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354 lines
6.7 KiB
Go
354 lines
6.7 KiB
Go
package binary
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import (
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"fmt"
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"io"
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"strings"
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"go.mau.fi/whatsmeow/binary/token"
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"go.mau.fi/whatsmeow/types"
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)
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type binaryDecoder struct {
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data []byte
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index int
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}
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func newDecoder(data []byte) *binaryDecoder {
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return &binaryDecoder{data, 0}
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}
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func (r *binaryDecoder) checkEOS(length int) error {
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if r.index+length > len(r.data) {
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return io.EOF
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}
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return nil
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}
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func (r *binaryDecoder) readByte() (byte, error) {
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if err := r.checkEOS(1); err != nil {
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return 0, err
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}
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b := r.data[r.index]
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r.index++
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return b, nil
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}
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func (r *binaryDecoder) readIntN(n int, littleEndian bool) (int, error) {
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if err := r.checkEOS(n); err != nil {
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return 0, err
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}
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var ret int
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for i := 0; i < n; i++ {
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var curShift int
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if littleEndian {
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curShift = i
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} else {
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curShift = n - i - 1
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}
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ret |= int(r.data[r.index+i]) << uint(curShift*8)
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}
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r.index += n
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return ret, nil
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}
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func (r *binaryDecoder) readInt8(littleEndian bool) (int, error) {
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return r.readIntN(1, littleEndian)
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}
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func (r *binaryDecoder) readInt16(littleEndian bool) (int, error) {
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return r.readIntN(2, littleEndian)
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}
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func (r *binaryDecoder) readInt20() (int, error) {
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if err := r.checkEOS(3); err != nil {
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return 0, err
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}
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ret := ((int(r.data[r.index]) & 15) << 16) + (int(r.data[r.index+1]) << 8) + int(r.data[r.index+2])
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r.index += 3
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return ret, nil
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}
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func (r *binaryDecoder) readInt32(littleEndian bool) (int, error) {
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return r.readIntN(4, littleEndian)
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}
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func (r *binaryDecoder) readPacked8(tag int) (string, error) {
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startByte, err := r.readByte()
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if err != nil {
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return "", err
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}
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var build strings.Builder
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for i := 0; i < int(startByte&127); i++ {
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currByte, err := r.readByte()
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if err != nil {
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return "", err
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}
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lower, err := unpackByte(tag, currByte&0xF0>>4)
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if err != nil {
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return "", err
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}
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upper, err := unpackByte(tag, currByte&0x0F)
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if err != nil {
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return "", err
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}
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build.WriteByte(lower)
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build.WriteByte(upper)
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}
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ret := build.String()
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if startByte>>7 != 0 {
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ret = ret[:len(ret)-1]
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}
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return ret, nil
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}
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func unpackByte(tag int, value byte) (byte, error) {
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switch tag {
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case token.Nibble8:
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return unpackNibble(value)
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case token.Hex8:
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return unpackHex(value)
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default:
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return 0, fmt.Errorf("unpackByte with unknown tag %d", tag)
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}
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}
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func unpackNibble(value byte) (byte, error) {
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switch {
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case value < 10:
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return '0' + value, nil
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case value == 10:
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return '-', nil
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case value == 11:
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return '.', nil
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case value == 15:
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return 0, nil
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default:
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return 0, fmt.Errorf("unpackNibble with value %d", value)
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}
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}
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func unpackHex(value byte) (byte, error) {
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switch {
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case value < 10:
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return '0' + value, nil
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case value < 16:
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return 'A' + value - 10, nil
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default:
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return 0, fmt.Errorf("unpackHex with value %d", value)
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}
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}
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func (r *binaryDecoder) readListSize(tag int) (int, error) {
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switch tag {
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case token.ListEmpty:
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return 0, nil
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case token.List8:
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return r.readInt8(false)
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case token.List16:
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return r.readInt16(false)
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default:
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return 0, fmt.Errorf("readListSize with unknown tag %d at position %d", tag, r.index)
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}
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}
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func (r *binaryDecoder) read(string bool) (interface{}, error) {
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tagByte, err := r.readByte()
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if err != nil {
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return nil, err
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}
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tag := int(tagByte)
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switch tag {
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case token.ListEmpty:
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return nil, nil
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case token.List8, token.List16:
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return r.readList(tag)
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case token.Binary8:
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size, err := r.readInt8(false)
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if err != nil {
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return nil, err
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}
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return r.readBytesOrString(size, string)
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case token.Binary20:
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size, err := r.readInt20()
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if err != nil {
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return nil, err
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}
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return r.readBytesOrString(size, string)
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case token.Binary32:
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size, err := r.readInt32(false)
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if err != nil {
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return nil, err
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}
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return r.readBytesOrString(size, string)
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case token.Dictionary0, token.Dictionary1, token.Dictionary2, token.Dictionary3:
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i, err := r.readInt8(false)
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if err != nil {
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return "", err
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}
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return token.GetDoubleToken(tag-token.Dictionary0, i)
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case token.JIDPair:
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return r.readJIDPair()
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case token.ADJID:
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return r.readADJID()
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case token.Nibble8, token.Hex8:
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return r.readPacked8(tag)
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default:
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if tag >= 1 && tag < len(token.SingleByteTokens) {
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return token.SingleByteTokens[tag], nil
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}
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return "", fmt.Errorf("%w %d at position %d", ErrInvalidToken, tag, r.index)
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}
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}
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func (r *binaryDecoder) readJIDPair() (interface{}, error) {
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user, err := r.read(true)
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if err != nil {
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return nil, err
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}
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server, err := r.read(true)
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if err != nil {
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return nil, err
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} else if server == nil {
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return nil, ErrInvalidJIDType
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} else if user == nil {
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return types.NewJID("", server.(string)), nil
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}
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return types.NewJID(user.(string), server.(string)), nil
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}
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func (r *binaryDecoder) readADJID() (interface{}, error) {
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agent, err := r.readByte()
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if err != nil {
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return nil, err
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}
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device, err := r.readByte()
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if err != nil {
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return nil, err
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}
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user, err := r.read(true)
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if err != nil {
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return nil, err
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}
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return types.NewADJID(user.(string), agent, device), nil
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}
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func (r *binaryDecoder) readAttributes(n int) (Attrs, error) {
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if n == 0 {
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return nil, nil
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}
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ret := make(Attrs)
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for i := 0; i < n; i++ {
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keyIfc, err := r.read(true)
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if err != nil {
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return nil, err
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}
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key, ok := keyIfc.(string)
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if !ok {
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return nil, fmt.Errorf("%[1]w at position %[3]d (%[2]T): %+[2]v", ErrNonStringKey, key, r.index)
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}
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ret[key], err = r.read(true)
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if err != nil {
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return nil, err
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}
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}
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return ret, nil
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}
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func (r *binaryDecoder) readList(tag int) ([]Node, error) {
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size, err := r.readListSize(tag)
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if err != nil {
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return nil, err
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}
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ret := make([]Node, size)
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for i := 0; i < size; i++ {
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n, err := r.readNode()
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if err != nil {
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return nil, err
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}
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ret[i] = *n
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}
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return ret, nil
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}
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func (r *binaryDecoder) readNode() (*Node, error) {
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ret := &Node{}
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size, err := r.readInt8(false)
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if err != nil {
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return nil, err
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}
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listSize, err := r.readListSize(size)
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if err != nil {
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return nil, err
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}
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rawDesc, err := r.read(true)
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if err != nil {
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return nil, err
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}
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ret.Tag = rawDesc.(string)
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if listSize == 0 || ret.Tag == "" {
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return nil, ErrInvalidNode
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}
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ret.Attrs, err = r.readAttributes((listSize - 1) >> 1)
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if err != nil {
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return nil, err
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}
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if listSize%2 == 1 {
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return ret, nil
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}
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ret.Content, err = r.read(false)
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return ret, err
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}
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func (r *binaryDecoder) readBytesOrString(length int, asString bool) (interface{}, error) {
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data, err := r.readRaw(length)
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if err != nil {
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return nil, err
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}
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if asString {
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return string(data), nil
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}
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return data, nil
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}
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func (r *binaryDecoder) readRaw(length int) ([]byte, error) {
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if err := r.checkEOS(length); err != nil {
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return nil, err
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}
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ret := r.data[r.index : r.index+length]
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r.index += length
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return ret, nil
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}
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