public GzipUncompressionFilter()
: base()
{
_crc = new PhpHash.HashPhpResource.CRC32B();
_state = UncompressionState.Header;
_chunkQueue = new BinaryChunkQueue();
}
/// <summary>
/// Changes state based on header flags. Is called by header-handling states only.
/// </summary>
private void UpdateHeaderState()
{
switch (_state)
{
case UncompressionState.Header:
if (HeaderFlag(Zlib.GZIP_HEADER_EXTRAFIELD))
_state = UncompressionState.HeaderExtraField;
else if (HeaderFlag(Zlib.GZIP_HEADER_FILENAME))
_state = UncompressionState.HeaderFilename;
else if (HeaderFlag(Zlib.GZIP_HEADER_COMMENT))
_state = UncompressionState.HeaderComment;
else if (HeaderFlag(Zlib.GZIP_HEADER_CRC))
_state = UncompressionState.HeaderCRC;
else
_state = UncompressionState.Data;
break;
case UncompressionState.HeaderExtraField:
if (HeaderFlag(Zlib.GZIP_HEADER_FILENAME))
_state = UncompressionState.HeaderFilename;
else if (HeaderFlag(Zlib.GZIP_HEADER_COMMENT))
_state = UncompressionState.HeaderComment;
else if (HeaderFlag(Zlib.GZIP_HEADER_CRC))
_state = UncompressionState.HeaderCRC;
else
_state = UncompressionState.Data;
break;
case UncompressionState.HeaderFilename:
if (HeaderFlag(Zlib.GZIP_HEADER_COMMENT))
_state = UncompressionState.HeaderComment;
else if (HeaderFlag(Zlib.GZIP_HEADER_CRC))
_state = UncompressionState.HeaderCRC;
else
_state = UncompressionState.Data;
break;
case UncompressionState.HeaderComment:
if (HeaderFlag(Zlib.GZIP_HEADER_CRC))
_state = UncompressionState.HeaderCRC;
else
_state = UncompressionState.Data;
break;
case UncompressionState.HeaderCRC:
_state = UncompressionState.Data;
break;
}
}
public override object Filter(object input, bool closing)
{
// TODO: not the most efficient method - after the filters are upgraded to bucket lists, update this
PhpBytes bInput = Core.Convert.ObjectToPhpBytes(input);
if (bInput != null)
{
if (_state == UncompressionState.Failed)
{
// failed filter should not get any more calls
PhpException.Throw(PhpError.Warning, "using filter in failed state");
return null;
}
if (_state == UncompressionState.PostTrailer)
{
// post trailer - ignore everything
if (closing)
{
_state = UncompressionState.Finished;
}
return new PhpBytes();
}
if (_state == UncompressionState.Finished)
{
// finished filter should not get any more data
PhpException.Throw(PhpError.Warning, "using filter in finished state");
return null;
}
if (_state == UncompressionState.Passthrough)
{
// this is not gzip data format - pass the data through
return new PhpBytes(bInput);
}
// enqueue the block
_chunkQueue.EnqueueByteBlock(bInput.ReadonlyData, 0, bInput.Length);
if (_state == UncompressionState.Header)
{
#region Header handling
//beginning of the stream
byte[] beginning = _chunkQueue.DequeueByteBlock(Zlib.GZIP_HEADER_LENGTH);
if (beginning == null && !closing)
{
// we do not have enough data, but we know there would be more data ahead
return new PhpBytes();
}
else
{
//check the header format
if (beginning.Length >= 2 && beginning[0] == Zlib.GZIP_HEADER[0] && beginning[1] == Zlib.GZIP_HEADER[1])
{
//header magic bytes are OK
if (beginning.Length < Zlib.GZIP_HEADER_LENGTH)
{
// header is too short -> this is an error
PhpException.Throw(PhpError.Warning, "unexpected end of file");
return null;
}
else
{
// check the rest of the header
if (beginning[2] != Zlib.Z_DEFLATED)
{
PhpException.Throw(PhpError.Warning, "unknown compression method");
return null;
}
if ((beginning[3] & Zlib.GZIP_HEADER_RESERVED_FLAGS) != 0)
{
PhpException.Throw(PhpError.Warning, "unknown header flags set");
return null;
}
_headerFlags = beginning[3];
//change the header state based on the header flags
UpdateHeaderState();
}
}
else
{
// this is not a gzip format -> passthrough the data
_state = UncompressionState.Passthrough;
return new PhpBytes(beginning);
}
}
#endregion
}
if (_state == UncompressionState.HeaderExtraField)
{
#region Header Extra Field Handling
if (_extraHeaderLength == null)
{
//length was not yet detected
if (_chunkQueue.AvailableBytes < 2)
{
//wait for more input
return new PhpBytes();
}
else
{
//assemble length
_extraHeaderLength = _chunkQueue.DequeueByte();
_extraHeaderLength &= (_chunkQueue.DequeueByte() << 8);
}
}
if (_extraHeaderLength != null)
{
//length was already read
if (_chunkQueue.AvailableBytes < _extraHeaderLength)
{
//wait for more input
return new PhpBytes();
}
else
{
Debug.Assert(_extraHeaderLength.HasValue);
//skip the extra header
_chunkQueue.SkipByteBlock(_extraHeaderLength.Value);
UpdateHeaderState();
}
}
#endregion
}
if (_state == UncompressionState.HeaderFilename || _state == UncompressionState.HeaderComment)
{
#region Header Filename and Comment Handling
// filename or comment
// cycle until input ends or zero character is encountered
while (true)
{
byte? nextByte = _chunkQueue.DequeueByte();
if (nextByte == null)
{
//wait for more input
return new PhpBytes();
}
if (nextByte == 0)
{
// end the cycle
break;
}
}
// go to the next state
UpdateHeaderState();
#endregion
}
if (_state == UncompressionState.HeaderCRC)
{
#region CRC Handling
// header CRC
if (_chunkQueue.AvailableBytes < 2)
{
//wait for more input
return new PhpBytes();
}
else
{
//skip the CRC
_chunkQueue.DequeueByte();
_chunkQueue.DequeueByte();
UpdateHeaderState();
}
#endregion
}
//filled by data handling and sometimes returned by trailer handling
byte[] output = null;
if (_state == UncompressionState.Data)
{
#region Deflated Data Handling
//get all available bytes
byte[] inputBytes = _chunkQueue.DequeueByteBlock(_chunkQueue.AvailableBytes);
int inputOffset = 0;
// perform the inner operation
try
{
output = FilterInner(inputBytes, ref inputOffset, closing);
}
catch
{
// exception was thrown
_state = UncompressionState.Failed;
throw;
}
if (output == null)
{
// error happened and exception was not thrown
_state = UncompressionState.Failed;
return null;
}
// update the hash algorithm
_crc.Update(output);
if (inputOffset != inputBytes.Length)
{
// push the rest of the data into the chunk queue
_chunkQueue.PushByteBlock(inputBytes, inputOffset, inputBytes.Length - inputOffset);
// end of deflated block reached
_state = UncompressionState.Trailer;
// pass through to Trailer handling
}
else
{
//normal decompressed block - return it
return new PhpBytes(output);
}
#endregion
}
if (_state == UncompressionState.Trailer)
{
#region Trailer Handling
// the deflate block has already ended, we are processing trailer
if (closing || _chunkQueue.AvailableBytes >= Zlib.GZIP_FOOTER_LENGTH)
{
byte[] trailer;
trailer = _chunkQueue.DequeueByteBlock(_chunkQueue.AvailableBytes);
if (trailer.Length >= Zlib.GZIP_FOOTER_LENGTH)
{
byte[] crc = _crc.Final();
if (crc[3] != trailer[0] || crc[2] != trailer[1] || crc[1] != trailer[2] || crc[0] != trailer[3])
{
_state = UncompressionState.Failed;
PhpException.Throw(PhpError.Warning, "incorrect data check");
return null;
}
if (BitConverter.ToInt32(trailer, 4) != _stream.total_out)
{
_state = UncompressionState.Failed;
PhpException.Throw(PhpError.Warning, "incorrect length check");
return null;
}
_state = closing ? UncompressionState.Finished : UncompressionState.PostTrailer;
// everything is fine, return the output if available
return output != null ? new PhpBytes(output) : new PhpBytes();
}
else
{
_state = UncompressionState.Failed;
PhpException.Throw(PhpError.Warning, "unexpected end of file");
return null;
}
}
else
{
//stream is not closing yet - return the remaining output, otherwise empty
return output != null ? new PhpBytes(output) : new PhpBytes();
}
#endregion
}
//this should not happen
Debug.Fail();
return null;
}
else
{
Debug.Fail("GzipUncompressionFilter expects chunks to be convertible to PhpBytes.");
return null;
}
}
public GzipUncompressionFilter()
: base()
{
_crc = new PhpHash.HashPhpResource.CRC32B();
_state = UncompressionState.Header;
_chunkQueue = new BinaryChunkQueue();
}
/// <summary>
/// Changes state based on header flags. Is called by header-handling states only.
/// </summary>
private void UpdateHeaderState()
{
switch (_state)
{
case UncompressionState.Header:
if (HeaderFlag(Zlib.GZIP_HEADER_EXTRAFIELD))
{
_state = UncompressionState.HeaderExtraField;
}
else if (HeaderFlag(Zlib.GZIP_HEADER_FILENAME))
{
_state = UncompressionState.HeaderFilename;
}
else if (HeaderFlag(Zlib.GZIP_HEADER_COMMENT))
{
_state = UncompressionState.HeaderComment;
}
else if (HeaderFlag(Zlib.GZIP_HEADER_CRC))
{
_state = UncompressionState.HeaderCRC;
}
else
{
_state = UncompressionState.Data;
}
break;
case UncompressionState.HeaderExtraField:
if (HeaderFlag(Zlib.GZIP_HEADER_FILENAME))
{
_state = UncompressionState.HeaderFilename;
}
else if (HeaderFlag(Zlib.GZIP_HEADER_COMMENT))
{
_state = UncompressionState.HeaderComment;
}
else if (HeaderFlag(Zlib.GZIP_HEADER_CRC))
{
_state = UncompressionState.HeaderCRC;
}
else
{
_state = UncompressionState.Data;
}
break;
case UncompressionState.HeaderFilename:
if (HeaderFlag(Zlib.GZIP_HEADER_COMMENT))
{
_state = UncompressionState.HeaderComment;
}
else if (HeaderFlag(Zlib.GZIP_HEADER_CRC))
{
_state = UncompressionState.HeaderCRC;
}
else
{
_state = UncompressionState.Data;
}
break;
case UncompressionState.HeaderComment:
if (HeaderFlag(Zlib.GZIP_HEADER_CRC))
{
_state = UncompressionState.HeaderCRC;
}
else
{
_state = UncompressionState.Data;
}
break;
case UncompressionState.HeaderCRC:
_state = UncompressionState.Data;
break;
}
}
public override object Filter(object input, bool closing)
{
// TODO: not the most efficient method - after the filters are upgraded to bucket lists, update this
PhpBytes bInput = Core.Convert.ObjectToPhpBytes(input);
if (bInput != null)
{
if (_state == UncompressionState.Failed)
{
// failed filter should not get any more calls
PhpException.Throw(PhpError.Warning, "using filter in failed state");
return(null);
}
if (_state == UncompressionState.PostTrailer)
{
// post trailer - ignore everything
if (closing)
{
_state = UncompressionState.Finished;
}
return(new PhpBytes());
}
if (_state == UncompressionState.Finished)
{
// finished filter should not get any more data
PhpException.Throw(PhpError.Warning, "using filter in finished state");
return(null);
}
if (_state == UncompressionState.Passthrough)
{
// this is not gzip data format - pass the data through
return(new PhpBytes(bInput));
}
// enqueue the block
_chunkQueue.EnqueueByteBlock(bInput.ReadonlyData, 0, bInput.Length);
if (_state == UncompressionState.Header)
{
#region Header handling
//beginning of the stream
byte[] beginning = _chunkQueue.DequeueByteBlock(Zlib.GZIP_HEADER_LENGTH);
if (beginning == null && !closing)
{
// we do not have enough data, but we know there would be more data ahead
return(new PhpBytes());
}
else
{
//check the header format
if (beginning.Length >= 2 && beginning[0] == Zlib.GZIP_HEADER[0] && beginning[1] == Zlib.GZIP_HEADER[1])
{
//header magic bytes are OK
if (beginning.Length < Zlib.GZIP_HEADER_LENGTH)
{
// header is too short -> this is an error
PhpException.Throw(PhpError.Warning, "unexpected end of file");
return(null);
}
else
{
// check the rest of the header
if (beginning[2] != Zlib.Z_DEFLATED)
{
PhpException.Throw(PhpError.Warning, "unknown compression method");
return(null);
}
if ((beginning[3] & Zlib.GZIP_HEADER_RESERVED_FLAGS) != 0)
{
PhpException.Throw(PhpError.Warning, "unknown header flags set");
return(null);
}
_headerFlags = beginning[3];
//change the header state based on the header flags
UpdateHeaderState();
}
}
else
{
// this is not a gzip format -> passthrough the data
_state = UncompressionState.Passthrough;
return(new PhpBytes(beginning));
}
}
#endregion
}
if (_state == UncompressionState.HeaderExtraField)
{
#region Header Extra Field Handling
if (_extraHeaderLength == null)
{
//length was not yet detected
if (_chunkQueue.AvailableBytes < 2)
{
//wait for more input
return(new PhpBytes());
}
else
{
//assemble length
_extraHeaderLength = _chunkQueue.DequeueByte();
_extraHeaderLength &= (_chunkQueue.DequeueByte() << 8);
}
}
if (_extraHeaderLength != null)
{
//length was already read
if (_chunkQueue.AvailableBytes < _extraHeaderLength)
{
//wait for more input
return(new PhpBytes());
}
else
{
Debug.Assert(_extraHeaderLength.HasValue);
//skip the extra header
_chunkQueue.SkipByteBlock(_extraHeaderLength.Value);
UpdateHeaderState();
}
}
#endregion
}
if (_state == UncompressionState.HeaderFilename || _state == UncompressionState.HeaderComment)
{
#region Header Filename and Comment Handling
// filename or comment
// cycle until input ends or zero character is encountered
while (true)
{
byte?nextByte = _chunkQueue.DequeueByte();
if (nextByte == null)
{
//wait for more input
return(new PhpBytes());
}
if (nextByte == 0)
{
// end the cycle
break;
}
}
// go to the next state
UpdateHeaderState();
#endregion
}
if (_state == UncompressionState.HeaderCRC)
{
#region CRC Handling
// header CRC
if (_chunkQueue.AvailableBytes < 2)
{
//wait for more input
return(new PhpBytes());
}
else
{
//skip the CRC
_chunkQueue.DequeueByte();
_chunkQueue.DequeueByte();
UpdateHeaderState();
}
#endregion
}
//filled by data handling and sometimes returned by trailer handling
byte[] output = null;
if (_state == UncompressionState.Data)
{
#region Deflated Data Handling
//get all available bytes
byte[] inputBytes = _chunkQueue.DequeueByteBlock(_chunkQueue.AvailableBytes);
int inputOffset = 0;
// perform the inner operation
try
{
output = FilterInner(inputBytes, ref inputOffset, closing);
}
catch
{
// exception was thrown
_state = UncompressionState.Failed;
throw;
}
if (output == null)
{
// error happened and exception was not thrown
_state = UncompressionState.Failed;
return(null);
}
// update the hash algorithm
_crc.Update(output);
if (inputOffset != inputBytes.Length)
{
// push the rest of the data into the chunk queue
_chunkQueue.PushByteBlock(inputBytes, inputOffset, inputBytes.Length - inputOffset);
// end of deflated block reached
_state = UncompressionState.Trailer;
// pass through to Trailer handling
}
else
{
//normal decompressed block - return it
return(new PhpBytes(output));
}
#endregion
}
if (_state == UncompressionState.Trailer)
{
#region Trailer Handling
// the deflate block has already ended, we are processing trailer
if (closing || _chunkQueue.AvailableBytes >= Zlib.GZIP_FOOTER_LENGTH)
{
byte[] trailer;
trailer = _chunkQueue.DequeueByteBlock(_chunkQueue.AvailableBytes);
if (trailer.Length >= Zlib.GZIP_FOOTER_LENGTH)
{
byte[] crc = _crc.Final();
if (crc[3] != trailer[0] || crc[2] != trailer[1] || crc[1] != trailer[2] || crc[0] != trailer[3])
{
_state = UncompressionState.Failed;
PhpException.Throw(PhpError.Warning, "incorrect data check");
return(null);
}
if (BitConverter.ToInt32(trailer, 4) != _stream.total_out)
{
_state = UncompressionState.Failed;
PhpException.Throw(PhpError.Warning, "incorrect length check");
return(null);
}
_state = closing ? UncompressionState.Finished : UncompressionState.PostTrailer;
// everything is fine, return the output if available
return(output != null ? new PhpBytes(output) : new PhpBytes());
}
else
{
_state = UncompressionState.Failed;
PhpException.Throw(PhpError.Warning, "unexpected end of file");
return(null);
}
}
else
{
//stream is not closing yet - return the remaining output, otherwise empty
return(output != null ? new PhpBytes(output) : new PhpBytes());
}
#endregion
}
//this should not happen
Debug.Fail(null);
return(null);
}
else
{
Debug.Fail("GzipUncompressionFilter expects chunks to be convertible to PhpBytes.");
return(null);
}
}
