/// <summary>
/// Serialize linked list and write to file stream.
/// </summary>
/// <param name="fs">File stream for writing serialized list</param>
/// <param name="list">Linked list to serialize</param>
public static void Serialize(FileStream fs, ListRand list)
{
Dictionary <ListNode, int> nodeToIndex = GetNodeToIndex(list);
string listJson = GetListJson(list, nodeToIndex);
byte[] bytes = new UTF8Encoding(true).GetBytes(listJson);
fs.Write(bytes, 0, bytes.Length);
}
/// <summary>
/// Restore linked list fields and node references.
/// </summary>
/// <param name="list">Linked list to restore</param>
/// <param name="nodeInfos">List of NodeInfo with nodes and their field values</param>
private static void FillList(ListRand list, List <NodeInfo> nodeInfos)
{
if (nodeInfos.Count <= 0)
{
return;
}
ConnectNodes(nodeInfos);
list.Head = nodeInfos.First().Node;
list.Tail = nodeInfos.Last().Node;
list.Count = nodeInfos.Count;
}
/// <summary>
/// Create a dictionary where each node is paired with it's index, if it was a simple array.
/// Stop creating dictionary when next node is null or hit cycle.
/// </summary>
/// <param name="list">Linked list</param>
/// <returns>Dictionary with nodes paired with their indexes</returns>
private static Dictionary <ListNode, int> GetNodeToIndex(ListRand list)
{
Dictionary <ListNode, int> nodeToIndex = new Dictionary <ListNode, int>();
ListNode node = list.Head;
int index = 0;
while (node != null && !nodeToIndex.ContainsKey(node))
{
nodeToIndex.Add(node, index++);
node = node.Next;
}
return(nodeToIndex);
}
/// <summary>
/// Deserialize linked list from file stream.
/// </summary>
/// <param name="fs">File stream to read from</param>
/// <param name="list">List to deserialize to</param>
/// <exception cref="UnexpectedEndException">Thrown when reach end of stream before finished deserializing</exception>
/// <exception cref="UnexpectedCharException">Thrown when found unexpected char</exception>
public static void Deserialize(FileStream fs, ListRand list)
{
CheckStreamBeginning(fs);
List <NodeInfo> nodeInfos = new List <NodeInfo>();
bool readNode = false;
while (true)
{
int b = fs.ReadByte();
if (b == '{' && !readNode)
{
readNode = true;
nodeInfos.Add(DeserializeNode(fs));
}
else if (b == ',' && readNode)
{
readNode = false;
}
else if (b == -1)
{
throw new UnexpectedEndException();
}
else if (b == ']')
{
break;
}
else
{
throw new UnexpectedCharException((char)b);
}
}
FillList(list, nodeInfos);
}
/// <summary>
/// Write list with all nodes to string in json format.
/// Stop writing json when next node is null or hit cycle.
/// </summary>
/// <param name="list">List to write to json</param>
/// <param name="nodeToIndex">Dictionary with nodes paired with their indexes</param>
/// <returns>List in json format</returns>
private static string GetListJson(ListRand list, Dictionary <ListNode, int> nodeToIndex)
{
StringBuilder sb = new StringBuilder();
sb.Append("[");
HashSet <ListNode> visitedNodes = new HashSet <ListNode>();
ListNode node = list.Head;
while (node != null)
{
visitedNodes.Add(node);
WriteNode(node, sb, nodeToIndex);
node = node.Next;
if (node == null || visitedNodes.Contains(node))
{
break;
}
sb.Append(",");
}
sb.Append("]");
return(sb.ToString());
}
