/// <summary>
/// Decode ASN.1 encoded node Stream data.
/// </summary>
/// <param name="xdata">Stream data.</param>
/// <returns>true:Succeed, false:Failed.</returns>
protected bool GeneralDecode(Stream xdata)
{
bool retval = false;
long nodeMaxLen;
nodeMaxLen = xdata.Length - xdata.Position;
tag = (byte)xdata.ReadByte();
long start, end;
start = xdata.Position;
dataLength = Asn1Util.DerLengthDecode(xdata, ref isIndefiniteLength);
if (dataLength < 0)
{
return(retval); // Node data length can not be negative.
}
end = xdata.Position;
lengthFieldBytes = end - start;
if (nodeMaxLen < (dataLength + TagLength + lengthFieldBytes))
{
return(retval);
}
if (ParentNode == null || ((ParentNode.tag & Asn1TagClasses.CONSTRUCTED) == 0))
{
if ((tag & Asn1Tag.TAG_MASK) <= 0 || (tag & Asn1Tag.TAG_MASK) > 0x1E)
{
return(retval);
}
}
if (tag == Asn1Tag.BIT_STRING)
{
// First byte of BIT_STRING is unused bits.
// BIT_STRING data does not include this byte.
// Fixed by Gustaf Bj�rklund.
if (dataLength < 1)
{
return(retval); // We cannot read less than 1 - 1 bytes.
}
unusedBits = (byte)xdata.ReadByte();
data = new byte[dataLength - 1];
xdata.Read(data, 0, (int)(dataLength - 1));
}
else
{
data = new byte[dataLength];
xdata.Read(data, 0, (int)(dataLength));
}
retval = true;
return(retval);
}
/// <summary>
/// Decode ASN.1 encoded complex data type Stream data.
/// </summary>
/// <param name="xdata">Stream data.</param>
/// <returns>true:Succeed, false:Failed.</returns>
protected bool ListDecode(Stream xdata)
{
bool retval = false;
long originalPosition = xdata.Position;
long childNodeMaxLen;
try
{
childNodeMaxLen = xdata.Length - xdata.Position;
tag = (byte)xdata.ReadByte();
long start, end, offset;
start = xdata.Position;
dataLength = Asn1Util.DerLengthDecode(xdata, ref isIndefiniteLength);
if (dataLength < 0 || childNodeMaxLen < dataLength)
{
return(retval);
}
end = xdata.Position;
lengthFieldBytes = end - start;
offset = dataOffset + TagLength + lengthFieldBytes;
Stream secData;
byte[] secByte;
if (tag == Asn1Tag.BIT_STRING)
{
// First byte of BIT_STRING is unused bits.
// BIT_STRING data does not include this byte.
unusedBits = (byte)xdata.ReadByte();
dataLength--;
offset++;
}
if (dataLength <= 0)
{
return(retval); // List data length cann't be zero.
}
secData = new MemoryStream((int)dataLength);
secByte = new byte[dataLength];
xdata.Read(secByte, 0, (int)(dataLength));
if (tag == Asn1Tag.BIT_STRING)
{
dataLength++;
}
secData.Write(secByte, 0, secByte.Length);
secData.Position = 0;
while (secData.Position < secData.Length)
{
Asn1Node node = new Asn1Node(this, offset);
node.parseEncapsulatedData = this.parseEncapsulatedData;
start = secData.Position;
if (!node.InternalLoadData(secData))
{
return(retval);
}
AddChild(node);
end = secData.Position;
offset += end - start;
}
retval = true;
}
finally
{
if (!retval)
{
xdata.Position = originalPosition;
ClearAll();
}
}
return(retval);
}
