// Create a new Application Tag
public BACnetObjectIdentifier(byte[] buf, ref int offset, BACnetEnums.TAG tagType, BACnetEnums.BACNET_APPLICATION_TAG appTag)
{
// is the next parameter even an application tag
if ((buf[offset] & 0x08) != 0x00)
{
// we have an unexpected context tag, sort this out
BACnetLibraryCL.Panic("Not a context tag");
// todo, now is there a way to avoid creating the object? Have to flag it at least...
return;
}
if ((BACnetEnums.BACNET_APPLICATION_TAG)(((buf[offset] & 0xf0) >> 4)) != appTag)
{
// we have an unexpected context tag, sort this out
BACnetLibraryCL.Panic("Unexpected application tag");
// todo, now is there a way to avoid creating the object? Have to flag it at least...
return;
}
int contextTagSize = buf[offset] & 0x07;
offset++;
switch (appTag)
{
case BACnetEnums.BACNET_APPLICATION_TAG.BACNET_APPLICATION_TAG_OBJECT_ID:
if (contextTagSize != 4)
{
// we dont have a legal object ID!
BACnetLibraryCL.Panic("Illegal length");
return;
}
this.objectType = (BACnetEnums.BACNET_OBJECT_TYPE)(((uint)buf[offset] << 2) | ((uint)buf[offset + 1] >> 6));
objectInstance = ((uint)buf[offset + 1] & 0x3f) << 16;
objectInstance |= ((uint)buf[offset + 2]) << 8;
objectInstance |= ((uint)buf[offset + 3]);
offset += 4;
return;
}
}
// Create a new Context Tag
public BACnetObjectIdentifier(byte[] buf, ref int offset, BACnetEnums.TAG tagType, int tagValue)
{
// is the next parameter even a context tag
if ((buf[offset] & 0x08) != 0x08)
{
// we have an unexpected context tag, sort this out
throw new Exception("m0177-Not a context tag");
// todo, now is there a way to avoid creating the object? Have to flag it at least...
//return;
}
if ((buf[offset] & 0xf0) != (tagValue << 4))
{
// we have an unexpected context tag, sort this out
throw new Exception("m0174-Unexpected context tag");
// todo, now is there a way to avoid creating the object? Have to flag it at least...
//return;
}
int contextTagSize = buf[offset] & 0x07;
// the length of a bacnet object identifier better be 4
if (contextTagSize != 4)
{
// we have an unexpected context tag, sort this out
throw new Exception("m0175-Unbelievable length of object identifier");
// todo, now is there a way to avoid creating the object? Have to flag it at least...
//return;
}
objectType = (BACnetEnums.BACNET_OBJECT_TYPE)(((uint)buf[offset + 1] << 2) | ((uint)buf[offset + 2] >> 6));
objectInstance = ((uint)buf[offset + 2] & 0x3f) << 16;
objectInstance |= ((uint)buf[offset + 3]) << 8;
objectInstance |= ((uint)buf[offset + 4]);
offset += 5;
}
