cocos2d 源码分析----Node子节点查找
为了加快根据字符串查找子节点的速度,node 在增加子节点时,将代表子节点的字符串进行散列运算,并保存其散列值,当根据字符串查找子节点时,先运算字符串的散列值,然后比对该 node 下所有子节点的 散列值,有效避免了,每次去比对字符串,提高效率,很巧妙。
void Node::setName(const std::string& name) { _name = name; std::hash<std::string> h; _hashOfName = h(name); } Node* Node::getChildByName(const std::string& name) const { CCASSERT(!name.empty(), "Invalid name"); std::hash<std::string> h; size_t hash = h(name); for (const auto& child : _children) { // Different strings may have the same hash code, but can use it to compare first for speed if(child->_hashOfName == hash && child->_name.compare(name) == 0) return child; } return nullptr; }