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package filesys
import (
"bytes"
"io"
"math"
"github.com/chrislusf/seaweedfs/weed/glog"
)
type IntervalNode struct {
Data []byte
Offset int64
Size int64
Next *IntervalNode
}
type IntervalLinkedList struct {
Head *IntervalNode
Tail *IntervalNode
}
type ContinuousIntervals struct {
lists []*IntervalLinkedList
}
func (list *IntervalLinkedList) Offset() int64 {
return list.Head.Offset
}
func (list *IntervalLinkedList) Size() int64 {
return list.Tail.Offset + list.Tail.Size - list.Head.Offset
}
func (list *IntervalLinkedList) addNodeToTail(node *IntervalNode) {
glog.V(4).Infof("add to tail [%d,%d) + [%d,%d) => [%d,%d)", list.Head.Offset, list.Tail.Offset+list.Tail.Size, node.Offset, node.Offset+node.Size, list.Head.Offset, node.Offset+node.Size)
list.Tail.Next = node
list.Tail = node
}
func (list *IntervalLinkedList) addNodeToHead(node *IntervalNode) {
glog.V(4).Infof("add to head [%d,%d) + [%d,%d) => [%d,%d)", node.Offset, node.Offset+node.Size, list.Head.Offset, list.Tail.Offset+list.Tail.Size, node.Offset, list.Tail.Offset+list.Tail.Size)
node.Next = list.Head
list.Head = node
}
func (list *IntervalLinkedList) ReadData(buf []byte, start, stop int64) {
t := list.Head
for {
nodeStart, nodeStop := max(start, t.Offset), min(stop, t.Offset+t.Size)
if nodeStart < nodeStop {
// glog.V(0).Infof("copying start=%d stop=%d t=[%d,%d) t.data=%d => bufSize=%d nodeStart=%d, nodeStop=%d", start, stop, t.Offset, t.Offset+t.Size, len(t.Data), len(buf), nodeStart, nodeStop)
copy(buf[nodeStart-start:], t.Data[nodeStart-t.Offset:nodeStop-t.Offset])
}
if t.Next == nil {
break
}
t = t.Next
}
}
func (c *ContinuousIntervals) TotalSize() (total int64) {
for _, list := range c.lists {
total += list.Size()
}
return
}
func (c *ContinuousIntervals) AddInterval(data []byte, offset int64) {
// TODO AddInterval needs to handle all possible out of order writes
interval := &IntervalNode{Data: data, Offset: offset, Size: int64(len(data))}
var prevList, nextList *IntervalLinkedList
for _, list := range c.lists {
if list.Head.Offset == interval.Offset+interval.Size {
nextList = list
break
}
if list.Head.Offset < interval.Offset+interval.Size && interval.Offset+interval.Size <= list.Head.Offset+list.Size() {
glog.V(0).Infof("unexpected [%d,%d) overlaps [%d,%d)", interval.Offset, interval.Offset+interval.Size, list.Head.Offset, list.Head.Offset+list.Size())
break
}
}
for _, list := range c.lists {
if list.Head.Offset+list.Size() == offset {
list.addNodeToTail(interval)
prevList = list
break
}
if list.Head.Offset <= offset && offset < list.Head.Offset+list.Size() {
// the new interval overwrites the old tail
dataStartIndex := list.Tail.Offset + list.Tail.Size - offset
glog.V(4).Infof("overlap data new [0,%d) same=%v", dataStartIndex, bytes.Compare(interval.Data[0:dataStartIndex], list.Tail.Data[len(list.Tail.Data)-int(dataStartIndex):]))
list.Tail.Data = list.Tail.Data[:len(list.Tail.Data)-int(dataStartIndex)]
list.Tail.Size -= dataStartIndex
glog.V(4).Infof("overlapping append as [%d,%d) dataSize=%d", interval.Offset, interval.Offset+interval.Size, len(interval.Data))
list.addNodeToTail(interval)
prevList = list
break
}
}
if prevList != nil && nextList != nil {
glog.V(4).Infof("connecting [%d,%d) + [%d,%d) => [%d,%d)", prevList.Head.Offset, prevList.Tail.Offset+prevList.Tail.Size, nextList.Head.Offset, nextList.Tail.Offset+nextList.Tail.Size, prevList.Head.Offset, nextList.Tail.Offset+nextList.Tail.Size)
prevList.Tail.Next = nextList.Head
prevList.Tail = nextList.Tail
c.removeList(nextList)
} else if nextList != nil {
// add to head was not done when checking
nextList.addNodeToHead(interval)
}
if prevList == nil && nextList == nil {
c.lists = append(c.lists, &IntervalLinkedList{
Head: interval,
Tail: interval,
})
}
return
}
func (c *ContinuousIntervals) RemoveLargestIntervalLinkedList() *IntervalLinkedList {
var maxSize int64
maxIndex := -1
for k, list := range c.lists {
if maxSize <= list.Size() {
maxSize = list.Size()
maxIndex = k
}
}
if maxSize <= 0 {
return nil
}
t := c.lists[maxIndex]
c.lists = append(c.lists[0:maxIndex], c.lists[maxIndex+1:]...)
return t
}
func (c *ContinuousIntervals) removeList(target *IntervalLinkedList) {
index := -1
for k, list := range c.lists {
if list.Offset() == target.Offset() {
index = k
}
}
if index < 0 {
return
}
c.lists = append(c.lists[0:index], c.lists[index+1:]...)
}
func (c *ContinuousIntervals) ReadData(data []byte, startOffset int64) (offset int64, size int) {
var minOffset int64 = math.MaxInt64
var maxStop int64
for _, list := range c.lists {
start := max(startOffset, list.Offset())
stop := min(startOffset+int64(len(data)), list.Offset()+list.Size())
if start <= stop {
list.ReadData(data[start-startOffset:], start, stop)
minOffset = min(minOffset, start)
maxStop = max(maxStop, stop)
}
}
if minOffset == math.MaxInt64 {
return 0, 0
}
offset = minOffset
size = int(maxStop - offset)
return
}
func (l *IntervalLinkedList) ToReader() io.Reader {
var readers []io.Reader
t := l.Head
readers = append(readers, bytes.NewReader(t.Data))
for t.Next != nil {
t = t.Next
readers = append(readers, bytes.NewReader(t.Data))
}
return io.MultiReader(readers...)
}
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