I'm trying to write an interface for commu开发者_C百科nicating with a network protocol, but the IEEE document describes the protocol at the bit level with information split accross a single byte.
What would be the best way to go about handling a C typedef such as
typedef struct {
Nibble transportSpecific;
Enumeration4 messageType;
UInteger4 versionPTP;
UInteger16 messageLength;
UInteger8 domainNumber;
Octet flagField[2];
Integer64 correctionfield;
PortIdentity sourcePortIdentity;
UInteger16 sequenceId;
UInteger8 controlField;
Integer8 logMessageInterval;
} MsgHeader;
when porting a compatibility layer to .Net?
FieldOffsetAttribute may be of help to you, although there is no way to represent values smaller than a byte.
I would use a byte to represent the two values for interop purposes, and then access the value via property getters.
unsafe struct MsgHeader
{
public Nibble transportSpecific;
//Enumeration4 messageType;
//UInteger4 versionPTP;
// use byte as place holder for these two fields
public byte union;
public ushort messageLength;
public byte domainNumber;
public fixed byte flagField[2];
public long correctionfield;
public PortIdentity sourcePortIdentity;
public ushort sequenceId;
public byte controlField;
public sbyte logMessageInterval;
// access value of two fields via getters
public byte messageType { get { return (byte)(union >> 4); } }
public byte versionPTP { get { return (byte)(union & 0xF); } }
}
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