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package filesys
import (
"bytes"
"io"
"github.com/chrislusf/seaweedfs/weed/util"
)
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) {
// log.Tracef("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) {
// log.Tracef("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 {
// log.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 subList(list *IntervalLinkedList, start, stop int64) *IntervalLinkedList {
var nodes []*IntervalNode
for t := list.Head; t != nil; t = t.Next {
nodeStart, nodeStop := max(start, t.Offset), min(stop, t.Offset+t.Size)
if nodeStart >= nodeStop {
// skip non overlapping IntervalNode
continue
}
nodes = append(nodes, &IntervalNode{
Data: t.Data[nodeStart-t.Offset : nodeStop-t.Offset],
Offset: nodeStart,
Size: nodeStop - nodeStart,
Next: nil,
})
}
for i := 1; i < len(nodes); i++ {
nodes[i-1].Next = nodes[i]
}
return &IntervalLinkedList{
Head: nodes[0],
Tail: nodes[len(nodes)-1],
}
}
func (c *ContinuousIntervals) AddInterval(data []byte, offset int64) {
interval := &IntervalNode{Data: data, Offset: offset, Size: int64(len(data))}
// append to the tail and return
if len(c.lists) == 1 {
lastSpan := c.lists[0]
if lastSpan.Tail.Offset+lastSpan.Tail.Size == offset {
lastSpan.addNodeToTail(interval)
return
}
}
var newLists []*IntervalLinkedList
for _, list := range c.lists {
// if list is to the left of new interval, add to the new list
if list.Tail.Offset+list.Tail.Size <= interval.Offset {
newLists = append(newLists, list)
}
// if list is to the right of new interval, add to the new list
if interval.Offset+interval.Size <= list.Head.Offset {
newLists = append(newLists, list)
}
// if new interval overwrite the right part of the list
if list.Head.Offset < interval.Offset && interval.Offset < list.Tail.Offset+list.Tail.Size {
// create a new list of the left part of existing list
newLists = append(newLists, subList(list, list.Offset(), interval.Offset))
}
// if new interval overwrite the left part of the list
if list.Head.Offset < interval.Offset+interval.Size && interval.Offset+interval.Size < list.Tail.Offset+list.Tail.Size {
// create a new list of the right part of existing list
newLists = append(newLists, subList(list, interval.Offset+interval.Size, list.Tail.Offset+list.Tail.Size))
}
// skip anything that is fully overwritten by the new interval
}
c.lists = newLists
// add the new interval to the lists, connecting neighbor lists
var prevList, nextList *IntervalLinkedList
for _, list := range c.lists {
if list.Head.Offset == interval.Offset+interval.Size {
nextList = list
break
}
}
for _, list := range c.lists {
if list.Head.Offset+list.Size() == offset {
list.addNodeToTail(interval)
prevList = list
break
}
}
if prevList != nil && nextList != nil {
// log.Tracef("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) ReadDataAt(data []byte, startOffset int64) (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)
maxStop = max(maxStop, stop)
}
}
return
}
func (l *IntervalLinkedList) ToReader() io.Reader {
var readers []io.Reader
t := l.Head
readers = append(readers, util.NewBytesReader(t.Data))
for t.Next != nil {
t = t.Next
readers = append(readers, bytes.NewReader(t.Data))
}
if len(readers) == 1 {
return readers[0]
}
return io.MultiReader(readers...)
}
|
