/// <summary>
/// Version of Intern that gathers statistics
/// </summary>
private string InternWithStatistics(IInternable candidate)
{
string result;
_stopwatch.Start();
bool?interned = TryIntern(candidate, out result);
_stopwatch.Stop();
if (interned.HasValue && !interned.Value)
{
// Could not intern.
_internMisses++;
int priorCount = 0;
_missedStrings.TryGetValue(result, out priorCount);
_missedStrings[result] = priorCount + 1;
return(result);
}
else if (interned == null)
{
// Decided not to attempt interning
_internRejects++;
int priorCount = 0;
_rejectedStrings.TryGetValue(result, out priorCount);
_rejectedStrings[result] = priorCount + 1;
return(result);
}
_internHits++;
if (!candidate.ReferenceEquals(result))
{
// Reference changed so 'candidate' is now released and should save memory.
_internEliminatedStrings++;
_internEliminatedChars += candidate.Length;
}
return(result);
}
/// <summary>
/// Try to get one element from the list. Upon leaving the function 'candidate' will be at the head of the Mru list.
/// This function is not thread-safe.
/// </summary>
internal bool TryGet(IInternable candidate, out string interned)
{
if (_size == 0)
{
interned = candidate.ExpensiveConvertToString();
return(false);
}
int length = candidate.Length;
Node secondPrior = null;
Node prior = null;
Node head = _mru;
bool found = false;
int itemCount = 0;
while (head != null && !found)
{
if (head.Value.Length == length)
{
if (candidate.IsOrdinalEqualToStringOfSameLength(head.Value))
{
found = true;
}
}
if (!found)
{
secondPrior = prior;
prior = head;
head = head.Next;
}
itemCount++;
}
if (found)
{
// Move it to the top and return the interned version.
if (prior != null)
{
if (!candidate.ReferenceEquals(head.Value))
{
// Wasn't at the top already, so move it there.
prior.Next = head.Next;
head.Next = _mru;
_mru = head;
interned = _mru.Value;
return(true);
}
else
{
// But don't move it up if there is reference equality so that multiple calls to Intern don't redundantly emphasize a string.
interned = head.Value;
return(true);
}
}
else
{
// Found the item in the top spot. No need to move anything.
interned = _mru.Value;
return(true);
}
}
else
{
// Not found. Create a new entry and place it at the top.
Node old = _mru;
_mru = new Node(candidate.ExpensiveConvertToString())
{
Next = old
};
// Cache miss. Use this opportunity to discard any element over the max size.
if (itemCount >= _size && secondPrior != null)
{
secondPrior.Next = null;
}
interned = _mru.Value;
return(false);
}
}
/// <summary>
/// Version of Intern that gathers statistics
/// </summary>
private string InternWithStatistics(IInternable candidate)
{
string result;
_stopwatch.Start();
bool? interned = TryIntern(candidate, out result);
_stopwatch.Stop();
if (interned.HasValue && !interned.Value)
{
// Could not intern.
_internMisses++;
int priorCount = 0;
_missedStrings.TryGetValue(result, out priorCount);
_missedStrings[result] = priorCount + 1;
return result;
}
else if (interned == null)
{
// Decided not to attempt interning
_internRejects++;
int priorCount = 0;
_rejectedStrings.TryGetValue(result, out priorCount);
_rejectedStrings[result] = priorCount + 1;
return result;
}
_internHits++;
if (!candidate.ReferenceEquals(result))
{
// Reference changed so 'candidate' is now released and should save memory.
_internEliminatedStrings++;
_internEliminatedChars += candidate.Length;
}
return result;
}
/// <summary>
/// Try to get one element from the list. Upon leaving the function 'candidate' will be at the head of the Mru list.
/// This function is not thread-safe.
/// </summary>
internal bool TryGet(IInternable candidate, out string interned)
{
if (_size == 0)
{
interned = candidate.ExpensiveConvertToString();
return false;
}
int length = candidate.Length;
Node secondPrior = null;
Node prior = null;
Node head = _mru;
bool found = false;
int itemCount = 0;
while (head != null && !found)
{
if (head.Value.Length == length)
{
if (candidate.IsOrdinalEqualToStringOfSameLength(head.Value))
{
found = true;
}
}
if (!found)
{
secondPrior = prior;
prior = head;
head = head.Next;
}
itemCount++;
}
if (found)
{
// Move it to the top and return the interned version.
if (prior != null)
{
if (!candidate.ReferenceEquals(head.Value))
{
// Wasn't at the top already, so move it there.
prior.Next = head.Next;
head.Next = _mru;
_mru = head;
interned = _mru.Value;
return true;
}
else
{
// But don't move it up if there is reference equality so that multiple calls to Intern don't redundantly emphasize a string.
interned = head.Value;
return true;
}
}
else
{
// Found the item in the top spot. No need to move anything.
interned = _mru.Value;
return true;
}
}
else
{
// Not found. Create a new entry and place it at the top.
Node old = _mru;
_mru = new Node(candidate.ExpensiveConvertToString());
_mru.Next = old;
// Cache miss. Use this opportunity to discard any element over the max size.
if (itemCount >= _size && secondPrior != null)
{
secondPrior.Next = null;
}
interned = _mru.Value;
return false;
}
}
