1 files changed, 194 insertions, 0 deletions
diff --git a/weed/storage/needle/compact_map.go b/weed/storage/needle/compact_map.go
new file mode 100644
index 000000000..ea2360fa7
--- /dev/null
+++ b/weed/storage/needle/compact_map.go
@@ -0,0 +1,194 @@
+package needle
+
+import (
+	"sync"
+)
+
+type CompactSection struct {
+	sync.RWMutex
+	values   []NeedleValue
+	overflow map[Key]NeedleValue
+	start    Key
+	end      Key
+	counter  int
+}
+
+func NewCompactSection(start Key) *CompactSection {
+	return &CompactSection{
+		values:   make([]NeedleValue, batch),
+		overflow: make(map[Key]NeedleValue),
+		start:    start,
+	}
+}
+
+//return old entry size
+func (cs *CompactSection) Set(key Key, offset, size uint32) (oldOffset, oldSize uint32) {
+	cs.Lock()
+	if key > cs.end {
+		cs.end = key
+	}
+	if i := cs.binarySearchValues(key); i >= 0 {
+		oldOffset, oldSize = cs.values[i].Offset, cs.values[i].Size
+		//println("key", key, "old size", ret)
+		cs.values[i].Offset, cs.values[i].Size = offset, size
+	} else {
+		needOverflow := cs.counter >= batch
+		needOverflow = needOverflow || cs.counter > 0 && cs.values[cs.counter-1].Key > key
+		if needOverflow {
+			//println("start", cs.start, "counter", cs.counter, "key", key)
+			if oldValue, found := cs.overflow[key]; found {
+				oldOffset, oldSize = oldValue.Offset, oldValue.Size
+			}
+			cs.overflow[key] = NeedleValue{Key: key, Offset: offset, Size: size}
+		} else {
+			p := &cs.values[cs.counter]
+			p.Key, p.Offset, p.Size = key, offset, size
+			//println("added index", cs.counter, "key", key, cs.values[cs.counter].Key)
+			cs.counter++
+		}
+	}
+	cs.Unlock()
+	return
+}
+
+//return old entry size
+func (cs *CompactSection) Delete(key Key) uint32 {
+	cs.Lock()
+	ret := uint32(0)
+	if i := cs.binarySearchValues(key); i >= 0 {
+		if cs.values[i].Size > 0 {
+			ret = cs.values[i].Size
+			cs.values[i].Size = 0
+		}
+	}
+	if v, found := cs.overflow[key]; found {
+		delete(cs.overflow, key)
+		ret = v.Size
+	}
+	cs.Unlock()
+	return ret
+}
+func (cs *CompactSection) Get(key Key) (*NeedleValue, bool) {
+	cs.RLock()
+	if v, ok := cs.overflow[key]; ok {
+		cs.RUnlock()
+		return &v, true
+	}
+	if i := cs.binarySearchValues(key); i >= 0 {
+		cs.RUnlock()
+		return &cs.values[i], true
+	}
+	cs.RUnlock()
+	return nil, false
+}
+func (cs *CompactSection) binarySearchValues(key Key) int {
+	l, h := 0, cs.counter-1
+	if h >= 0 && cs.values[h].Key < key {
+		return -2
+	}
+	//println("looking for key", key)
+	for l <= h {
+		m := (l + h) / 2
+		//println("mid", m, "key", cs.values[m].Key, cs.values[m].Offset, cs.values[m].Size)
+		if cs.values[m].Key < key {
+			l = m + 1
+		} else if key < cs.values[m].Key {
+			h = m - 1
+		} else {
+			//println("found", m)
+			return m
+		}
+	}
+	return -1
+}
+
+//This map assumes mostly inserting increasing keys
+//This map assumes mostly inserting increasing keys
+type CompactMap struct {
+	list []*CompactSection
+}
+
+func NewCompactMap() *CompactMap {
+	return &CompactMap{}
+}
+
+func (cm *CompactMap) Set(key Key, offset, size uint32) (oldOffset, oldSize uint32) {
+	x := cm.binarySearchCompactSection(key)
+	if x < 0 {
+		//println(x, "creating", len(cm.list), "section, starting", key)
+		cm.list = append(cm.list, NewCompactSection(key))
+		x = len(cm.list) - 1
+		//keep compact section sorted by start
+		for x > 0 {
+			if cm.list[x-1].start > cm.list[x].start {
+				cm.list[x-1], cm.list[x] = cm.list[x], cm.list[x-1]
+				x = x - 1
+			} else {
+				break
+			}
+		}
+	}
+	return cm.list[x].Set(key, offset, size)
+}
+func (cm *CompactMap) Delete(key Key) uint32 {
+	x := cm.binarySearchCompactSection(key)
+	if x < 0 {
+		return uint32(0)
+	}
+	return cm.list[x].Delete(key)
+}
+func (cm *CompactMap) Get(key Key) (*NeedleValue, bool) {
+	x := cm.binarySearchCompactSection(key)
+	if x < 0 {
+		return nil, false
+	}
+	return cm.list[x].Get(key)
+}
+func (cm *CompactMap) binarySearchCompactSection(key Key) int {
+	l, h := 0, len(cm.list)-1
+	if h < 0 {
+		return -5
+	}
+	if cm.list[h].start <= key {
+		if cm.list[h].counter < batch || key <= cm.list[h].end {
+			return h
+		}
+		return -4
+	}
+	for l <= h {
+		m := (l + h) / 2
+		if key < cm.list[m].start {
+			h = m - 1
+		} else { // cm.list[m].start <= key
+			if cm.list[m+1].start <= key {
+				l = m + 1
+			} else {
+				return m
+			}
+		}
+	}
+	return -3
+}
+
+// Visit visits all entries or stop if any error when visiting
+func (cm *CompactMap) Visit(visit func(NeedleValue) error) error {
+	for _, cs := range cm.list {
+		cs.RLock()
+		for _, v := range cs.overflow {
+			if err := visit(v); err != nil {
+				cs.RUnlock()
+				return err
+			}
+		}
+		for _, v := range cs.values {
+			if _, found := cs.overflow[v.Key]; !found {
+				if err := visit(v); err != nil {
+					cs.RUnlock()
+					return err
+				}
+			}
+		}
+		cs.RUnlock()
+	}
+	return nil
+}