/// <summary>
/// Remove and return the oldest header field from the dynamic table.
/// </summary>
private HeaderField Remove()
{
if (this.size == 0)
{
return(null);
}
HeaderEntry eldest = head.After;
int h = eldest.Hash;
int i = Encoder.Index(h);
HeaderEntry prev = headerFields[i];
HeaderEntry e = prev;
while (e != null)
{
HeaderEntry next = e.Next;
if (e == eldest)
{
if (prev == eldest)
{
headerFields[i] = next;
}
else
{
prev.Next = next;
}
eldest.Remove();
this.size -= eldest.Size;
return(eldest);
}
prev = e;
e = next;
}
return(null);
}
/// <summary>
/// Add the header field to the dynamic table.
/// Entries are evicted from the dynamic table until the size of the table
/// and the new header field is less than the table's capacity.
/// If the size of the new entry is larger than the table's capacity,
/// the dynamic table will be cleared.
/// </summary>
/// <param name="name">Name.</param>
/// <param name="value">Value.</param>
private void Add(byte[] name, byte[] value)
{
int headerSize = HeaderField.SizeOf(name, value);
// Clear the table if the header field size is larger than the capacity.
if (headerSize > this.capacity)
{
this.Clear();
return;
}
// Evict oldest entries until we have enough capacity.
while (this.size + headerSize > this.capacity)
{
this.Remove();
}
// Copy name and value that modifications of original do not affect the dynamic table.
name.CopyTo(name, 0);
value.CopyTo(value, 0);
int h = Encoder.Hash(name);
int i = Encoder.Index(h);
HeaderEntry old = headerFields[i];
HeaderEntry e = new HeaderEntry(h, name, value, head.Before.Index - 1, old);
headerFields[i] = e;
e.AddBefore(head);
this.size += headerSize;
}
/// <summary>
/// Returns the header entry with the lowest index value for the header field.
/// Returns null if header field is not in the dynamic table.
/// </summary>
/// <returns>The entry.</returns>
/// <param name="name">Name.</param>
/// <param name="value">Value.</param>
private HeaderEntry GetEntry(byte[] name, byte[] value)
{
if (this.Length() == 0 || name == null || value == null)
{
return(null);
}
int h = Encoder.Hash(name);
int i = Encoder.Index(h);
for (HeaderEntry e = headerFields[i]; e != null; e = e.Next)
{
if (e.Hash == h && HPackUtil.Equals(name, e.Name) && HPackUtil.Equals(value, e.Value))
{
return(e);
}
}
return(null);
}
/// <summary>
/// Returns the lowest index value for the header field name in the dynamic table.
/// Returns -1 if the header field name is not in the dynamic table.
/// </summary>
/// <returns>The index.</returns>
/// <param name="name">Name.</param>
private int GetIndex(byte[] name)
{
if (this.Length() == 0 || name == null)
{
return(-1);
}
int h = Encoder.Hash(name);
int i = Encoder.Index(h);
int index = -1;
for (HeaderEntry e = headerFields[i]; e != null; e = e.Next)
{
if (e.Hash == h && HPackUtil.Equals(name, e.Name))
{
index = e.Index;
break;
}
}
return(this.GetIndex(index));
}