mirror of
https://github.com/superseriousbusiness/gotosocial
synced 2024-12-24 19:53:11 +00:00
452 lines
12 KiB
Go
452 lines
12 KiB
Go
package decoder
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import (
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"bytes"
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"fmt"
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"reflect"
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"unicode"
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"unicode/utf16"
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"unicode/utf8"
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"unsafe"
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"github.com/goccy/go-json/internal/errors"
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)
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type stringDecoder struct {
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structName string
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fieldName string
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}
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func newStringDecoder(structName, fieldName string) *stringDecoder {
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return &stringDecoder{
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structName: structName,
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fieldName: fieldName,
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}
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}
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func (d *stringDecoder) errUnmarshalType(typeName string, offset int64) *errors.UnmarshalTypeError {
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return &errors.UnmarshalTypeError{
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Value: typeName,
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Type: reflect.TypeOf(""),
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Offset: offset,
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Struct: d.structName,
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Field: d.fieldName,
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}
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}
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func (d *stringDecoder) DecodeStream(s *Stream, depth int64, p unsafe.Pointer) error {
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bytes, err := d.decodeStreamByte(s)
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if err != nil {
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return err
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}
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if bytes == nil {
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return nil
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}
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**(**string)(unsafe.Pointer(&p)) = *(*string)(unsafe.Pointer(&bytes))
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s.reset()
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return nil
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}
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func (d *stringDecoder) Decode(ctx *RuntimeContext, cursor, depth int64, p unsafe.Pointer) (int64, error) {
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bytes, c, err := d.decodeByte(ctx.Buf, cursor)
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if err != nil {
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return 0, err
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}
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if bytes == nil {
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return c, nil
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}
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cursor = c
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**(**string)(unsafe.Pointer(&p)) = *(*string)(unsafe.Pointer(&bytes))
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return cursor, nil
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}
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func (d *stringDecoder) DecodePath(ctx *RuntimeContext, cursor, depth int64) ([][]byte, int64, error) {
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bytes, c, err := d.decodeByte(ctx.Buf, cursor)
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if err != nil {
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return nil, 0, err
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}
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if bytes == nil {
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return [][]byte{nullbytes}, c, nil
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}
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return [][]byte{bytes}, c, nil
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}
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var (
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hexToInt = [256]int{
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'0': 0,
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'1': 1,
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'2': 2,
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'3': 3,
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'4': 4,
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'5': 5,
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'6': 6,
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'7': 7,
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'8': 8,
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'9': 9,
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'A': 10,
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'B': 11,
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'C': 12,
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'D': 13,
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'E': 14,
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'F': 15,
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'a': 10,
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'b': 11,
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'c': 12,
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'd': 13,
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'e': 14,
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'f': 15,
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}
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)
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func unicodeToRune(code []byte) rune {
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var r rune
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for i := 0; i < len(code); i++ {
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r = r*16 + rune(hexToInt[code[i]])
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}
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return r
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}
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func readAtLeast(s *Stream, n int64, p *unsafe.Pointer) bool {
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for s.cursor+n >= s.length {
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if !s.read() {
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return false
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}
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*p = s.bufptr()
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}
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return true
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}
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func decodeUnicodeRune(s *Stream, p unsafe.Pointer) (rune, int64, unsafe.Pointer, error) {
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const defaultOffset = 5
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const surrogateOffset = 11
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if !readAtLeast(s, defaultOffset, &p) {
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return rune(0), 0, nil, errors.ErrInvalidCharacter(s.char(), "escaped string", s.totalOffset())
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}
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r := unicodeToRune(s.buf[s.cursor+1 : s.cursor+defaultOffset])
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if utf16.IsSurrogate(r) {
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if !readAtLeast(s, surrogateOffset, &p) {
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return unicode.ReplacementChar, defaultOffset, p, nil
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}
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if s.buf[s.cursor+defaultOffset] != '\\' || s.buf[s.cursor+defaultOffset+1] != 'u' {
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return unicode.ReplacementChar, defaultOffset, p, nil
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}
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r2 := unicodeToRune(s.buf[s.cursor+defaultOffset+2 : s.cursor+surrogateOffset])
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if r := utf16.DecodeRune(r, r2); r != unicode.ReplacementChar {
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return r, surrogateOffset, p, nil
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}
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}
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return r, defaultOffset, p, nil
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}
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func decodeUnicode(s *Stream, p unsafe.Pointer) (unsafe.Pointer, error) {
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const backSlashAndULen = 2 // length of \u
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r, offset, pp, err := decodeUnicodeRune(s, p)
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if err != nil {
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return nil, err
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}
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unicode := []byte(string(r))
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unicodeLen := int64(len(unicode))
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s.buf = append(append(s.buf[:s.cursor-1], unicode...), s.buf[s.cursor+offset:]...)
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unicodeOrgLen := offset - 1
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s.length = s.length - (backSlashAndULen + (unicodeOrgLen - unicodeLen))
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s.cursor = s.cursor - backSlashAndULen + unicodeLen
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return pp, nil
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}
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func decodeEscapeString(s *Stream, p unsafe.Pointer) (unsafe.Pointer, error) {
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s.cursor++
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RETRY:
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switch s.buf[s.cursor] {
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case '"':
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s.buf[s.cursor] = '"'
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case '\\':
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s.buf[s.cursor] = '\\'
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case '/':
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s.buf[s.cursor] = '/'
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case 'b':
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s.buf[s.cursor] = '\b'
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case 'f':
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s.buf[s.cursor] = '\f'
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case 'n':
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s.buf[s.cursor] = '\n'
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case 'r':
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s.buf[s.cursor] = '\r'
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case 't':
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s.buf[s.cursor] = '\t'
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case 'u':
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return decodeUnicode(s, p)
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case nul:
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if !s.read() {
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return nil, errors.ErrInvalidCharacter(s.char(), "escaped string", s.totalOffset())
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}
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p = s.bufptr()
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goto RETRY
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default:
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return nil, errors.ErrUnexpectedEndOfJSON("string", s.totalOffset())
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}
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s.buf = append(s.buf[:s.cursor-1], s.buf[s.cursor:]...)
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s.length--
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s.cursor--
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p = s.bufptr()
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return p, nil
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}
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var (
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runeErrBytes = []byte(string(utf8.RuneError))
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runeErrBytesLen = int64(len(runeErrBytes))
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)
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func stringBytes(s *Stream) ([]byte, error) {
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_, cursor, p := s.stat()
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cursor++ // skip double quote char
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start := cursor
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for {
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switch char(p, cursor) {
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case '\\':
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s.cursor = cursor
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pp, err := decodeEscapeString(s, p)
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if err != nil {
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return nil, err
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}
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p = pp
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cursor = s.cursor
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case '"':
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literal := s.buf[start:cursor]
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cursor++
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s.cursor = cursor
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return literal, nil
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case
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// 0x00 is nul, 0x5c is '\\', 0x22 is '"' .
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0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, // 0x00-0x0F
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0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, // 0x10-0x1F
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0x20, 0x21 /*0x22,*/, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F, // 0x20-0x2F
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0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F, // 0x30-0x3F
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0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, // 0x40-0x4F
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0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B /*0x5C,*/, 0x5D, 0x5E, 0x5F, // 0x50-0x5F
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0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F, // 0x60-0x6F
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0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7C, 0x7D, 0x7E, 0x7F: // 0x70-0x7F
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// character is ASCII. skip to next char
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case
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0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, // 0x80-0x8F
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0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D, 0x9E, 0x9F, // 0x90-0x9F
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0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF, // 0xA0-0xAF
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0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE, 0xBF, // 0xB0-0xBF
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0xC0, 0xC1, // 0xC0-0xC1
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0xF5, 0xF6, 0xF7, 0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFF: // 0xF5-0xFE
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// character is invalid
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s.buf = append(append(append([]byte{}, s.buf[:cursor]...), runeErrBytes...), s.buf[cursor+1:]...)
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_, _, p = s.stat()
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cursor += runeErrBytesLen
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s.length += runeErrBytesLen
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continue
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case nul:
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s.cursor = cursor
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if s.read() {
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_, cursor, p = s.stat()
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continue
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}
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goto ERROR
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case 0xEF:
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// RuneError is {0xEF, 0xBF, 0xBD}
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if s.buf[cursor+1] == 0xBF && s.buf[cursor+2] == 0xBD {
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// found RuneError: skip
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cursor += 2
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break
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}
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fallthrough
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default:
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// multi bytes character
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if !utf8.FullRune(s.buf[cursor : len(s.buf)-1]) {
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s.cursor = cursor
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if s.read() {
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_, cursor, p = s.stat()
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continue
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}
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goto ERROR
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}
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r, size := utf8.DecodeRune(s.buf[cursor:])
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if r == utf8.RuneError {
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s.buf = append(append(append([]byte{}, s.buf[:cursor]...), runeErrBytes...), s.buf[cursor+1:]...)
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cursor += runeErrBytesLen
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s.length += runeErrBytesLen
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_, _, p = s.stat()
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} else {
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cursor += int64(size)
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}
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continue
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}
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cursor++
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}
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ERROR:
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return nil, errors.ErrUnexpectedEndOfJSON("string", s.totalOffset())
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}
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func (d *stringDecoder) decodeStreamByte(s *Stream) ([]byte, error) {
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for {
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switch s.char() {
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case ' ', '\n', '\t', '\r':
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s.cursor++
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continue
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case '[':
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return nil, d.errUnmarshalType("array", s.totalOffset())
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case '{':
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return nil, d.errUnmarshalType("object", s.totalOffset())
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case '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
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return nil, d.errUnmarshalType("number", s.totalOffset())
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case '"':
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return stringBytes(s)
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case 'n':
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if err := nullBytes(s); err != nil {
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return nil, err
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}
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return nil, nil
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case nul:
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if s.read() {
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continue
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}
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}
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break
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}
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return nil, errors.ErrInvalidBeginningOfValue(s.char(), s.totalOffset())
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}
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func (d *stringDecoder) decodeByte(buf []byte, cursor int64) ([]byte, int64, error) {
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for {
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switch buf[cursor] {
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case ' ', '\n', '\t', '\r':
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cursor++
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case '[':
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return nil, 0, d.errUnmarshalType("array", cursor)
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case '{':
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return nil, 0, d.errUnmarshalType("object", cursor)
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case '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
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return nil, 0, d.errUnmarshalType("number", cursor)
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case '"':
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cursor++
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start := cursor
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b := (*sliceHeader)(unsafe.Pointer(&buf)).data
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escaped := 0
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for {
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switch char(b, cursor) {
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case '\\':
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escaped++
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cursor++
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switch char(b, cursor) {
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case '"', '\\', '/', 'b', 'f', 'n', 'r', 't':
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cursor++
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case 'u':
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buflen := int64(len(buf))
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if cursor+5 >= buflen {
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return nil, 0, errors.ErrUnexpectedEndOfJSON("escaped string", cursor)
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}
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for i := int64(1); i <= 4; i++ {
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c := char(b, cursor+i)
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if !(('0' <= c && c <= '9') || ('a' <= c && c <= 'f') || ('A' <= c && c <= 'F')) {
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return nil, 0, errors.ErrSyntax(fmt.Sprintf("json: invalid character %c in \\u hexadecimal character escape", c), cursor+i)
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}
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}
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cursor += 5
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default:
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return nil, 0, errors.ErrUnexpectedEndOfJSON("escaped string", cursor)
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}
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continue
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case '"':
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literal := buf[start:cursor]
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if escaped > 0 {
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literal = literal[:unescapeString(literal)]
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}
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cursor++
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return literal, cursor, nil
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case nul:
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return nil, 0, errors.ErrUnexpectedEndOfJSON("string", cursor)
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}
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cursor++
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}
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case 'n':
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if err := validateNull(buf, cursor); err != nil {
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return nil, 0, err
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}
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cursor += 4
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return nil, cursor, nil
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default:
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return nil, 0, errors.ErrInvalidBeginningOfValue(buf[cursor], cursor)
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}
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}
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}
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var unescapeMap = [256]byte{
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'"': '"',
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'\\': '\\',
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'/': '/',
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'b': '\b',
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'f': '\f',
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'n': '\n',
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'r': '\r',
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't': '\t',
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}
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func unsafeAdd(ptr unsafe.Pointer, offset int) unsafe.Pointer {
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return unsafe.Pointer(uintptr(ptr) + uintptr(offset))
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}
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func unescapeString(buf []byte) int {
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p := (*sliceHeader)(unsafe.Pointer(&buf)).data
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end := unsafeAdd(p, len(buf))
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src := unsafeAdd(p, bytes.IndexByte(buf, '\\'))
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dst := src
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for src != end {
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c := char(src, 0)
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if c == '\\' {
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escapeChar := char(src, 1)
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if escapeChar != 'u' {
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*(*byte)(dst) = unescapeMap[escapeChar]
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src = unsafeAdd(src, 2)
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dst = unsafeAdd(dst, 1)
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} else {
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v1 := hexToInt[char(src, 2)]
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v2 := hexToInt[char(src, 3)]
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v3 := hexToInt[char(src, 4)]
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v4 := hexToInt[char(src, 5)]
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code := rune((v1 << 12) | (v2 << 8) | (v3 << 4) | v4)
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if code >= 0xd800 && code < 0xdc00 && uintptr(unsafeAdd(src, 11)) < uintptr(end) {
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if char(src, 6) == '\\' && char(src, 7) == 'u' {
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v1 := hexToInt[char(src, 8)]
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v2 := hexToInt[char(src, 9)]
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v3 := hexToInt[char(src, 10)]
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v4 := hexToInt[char(src, 11)]
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lo := rune((v1 << 12) | (v2 << 8) | (v3 << 4) | v4)
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if lo >= 0xdc00 && lo < 0xe000 {
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code = (code-0xd800)<<10 | (lo - 0xdc00) + 0x10000
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src = unsafeAdd(src, 6)
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}
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}
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}
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var b [utf8.UTFMax]byte
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n := utf8.EncodeRune(b[:], code)
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switch n {
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case 4:
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*(*byte)(unsafeAdd(dst, 3)) = b[3]
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fallthrough
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case 3:
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*(*byte)(unsafeAdd(dst, 2)) = b[2]
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fallthrough
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case 2:
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*(*byte)(unsafeAdd(dst, 1)) = b[1]
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fallthrough
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case 1:
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*(*byte)(unsafeAdd(dst, 0)) = b[0]
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}
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src = unsafeAdd(src, 6)
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dst = unsafeAdd(dst, n)
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}
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} else {
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*(*byte)(dst) = c
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src = unsafeAdd(src, 1)
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dst = unsafeAdd(dst, 1)
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}
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}
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return int(uintptr(dst) - uintptr(p))
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}
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