private EncoderHeaderEntry?RemoveHeaderEntry()
{
if (_headerTableSize == 0)
{
return(null);
}
EncoderHeaderEntry?eldest = Head.After;
int hash = eldest.Hash;
int bucketIndex = CalculateBucketIndex(hash);
EncoderHeaderEntry?prev = _headerBuckets[bucketIndex];
EncoderHeaderEntry?e = prev;
while (e != null)
{
EncoderHeaderEntry next = e.Next;
if (e == eldest)
{
if (prev == eldest)
{
_headerBuckets[bucketIndex] = next;
}
else
{
prev.Next = next;
}
_headerTableSize -= eldest.CalculateSize();
eldest.Remove();
return(eldest);
}
prev = e;
e = next;
}
return(null);
}
/// <summary>
/// Add before an entry in the linked list.
/// </summary>
public void AddBefore(EncoderHeaderEntry existingEntry)
{
After = existingEntry;
Before = existingEntry.Before;
Before !.After = this;
After !.Before = this;
}
private void PushRemovedEntry(EncoderHeaderEntry removed)
{
if (_removed != null)
{
removed.Next = _removed;
}
_removed = removed;
}
/// <summary>
/// Remove entry from the linked list and reset header values.
/// </summary>
public void Remove()
{
Before.After = After;
After.Before = Before;
Before = null;
After = null;
Next = null;
Hash = 0;
Name = null;
Value = null;
}
/// <summary>
/// Initialize header values. An entry will be reinitialized when reused.
/// </summary>
public void Initialize(int hash, string name, string value, int index, EncoderHeaderEntry next)
{
Debug.Assert(name != null);
Debug.Assert(value != null);
Name = name;
Value = value;
Index = index;
Hash = hash;
Next = next;
}
public HPackEncoder(bool allowDynamicCompression = true, uint maxHeaderTableSize = DefaultHeaderTableSize)
{
_allowDynamicCompression = allowDynamicCompression;
_maxHeaderTableSize = maxHeaderTableSize;
Head = new EncoderHeaderEntry();
Head.Initialize(-1, string.Empty, string.Empty, int.MaxValue, null);
// Bucket count balances memory usage and the expected low number of headers (constrained by the header table size).
// Performance with different bucket counts hasn't been measured in detail.
_headerBuckets = new EncoderHeaderEntry[16];
_hashMask = (byte)(_headerBuckets.Length - 1);
Head.Before = Head.After = Head;
}
