forked from mirror/ledisdb
333 lines
6.4 KiB
Go
333 lines
6.4 KiB
Go
// Copyright 2014 Wandoujia Inc. All Rights Reserved.
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// Licensed under the MIT (MIT-LICENSE.txt) license.
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package rdb
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import (
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"bytes"
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"encoding/binary"
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"fmt"
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"io"
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"math"
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"strconv"
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)
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const (
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Version = 6
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)
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const (
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rdbTypeString = 0
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rdbTypeList = 1
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rdbTypeSet = 2
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rdbTypeZSet = 3
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rdbTypeHash = 4
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rdbTypeHashZipmap = 9
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rdbTypeListZiplist = 10
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rdbTypeSetIntset = 11
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rdbTypeZSetZiplist = 12
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rdbTypeHashZiplist = 13
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rdbFlagExpiryMS = 0xfc
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rdbFlagExpiry = 0xfd
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rdbFlagSelectDB = 0xfe
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rdbFlagEOF = 0xff
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)
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const (
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rdb6bitLen = 0
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rdb14bitLen = 1
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rdb32bitLen = 2
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rdbEncVal = 3
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rdbEncInt8 = 0
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rdbEncInt16 = 1
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rdbEncInt32 = 2
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rdbEncLZF = 3
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rdbZiplist6bitlenString = 0
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rdbZiplist14bitlenString = 1
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rdbZiplist32bitlenString = 2
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rdbZiplistInt16 = 0xc0
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rdbZiplistInt32 = 0xd0
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rdbZiplistInt64 = 0xe0
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rdbZiplistInt24 = 0xf0
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rdbZiplistInt8 = 0xfe
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rdbZiplistInt4 = 15
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)
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type rdbReader struct {
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raw io.Reader
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buf [8]byte
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nread int64
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}
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func newRdbReader(r io.Reader) *rdbReader {
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return &rdbReader{raw: r}
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}
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func (r *rdbReader) Read(p []byte) (int, error) {
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n, err := r.raw.Read(p)
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r.nread += int64(n)
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return n, err
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}
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func (r *rdbReader) offset() int64 {
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return r.nread
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}
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func (r *rdbReader) readObject(otype byte) ([]byte, error) {
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var b bytes.Buffer
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r = newRdbReader(io.TeeReader(r, &b))
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switch otype {
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default:
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return nil, fmt.Errorf("unknown object-type %02x", otype)
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case rdbTypeHashZipmap:
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fallthrough
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case rdbTypeListZiplist:
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fallthrough
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case rdbTypeSetIntset:
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fallthrough
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case rdbTypeZSetZiplist:
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fallthrough
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case rdbTypeHashZiplist:
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fallthrough
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case rdbTypeString:
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if _, err := r.readString(); err != nil {
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return nil, err
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}
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case rdbTypeList, rdbTypeSet:
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if n, err := r.readLength(); err != nil {
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return nil, err
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} else {
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for i := 0; i < int(n); i++ {
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if _, err := r.readString(); err != nil {
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return nil, err
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}
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}
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}
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case rdbTypeZSet:
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if n, err := r.readLength(); err != nil {
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return nil, err
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} else {
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for i := 0; i < int(n); i++ {
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if _, err := r.readString(); err != nil {
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return nil, err
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}
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if _, err := r.readFloat(); err != nil {
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return nil, err
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}
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}
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}
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case rdbTypeHash:
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if n, err := r.readLength(); err != nil {
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return nil, err
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} else {
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for i := 0; i < int(n); i++ {
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if _, err := r.readString(); err != nil {
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return nil, err
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}
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if _, err := r.readString(); err != nil {
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return nil, err
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}
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}
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}
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}
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return b.Bytes(), nil
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}
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func (r *rdbReader) readString() ([]byte, error) {
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length, encoded, err := r.readEncodedLength()
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if err != nil {
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return nil, err
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}
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if !encoded {
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return r.readBytes(int(length))
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}
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switch t := uint8(length); t {
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default:
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return nil, fmt.Errorf("invalid encoded-string %02x", t)
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case rdbEncInt8:
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i, err := r.readInt8()
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return []byte(strconv.FormatInt(int64(i), 10)), err
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case rdbEncInt16:
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i, err := r.readInt16()
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return []byte(strconv.FormatInt(int64(i), 10)), err
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case rdbEncInt32:
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i, err := r.readInt32()
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return []byte(strconv.FormatInt(int64(i), 10)), err
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case rdbEncLZF:
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var inlen, outlen uint32
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if inlen, err = r.readLength(); err != nil {
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return nil, err
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}
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if outlen, err = r.readLength(); err != nil {
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return nil, err
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}
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if in, err := r.readBytes(int(inlen)); err != nil {
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return nil, err
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} else {
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return lzfDecompress(in, int(outlen))
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}
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}
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}
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func (r *rdbReader) readEncodedLength() (length uint32, encoded bool, err error) {
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var u uint8
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if u, err = r.readUint8(); err != nil {
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return
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}
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length = uint32(u & 0x3f)
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switch u >> 6 {
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case rdb6bitLen:
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case rdb14bitLen:
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u, err = r.readUint8()
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length = (length << 8) + uint32(u)
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case rdbEncVal:
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encoded = true
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default:
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length, err = r.readUint32BigEndian()
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}
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return
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}
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func (r *rdbReader) readLength() (uint32, error) {
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length, encoded, err := r.readEncodedLength()
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if err == nil && encoded {
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err = fmt.Errorf("encoded-length")
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}
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return length, err
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}
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func (r *rdbReader) readFloat() (float64, error) {
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u, err := r.readUint8()
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if err != nil {
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return 0, err
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}
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switch u {
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case 253:
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return math.NaN(), nil
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case 254:
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return math.Inf(0), nil
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case 255:
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return math.Inf(-1), nil
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default:
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if b, err := r.readBytes(int(u)); err != nil {
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return 0, err
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} else {
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v, err := strconv.ParseFloat(string(b), 64)
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return v, err
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}
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}
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}
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func (r *rdbReader) readByte() (byte, error) {
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b := r.buf[:1]
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_, err := r.Read(b)
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return b[0], err
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}
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func (r *rdbReader) readFull(p []byte) error {
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_, err := io.ReadFull(r, p)
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return err
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}
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func (r *rdbReader) readBytes(n int) ([]byte, error) {
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p := make([]byte, n)
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return p, r.readFull(p)
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}
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func (r *rdbReader) readUint8() (uint8, error) {
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b, err := r.readByte()
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return uint8(b), err
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}
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func (r *rdbReader) readUint16() (uint16, error) {
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b := r.buf[:2]
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err := r.readFull(b)
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return binary.LittleEndian.Uint16(b), err
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}
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func (r *rdbReader) readUint32() (uint32, error) {
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b := r.buf[:4]
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err := r.readFull(b)
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return binary.LittleEndian.Uint32(b), err
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}
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func (r *rdbReader) readUint64() (uint64, error) {
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b := r.buf[:8]
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err := r.readFull(b)
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return binary.LittleEndian.Uint64(b), err
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}
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func (r *rdbReader) readUint32BigEndian() (uint32, error) {
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b := r.buf[:4]
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err := r.readFull(b)
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return binary.BigEndian.Uint32(b), err
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}
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func (r *rdbReader) readInt8() (int8, error) {
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u, err := r.readUint8()
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return int8(u), err
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}
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func (r *rdbReader) readInt16() (int16, error) {
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u, err := r.readUint16()
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return int16(u), err
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}
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func (r *rdbReader) readInt32() (int32, error) {
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u, err := r.readUint32()
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return int32(u), err
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}
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func (r *rdbReader) readInt64() (int64, error) {
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u, err := r.readUint64()
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return int64(u), err
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}
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func (r *rdbReader) readInt32BigEndian() (int32, error) {
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u, err := r.readUint32BigEndian()
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return int32(u), err
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}
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func lzfDecompress(in []byte, outlen int) (out []byte, err error) {
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defer func() {
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if x := recover(); x != nil {
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err = fmt.Errorf("decompress exception: %v", x)
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}
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}()
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out = make([]byte, outlen)
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i, o := 0, 0
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for i < len(in) {
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ctrl := int(in[i])
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i++
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if ctrl < 32 {
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for x := 0; x <= ctrl; x++ {
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out[o] = in[i]
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i++
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o++
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}
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} else {
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length := ctrl >> 5
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if length == 7 {
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length = length + int(in[i])
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i++
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}
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ref := o - ((ctrl & 0x1f) << 8) - int(in[i]) - 1
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i++
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for x := 0; x <= length+1; x++ {
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out[o] = out[ref]
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ref++
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o++
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}
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}
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}
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if o != outlen {
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return nil, fmt.Errorf("decompress length is %d != expected %d", o, outlen)
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}
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return out, nil
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}
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