forked from mirror/ledisdb
366 lines
7.9 KiB
Go
366 lines
7.9 KiB
Go
package ledis
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import (
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"encoding/binary"
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"errors"
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"github.com/siddontang/ledisdb/leveldb"
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)
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const (
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OPand byte = iota + 1
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OPor
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OPxor
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OPnot
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)
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const (
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// byte
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segByteWidth uint32 = 9
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segByteSize uint32 = 1 << segByteWidth
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// bit
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segBitWidth uint32 = segByteWidth + 3
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segBitSize uint32 = segByteSize << 3
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minSeq uint32 = 0
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maxSeq uint32 = uint32((1 << 31) - 1)
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)
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var bitsInByte = [256]int32{0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8}
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var errBinKey = errors.New("invalid bin key")
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var errOffset = errors.New("invalid offset")
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func getBit(sz []byte, offset uint32) uint8 {
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index := offset >> 3
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if index >= uint32(len(sz)) {
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return 0 // error("overflow")
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}
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offset -= index << 3
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return sz[index] >> offset & 1
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}
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func setBit(sz []byte, offset uint32, val uint8) bool {
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if val != 1 && val != 0 {
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return false // error("invalid val")
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}
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index := offset >> 3
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if index >= uint32(len(sz)) {
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return false // error("overflow")
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}
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offset -= index << 3
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if sz[index]>>offset&1 != val {
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sz[index] ^= (1 << offset)
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}
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return true
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}
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func (db *DB) bEncodeMetaKey(key []byte) []byte {
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mk := make([]byte, len(key)+2)
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mk[0] = db.index
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mk[1] = binMetaType
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copy(mk, key)
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return mk
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}
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func (db *DB) bEncodeBinKey(key []byte, seq uint32) []byte {
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bk := make([]byte, len(key)+8)
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pos := 0
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bk[pos] = db.index
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pos++
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bk[pos] = binType
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pos++
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binary.BigEndian.PutUint16(bk[pos:], uint16(len(key)))
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pos += 2
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copy(bk[pos:], key)
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pos += len(key)
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binary.BigEndian.PutUint32(bk[pos:], seq)
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return bk
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}
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func (db *DB) bDecodeBinKey(bkey []byte) (key []byte, seq uint32, err error) {
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if len(bkey) < 8 || bkey[0] != db.index {
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err = errBinKey
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return
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}
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keyLen := binary.BigEndian.Uint16(bkey[2:4])
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if int(keyLen+8) != len(bkey) {
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err = errBinKey
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return
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}
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key = bkey[4 : 4+keyLen]
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seq = uint32(binary.BigEndian.Uint32(bkey[4+keyLen:]))
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return
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}
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func (db *DB) bCapByteSize(seq uint32, off uint32) uint32 {
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var offByteSize uint32 = (off >> 3) + 1
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if offByteSize > segByteSize {
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offByteSize = segByteSize
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}
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return seq<<segByteWidth + offByteSize
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}
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func (db *DB) bParseOffset(key []byte, offset int32) (seq uint32, off uint32, err error) {
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if offset < 0 {
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if tailSeq, tailOff, e := db.bGetMeta(key); e != nil {
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err = e
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return
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} else {
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offset += int32(tailSeq<<segBitWidth | tailOff)
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if offset < 0 {
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err = errOffset
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return
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}
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}
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}
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off = uint32(offset)
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seq = off >> segBitWidth
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off &= (segBitSize - 1)
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return
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}
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func (db *DB) bGetMeta(key []byte) (tailSeq uint32, tailOff uint32, err error) {
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var v []byte
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mk := db.bEncodeMetaKey(key)
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v, err = db.db.Get(mk)
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if err != nil {
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return
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}
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if v != nil {
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tailSeq = binary.LittleEndian.Uint32(v[0:4])
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tailOff = binary.LittleEndian.Uint32(v[4:8])
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}
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return
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}
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func (db *DB) bSetMeta(t *tx, key []byte, tailSeq uint32, tailOff uint32) {
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ek := db.bEncodeMetaKey(key)
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// todo ..
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// if size == 0 // headSeq == tailSeq
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// t.Delete(ek)
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buf := make([]byte, 8)
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binary.LittleEndian.PutUint32(buf[0:4], tailSeq)
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binary.LittleEndian.PutUint32(buf[4:8], tailOff)
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t.Put(ek, buf)
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return
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}
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func (db *DB) bUpdateMeta(t *tx, key []byte, seq uint32, off uint32) (tailSeq uint32, tailOff uint32, err error) {
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if tailSeq, tailOff, err = db.bGetMeta(key); err != nil {
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return
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}
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if seq > tailSeq || (seq == tailSeq && off > tailOff) {
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db.bSetMeta(t, key, seq, off)
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tailSeq = seq
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tailOff = off
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}
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return
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}
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// func (db *DB) bDelete(key []byte) int64 {
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// return 0
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// }
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func (db *DB) BGet(key []byte) (data []byte, err error) {
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if err = checkKeySize(key); err != nil {
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return
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}
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var tailSeq, tailOff uint32
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if tailSeq, tailOff, err = db.bGetMeta(key); err != nil {
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return
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}
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var capByteSize uint32 = db.bCapByteSize(tailSeq, tailOff)
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data = make([]byte, capByteSize, capByteSize)
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minKey := db.bEncodeBinKey(key, minSeq)
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maxKey := db.bEncodeBinKey(key, tailSeq)
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it := db.db.RangeLimitIterator(minKey, maxKey, leveldb.RangeClose, 0, -1)
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var seq, s, e uint32
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for ; it.Valid(); it.Next() {
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if _, seq, err = db.bDecodeBinKey(it.Key()); err != nil {
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data = nil
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break
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}
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s = seq << segByteWidth
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e = s + segByteSize
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if e > capByteSize {
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e = capByteSize
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}
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copy(data[s:e], it.Value())
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}
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it.Close()
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return
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}
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// func (db *DB) BDelete(key []byte) (int8, error) {
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// }
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func (db *DB) getSegment(key []byte, seq uint32) ([]byte, []byte, error) {
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bk := db.bEncodeBinKey(key, seq)
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segment, err := db.db.Get(bk)
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if err != nil {
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return bk, nil, err
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}
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return bk, segment, nil
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}
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func (db *DB) allocateSegment(key []byte, seq uint32) ([]byte, []byte, error) {
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bk, segment, err := db.getSegment(key, seq)
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if err == nil && segment == nil {
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segment = make([]byte, segByteSize, segByteSize) // can be optimize ?
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}
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return bk, segment, err
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}
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func (db *DB) BSetBit(key []byte, offset int32, val uint8) (ori uint8, err error) {
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if err = checkKeySize(key); err != nil {
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return
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}
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// todo : check offset
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var seq, off uint32
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if seq, off, err = db.bParseOffset(key, offset); err != nil {
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return 0, err
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}
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var bk, segment []byte
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if bk, segment, err = db.allocateSegment(key, seq); err != nil {
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return 0, err
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}
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if segment != nil {
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ori = getBit(segment, off)
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setBit(segment, off, val)
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t := db.binTx
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t.Lock()
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t.Put(bk, segment)
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if _, _, e := db.bUpdateMeta(t, key, seq, off); e != nil {
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err = e
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return
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}
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err = t.Commit()
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t.Unlock()
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}
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return
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}
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func (db *DB) BGetBit(key []byte, offset int32) (uint8, error) {
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if seq, off, err := db.bParseOffset(key, offset); err != nil {
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return 0, err
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} else {
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_, segment, err := db.getSegment(key, seq)
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if err != nil {
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return 0, err
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}
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if segment == nil {
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return 0, nil
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} else {
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return getBit(segment, off), nil
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}
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}
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}
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// func (db *DB) BGetRange(key []byte, start int32, end int32) ([]byte, error) {
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// section := make([]byte)
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// return
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// }
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func (db *DB) BCount(key []byte, start int32, end int32) (cnt int32, err error) {
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var sseq uint32
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if sseq, _, err = db.bParseOffset(key, start); err != nil {
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return
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}
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var eseq uint32
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if eseq, _, err = db.bParseOffset(key, end); err != nil {
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return
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}
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var segment []byte
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skey := db.bEncodeBinKey(key, sseq)
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ekey := db.bEncodeBinKey(key, eseq)
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it := db.db.RangeLimitIterator(skey, ekey, leveldb.RangeClose, 0, -1)
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for ; it.Valid(); it.Next() {
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segment = it.Value()
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for _, bit := range segment {
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cnt += bitsInByte[bit]
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}
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}
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it.Close()
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return
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}
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func (db *DB) BTail(key []byte) (uint32, error) {
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// effective length of data, the highest bit-pos set in history
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tailSeq, tailOff, err := db.bGetMeta(key)
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if err != nil {
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return 0, err
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}
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return tailSeq<<segBitWidth | tailOff, nil
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}
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// func (db *DB) BOperation(op byte, dstkey []byte, srckeys ...[]byte) (int32, error) {
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// // return :
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// // The size of the string stored in the destination key,
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// // that is equal to the size of the longest input string.
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// if op < OPand || op > OPnot {
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// return
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// }
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// }
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// func (db *DB) BExpire(key []byte, duration int64) (int64, error) {
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// }
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// func (db *DB) BExpireAt(key []byte, when int64) (int64, error) {
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// }
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// func (db *DB) BTTL(key []byte) (int64, error) {
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// }
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// func (db *DB) BScan(key []byte, count int, inclusive bool) ([]KVPair, error) {
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// }
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// func (db *DB) bFlush() (drop int64, err error) {
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// }
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