.Kind() != reflect.Ptr {
return ErrDecodePointer
}
name := typ.String()
op, exists := cachedDecodeOp[name]
if !exists {
decodeOp, err := d.compile(rv.Elem())
if err != nil {
return err
}
if name != "" {
cachedDecodeOp[name] = decodeOp
}
op = decodeOp
}
ptr := rv.Pointer()
ctx := ctxPool.Get().(*context)
if err := d.decode(ctx, src, ptr, op); err != nil {
ctxPool.Put(ctx)
return err
}
ctxPool.Put(ctx)
return nil
}
func (d *Decoder) Decode(v interface{}) error {
rv := reflect.ValueOf(v)
typ := rv.Type()
if typ.Kind() != reflect.Ptr {
return ErrDecodePointer
}
name := typ.String()
op, exists := cachedDecodeOp[name]
if !exists {
decodeOp, err := d.compile(rv.Elem())
if err != nil {
return err
}
if name != "" {
cachedDecodeOp[name] = decodeOp
}
op = decodeOp
}
ptr := rv.Pointer()
ctx := ctxPool.Get().(*context)
defer ctxPool.Put(ctx)
for {
buf := make([]byte, 1024)
n, err := d.r.Read(buf)
if n == 0 || err == io.EOF {
return nil
}
if err != nil {
return err
}
if err := d.decode(ctx, buf[:n], ptr, op); err != nil {
return err
}
}
return nil
}
type DecodeOp func(uintptr, []byte, []byte) error
func (d *Decoder) compile(v reflect.Value) (DecodeOp, error) {
switch v.Type().Kind() {
case reflect.Struct:
return d.compileStruct(v)
case reflect.Int:
return d.compileInt()
case reflect.Int8:
return d.compileInt8()
case reflect.Int16:
return d.compileInt16()
case reflect.Int32:
return d.compileInt32()
case reflect.Int64:
return d.compileInt64()
case reflect.Uint:
return d.compileUint()
case reflect.Uint8:
return d.compileUint8()
case reflect.Uint16:
return d.compileUint16()
case reflect.Uint32:
return d.compileUint32()
case reflect.Uint64:
return d.compileUint64()
case reflect.String:
return d.compileString()
}
return nil, nil
}
func parseInt(b []byte) (int64, error) {
isNegative := false
if b[0] == '-' {
b = b[1:]
isNegative = true
}
maxDigit := len(b)
sum := int64(0)
for i := 0; i < maxDigit; i++ {
c := int64(b[i]) - 48
if 0 <= c && c <= 9 {
digitValue := int64(math.Pow10(maxDigit - i - 1))
sum += c * digitValue
} else {
return 0, errors.New("failed to parse int")
}
}
if isNegative {
return -1 * sum, nil
}
return sum, nil
}
func parseUint(b []byte) (uint64, error) {
maxDigit := len(b)
sum := uint64(0)
for i := 0; i < maxDigit; i++ {
c := uint64(b[i]) - 48
if 0 <= c && c <= 9 {
digitValue := uint64(math.Pow10(maxDigit - i - 1))
sum += c * digitValue
} else {
return 0, errors.New("failed to parse uint")
}
}
return sum, nil
}
func (d *Decoder) compileInt() (DecodeOp, error) {
return func(p uintptr, src []byte, _ []byte) error {
i64, err := parseInt(src)
if err != nil {
return err
}
*(*int)(unsafe.Pointer(p)) = int(i64)
return nil
}, nil
}
func (d *Decoder) compileInt8() (DecodeOp, error) {
return func(p uintptr, src []byte, _ []byte) error {
i64, err := parseInt(src)
if err != nil {
return err
}
*(*int8)(unsafe.Pointer(p)) = int8(i64)
return nil
}, nil
}
func (d *Decoder) compileInt16() (DecodeOp, error) {
return func(p uintptr, src []byte, _ []byte) error {
i64, err := parseInt(src)
if err != nil {
return err
}
*(*int16)(unsafe.Pointer(p)) = int16(i64)
return nil
}, nil
}
func (d *Decoder) compileInt32() (DecodeOp, error) {
return func(p uintptr, src []byte, _ []byte) error {
i64, err := parseInt(src)
if err != nil {
return err
}
*(*int32)(unsafe.Pointer(p)) = int32(i64)
return nil
}, nil
}
func (d *Decoder) compileInt64() (DecodeOp, error) {
return func(p uintptr, src []byte, _ []byte) error {
i64, err := parseInt(src)
if err != nil {
return err
}
*(*int64)(unsafe.Pointer(p)) = i64
return nil
}, nil
}
func (d *Decoder) compileUint() (DecodeOp, error) {
return func(p uintptr, src []byte, _ []byte) error {
u64, err := parseUint(src)
if err != nil {
return err
}
*(*uint)(unsafe.Pointer(p)) = uint(u64)
return nil
}, nil
}
func (d *Decoder) compileUint8() (DecodeOp, error) {
return func(p uintptr, src []byte, _ []byte) error {
u64, err := parseUint(src)
if err != nil {
return err
}
*(*uint8)(unsafe.Pointer(p)) = uint8(u64)
return nil
}, nil
}
func (d *Decoder) compileUint16() (DecodeOp, error) {
return func(p uintptr, src []byte, _ []byte) error {
u64, err := parseUint(src)
if err != nil {
return err
}
*(*uint16)(unsafe.Pointer(p)) = uint16(u64)
return nil
}, nil
}
func (d *Decoder) compileUint32() (DecodeOp, error) {
return func(p uintptr, src []byte, _ []byte) error {
u64, err := parseUint(src)
if err != nil {
return err
}
*(*uint32)(unsafe.Pointer(p)) = uint32(u64)
return nil
}, nil
}
func (d *Decoder) compileUint64() (DecodeOp, error) {
return func(p uintptr, src []byte, _ []byte) error {
u64, err := parseUint(src)
if err != nil {
return err
}
*(*uint64)(unsafe.Pointer(p)) = u64
return nil
}, nil
}
func (d *Decoder) compileString() (DecodeOp, error) {
return func(p uintptr, src []byte, _ []byte) error {
*(*string)(unsafe.Pointer(p)) = *(*string)(unsafe.Pointer(&src))
return nil
}, nil
}
func (d *Decoder) getTag(field reflect.StructField) string {
return field.Tag.Get("json")
}
func (d *Decoder) isIgnoredStructField(field reflect.StructField) bool {
if field.PkgPath != "" && !field.Anonymous {
// private field
return true
}
tag := d.getTag(field)
if tag == "-" {
return true
}
return false
}
func (d *Decoder) compileStruct(v reflect.Value) (DecodeOp, error) {
type opset struct {
key []byte
op func(uintptr, []byte) error
}
typ := v.Type()
fieldNum := typ.NumField()
opMap := map[string]func(uintptr, []byte) error{}
for i := 0; i < fieldNum; i++ {
field := typ.Field(i)
if d.isIgnoredStructField(field) {
continue
}
keyName := field.Name
tag := d.getTag(field)
opts := strings.Split(tag, ",")
if len(opts) > 0 {
if opts[0] != "" {
keyName = opts[0]
}
}
op, err := d.compile(v.Field(i))
if err != nil {
return nil, err
}
if op == nil {
continue
}
fieldOp := func(base uintptr, value []byte) error {
return op(base+field.Offset, value, nil)
}
opMap[field.Name] = fieldOp
opMap[keyName] = fieldOp
opMap[strings.ToLower(keyName)] = fieldOp
}
return func(p uintptr, key []byte, value []byte) error {
k := *(*string)(unsafe.Pointer(&key))
op, exists := opMap[k]
if !exists {
return nil
}
return op(p, value)
}, nil
}
func (d *Decoder) decode(ctx *context, src []byte, ptr uintptr, op DecodeOp) error {
slen := len(src)
for i := ctx.idx; i < slen; i++ {
c := src[i]
switch c {
case ' ':
ctx.start++
case '{':
ctx.pushStack()
case '}':
key, err := ctx.key()
if err != nil {
return err
}
if err := op(ptr, key, src[ctx.start:i]); err != nil {
return err
}
ctx.popStack()
case '[':
d.state = stateArray
case ']':
d.state = stateNone
case ':':
if len(d.literal) == 0 {
return errors.New("unexpected error")
}
ctx.setKey(d.literal)
ctx.start = i + 1
case ',':
literal := src[ctx.start:i]
key, err := ctx.key()
if err != nil {
return err
}
if err := op(ptr, key, literal); err != nil {
return err
}
case '"':
start := i + 1
for i = start; i < slen && src[i] != '"'; i++ {
if src[i] == '\\' {
i++
}
}
end := i
if end <= start {
return errors.New("unexpected error")
}
d.literal = src[start:end]
}
}
return nil
}
func (d *Decoder) parse(tokens []Token) {
}
func (d *Decoder) DisallowUnknownFields() {
}
func (d *Decoder) InputOffset() int64 {
return 0
}
func (d *Decoder) More() bool {
return false
}
func (d *Decoder) Token() (Token, error) {
return nil, nil
}
func (d *Decoder) UseNumber() {
}

17
decode_test.go Normal file
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@ -0,0 +1,17 @@
package json_test
import (
"testing"
"github.com/goccy/go-json"
)
func Test_Decoder(t *testing.T) {
t.Run("struct", func(t *testing.T) {
var v struct {
A int
}
assertErr(t, json.Unmarshal([]byte(`{"a":123}`), &v))
assertEq(t, "struct.A", v.A, 123)
})
}

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@ -89,8 +89,8 @@ func (e *Encoder) SetIndent(prefix, indent string) {
}
func (e *Encoder) release() {
e.pool.Put(e)
e.w = nil
e.pool.Put(e)
}
func (e *Encoder) reset() {

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@ -5,4 +5,5 @@ import "golang.org/x/xerrors"
var (
ErrUnsupportedType = xerrors.New("json: unsupported type")
ErrCompileSlowPath = xerrors.New("json: detect dynamic type ( interface{} ) and compile with slow path")
ErrDecodePointer = xerrors.New("json: required pointer type")
)

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@ -8,3 +8,10 @@ func Marshal(v interface{}) ([]byte, error) {
defer enc.release()
return enc.encodeForMarshal(v)
}
func Unmarshal(data []byte, v interface{}) error {
src := make([]byte, len(data))
copy(src, data)
var dec Decoder
return dec.decodeForUnmarshal(src, v)
}