/// <summary>
/// Scans for the location of an item within the internal list.
/// </summary>
/// <remarks>
/// Performs a binary search within the list with forward and backward scanning.
/// Will throw an exception if item is not found. USE ONLY to find an item by key when you KNOW it's there.
/// </remarks>
/// <param name="Key">Item Key</param>
/// <param name="entryValueItem">The Item Value</param>
/// <returns>The zer-based index of the items location</returns>
private int BinaryLocate(TKey Key, TimeTaggedItem <TValue> entryValueItem)
{
int index = list.BinarySearch(new TimeTaggedItem <TKey>(entryValueItem.TimeStamp, Key));
if (index < 0)
{
throw new InvalidOperationException("Use BinaryLocate only when the item exists in the List");
}
//This might not be the one corresponding to the right key
int b = 0, f = 0;
while (!list[index].Value.Equals(Key))
{
//So scan backwards and forwards silmultaneously
b++;
f++;
if (index - b >= 0)
{
if (list[index - b].Value.Equals(Key))
{
index = index - b;
break;
}
}
if (index + f <= list.Count - 1)
{
if (list[index + f].Value.Equals(Key))
{
index = index + f;
break;
}
}
if ((index + f > list.Count - 1) && (index - b < 0))
{
throw new InvalidOperationException("Use BinaryLocate only when the item exists in the List");
}
}
return(index);
}
/// <summary>
/// Adds or updates an item in the dictionary
/// </summary>
/// <param name="TimeStamp">The timestamp to set for the item</param>
/// <param name="Key">The Item Key</param>
/// <param name="Value">The Item Value</param>
public void Add(DateTime TimeStamp, TKey Key, TValue Value)
{
lock (sync)
{
TimeTaggedItem <TValue> entryValueItem;
if (dict.TryGetValue(Key, out entryValueItem))
{
//This item exists so update both dictionary and list
//First update list
//Look for existing item using the found entry
int index = BinaryLocate(Key, entryValueItem);
//Remove it
list.RemoveAt(index);
//Reinsert it in the right place in the ordered timestamp list
//1. Look for next largest item in list for the new timestamp
TimeTaggedItem <TKey> listItem = new TimeTaggedItem <TKey>(TimeStamp, Key);
index = list.BinarySearch(listItem);
//2. Insert it there
list.Insert(index < 0 ? ~index : index, listItem);
//Secondly update dictionary with the value
dict[Key] = new TimeTaggedItem <TValue>(TimeStamp, Value);
}
else
{
//This item does not exist so insert into both dictionary and list
//First insert into list
//Look for next largest item in list
TimeTaggedItem <TKey> listItem = new TimeTaggedItem <TKey>(TimeStamp, Key);
int index = list.BinarySearch(listItem);
//Insert it there
list.Insert(index < 0 ? ~index : index, listItem);
//Secondly insert into dictionary
dict.Add(Key, new TimeTaggedItem <TValue>(TimeStamp, Value));
}
}
}
public int CompareTo(TimeTaggedItem <T> other)
{
return(TimeStamp.CompareTo(other.TimeStamp));
}
