/// <summary>
/// create a map of header name to index value to allow quick lookup
/// </summary>
/// <returns>The map.</returns>
private static Dictionary <string, int> CreateMap()
{
int length = STATIC_TABLE.Count;
var ret = new Dictionary <string, int>(length);
// Iterate through the static table in reverse order to
// save the smallest index for a given name in the map.
for (int index = length; index > 0; index--)
{
HeaderField entry = GetEntry(index);
string name = Encoding.UTF8.GetString(entry.Name);
ret[name] = index;
}
return(ret);
}
/// <summary>
/// Remove and return the oldest header field from the dynamic table.
/// </summary>
public HeaderField Remove()
{
HeaderField removed = headerFields[tail];
if (removed == null)
{
return(null);
}
size -= removed.Size;
headerFields[tail++] = null;
if (tail == headerFields.Length)
{
tail = 0;
}
return(removed);
}
private void IndexHeader(int index, AddHeaderDelegate addHeaderDelegate)
{
if (index <= StaticTable.Length)
{
HeaderField headerField = StaticTable.GetEntry(index);
this.AddHeader(addHeaderDelegate, headerField.Name, headerField.Value, false);
}
else if (index - StaticTable.Length <= this.dynamicTable.Length())
{
HeaderField headerField = this.dynamicTable.GetEntry(index - StaticTable.Length);
this.AddHeader(addHeaderDelegate, headerField.Name, headerField.Value, false);
}
else
{
throw new IOException("illegal index value (" + index + ")");
}
}
private void ReadName(int index)
{
if (index <= StaticTable.Length)
{
HeaderField headerField = StaticTable.GetEntry(index);
name = headerField.Name;
}
else if (index - StaticTable.Length <= this.dynamicTable.Length())
{
HeaderField headerField = this.dynamicTable.GetEntry(index - StaticTable.Length);
name = headerField.Name;
}
else
{
throw new IOException("illegal index value (" + index + ")");
}
}
/// <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 or equal to 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="header">Header.</param>
public void Add(HeaderField header)
{
int headerSize = header.Size;
if (headerSize > capacity)
{
this.Clear();
return;
}
while (size + headerSize > capacity)
{
this.Remove();
}
headerFields[head++] = header;
size += header.Size;
if (head == headerFields.Length)
{
head = 0;
}
}
/// <summary>
/// Encode the header field into the header block.
/// </summary>
/// <param name="output">Output.</param>
/// <param name="name">Name.</param>
/// <param name="value">Value.</param>
/// <param name="sensitive">If set to <c>true</c> sensitive.</param>
public void EncodeHeader(BinaryWriter output, byte[] name, byte[] value, bool sensitive)
{
// If the header value is sensitive then it must never be indexed
if (sensitive)
{
int nameIndex = this.GetNameIndex(name);
this.EncodeLiteral(output, name, value, HPackUtil.IndexType.NEVER, nameIndex);
return;
}
// If the peer will only use the static table
if (this.capacity == 0)
{
int staticTableIndex = StaticTable.GetIndex(name, value);
if (staticTableIndex == -1)
{
int nameIndex = StaticTable.GetIndex(name);
this.EncodeLiteral(output, name, value, HPackUtil.IndexType.NONE, nameIndex);
}
else
{
Encoder.EncodeInteger(output, 0x80, 7, staticTableIndex);
}
return;
}
int headerSize = HeaderField.SizeOf(name, value);
// If the headerSize is greater than the max table size then it must be encoded literally
if (headerSize > this.capacity)
{
int nameIndex = this.GetNameIndex(name);
this.EncodeLiteral(output, name, value, HPackUtil.IndexType.NONE, nameIndex);
return;
}
HeaderEntry headerField = this.GetEntry(name, value);
if (headerField != null)
{
int index = this.GetIndex(headerField.Index) + StaticTable.Length;
// Section 6.1. Indexed Header Field Representation
Encoder.EncodeInteger(output, 0x80, 7, index);
}
else
{
int staticTableIndex = StaticTable.GetIndex(name, value);
if (staticTableIndex != -1)
{
// Section 6.1. Indexed Header Field Representation
Encoder.EncodeInteger(output, 0x80, 7, staticTableIndex);
}
else
{
int nameIndex = this.GetNameIndex(name);
if (useIndexing)
{
this.EnsureCapacity(headerSize);
}
var indexType = useIndexing ? HPackUtil.IndexType.INCREMENTAL : HPackUtil.IndexType.NONE;
this.EncodeLiteral(output, name, value, indexType, nameIndex);
if (useIndexing)
{
this.Add(name, value);
}
}
}
}
