You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
192 lines
4.6 KiB
192 lines
4.6 KiB
// Copyright 2019 PingCAP, Inc.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package rowcodec
|
|
|
|
import (
|
|
"encoding/binary"
|
|
)
|
|
|
|
// row is the struct type used to access the a row.
|
|
type row struct {
|
|
// small: colID []byte, offsets []uint16, optimized for most cases.
|
|
// large: colID []uint32, offsets []uint32.
|
|
large bool
|
|
numNotNullCols uint16
|
|
numNullCols uint16
|
|
colIDs []byte
|
|
|
|
offsets []uint16
|
|
data []byte
|
|
|
|
// for large row
|
|
colIDs32 []uint32
|
|
offsets32 []uint32
|
|
}
|
|
|
|
func (r *row) getData(i int) []byte {
|
|
var start, end uint32
|
|
if r.large {
|
|
if i > 0 {
|
|
start = r.offsets32[i-1]
|
|
}
|
|
end = r.offsets32[i]
|
|
} else {
|
|
if i > 0 {
|
|
start = uint32(r.offsets[i-1])
|
|
}
|
|
end = uint32(r.offsets[i])
|
|
}
|
|
return r.data[start:end]
|
|
}
|
|
|
|
func (r *row) fromBytes(rowData []byte) error {
|
|
if rowData[0] != CodecVer {
|
|
return errInvalidCodecVer
|
|
}
|
|
r.large = rowData[1]&1 > 0
|
|
r.numNotNullCols = binary.LittleEndian.Uint16(rowData[2:])
|
|
r.numNullCols = binary.LittleEndian.Uint16(rowData[4:])
|
|
cursor := 6
|
|
if r.large {
|
|
colIDsLen := int(r.numNotNullCols+r.numNullCols) * 4
|
|
r.colIDs32 = bytesToU32Slice(rowData[cursor : cursor+colIDsLen])
|
|
cursor += colIDsLen
|
|
offsetsLen := int(r.numNotNullCols) * 4
|
|
r.offsets32 = bytesToU32Slice(rowData[cursor : cursor+offsetsLen])
|
|
cursor += offsetsLen
|
|
} else {
|
|
colIDsLen := int(r.numNotNullCols + r.numNullCols)
|
|
r.colIDs = rowData[cursor : cursor+colIDsLen]
|
|
cursor += colIDsLen
|
|
offsetsLen := int(r.numNotNullCols) * 2
|
|
r.offsets = bytes2U16Slice(rowData[cursor : cursor+offsetsLen])
|
|
cursor += offsetsLen
|
|
}
|
|
r.data = rowData[cursor:]
|
|
return nil
|
|
}
|
|
|
|
func (r *row) toBytes(buf []byte) []byte {
|
|
buf = append(buf, CodecVer)
|
|
flag := byte(0)
|
|
if r.large {
|
|
flag = 1
|
|
}
|
|
buf = append(buf, flag)
|
|
buf = append(buf, byte(r.numNotNullCols), byte(r.numNotNullCols>>8))
|
|
buf = append(buf, byte(r.numNullCols), byte(r.numNullCols>>8))
|
|
if r.large {
|
|
buf = append(buf, u32SliceToBytes(r.colIDs32)...)
|
|
buf = append(buf, u32SliceToBytes(r.offsets32)...)
|
|
} else {
|
|
buf = append(buf, r.colIDs...)
|
|
buf = append(buf, u16SliceToBytes(r.offsets)...)
|
|
}
|
|
buf = append(buf, r.data...)
|
|
return buf
|
|
}
|
|
|
|
func (r *row) findColID(colID int64) (idx int, isNil, notFound bool) {
|
|
// Search the column in not-null columns array.
|
|
i, j := 0, int(r.numNotNullCols)
|
|
for i < j {
|
|
h := int(uint(i+j) >> 1) // avoid overflow when computing h
|
|
// i ≤ h < j
|
|
var v int64
|
|
if r.large {
|
|
v = int64(r.colIDs32[h])
|
|
} else {
|
|
v = int64(r.colIDs[h])
|
|
}
|
|
if v < colID {
|
|
i = h + 1
|
|
} else if v > colID {
|
|
j = h
|
|
} else {
|
|
idx = h
|
|
return
|
|
}
|
|
}
|
|
|
|
// Search the column in null columns array.
|
|
i, j = int(r.numNotNullCols), int(r.numNotNullCols+r.numNullCols)
|
|
for i < j {
|
|
h := int(uint(i+j) >> 1) // avoid overflow when computing h
|
|
// i ≤ h < j
|
|
var v int64
|
|
if r.large {
|
|
v = int64(r.colIDs32[h])
|
|
} else {
|
|
v = int64(r.colIDs[h])
|
|
}
|
|
if v < colID {
|
|
i = h + 1
|
|
} else if v > colID {
|
|
j = h
|
|
} else {
|
|
isNil = true
|
|
return
|
|
}
|
|
}
|
|
notFound = true
|
|
return
|
|
}
|
|
|
|
// ColumnIsNull returns if the column value is null. Mainly used for count column aggregation.
|
|
// this method will used in unistore.
|
|
func (r *row) ColumnIsNull(rowData []byte, colID int64, defaultVal []byte) (bool, error) {
|
|
err := r.fromBytes(rowData)
|
|
if err != nil {
|
|
return false, err
|
|
}
|
|
_, isNil, notFound := r.findColID(colID)
|
|
if notFound {
|
|
return defaultVal == nil, nil
|
|
}
|
|
return isNil, nil
|
|
}
|
|
|
|
func (r *row) initColIDs() {
|
|
numCols := int(r.numNotNullCols + r.numNullCols)
|
|
if cap(r.colIDs) >= numCols {
|
|
r.colIDs = r.colIDs[:numCols]
|
|
} else {
|
|
r.colIDs = make([]byte, numCols)
|
|
}
|
|
}
|
|
|
|
func (r *row) initColIDs32() {
|
|
numCols := int(r.numNotNullCols + r.numNullCols)
|
|
if cap(r.colIDs32) >= numCols {
|
|
r.colIDs32 = r.colIDs32[:numCols]
|
|
} else {
|
|
r.colIDs32 = make([]uint32, numCols)
|
|
}
|
|
}
|
|
|
|
func (r *row) initOffsets() {
|
|
if cap(r.offsets) >= int(r.numNotNullCols) {
|
|
r.offsets = r.offsets[:r.numNotNullCols]
|
|
} else {
|
|
r.offsets = make([]uint16, r.numNotNullCols)
|
|
}
|
|
}
|
|
|
|
func (r *row) initOffsets32() {
|
|
if cap(r.offsets32) >= int(r.numNotNullCols) {
|
|
r.offsets32 = r.offsets32[:r.numNotNullCols]
|
|
} else {
|
|
r.offsets32 = make([]uint32, r.numNotNullCols)
|
|
}
|
|
}
|
|
|