/// <summary>
/// Fill the char pointer's content into a given area node
/// Be caution to make sure tail-recurse optimization is implementation
/// Can C# do it for us?
/// </summary>
/// <param name="ptr"></param>
/// <param name="node"></param>
private unsafe static void Node_Fill(char *ptr, AreaNode node)
{
char c = *ptr;
if (c == '省' || c == '市' || c == '县' || c == '\0')
{
return;
}
if (node.Areas.ContainsKey(c))
{
Node_Fill(++ptr, node.Areas[c]);
}
else
{
var subNode = new AreaNode();
node.Areas[c] = subNode;
Node_Fill(++ptr, subNode);
}
}
public unsafe static AreaNode AreaTree_Load(string path)
{
var root = new AreaNode();
if (!File.Exists(path))
{
return(root);
}
var strings = File.ReadAllLines(path);
foreach (var str in strings)
{
if (string.IsNullOrWhiteSpace(str))
continue;
fixed(char *ptr = str)
{
Node_Fill(ptr, root);
}
}
return(root);
}