rename files

weed/filesys/page_writer/chunk_interval_list.go

@@ -0,0 +1,100 @@
+package page_writer
+
+import "math"
+
+// ChunkWrittenInterval mark one written interval within one page chunk
+type ChunkWrittenInterval struct {
+	startOffset int64
+	stopOffset  int64
+	prev        *ChunkWrittenInterval
+	next        *ChunkWrittenInterval
+}
+
+func (interval *ChunkWrittenInterval) Size() int64 {
+	return interval.stopOffset - interval.startOffset
+}
+
+// ChunkWrittenIntervalList mark written intervals within one page chunk
+type ChunkWrittenIntervalList struct {
+	head *ChunkWrittenInterval
+	tail *ChunkWrittenInterval
+}
+
+func newChunkWrittenIntervalList() *ChunkWrittenIntervalList {
+	list := &ChunkWrittenIntervalList{
+		head: &ChunkWrittenInterval{
+			startOffset: -1,
+			stopOffset:  -1,
+		},
+		tail: &ChunkWrittenInterval{
+			startOffset: math.MaxInt64,
+			stopOffset:  math.MaxInt64,
+		},
+	}
+	list.head.next = list.tail
+	list.tail.prev = list.head
+	return list
+}
+
+func (list *ChunkWrittenIntervalList) MarkWritten(startOffset, stopOffset int64) {
+	interval := &ChunkWrittenInterval{
+		startOffset: startOffset,
+		stopOffset:  stopOffset,
+	}
+	list.addInterval(interval)
+}
+func (list *ChunkWrittenIntervalList) addInterval(interval *ChunkWrittenInterval) {
+
+	p := list.head
+	for ; p.next != nil && p.next.startOffset <= interval.startOffset; p = p.next {
+	}
+	q := list.tail
+	for ; q.prev != nil && q.prev.stopOffset >= interval.stopOffset; q = q.prev {
+	}
+
+	if interval.startOffset <= p.stopOffset && q.startOffset <= interval.stopOffset {
+		// merge p and q together
+		p.stopOffset = q.stopOffset
+		unlinkNodesBetween(p, q.next)
+		return
+	}
+	if interval.startOffset <= p.stopOffset {
+		// merge new interval into p
+		p.stopOffset = interval.stopOffset
+		unlinkNodesBetween(p, q)
+		return
+	}
+	if q.startOffset <= interval.stopOffset {
+		// merge new interval into q
+		q.startOffset = interval.startOffset
+		unlinkNodesBetween(p, q)
+		return
+	}
+
+	// add the new interval between p and q
+	unlinkNodesBetween(p, q)
+	p.next = interval
+	interval.prev = p
+	q.prev = interval
+	interval.next = q
+
+}
+
+// unlinkNodesBetween remove all nodes after start and before stop, exclusive
+func unlinkNodesBetween(start *ChunkWrittenInterval, stop *ChunkWrittenInterval) {
+	if start.next == stop {
+		return
+	}
+	start.next.prev = nil
+	start.next = stop
+	stop.prev.next = nil
+	stop.prev = start
+}
+
+func (list *ChunkWrittenIntervalList) size() int {
+	var count int
+	for t := list.head; t != nil; t = t.next {
+		count++
+	}
+	return count - 2
+}