I am a newbie to JNA and facing a problem with respect to Pointer mapping
Native Method:
- EXTERNC T_PDU_ERROR PDUStartComPrimitive(UNUM32 hMod,UNUM32 hCLL,T_PDU_COPT CopType,UNUM32 CoPDataSize,UNUM8
*pCopData,PDU_COP_CTRL_DATA *pCopCtrlData, void *pCopTag, UNUM32 *phCoP)
JNA Method:
int PDUStartComPrimitive(int hMod, int hCLL, int CoPType, int
CoPDataSize, byte[] pCoPData, PDU_COP_CTRL_DATA.ByReference
pCopCtrlData, Pointer pCoPTag, IntByReference phCoP);
Native Structure(s):
typedef struct{
UNUM32 Time;
SNUM32 NumSendCycles;
SNUM32 NumReceiveCycles;
UNUM32 TempParamUpdate;
PDU_FLAG_DATA TxFlag;
UNUM32 NumPossibleExpectedResponses;
PDU_EXP_RESP_DATA *pExpectedResponseArray;
}PDU_COP_CTRL_DATA;
typedef struct{
UNUM32 ResponseType;
UNUM32 AcceptanceId;
UNUM32 NumMaskPatternBytes;
UNUM8 *pMaskData;
UNUM8 *pPatternData;
UNUM32 NumUniqueRespIds;
UNUM32 *pUniqueRespIds;
}PDU_EXP_RESP_DATA;
JNA Mapping:
public class PDU_COP_CTRL_DATA extends Structure{
public int time;
public int numSendCycles;
public int numReceiveCycles;
public int tempParamUpdate;
public PDU_FLAG_DATA txFlag;
public int numPossibleExpectedResponses;
public Pointer pExpectedResponseArray;
public static class ByReference extends PDU_COP_CTRL_DATA implements Structure.ByReference {
};
}
public class PDU_EXP_RESP_DATA extends Structure{
public int responseType;
public int acceptanceId;
public int numMaskPatternBytes;
public byte[] pMaskData= new byte[1];
public byte[] pPatternData = new byte[1];
public int numUniqueRespIds;
/* Array containing unique response identifiers. Only responses with a unique response identifier found in this array are considered, when trying to match them to this expected response. */
public Pointer pUniqueRespIds;
public static class ByReference extends PDU_EXP_RESP_DATA implements Structure.ByReference {
};
}
When I execute the PDUStartComPrimitive method in Java and have a look at the underlyng dll log I see that for the PDU_COP_CTRL_DATA strucutre field *pExpectedResponseArray I get Invalid *PDU_EXP_RESP_DATA pointer.
My JNA code to setup the PDUStartComPrimitive execution
byte[] sendata = new byte[requestData.length() / 2];
int byteIndex = 0;
for (String byteString : requestData.split(" ")) {
sendata[byteIndex] = Byte.parseByte(byteString, 16);
byteIndex++;
}
/* Setting of the expected responses ends */
PDU_COP_CTRL_DATA.ByReference objCopCtrlData = new PDU_COP_CTRL_DATA.ByReference();
objCopCtrlData.numPossibleExpectedResponses = 1;
objCopCtrlData.numReceiveCycles = 1;
objCopCtrlData.numSendCycles = 1;
objCopCtrlData.tempParamUpdate = 0;
objCopCtrlData.time = 0;
PDU_EXP_RESP_DATA expRespStruct = new PDU_EXP_RESP_DATA();
expRespStruct.acceptanceId = 0;
expRespStruct.numMaskPatternBytes = 1;
expRespStruct.numUniqueRespIds = 0;
expRespStruct.pUniqueRespIds = new Pointer(0);
expRespStruct.responseType = 0;
byte[] mskByte = byte int[] { 0 };
byte[] patternByte = new byte[] { 0 };
expRespStruct.pMaskData = mskByte;
expRespStruct.pPatternData = patternByte;
PDU_EXP_RESP_DATA[] refArr = (PDU_EXP_RESP_DATA[]) expRespStruct.toArray(1);
refArr[0] = expRespStruct;
expRespStruct.autoWrite();
objCopCtrlData.pExpectedResponseArray = expRespStruct.getPointer();
PDU_FLAG_DATA.ByValue objTxFlagData = new PDU_FLAG_DATA.ByValue();
objCopCtrlData.txFlag = objTxFlagData;
String strComAction = "SEND_RECV";
Pointer apiTag = new NativeString(strComAction, true).getPointer();
IntByReference phCop = new IntByReference();
int errorCode = PDUStartComPrimitive(1, 1,0x8004, sendata.length,sendata, objCopCtrlData, apiTag, phCop);
I have a suspicion this maybe because of wrong JNA mapping. Could you please help me with any ideas/suggestions. Thanks
Primitive arrays within a Structure
are interpreted as inline arrays, which results in a field of aggregate (array) type. Your native structure indicates a pointer type for those fields, so you need to use Pointer, PointerType, or NIO Buffer.
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