private void OnIndexedHeaderField(int index, IHttpHeadersHandler handler)
{
var header = GetHeader(index);
handler.OnHeader(new Span <byte>(header.Name), new Span <byte>(header.Value));
_state = State.Ready;
}
public void Decode(Span <byte> data, bool endHeaders, IHttpHeadersHandler handler)
{
for (var i = 0; i < data.Length; i++)
{
OnByte(data[i], handler);
}
if (endHeaders && _state != State.Ready)
{
throw new HPackDecodingException(CoreStrings.HPackErrorIncompleteHeaderBlock);
}
}
private void ProcessHeaderValue(IHttpHeadersHandler handler)
{
OnString(nextState: State.Ready);
var headerNameSpan = new Span <byte>(_headerName, 0, _headerNameLength);
var headerValueSpan = new Span <byte>(_headerValueOctets, 0, _headerValueLength);
handler.OnHeader(headerNameSpan, headerValueSpan);
if (_index)
{
_dynamicTable.Insert(headerNameSpan, headerValueSpan);
}
}
public void Decode(ReadOnlySequence <byte> data, bool endHeaders, IHttpHeadersHandler handler)
{
foreach (var segment in data)
{
var span = segment.Span;
for (var i = 0; i < span.Length; i++)
{
OnByte(span[i], handler);
}
}
if (endHeaders)
{
if (_state != State.Ready)
{
throw new HPackDecodingException(CoreStrings.HPackErrorIncompleteHeaderBlock);
}
_headersObserved = false;
}
}
private void OnByte(byte b, IHttpHeadersHandler handler)
{
int intResult;
switch (_state)
{
case State.Ready:
if ((b & IndexedHeaderFieldMask) == IndexedHeaderFieldRepresentation)
{
_headersObserved = true;
var val = b & ~IndexedHeaderFieldMask;
if (_integerDecoder.BeginTryDecode((byte)val, IndexedHeaderFieldPrefix, out intResult))
{
OnIndexedHeaderField(intResult, handler);
}
else
{
_state = State.HeaderFieldIndex;
}
}
else if ((b & LiteralHeaderFieldWithIncrementalIndexingMask) == LiteralHeaderFieldWithIncrementalIndexingRepresentation)
{
_headersObserved = true;
_index = true;
var val = b & ~LiteralHeaderFieldWithIncrementalIndexingMask;
if (val == 0)
{
_state = State.HeaderNameLength;
}
else if (_integerDecoder.BeginTryDecode((byte)val, LiteralHeaderFieldWithIncrementalIndexingPrefix, out intResult))
{
OnIndexedHeaderName(intResult);
}
else
{
_state = State.HeaderNameIndex;
}
}
else if ((b & LiteralHeaderFieldWithoutIndexingMask) == LiteralHeaderFieldWithoutIndexingRepresentation)
{
_headersObserved = true;
_index = false;
var val = b & ~LiteralHeaderFieldWithoutIndexingMask;
if (val == 0)
{
_state = State.HeaderNameLength;
}
else if (_integerDecoder.BeginTryDecode((byte)val, LiteralHeaderFieldWithoutIndexingPrefix, out intResult))
{
OnIndexedHeaderName(intResult);
}
else
{
_state = State.HeaderNameIndex;
}
}
else if ((b & LiteralHeaderFieldNeverIndexedMask) == LiteralHeaderFieldNeverIndexedRepresentation)
{
_headersObserved = true;
_index = false;
var val = b & ~LiteralHeaderFieldNeverIndexedMask;
if (val == 0)
{
_state = State.HeaderNameLength;
}
else if (_integerDecoder.BeginTryDecode((byte)val, LiteralHeaderFieldNeverIndexedPrefix, out intResult))
{
OnIndexedHeaderName(intResult);
}
else
{
_state = State.HeaderNameIndex;
}
}
else if ((b & DynamicTableSizeUpdateMask) == DynamicTableSizeUpdateRepresentation)
{
// https://tools.ietf.org/html/rfc7541#section-4.2
// This dynamic table size
// update MUST occur at the beginning of the first header block
// following the change to the dynamic table size.
if (_headersObserved)
{
throw new HPackDecodingException(CoreStrings.HPackErrorDynamicTableSizeUpdateNotAtBeginningOfHeaderBlock);
}
if (_integerDecoder.BeginTryDecode((byte)(b & ~DynamicTableSizeUpdateMask), DynamicTableSizeUpdatePrefix, out intResult))
{
SetDynamicHeaderTableSize(intResult);
}
else
{
_state = State.DynamicTableSizeUpdate;
}
}
else
{
// Can't happen
throw new HPackDecodingException($"Byte value {b} does not encode a valid header field representation.");
}
break;
case State.HeaderFieldIndex:
if (_integerDecoder.TryDecode(b, out intResult))
{
OnIndexedHeaderField(intResult, handler);
}
break;
case State.HeaderNameIndex:
if (_integerDecoder.TryDecode(b, out intResult))
{
OnIndexedHeaderName(intResult);
}
break;
case State.HeaderNameLength:
_huffman = (b & HuffmanMask) != 0;
if (_integerDecoder.BeginTryDecode((byte)(b & ~HuffmanMask), StringLengthPrefix, out intResult))
{
OnStringLength(intResult, nextState: State.HeaderName);
}
else
{
_state = State.HeaderNameLengthContinue;
}
break;
case State.HeaderNameLengthContinue:
if (_integerDecoder.TryDecode(b, out intResult))
{
OnStringLength(intResult, nextState: State.HeaderName);
}
break;
case State.HeaderName:
_stringOctets[_stringIndex++] = b;
if (_stringIndex == _stringLength)
{
OnString(nextState: State.HeaderValueLength);
}
break;
case State.HeaderValueLength:
_huffman = (b & HuffmanMask) != 0;
if (_integerDecoder.BeginTryDecode((byte)(b & ~HuffmanMask), StringLengthPrefix, out intResult))
{
OnStringLength(intResult, nextState: State.HeaderValue);
if (intResult == 0)
{
ProcessHeaderValue(handler);
}
}
else
{
_state = State.HeaderValueLengthContinue;
}
break;
case State.HeaderValueLengthContinue:
if (_integerDecoder.TryDecode(b, out intResult))
{
OnStringLength(intResult, nextState: State.HeaderValue);
if (intResult == 0)
{
ProcessHeaderValue(handler);
}
}
break;
case State.HeaderValue:
_stringOctets[_stringIndex++] = b;
if (_stringIndex == _stringLength)
{
ProcessHeaderValue(handler);
}
break;
case State.DynamicTableSizeUpdate:
if (_integerDecoder.TryDecode(b, out intResult))
{
SetDynamicHeaderTableSize(intResult);
_state = State.Ready;
}
break;
default:
// Can't happen
throw new HPackDecodingException("The HPACK decoder reached an invalid state.");
}
}
public void OnByte(byte b, IHttpHeadersHandler handler)
{
switch (_state)
{
case State.Ready:
if ((b & IndexedHeaderFieldMask) == IndexedHeaderFieldRepresentation)
{
var val = b & ~IndexedHeaderFieldMask;
if (_integerDecoder.BeginDecode((byte)val, IndexedHeaderFieldPrefix))
{
OnIndexedHeaderField(_integerDecoder.Value, handler);
}
else
{
_state = State.HeaderFieldIndex;
}
}
else if ((b & LiteralHeaderFieldWithIncrementalIndexingMask) == LiteralHeaderFieldWithIncrementalIndexingRepresentation)
{
_index = true;
var val = b & ~LiteralHeaderFieldWithIncrementalIndexingMask;
if (val == 0)
{
_state = State.HeaderNameLength;
}
else if (_integerDecoder.BeginDecode((byte)val, LiteralHeaderFieldWithIncrementalIndexingPrefix))
{
OnIndexedHeaderName(_integerDecoder.Value);
}
else
{
_state = State.HeaderNameIndex;
}
}
else if ((b & LiteralHeaderFieldWithoutIndexingMask) == LiteralHeaderFieldWithoutIndexingRepresentation)
{
_index = false;
var val = b & ~LiteralHeaderFieldWithoutIndexingMask;
if (val == 0)
{
_state = State.HeaderNameLength;
}
else if (_integerDecoder.BeginDecode((byte)val, LiteralHeaderFieldWithoutIndexingPrefix))
{
OnIndexedHeaderName(_integerDecoder.Value);
}
else
{
_state = State.HeaderNameIndex;
}
}
else if ((b & LiteralHeaderFieldNeverIndexedMask) == LiteralHeaderFieldNeverIndexedRepresentation)
{
_index = false;
var val = b & ~LiteralHeaderFieldNeverIndexedMask;
if (val == 0)
{
_state = State.HeaderNameLength;
}
else if (_integerDecoder.BeginDecode((byte)val, LiteralHeaderFieldNeverIndexedPrefix))
{
OnIndexedHeaderName(_integerDecoder.Value);
}
else
{
_state = State.HeaderNameIndex;
}
}
else if ((b & DynamicTableSizeUpdateMask) == DynamicTableSizeUpdateRepresentation)
{
if (_integerDecoder.BeginDecode((byte)(b & ~DynamicTableSizeUpdateMask), DynamicTableSizeUpdatePrefix))
{
// TODO: validate that it's less than what's defined via SETTINGS
_dynamicTable.Resize(_integerDecoder.Value);
}
else
{
_state = State.DynamicTableSizeUpdate;
}
}
else
{
// Can't happen
throw new HPackDecodingException($"Byte value {b} does not encode a valid header field representation.");
}
break;
case State.HeaderFieldIndex:
if (_integerDecoder.Decode(b))
{
OnIndexedHeaderField(_integerDecoder.Value, handler);
}
break;
case State.HeaderNameIndex:
if (_integerDecoder.Decode(b))
{
OnIndexedHeaderName(_integerDecoder.Value);
}
break;
case State.HeaderNameLength:
_huffman = (b & HuffmanMask) != 0;
if (_integerDecoder.BeginDecode((byte)(b & ~HuffmanMask), StringLengthPrefix))
{
OnStringLength(_integerDecoder.Value, nextState: State.HeaderName);
}
else
{
_state = State.HeaderNameLengthContinue;
}
break;
case State.HeaderNameLengthContinue:
if (_integerDecoder.Decode(b))
{
OnStringLength(_integerDecoder.Value, nextState: State.HeaderName);
}
break;
case State.HeaderName:
_stringOctets[_stringIndex++] = b;
if (_stringIndex == _stringLength)
{
OnString(nextState: State.HeaderValueLength);
}
break;
case State.HeaderValueLength:
_huffman = (b & HuffmanMask) != 0;
if (_integerDecoder.BeginDecode((byte)(b & ~HuffmanMask), StringLengthPrefix))
{
OnStringLength(_integerDecoder.Value, nextState: State.HeaderValue);
if (_integerDecoder.Value == 0)
{
ProcessHeaderValue(handler);
}
}
else
{
_state = State.HeaderValueLengthContinue;
}
break;
case State.HeaderValueLengthContinue:
if (_integerDecoder.Decode(b))
{
OnStringLength(_integerDecoder.Value, nextState: State.HeaderValue);
if (_integerDecoder.Value == 0)
{
ProcessHeaderValue(handler);
}
}
break;
case State.HeaderValue:
_stringOctets[_stringIndex++] = b;
if (_stringIndex == _stringLength)
{
ProcessHeaderValue(handler);
}
break;
case State.DynamicTableSizeUpdate:
if (_integerDecoder.Decode(b))
{
if (_integerDecoder.Value > _maxDynamicTableSize)
{
throw new HPackDecodingException(
CoreStrings.FormatHPackErrorDynamicTableSizeUpdateTooLarge(_integerDecoder.Value, _maxDynamicTableSize));
}
_dynamicTable.Resize(_integerDecoder.Value);
_state = State.Ready;
}
break;
default:
// Can't happen
throw new HPackDecodingException("The HPACK decoder reached an invalid state.");
}
}
