convert c++ .h to c#

hey all

i have a c++ header file with a crazy looking struct which is about 150 lines. anyone here know of a tool which can convert that into c# ...even partially so i can fix up the odd things because right now i have no idea where to begin.

heres some part of the struct
...
struct LINK_MESSAGE {
  unsigned char MessageLength;
  union {
    unsigned char Data[255];
    struct {
      unsigned char MessageType;
      union {
        struct /* NAME_DATA (8 bit) */ {
          unsigned char ItemType8;
          unsigned char ItemNumber8;
          unsigned char ItemName8[16];
        };
        struct /* NAME_DATA (16 bit) */ {
          unsigned char ItemType16;
          unsigned char ItemNumber16MSB;
          unsigned char ItemNumber16LSB;
          unsigned char ItemName16[16];
        };
...and it goes on and on

One possibility is just to do this and be done with it.

struct LINK_MESSAGE {
  unsigned char MessageLength;
  unsigned char Data[255];
}

i dont know if that'll work because i need to interept and construct messages. for example:

LINK_MESSAGE msg;
msg.MessageLength = i;
msg.MessageType = MessegeType.TEXT;
msg.Data[n] = x;
msg.Data[n+1] = y;
msg.UserCode = "blahblah";
...etc

The more lengthy way is to make a list of all the struct members, their types, and their byte offsets... then use StructLayout to place each member at the byte offset it belongs.

See Sven's post

ok, after messing around for awhile this is where im getting stuck.

struct R_OMNI_LINK_MESSAGE {
  unsigned char MessageLength; // fieldoffset = 0
  union {
    unsigned char Data[255]; // filedoffset = 4
    struct { // stuct has no name?
      unsigned char MessageType; // since this struct is inside a union offset is 4?
      union {
        struct /* olmNAME_DATA (8 bit) */ { // offset of this??
          unsigned char ItemType8;
        };
      };  // union
    };  // struct
  }; // union
};

c# code i came up with for the above bit of code is:
[StructLayout(LayoutKind.Explicit)]
        public struct R_OMNI_LINK_MESSAGE
        {
        [FieldOffset(0)] public int MessageLength;
        [FieldOffset(4)][MarshalAs(UnmanagedType.ByValTStr, SizeConst=255)] public string Data;
        [FieldOffset(??)] public int MessageType;

        //olmNAME_DATA (8 bit)
        [FieldOffset(??)][MarshalAs(UnmanagedType.LPStr)] public string ItemType8;
...

any ideas?

matrixr wrote:

ok, after messing around for awhile this is where im getting stuck.

struct R_OMNI_LINK_MESSAGE {
  unsigned char MessageLength; // fieldoffset = 0 yup
  union {
    unsigned char Data[255]; // filedoffset = 4 no, 1 - a char is one byte
    struct { // stuct has no name? field offset is still 1
      unsigned char MessageType; // since this struct is inside a union offset is 4? field offset is still 1
      union { now field offset is 2
        struct /* olmNAME_DATA (8 bit) */ { // offset of this?? still 2
          unsigned char ItemType8; still 2
        };
      };  // union
    };  // struct
  }; // union
};

c# code i came up with for the above bit of code is:
[StructLayout(LayoutKind.Explicit)]
        public struct R_OMNI_LINK_MESSAGE
        {
        [FieldOffset(0)] public intbyte MessageLength;
        [FieldOffset(41)][MarshalAs(UnmanagedType.ByValTStr, SizeConst=255)] public string Data;
        [FieldOffset(??1)] public int byte MessageType;

        //olmNAME_DATA (8 bit)
        [FieldOffset(??2)][MarshalAs(UnmanagedType.LPStr)] public string ItemType8;
...

any ideas?

your right LPStr and ByValTStr doesnt work, byte works.
[FieldOffset(1)][MarshalAs(UnmanagedType.U1, SizeConst=255)] public byte Data; // UnmanagedType.U1 seems to get rid of the 'incorrectly aligned or overlapped' error.

now it errors out near this part
struct /* olmSYSTEM_STATUS */ { // offset is 2
    unsigned char TimeDateValidFlag;
    unsigned char AreaSecurityMode[8];
    struct { // another struct here? if i give it offset 2 ...i get incorrectly aligned error
        unsigned char Status;
    } ExpansionEnclosure[8];
};

[FieldOffset(2)][MarshalAs(UnmanagedType.U1, SizeConst=8)] public ExpansionEnclosure[] Enclosure;

[StructLayout(LayoutKind.Sequential)]
        public struct ExpansionEnclosure
        {
            public byte Status;
        }
tried giving it 3 since currentoffset(2)+1 byte inside ExpansionEnclosure struct, still get incorrectly aligned error.

matrixr wrote:

your right LPStr and ByValTStr doesnt work, byte works.
[FieldOffset(1)][MarshalAs(UnmanagedType.U1, SizeConst=255)] public byte Data; // UnmanagedType.U1 seems to get rid of the 'incorrectly aligned or overlapped' error.

now it errors out near this part
struct /* olmSYSTEM_STATUS */ { // offset is 2 ok, I'll take your word for it
    unsigned char TimeDateValidFlag; // offset is still 2
    unsigned char AreaSecurityMode[8]; // offset is 3 but this is a char*, not a char so it's four bytes
    struct { // another struct here? if i give it offset 2 ...i get incorrectly aligned error // see the next line down
        unsigned char Status;
    } ExpansionEnclosure[8]; // a struct {} * - four bytes.  offset is 7 (3 + 4), next offset would be 11 (7 + 4)
};

[FieldOffset(2)][MarshalAs(UnmanagedType.U1, SizeConst=8)] public ExpansionEnclosure[] Enclosure;

[StructLayout(LayoutKind.Sequential)]
        public struct ExpansionEnclosure
        {
            public byte Status;
        }
tried giving it 3 since currentoffset(2)+1 byte inside ExpansionEnclosure struct, still get incorrectly aligned error.

Maybe you're using the wrong tool for the job?

Could be easier to create a wrapper class with Managed C++ which you then can use from C#.

hmm, dont i still have to create the equivalent managed structure?

C# makes me hate c++