mirror of
https://github.com/astaxie/beego.git
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335 lines
5.6 KiB
Go
335 lines
5.6 KiB
Go
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package store
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import (
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"bytes"
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"github.com/siddontang/ledisdb/store/driver"
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)
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const (
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IteratorForward uint8 = 0
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IteratorBackward uint8 = 1
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)
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const (
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RangeClose uint8 = 0x00
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RangeLOpen uint8 = 0x01
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RangeROpen uint8 = 0x10
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RangeOpen uint8 = 0x11
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)
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// min must less or equal than max
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//
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// range type:
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//
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// close: [min, max]
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// open: (min, max)
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// lopen: (min, max]
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// ropen: [min, max)
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//
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type Range struct {
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Min []byte
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Max []byte
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Type uint8
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}
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type Limit struct {
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Offset int
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Count int
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}
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type Iterator struct {
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it driver.IIterator
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st *Stat
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}
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// Returns a copy of key.
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func (it *Iterator) Key() []byte {
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k := it.it.Key()
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if k == nil {
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return nil
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}
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return append([]byte{}, k...)
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}
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// Returns a copy of value.
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func (it *Iterator) Value() []byte {
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v := it.it.Value()
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if v == nil {
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return nil
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}
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return append([]byte{}, v...)
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}
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// Returns a reference of key.
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// you must be careful that it will be changed after next iterate.
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func (it *Iterator) RawKey() []byte {
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return it.it.Key()
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}
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// Returns a reference of value.
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// you must be careful that it will be changed after next iterate.
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func (it *Iterator) RawValue() []byte {
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return it.it.Value()
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}
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// Copy key to b, if b len is small or nil, returns a new one.
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func (it *Iterator) BufKey(b []byte) []byte {
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k := it.RawKey()
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if k == nil {
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return nil
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}
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if b == nil {
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b = []byte{}
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}
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b = b[0:0]
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return append(b, k...)
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}
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// Copy value to b, if b len is small or nil, returns a new one.
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func (it *Iterator) BufValue(b []byte) []byte {
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v := it.RawValue()
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if v == nil {
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return nil
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}
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if b == nil {
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b = []byte{}
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}
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b = b[0:0]
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return append(b, v...)
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}
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func (it *Iterator) Close() {
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if it.it != nil {
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it.st.IterCloseNum.Add(1)
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it.it.Close()
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it.it = nil
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}
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}
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func (it *Iterator) Valid() bool {
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return it.it.Valid()
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}
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func (it *Iterator) Next() {
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it.st.IterSeekNum.Add(1)
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it.it.Next()
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}
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func (it *Iterator) Prev() {
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it.st.IterSeekNum.Add(1)
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it.it.Prev()
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}
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func (it *Iterator) SeekToFirst() {
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it.st.IterSeekNum.Add(1)
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it.it.First()
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}
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func (it *Iterator) SeekToLast() {
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it.st.IterSeekNum.Add(1)
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it.it.Last()
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}
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func (it *Iterator) Seek(key []byte) {
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it.st.IterSeekNum.Add(1)
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it.it.Seek(key)
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}
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// Finds by key, if not found, nil returns.
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func (it *Iterator) Find(key []byte) []byte {
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it.Seek(key)
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if it.Valid() {
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k := it.RawKey()
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if k == nil {
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return nil
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} else if bytes.Equal(k, key) {
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return it.Value()
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}
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}
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return nil
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}
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// Finds by key, if not found, nil returns, else a reference of value returns.
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// you must be careful that it will be changed after next iterate.
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func (it *Iterator) RawFind(key []byte) []byte {
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it.Seek(key)
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if it.Valid() {
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k := it.RawKey()
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if k == nil {
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return nil
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} else if bytes.Equal(k, key) {
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return it.RawValue()
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}
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}
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return nil
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}
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type RangeLimitIterator struct {
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it *Iterator
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r *Range
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l *Limit
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step int
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//0 for IteratorForward, 1 for IteratorBackward
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direction uint8
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}
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func (it *RangeLimitIterator) Key() []byte {
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return it.it.Key()
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}
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func (it *RangeLimitIterator) Value() []byte {
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return it.it.Value()
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}
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func (it *RangeLimitIterator) RawKey() []byte {
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return it.it.RawKey()
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}
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func (it *RangeLimitIterator) RawValue() []byte {
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return it.it.RawValue()
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}
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func (it *RangeLimitIterator) BufKey(b []byte) []byte {
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return it.it.BufKey(b)
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}
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func (it *RangeLimitIterator) BufValue(b []byte) []byte {
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return it.it.BufValue(b)
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}
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func (it *RangeLimitIterator) Valid() bool {
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if it.l.Offset < 0 {
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return false
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} else if !it.it.Valid() {
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return false
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} else if it.l.Count >= 0 && it.step >= it.l.Count {
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return false
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}
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if it.direction == IteratorForward {
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if it.r.Max != nil {
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r := bytes.Compare(it.it.RawKey(), it.r.Max)
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if it.r.Type&RangeROpen > 0 {
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return !(r >= 0)
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} else {
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return !(r > 0)
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}
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}
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} else {
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if it.r.Min != nil {
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r := bytes.Compare(it.it.RawKey(), it.r.Min)
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if it.r.Type&RangeLOpen > 0 {
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return !(r <= 0)
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} else {
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return !(r < 0)
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}
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}
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}
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return true
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}
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func (it *RangeLimitIterator) Next() {
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it.step++
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if it.direction == IteratorForward {
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it.it.Next()
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} else {
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it.it.Prev()
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}
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}
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func (it *RangeLimitIterator) Close() {
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it.it.Close()
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}
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func NewRangeLimitIterator(i *Iterator, r *Range, l *Limit) *RangeLimitIterator {
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return rangeLimitIterator(i, r, l, IteratorForward)
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}
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func NewRevRangeLimitIterator(i *Iterator, r *Range, l *Limit) *RangeLimitIterator {
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return rangeLimitIterator(i, r, l, IteratorBackward)
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}
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func NewRangeIterator(i *Iterator, r *Range) *RangeLimitIterator {
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return rangeLimitIterator(i, r, &Limit{0, -1}, IteratorForward)
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}
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func NewRevRangeIterator(i *Iterator, r *Range) *RangeLimitIterator {
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return rangeLimitIterator(i, r, &Limit{0, -1}, IteratorBackward)
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}
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func rangeLimitIterator(i *Iterator, r *Range, l *Limit, direction uint8) *RangeLimitIterator {
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it := new(RangeLimitIterator)
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it.it = i
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it.r = r
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it.l = l
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it.direction = direction
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it.step = 0
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if l.Offset < 0 {
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return it
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}
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if direction == IteratorForward {
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if r.Min == nil {
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it.it.SeekToFirst()
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} else {
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it.it.Seek(r.Min)
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if r.Type&RangeLOpen > 0 {
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if it.it.Valid() && bytes.Equal(it.it.RawKey(), r.Min) {
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it.it.Next()
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}
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}
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}
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} else {
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if r.Max == nil {
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it.it.SeekToLast()
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} else {
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it.it.Seek(r.Max)
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if !it.it.Valid() {
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it.it.SeekToLast()
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} else {
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if !bytes.Equal(it.it.RawKey(), r.Max) {
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it.it.Prev()
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}
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}
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if r.Type&RangeROpen > 0 {
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if it.it.Valid() && bytes.Equal(it.it.RawKey(), r.Max) {
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it.it.Prev()
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}
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}
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}
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}
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for i := 0; i < l.Offset; i++ {
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if it.it.Valid() {
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if it.direction == IteratorForward {
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it.it.Next()
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} else {
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it.it.Prev()
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}
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}
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}
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return it
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}
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