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166 lines
4.2 KiB
Go
166 lines
4.2 KiB
Go
// Copyright 2015 PingCAP, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package codec
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import (
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"time"
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"github.com/juju/errors"
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"github.com/pingcap/tidb/mysql"
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"github.com/pingcap/tidb/util/types"
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)
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const (
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nilFlag byte = iota
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bytesFlag
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compactBytesFlag
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intFlag
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uintFlag
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floatFlag
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decimalFlag
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durationFlag
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)
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func encode(b []byte, vals []types.Datum, comparable bool) ([]byte, error) {
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for _, val := range vals {
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switch val.Kind() {
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case types.KindInt64:
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b = append(b, intFlag)
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b = EncodeInt(b, val.GetInt64())
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case types.KindUint64:
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b = append(b, uintFlag)
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b = EncodeUint(b, val.GetUint64())
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case types.KindFloat32, types.KindFloat64:
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b = append(b, floatFlag)
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b = EncodeFloat(b, val.GetFloat64())
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case types.KindString, types.KindBytes:
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b = encodeBytes(b, val.GetBytes(), comparable)
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case types.KindMysqlTime:
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b = encodeBytes(b, []byte(val.GetMysqlTime().String()), comparable)
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case types.KindMysqlDuration:
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// duration may have negative value, so we cannot use String to encode directly.
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b = append(b, durationFlag)
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b = EncodeInt(b, int64(val.GetMysqlDuration().Duration))
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case types.KindMysqlDecimal:
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b = append(b, decimalFlag)
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b = EncodeDecimal(b, val.GetMysqlDecimal())
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case types.KindMysqlHex:
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b = append(b, intFlag)
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b = EncodeInt(b, int64(val.GetMysqlHex().ToNumber()))
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case types.KindMysqlBit:
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b = append(b, uintFlag)
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b = EncodeUint(b, uint64(val.GetMysqlBit().ToNumber()))
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case types.KindMysqlEnum:
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b = append(b, uintFlag)
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b = EncodeUint(b, uint64(val.GetMysqlEnum().ToNumber()))
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case types.KindMysqlSet:
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b = append(b, uintFlag)
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b = EncodeUint(b, uint64(val.GetMysqlSet().ToNumber()))
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case types.KindNull:
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b = append(b, nilFlag)
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default:
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return nil, errors.Errorf("unsupport encode type %d", val.Kind())
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}
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}
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return b, nil
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}
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func encodeBytes(b []byte, v []byte, comparable bool) []byte {
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if comparable {
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b = append(b, bytesFlag)
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b = EncodeBytes(b, v)
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} else {
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b = append(b, compactBytesFlag)
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b = EncodeCompactBytes(b, v)
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}
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return b
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}
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// EncodeKey appends the encoded values to byte slice b, returns the appended
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// slice. It guarantees the encoded value is in ascending order for comparison.
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func EncodeKey(b []byte, v ...types.Datum) ([]byte, error) {
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return encode(b, v, true)
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}
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// EncodeValue appends the encoded values to byte slice b, returning the appended
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// slice. It does not guarantee the order for comparison.
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func EncodeValue(b []byte, v ...types.Datum) ([]byte, error) {
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return encode(b, v, false)
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}
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// Decode decodes values from a byte slice generated with EncodeKey or EncodeValue
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// before.
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func Decode(b []byte) ([]types.Datum, error) {
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if len(b) < 1 {
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return nil, errors.New("invalid encoded key")
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}
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var (
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flag byte
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err error
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values = make([]types.Datum, 0, 1)
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)
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for len(b) > 0 {
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flag = b[0]
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b = b[1:]
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var d types.Datum
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switch flag {
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case intFlag:
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var v int64
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b, v, err = DecodeInt(b)
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d.SetInt64(v)
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case uintFlag:
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var v uint64
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b, v, err = DecodeUint(b)
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d.SetUint64(v)
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case floatFlag:
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var v float64
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b, v, err = DecodeFloat(b)
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d.SetFloat64(v)
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case bytesFlag:
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var v []byte
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b, v, err = DecodeBytes(b)
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d.SetBytes(v)
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case compactBytesFlag:
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var v []byte
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b, v, err = DecodeCompactBytes(b)
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d.SetBytes(v)
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case decimalFlag:
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var v mysql.Decimal
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b, v, err = DecodeDecimal(b)
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d.SetValue(v)
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case durationFlag:
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var r int64
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b, r, err = DecodeInt(b)
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if err == nil {
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// use max fsp, let outer to do round manually.
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v := mysql.Duration{Duration: time.Duration(r), Fsp: mysql.MaxFsp}
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d.SetValue(v)
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}
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case nilFlag:
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default:
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return nil, errors.Errorf("invalid encoded key flag %v", flag)
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}
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if err != nil {
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return nil, errors.Trace(err)
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}
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values = append(values, d)
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}
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return values, nil
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}
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