/// <summary>
/// Compress incremental.
/// </summary>
/// <param name="header">The header.</param>
private void CompressIncremental(KeyValuePair <string, string> header)
{
const byte prefix = (byte)UVarIntPrefix.Incremental;
/* 12 -> 8.1.3
* Just as in HTTP/1.x, header field names are strings of ASCII
* characters that are compared in a case-insensitive fashion. However,
* header field names MUST be converted to lowercase prior to their
* encoding in HTTP/2. */
int index = _remoteHeadersTable.FindIndex(kv => kv.Key.Equals(header.Key, StringComparison.OrdinalIgnoreCase));
bool isFound = index != -1;
/* 07 -> 3.1.4
* <---------- Index Address Space ---------->
* <-- Header Table --> <-- Static Table -->
+---+-----------+---+ +---+-----------+---+
| 1 | ... | k | |k+1| ... | n |
+---+-----------+---+ +---+-----------+---+
| ^ |
| V
| Insertion Point Drop Point
*/
// It's necessary to form result array because partial writeToOutput stream
// can cause problems because of multithreading
using (var stream = new MemoryStream(64))
{
byte[] indexBinary;
byte[] nameBinary = new byte[0];
byte[] valueBinary;
if (isFound)
{
// Header key was found in the header table. Hence we should encode only value
indexBinary = (index + 1).ToUVarInt(prefix);
valueBinary = EncodeString(header.Value, true);
}
else
{
// Header key was not found in the header table. Hence we should encode name and value
indexBinary = 0.ToUVarInt(prefix);
nameBinary = EncodeString(header.Key, true);
valueBinary = EncodeString(header.Value, true);
}
// Set without index type
indexBinary[0] |= (byte)IndexationType.Incremental;
stream.Write(indexBinary, 0, indexBinary.Length);
stream.Write(nameBinary, 0, nameBinary.Length);
stream.Write(valueBinary, 0, valueBinary.Length);
WriteToOutput(stream.GetBuffer(), 0, (int)stream.Position);
}
InsertToHeadersTable(header, _remoteRefSet, _remoteHeadersTable);
}
