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|
package jsoniter
import (
"encoding/json"
"io"
"math/big"
"strconv"
"strings"
"unsafe"
)
var floatDigits []int8
const invalidCharForNumber = int8(-1)
const endOfNumber = int8(-2)
const dotInNumber = int8(-3)
func init() {
floatDigits = make([]int8, 256)
for i := 0; i < len(floatDigits); i++ {
floatDigits[i] = invalidCharForNumber
}
for i := int8('0'); i <= int8('9'); i++ {
floatDigits[i] = i - int8('0')
}
floatDigits[','] = endOfNumber
floatDigits[']'] = endOfNumber
floatDigits['}'] = endOfNumber
floatDigits[' '] = endOfNumber
floatDigits['\t'] = endOfNumber
floatDigits['\n'] = endOfNumber
floatDigits['.'] = dotInNumber
}
// ReadBigFloat read big.Float
func (iter *Iterator) ReadBigFloat() (ret *big.Float) {
str := iter.readNumberAsString()
if iter.Error != nil && iter.Error != io.EOF {
return nil
}
prec := 64
if len(str) > prec {
prec = len(str)
}
val, _, err := big.ParseFloat(str, 10, uint(prec), big.ToZero)
if err != nil {
iter.Error = err
return nil
}
return val
}
// ReadBigInt read big.Int
func (iter *Iterator) ReadBigInt() (ret *big.Int) {
str := iter.readNumberAsString()
if iter.Error != nil && iter.Error != io.EOF {
return nil
}
ret = big.NewInt(0)
var success bool
ret, success = ret.SetString(str, 10)
if !success {
iter.ReportError("ReadBigInt", "invalid big int")
return nil
}
return ret
}
//ReadFloat32 read float32
func (iter *Iterator) ReadFloat32() (ret float32) {
c := iter.nextToken()
if c == '-' {
return -iter.readPositiveFloat32()
}
iter.unreadByte()
return iter.readPositiveFloat32()
}
func (iter *Iterator) readPositiveFloat32() (ret float32) {
i := iter.head
// first char
if i == iter.tail {
return iter.readFloat32SlowPath()
}
c := iter.buf[i]
i++
ind := floatDigits[c]
switch ind {
case invalidCharForNumber:
return iter.readFloat32SlowPath()
case endOfNumber:
iter.ReportError("readFloat32", "empty number")
return
case dotInNumber:
iter.ReportError("readFloat32", "leading dot is invalid")
return
case 0:
if i == iter.tail {
return iter.readFloat32SlowPath()
}
c = iter.buf[i]
switch c {
case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
iter.ReportError("readFloat32", "leading zero is invalid")
return
}
}
value := uint64(ind)
// chars before dot
non_decimal_loop:
for ; i < iter.tail; i++ {
c = iter.buf[i]
ind := floatDigits[c]
switch ind {
case invalidCharForNumber:
return iter.readFloat32SlowPath()
case endOfNumber:
iter.head = i
return float32(value)
case dotInNumber:
break non_decimal_loop
}
if value > uint64SafeToMultiple10 {
return iter.readFloat32SlowPath()
}
value = (value << 3) + (value << 1) + uint64(ind) // value = value * 10 + ind;
}
// chars after dot
if c == '.' {
i++
decimalPlaces := 0
if i == iter.tail {
return iter.readFloat32SlowPath()
}
for ; i < iter.tail; i++ {
c = iter.buf[i]
ind := floatDigits[c]
switch ind {
case endOfNumber:
if decimalPlaces > 0 && decimalPlaces < len(pow10) {
iter.head = i
return float32(float64(value) / float64(pow10[decimalPlaces]))
}
// too many decimal places
return iter.readFloat32SlowPath()
case invalidCharForNumber, dotInNumber:
return iter.readFloat32SlowPath()
}
decimalPlaces++
if value > uint64SafeToMultiple10 {
return iter.readFloat32SlowPath()
}
value = (value << 3) + (value << 1) + uint64(ind)
}
}
return iter.readFloat32SlowPath()
}
func (iter *Iterator) readNumberAsString() (ret string) {
strBuf := [16]byte{}
str := strBuf[0:0]
load_loop:
for {
for i := iter.head; i < iter.tail; i++ {
c := iter.buf[i]
switch c {
case '+', '-', '.', 'e', 'E', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
str = append(str, c)
continue
default:
iter.head = i
break load_loop
}
}
if !iter.loadMore() {
break
}
}
if iter.Error != nil && iter.Error != io.EOF {
return
}
if len(str) == 0 {
iter.ReportError("readNumberAsString", "invalid number")
}
return *(*string)(unsafe.Pointer(&str))
}
func (iter *Iterator) readFloat32SlowPath() (ret float32) {
str := iter.readNumberAsString()
if iter.Error != nil && iter.Error != io.EOF {
return
}
errMsg := validateFloat(str)
if errMsg != "" {
iter.ReportError("readFloat32SlowPath", errMsg)
return
}
val, err := strconv.ParseFloat(str, 32)
if err != nil {
iter.Error = err
return
}
return float32(val)
}
// ReadFloat64 read float64
func (iter *Iterator) ReadFloat64() (ret float64) {
c := iter.nextToken()
if c == '-' {
return -iter.readPositiveFloat64()
}
iter.unreadByte()
return iter.readPositiveFloat64()
}
func (iter *Iterator) readPositiveFloat64() (ret float64) {
i := iter.head
// first char
if i == iter.tail {
return iter.readFloat64SlowPath()
}
c := iter.buf[i]
i++
ind := floatDigits[c]
switch ind {
case invalidCharForNumber:
return iter.readFloat64SlowPath()
case endOfNumber:
iter.ReportError("readFloat64", "empty number")
return
case dotInNumber:
iter.ReportError("readFloat64", "leading dot is invalid")
return
case 0:
if i == iter.tail {
return iter.readFloat64SlowPath()
}
c = iter.buf[i]
switch c {
case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
iter.ReportError("readFloat64", "leading zero is invalid")
return
}
}
value := uint64(ind)
// chars before dot
non_decimal_loop:
for ; i < iter.tail; i++ {
c = iter.buf[i]
ind := floatDigits[c]
switch ind {
case invalidCharForNumber:
return iter.readFloat64SlowPath()
case endOfNumber:
iter.head = i
return float64(value)
case dotInNumber:
break non_decimal_loop
}
if value > uint64SafeToMultiple10 {
return iter.readFloat64SlowPath()
}
value = (value << 3) + (value << 1) + uint64(ind) // value = value * 10 + ind;
}
// chars after dot
if c == '.' {
i++
decimalPlaces := 0
if i == iter.tail {
return iter.readFloat64SlowPath()
}
for ; i < iter.tail; i++ {
c = iter.buf[i]
ind := floatDigits[c]
switch ind {
case endOfNumber:
if decimalPlaces > 0 && decimalPlaces < len(pow10) {
iter.head = i
return float64(value) / float64(pow10[decimalPlaces])
}
// too many decimal places
return iter.readFloat64SlowPath()
case invalidCharForNumber, dotInNumber:
return iter.readFloat64SlowPath()
}
decimalPlaces++
if value > uint64SafeToMultiple10 {
return iter.readFloat64SlowPath()
}
value = (value << 3) + (value << 1) + uint64(ind)
if value > maxFloat64 {
return iter.readFloat64SlowPath()
}
}
}
return iter.readFloat64SlowPath()
}
func (iter *Iterator) readFloat64SlowPath() (ret float64) {
str := iter.readNumberAsString()
if iter.Error != nil && iter.Error != io.EOF {
return
}
errMsg := validateFloat(str)
if errMsg != "" {
iter.ReportError("readFloat64SlowPath", errMsg)
return
}
val, err := strconv.ParseFloat(str, 64)
if err != nil {
iter.Error = err
return
}
return val
}
func validateFloat(str string) string {
// strconv.ParseFloat is not validating `1.` or `1.e1`
if len(str) == 0 {
return "empty number"
}
if str[0] == '-' {
return "-- is not valid"
}
dotPos := strings.IndexByte(str, '.')
if dotPos != -1 {
if dotPos == len(str)-1 {
return "dot can not be last character"
}
switch str[dotPos+1] {
case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
default:
return "missing digit after dot"
}
}
return ""
}
// ReadNumber read json.Number
func (iter *Iterator) ReadNumber() (ret json.Number) {
return json.Number(iter.readNumberAsString())
}
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