add libraries module which includes asio, container,interprocess and …

…multiindex

Signed-off-by: yuanchao <541436194@qq.com>

libraries/container/redblacktree/iterator.go

@@ -0,0 +1,230 @@
+// Copyright (c) 2015, Emir Pasic. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package redblacktree
+
+// Iterator holding the iterator's state
+type Iterator struct {
+	tree     *Tree
+	node     *Node
+	position position
+}
+
+type position byte
+
+const (
+	begin, between, end position = 0, 1, 2
+)
+
+// Iterator returns a stateful iterator whose elements are key/value pairs.
+func (tree *Tree) Iterator() Iterator {
+	return Iterator{tree: tree, node: nil, position: begin}
+}
+
+func (tree *Tree) Begin() Iterator {
+	itr := Iterator{tree: tree, node: nil, position: begin}
+	itr.Next()
+	return itr
+}
+
+func (tree *Tree) End() Iterator {
+	return Iterator{tree: tree, node: nil, position: end}
+}
+
+// Next moves the iterator to the next element and returns true if there was a next element in the container.
+// If Next() returns true, then next element's key and value can be retrieved by Key() and Value().
+// If Next() was called for the first time, then it will point the iterator to the first element if it exists.
+// Modifies the state of the iterator.
+func (iterator *Iterator) Next() bool {
+	if iterator.position == end {
+		goto end
+	}
+	if iterator.position == begin {
+		left := iterator.tree.Left()
+		if left == nil {
+			goto end
+		}
+		iterator.node = left
+		goto between
+	}
+	if iterator.node.Right != nil {
+		iterator.node = iterator.node.Right
+		for iterator.node.Left != nil {
+			iterator.node = iterator.node.Left
+		}
+		goto between
+	}
+	if iterator.node.Parent != nil {
+		node := iterator.node
+		for iterator.node.Parent != nil {
+			iterator.node = iterator.node.Parent
+			if node == iterator.node.Left {
+				goto between
+			}
+			node = iterator.node
+			//if iterator.tree.Comparator(node.Key, iterator.node.Key) <= 0 {
+			//	goto between
+			//}
+		}
+	}
+
+end:
+	iterator.node = nil
+	iterator.position = end
+	return false
+
+between:
+	iterator.position = between
+	return true
+}
+
+// Prev moves the iterator to the previous element and returns true if there was a previous element in the container.
+// If Prev() returns true, then previous element's key and value can be retrieved by Key() and Value().
+// Modifies the state of the iterator.
+func (iterator *Iterator) Prev() bool {
+	if iterator.position == begin {
+		goto begin
+	}
+	if iterator.position == end {
+		right := iterator.tree.Right()
+		if right == nil {
+			goto begin
+		}
+		iterator.node = right
+		goto between
+	}
+	if iterator.node.Left != nil {
+		iterator.node = iterator.node.Left
+		for iterator.node.Right != nil {
+			iterator.node = iterator.node.Right
+		}
+		goto between
+	}
+	if iterator.node.Parent != nil {
+		node := iterator.node
+		for iterator.node.Parent != nil {
+			iterator.node = iterator.node.Parent
+			if node == iterator.node.Right {
+				goto between
+			}
+			node = iterator.node
+			//if iterator.tree.Comparator(node.Key, iterator.node.Key) >= 0 {
+			//	goto between
+			//}
+		}
+	}
+
+begin:
+	iterator.node = nil
+	iterator.position = begin
+	return false
+
+between:
+	iterator.position = between
+	return true
+}
+
+func (iterator *Iterator) HasNext() bool {
+	return iterator.position != end
+}
+
+func (iterator *Iterator) HasPrev() bool {
+	return iterator.position != begin
+}
+
+// Value returns the current element's value.
+// Does not modify the state of the iterator.
+func (iterator Iterator) Value() interface{} {
+	return iterator.node.Value
+}
+
+// Key returns the current element's key.
+// Does not modify the state of the iterator.
+func (iterator Iterator) Key() interface{} {
+	return iterator.node.Key
+}
+
+// Begin resets the iterator to its initial state (one-before-first)
+// Call Next() to fetch the first element if any.
+func (iterator *Iterator) Begin() {
+	iterator.node = nil
+	iterator.position = begin
+}
+
+func (iterator Iterator) IsBegin() bool {
+	return iterator.position == begin
+}
+
+// End moves the iterator past the last element (one-past-the-end).
+// Call Prev() to fetch the last element if any.
+func (iterator *Iterator) End() {
+	iterator.node = nil
+	iterator.position = end
+}
+
+func (iterator Iterator) IsEnd() bool {
+	return iterator.position == end
+}
+
+// First moves the iterator to the first element and returns true if there was a first element in the container.
+// If First() returns true, then first element's key and value can be retrieved by Key() and Value().
+// Modifies the state of the iterator
+func (iterator *Iterator) First() bool {
+	iterator.Begin()
+	return iterator.Next()
+}
+
+// Last moves the iterator to the last element and returns true if there was a last element in the container.
+// If Last() returns true, then last element's key and value can be retrieved by Key() and Value().
+// Modifies the state of the iterator.
+func (iterator *Iterator) Last() bool {
+	iterator.End()
+	return iterator.Prev()
+}
+
+// Delete remove the node which pointed by the iterator
+// Modifies the state of the iterator.
+//func (iterator *Iterator) Delete() {
+//	node := iterator.node
+//	//iterator.Prev()
+//	iterator.tree.remove(node)
+//}
+
+//func (iterator *Iterator) inPlace(key interface{}) bool {
+//	prev := *iterator
+//	next := *iterator
+//	prev.Prev()
+//	next.Next()
+//
+//	var (
+//		comparator = iterator.tree.Comparator
+//		prevResult int
+//		nextResult int
+//	)
+//
+//	if prev.IsBegin() {
+//		prevResult = 1
+//	} else {
+//		prevResult = comparator(key, prev.Key())
+//	}
+//
+//	if next.IsEnd() {
+//		nextResult = -1
+//	} else {
+//		nextResult = comparator(key, next.Key())
+//	}
+//
+//	return (iterator.tree.isMulti && prevResult >= 0 && nextResult <= 0) || (prevResult > 0 && nextResult < 0)
+//}
+//
+//func (iterator *Iterator) Modify(key interface{}, value interface{}) Iterator {
+//	if iterator.inPlace(key) {
+//		iterator.node.Key = key
+//		iterator.node.Value = value
+//		return *iterator
+//	}
+//
+//	iterator.Delete()
+//	return iterator.tree.Insert(key, value)
+//}