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/
record.go
159 lines (131 loc) · 3.37 KB
/
record.go
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package bitbutt
import (
"encoding/binary"
"errors"
"hash/crc32"
"io"
"time"
)
const (
maxKeyLen = 1<<16 - 1
maxValueLen = 1<<32 - 2
tombStone = 1<<32 - 1
)
var (
errShortWrite = errors.New("short write")
)
type record struct {
key []byte
value []byte
ts time.Time
recordLen uint64
deleted bool
}
type hintRecord struct {
ts time.Time
recordSize uint64
recordPos int64
key []byte
}
func (r *record) Bytes() []byte {
buf := make([]byte, 4+4+2+4+len(r.key)+len(r.value))
binary.BigEndian.PutUint32(buf[4:8], uint32(r.ts.Unix()))
binary.BigEndian.PutUint16(buf[8:10], uint16(len(r.key)))
binary.BigEndian.PutUint32(buf[10:14], uint32(len(r.value)))
copy(buf[14:14+len(r.key)], r.key)
copy(buf[14+len(r.key):], r.value)
checksum := crc32.ChecksumIEEE(buf[4:])
binary.BigEndian.PutUint32(buf[0:4], checksum)
return buf
}
func getDeleteRecord(key []byte, ts time.Time) []byte {
buf := make([]byte, 4+4+2+4+len(key))
binary.BigEndian.PutUint32(buf[4:8], uint32(ts.Unix()))
binary.BigEndian.PutUint16(buf[8:10], uint16(len(key)))
binary.BigEndian.PutUint32(buf[10:14], uint32(tombStone))
copy(buf[14:], key)
checksum := crc32.ChecksumIEEE(buf[4:])
binary.BigEndian.PutUint32(buf[0:4], checksum)
return buf
}
func readRecord(r io.Reader) (*record, error) {
var (
crc uint32
ts int32
keyLen uint16
recordSize uint32
key, value []byte
deleted bool
)
var buf [14]byte
if _, err := io.ReadFull(r, buf[:]); err != nil {
return nil, err
}
crc = binary.BigEndian.Uint32(buf[0:4])
_ = crc // TODO: verify CRC.
ts = int32(binary.BigEndian.Uint32(buf[4:8]))
keyLen = binary.BigEndian.Uint16(buf[8:10])
recordSize = binary.BigEndian.Uint32(buf[10:14])
key = make([]byte, int(keyLen))
if _, err := io.ReadFull(r, key); err != nil {
return nil, err
}
if recordSize == tombStone {
deleted = true
} else {
value = make([]byte, int(recordSize))
if _, err := io.ReadFull(r, value); err != nil {
return nil, err
}
}
return &record{
key: key,
value: value,
ts: time.Unix(int64(ts), 0),
recordLen: uint64(14 + len(key) + len(value)),
deleted: deleted,
}, nil
}
func readHintRecord(r io.Reader) (*hintRecord, error) {
var (
ts int32
keyLen uint16
recordSize uint32
recordPos uint64
)
var buf [18]byte
if _, err := io.ReadFull(r, buf[:]); err != nil {
return nil, err
}
ts = int32(binary.BigEndian.Uint32(buf[0:4]))
keyLen = binary.BigEndian.Uint16(buf[4:6])
recordSize = binary.BigEndian.Uint32(buf[6:10])
recordPos = binary.BigEndian.Uint64(buf[10:18])
key := make([]byte, keyLen)
if _, err := io.ReadFull(r, key); err != nil {
return nil, err
}
return &hintRecord{
ts: time.Unix(int64(ts), 0),
recordSize: uint64(recordSize),
recordPos: int64(recordPos),
key: key,
}, nil
}
func (r *hintRecord) WriteTo(w io.Writer) (int64, error) {
recordSize := 4 + 2 + 4 + 8 + len(r.key)
buf := make([]byte, recordSize)
binary.BigEndian.PutUint32(buf[0:4], uint32(r.ts.Unix()))
binary.BigEndian.PutUint16(buf[4:6], uint16(len(r.key)))
binary.BigEndian.PutUint32(buf[6:10], uint32(r.recordSize))
binary.BigEndian.PutUint64(buf[10:18], uint64(r.recordPos))
copy(buf[18:], r.key)
n, err := w.Write(buf)
if err != nil {
return 0, err
}
if n != recordSize {
return int64(n), errShortWrite
}
return int64(len(buf)), nil
}