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iterator.go
136 lines (123 loc) · 2.04 KB
/
iterator.go
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package sst
import (
"encoding/binary"
"errors"
)
type Iterator interface {
Next() bool
Key() []byte
Value() []byte
Close() error
}
type iterator struct {
data []byte
key, val []byte
err error
soi, eoi bool
}
type tableIterator struct {
reader *Reader
data *iterator
index *iterator
err error
}
func (i *iterator) Next() bool {
if i.eoi || i.err != nil {
return false
}
if i.soi {
i.soi = false
return true
}
if len(i.data) == 0 {
i.Close()
return false
}
v0, n0 := binary.Uvarint(i.data)
v1, n1 := binary.Uvarint(i.data[n0:])
v2, n2 := binary.Uvarint(i.data[n0+n1:])
n := n0 + n1 + n2
i.key = append(i.key[:v0], i.data[n:n+int(v1)]...)
i.val = i.data[n+int(v1) : n+int(v1+v2)]
i.data = i.data[n+int(v1+v2):]
return true
}
func (i *iterator) Key() []byte {
if i.soi {
return nil
}
return i.key[:]
}
func (i *iterator) Value() []byte {
if i.soi {
return nil
}
return i.val[:]
}
func (i *iterator) Close() error {
i.key = nil
i.val = nil
i.eoi = true
return i.err
}
func (i *tableIterator) nextBlock(key []byte) bool {
if !i.index.Next() {
i.err = i.index.err
return false
}
// Load the next block.
v := i.index.Value()
h, n := decodeBlockHandle(v)
if n == 0 || n != len(v) {
i.err = errors.New("leveldb/table: corrupt index entry")
return false
}
k, err := i.reader.readBlock(h)
if err != nil {
i.err = err
return false
}
// Look for the key inside that block.
data, err := seek(k, key)
if err != nil {
i.err = err
return false
}
i.data = data
return true
}
func (i *tableIterator) Next() bool {
if i.data == nil {
return false
}
for {
if i.data.Next() {
return true
}
if i.data.err != nil {
i.err = i.data.err
break
}
if !i.nextBlock(nil) {
break
}
}
i.Close()
return false
}
func (i *tableIterator) Key() []byte {
if i.data == nil {
return nil
}
return i.data.Key()
}
func (i *tableIterator) Value() []byte {
if i.data == nil {
return nil
}
return i.data.Value()
}
func (i *tableIterator) Close() error {
i.data = nil
return i.err
}