// DecodeRow decodes a byte slice into datums.
// Row layout: colID1, value1, colID2, value2, .....
func DecodeRow(b []byte, cols map[int64]*types.FieldType) (map[int64]types.Datum, error) {
if b == nil {
return nil, nil
}
if len(b) == 1 && b[0] == codec.NilFlag {
return nil, nil
}
row := make(map[int64]types.Datum, len(cols))
cnt := 0
var (
data []byte
err error
)
for len(b) > 0 {
// Get col id.
data, b, err = codec.CutOne(b)
if err != nil {
return nil, errors.Trace(err)
}
_, cid, err := codec.DecodeOne(data)
if err != nil {
return nil, errors.Trace(err)
}
// Get col value.
data, b, err = codec.CutOne(b)
if err != nil {
return nil, errors.Trace(err)
}
id := cid.GetInt64()
ft, ok := cols[id]
if ok {
_, v, err := codec.DecodeOne(data)
if err != nil {
return nil, errors.Trace(err)
}
v, err = Unflatten(v, ft, false)
if err != nil {
return nil, errors.Trace(err)
}
row[id] = v
cnt++
if cnt == len(cols) {
// Get enough data.
break
}
}
}
return row, nil
}
// CutRow cut encoded row into byte slices and return interested columns' byte slice.
// Row layout: colID1, value1, colID2, value2, .....
func CutRow(data []byte, cols map[int64]*types.FieldType) (map[int64][]byte, error) {
if data == nil {
return nil, nil
}
if len(data) == 1 && data[0] == codec.NilFlag {
return nil, nil
}
row := make(map[int64][]byte, len(cols))
cnt := 0
var (
b []byte
err error
)
for len(data) > 0 {
// Get col id.
b, data, err = codec.CutOne(data)
if err != nil {
return nil, errors.Trace(err)
}
_, cid, err := codec.DecodeOne(b)
if err != nil {
return nil, errors.Trace(err)
}
// Get col value.
b, data, err = codec.CutOne(data)
if err != nil {
return nil, errors.Trace(err)
}
id := cid.GetInt64()
_, ok := cols[id]
if ok {
row[id] = b
cnt++
if cnt == len(cols) {
break
}
}
}
return row, nil
}
// CutIndexKey cuts encoded index key into colIDs to bytes slices map.
// The returned value b is the remaining bytes of the key which would be empty if it is unique index or handle data
// if it is non-unique index.
func CutIndexKey(key kv.Key, colIDs []int64) (values map[int64][]byte, b []byte, err error) {
b = key[prefixLen+idLen:]
values = make(map[int64][]byte)
for _, id := range colIDs {
var val []byte
val, b, err = codec.CutOne(b)
if err != nil {
return nil, nil, errors.Trace(err)
}
values[id] = val
}
return
}