public static Header ReadHeader(ref ReadableBuffer buffer, ref HeaderTable headerTable, IBufferPool memoryPool)
{
int firstByte = buffer.Peek();
if (firstByte < 0)
{
ThrowEndOfStreamException();
}
buffer = buffer.Slice(1);
if ((firstByte & 0x80) != 0)
{
// 6.1. Indexed Header Field Representation
return(headerTable.GetHeader(ReadUInt32(ref buffer, firstByte, 7)));
}
else if ((firstByte & 0x40) != 0)
{
// 6.2.1. Literal Header Field with Incremental Indexing
var result = ReadHeader(ref buffer, ref headerTable, firstByte, 6, HeaderOptions.IndexAddNewValue);
headerTable = headerTable.Add(result, memoryPool);
return(result);
}
else if ((firstByte & 0x20) != 0)
{
// 6.3. Dynamic Table Size Update
var newSize = ReadInt32(ref buffer, firstByte, 5);
headerTable = headerTable.SetMaxLength(newSize, memoryPool);
return(Header.Resize(newSize));
}
else
{
// 6.2.2.Literal Header Field without Indexing
// 6.2.3.Literal Header Field Never Indexed
return(ReadHeader(ref buffer, ref headerTable, firstByte, 4,
(firstByte & 0x10) == 0
? HeaderOptions.IndexNotIndexed
: HeaderOptions.IndexNeverIndexed));
}
}
public static void WriteHeader(WritableBuffer buffer, Header header, ref HeaderTable headerTable, MemoryPool memoryPool)
{
switch (header.Options & HeaderOptions.IndexMask)
{
case HeaderOptions.IndexAddNewValue:
WriteKeyName(buffer, header, ref headerTable, 0x40, 6);
WriteValueString(buffer, header.Value, header.Options);
headerTable = headerTable.Add(header, memoryPool);
break;
case HeaderOptions.IndexExistingValue:
var index = headerTable.GetKey(header.Name, header.Value);
if (index == 0)
{
throw new InvalidOperationException("Attempted to use a header that did not exist: " + header.ToString() + Environment.NewLine + headerTable.ToString());
}
WriteUInt32(buffer, index, 0x80, 7);
break;
case HeaderOptions.IndexNeverIndexed:
WriteKeyName(buffer, header, ref headerTable, 0x10, 4);
WriteValueString(buffer, header.Value, header.Options);
break;
case HeaderOptions.IndexNotIndexed:
WriteKeyName(buffer, header, ref headerTable, 0x00, 4);
WriteValueString(buffer, header.Value, header.Options);
break;
case HeaderOptions.IndexResize:
uint len;
if (!uint.TryParse(header.Value, out len))
{
throw new InvalidOperationException("Invalid index length change: " + header.Value);
}
WriteUInt32(buffer, len, 0x20, 5);
break;
case HeaderOptions.IndexAutomatic:
index = headerTable.GetKey(header.Name, header.Value);
if (index == 0)
{
index = headerTable.GetKey(header.Name);
switch (index)
{
case 1: // :authority
case 15: // accept-charset
case 16: // accept-encoding
case 17: // accept-language
case 38: // host
case 58: // user-agent
// AddNewValue
WriteUInt32(buffer, index, 0x40, 6);
headerTable = headerTable.Add(header, memoryPool);
break;
default:
// NotIndexed
WriteUInt32(buffer, index, 0x00, 4);
if (index == 0)
{
WriteNameString(buffer, header.Name, header.Options);
}
break;
}
WriteValueString(buffer, header.Value, header.Options);
}
else
{
// ExistingValue
WriteUInt32(buffer, index, 0x80, 7);
}
break;
default:
throw new InvalidOperationException("Invalid header indexing: " + header.Options);
}
}