Post by ihatemaryfisher on Sorting array of any-sized structure ^{CODESYS Forge talk (Post)}
In my machine's operation, I need to display multiples tables containing arrays of structured variables. The arrays change during operation, and my supervisor has advised me to write a new bubble-sort for each array. I think I can make a function to sort an array of any data type. This was my own project, and I'm a relatively new coder. I want to know the weaknesses in my approach, and a better method, if one exists. As far as I can test, the function accepts an array of a structured variable of any size, and sort it by any VAR in that structure. But it relies heavily on pointers, which I've heard are bad practice? Function call: // SORT BY BYTE-SIZED VAR IF xDoIt[6] THEN FUNBubbleSortSansBuffer( IN_pbySourcePointer := ADR(astArray[1]), // address of first byte in first element of array IN_pbyComparePointer:= ADR(astArray[1].byCompByte), // points to first byte of the comparing variable (variable you sort by) IN_uiStructureSize := SIZEOF(TYPE_STRUCTURE), // size, in bytes, of the structured variable IN_uiCompareSize := SIZEOF(astArray[1].byCompByte), // size, in bytes, of the comparing variable (variable you sort by) diArrayElements := UPPER_BOUND(astArray,1), // number of elements in array IN_xSmallToLarge := xSortOrder // whether to sort by small2large or large2small ); END_IF Function: FUNCTION FUNBubbleSortSansBuffer : BOOL VAR_INPUT IN_pbySourcePointer : POINTER TO BYTE; // points to beginning of array (first byte of first element) IN_pbyComparePointer: POINTER TO BYTE; // points to first byte of the comparing variable (variable you sort by) IN_uiStructureSize : UINT; // size, in bytes, of the structured variable IN_uiCompareSize : UINT; // size, in bytes, of the comparing variable (variable you sort by) diArrayElements : DINT; // number of elements in array IN_xSmallToLarge : BOOL; // whether to sort by small2large or large2small END_VAR VAR j : DINT; // repeat iteration over array until array ends i : DINT; // iterarte over array, swapping when necesary k : DINT; // iterator from 1 to size of structure (stepping 'through' a single element in array) dwSize : DWORD; // internal var for use in MEMUtils.MemCpy(<size>) // FOR SORTING BY BYTE VAR pbySourcePointer : POINTER TO BYTE; pbySourcePointer2 : POINTER TO BYTE; pbyComparePointer : POINTER TO BYTE; pbyComparePointer2 : POINTER TO BYTE; pbyPointerToBuffer : POINTER TO BYTE; // pointer to single byte buffer byBufferByte : BYTE; // single byte buffer END_VAR dwSize := UINT_TO_DWORD(IN_uiStructureSize); // get structure size (number of bytes) pbyPointerToBuffer := ADR(byBufferByte); // assign pointer to address of buffer byte (because MEMUtils.MemCpy requires a pointer input) CASE IN_uiCompareSize OF // depending on the size of the VAR to sort by (current functionality for BYTE and WORD/INT 1: // BYTE (8 BIT) FOR j := 1 TO diArrayElements DO // for number of elements in array FOR i := 1 TO (diArrayElements-1) DO // same thing, but row[i+1] row is included in swap logic pbySourcePointer := IN_pbySourcePointer + dwSize*(i-1); // point at #1 byte in array element[i] pbySourcePointer2 := pbySourcePointer + dwSize; // point at #1 byte in array element[i+1] // NOTE: because of memory locations, each array element is offset from one another by a number of bytes equal to the size of the structure // We can "walk" from array[i] to array[i+1] via steps equal to the size of the structure // e.g., ADR(array[i+1]) == ADR(array[i]) + SIZEOF([array datatype]) pbyComparePointer := IN_pbyComparePointer + dwSize*(i-1); // point to sorting variable in array element[i] pbyComparePointer2 := pbyComparePointer + dwSize; // point to sorting variable in array element[i+1] // using sort order (small -> large/large -> small) IF SEL(IN_xSmallToLarge, (pbyComparePointer2^ > pbyComparePointer^),(pbyComparePointer2^ < pbyComparePointer^)) THEN // This is where it gets tricky. We've identified pointers for the starting bytes of aArray[i] and aArray[i+1] // and we know the size of aArray[i]. We are going to swap individual bytes, one at a time, from aArray[i] and aArray[i+1] // this allows us to use only a single byte var as a buffer or temporary data storage // e.g., consider a structure consisting of a word, a byte, and a string. it is stored like this // |------WORD-------| |--BYTE-| |STRING------...| // astArray[1] == 1000 0100 0010 0001 1100 0011 1010 1010.... etc // astArray[2] == 0001 0010 0100 1000 0011 1100 0101 0101.... etc // performing a single swap (copy into a buffer, etc.) of the first byte of each array element creates this // astArray[1] == 0001 0100 0010 0001 1100 0011 1010 1010.... etc // astArray[2] == 1000 0010 0100 1000 0011 1100 0101 0101.... etc // incrementing the pointer adresses for the swap by 1 and swapping again swaps the next byte in each array element // astArray[1] == 0001 0010 0010 0001 1100 0011 1010 1010.... etc // astArray[2] == 1000 0100 0100 1000 0011 1100 0101 0101.... etc // continuing this from k to SIZEOF(TYPE_STRUCTURE) results in a toally swapped row FOR k := 1 TO IN_uiStructureSize DO // copy single byte[k] of array element 1 to buffer MEMUtils.MemCpy(pbyDest := (pbyPointerToBuffer), pbySrc := (pbySourcePointer+k-1), dwSize := 1); // copy single byte[k] of array element 2 to 1 MEMUtils.MemCpy(pbyDest := pbySourcePointer+k-1, pbySrc := (pbySourcePointer2+k-1), dwSize := 1); // copy buffer to byte[k] array element 2 MEMUtils.MemCpy(pbyDest := (pbySourcePointer2+k-1), pbySrc := pbyPointerToBuffer, dwSize := 1); END_FOR END_IF END_FOR END_FOR
Last updated: 2023-08-17

Post by mondinmr on Direct Pointers in IOMapping for EtherCAT with IoDrvEthercatLib.ETCSlave_Dia ^{CODESYS Forge talk (Post)}
I have found a very interesting solution using: IoConfigTaskMap IoConfigConnectorMap IoConfigChannelMap The first is the list of IO tasks. The second is the connector for each IO module in the IOMap. The third is the individual input or output on the IOMap. One of the properties of the connector is another pointer to a connector, which corresponds with the connector of the EtherCAT slave. Through this information, it is possible to understand to which EtherCAT slave an IO connectormap corresponds. I am attaching an FB that allows for the construction of an IO map and finding the pointer to the actual IOs in the IOMap based on the bitoffset. FUNCTION_BLOCK IOExplorer VAR_INPUT END_VAR VAR_OUTPUT END_VAR VAR inputChannels: COL.LinkedList; outputChannels: COL.LinkedList; ulintFactory: COL.UlintElementFactory; END_VAR METHOD inputAtBitOffsetOfConnector : POINTER TO BYTE VAR_INPUT conn: POINTER TO IoConfigConnectorMap; bitOffset: UDINT; END_VAR VAR it: COL.LinkedListIterator; itf: COL.IElement; elem: COL.iUlintElement; channelInfo: POINTER TO ADVChannelInfo; bitOffsetR: UDINT; END_VAR inputChannels.ElementIterator(it); WHILE it.HasNext() DO it.Next(itfElement => itf); __QUERYINTERFACE(itf, elem); {warning disable C0033} channelInfo := TO___UXINT(elem.UlintValue); {warning restire C0033} IF channelInfo^.connectorField = conn THEN IF bitOffsetR = bitOffset THEN inputAtBitOffsetOfConnector := channelInfo^.addr; RETURN; END_IF bitOffsetR := bitOffsetR + channelInfo^.size; ELSE bitOffsetR := 0; END_IF END_WHILE inputAtBitOffsetOfConnector := 0; END_METHOD METHOD outputAtBitOffsetOfConnector : POINTER TO BYTE VAR_INPUT conn: POINTER TO IoConfigConnectorMap; bitOffset: UDINT; END_VAR VAR it: COL.LinkedListIterator; itf: COL.IElement; elem: COL.iUlintElement; channelInfo: POINTER TO ADVChannelInfo; bitOffsetR: UDINT; END_VAR outputChannels.ElementIterator(it); WHILE it.HasNext() DO it.Next(itfElement => itf); __QUERYINTERFACE(itf, elem); {warning disable C0033} channelInfo := TO___UXINT(elem.UlintValue); {warning restire C0033} IF channelInfo^.connectorField = conn THEN IF bitOffsetR = bitOffset THEN outputAtBitOffsetOfConnector := channelInfo^.addr; RETURN; END_IF bitOffsetR := bitOffsetR + channelInfo^.size; ELSE bitOffsetR := 0; END_IF END_WHILE outputAtBitOffsetOfConnector := 0; END_METHOD METHOD scanIO VAR_INPUT END_VAR VAR numTasks: DINT := IoConfig_Globals.nIoConfigTaskMapCount; tType: WORD; ioTask: POINTER TO IoConfigTaskMap; numCon: WORD; connector: POINTER TO IoConfigConnectorMap; numCh: DWORD; channelInfo: POINTER TO ADVChannelInfo; iTsk: DINT; iCon: WORD; iCh: DWORD; i: DINT; _tmpConnList: COL.IList; elem: COL.IUlintElement; itf: COL.IElement; tmpCh: POINTER TO ADVChannelInfo; lastE: DINT; e: COL.COLLECTION_ERROR; e1: Error; END_VAR VAR_INST lF: COL.ListFactory; END_VAR IF outputChannels.CountElements() > 0 OR inputChannels.CountElements() > 0 THEN RETURN; END_IF _tmpConnList := lF.CreateDynamicList(16, 16); //Iterate through all IO tasks FOR iTsk := 0 TO numTasks - 1 DO ioTask := ADR(IoConfig_Globals.pIoConfigTaskMap[iTsk]); //Store the type of the task (Input or Output) tType := ioTask^.wType; numCon := ioTask^.wNumOfConnectorMap; //Iterate through all connectors of the task FOR iCon := 0 TO numCon - 1 DO connector := ADR(ioTask^.pConnectorMapList[iCon]); numCh := connector^.dwNumOfChannels; //Iterate through all channels of the connector FOR iCh := 0 TO numCh - 1 DO //Create a new channel info object and fill it with the address, connector and size of the channel //Connectors is address of field connector in this case like EtherCAT slave //Address is the address of the IOMap //Size is the size of channel data in bits in IOMap channelInfo := __NEW(ADVChannelInfo); channelInfo^.addr := connector^.pChannelMapList[iCh].pbyIecAddress; channelInfo^.connectorField := connector^.pConnector; channelInfo^.size := connector^.pChannelMapList[iCh].wSize; //We put the channel info a temporary ordered list //Order is based on the address of IOMap lastE := TO_DINT(_tmpConnList.CountElements()) - 1; FOR i := 0 TO lastE DO _tmpConnList.GetElementAt(udiPosition := TO_UDINT(i), itfElement => itf); __QUERYINTERFACE(itf, elem); {warning disable C0033} tmpCh := TO___UXINT(elem.UlintValue); {warning restire C0033} //If the address of the channel is smaller than the address of the channel in the list IF tmpCh^.addr > channelInfo^.addr THEN //Insert the channel in the list at the current position _tmpConnList.InsertElementAt(TO_UDINT(i), ulintFactory.Create(TO_ULINT(channelInfo))); //Clear the channel info pointer channelInfo := 0; //Exit the loop i := lastE + 1; END_IF END_FOR //If the channel info is not 0, it means that the channel was not inserted in the list IF channelInfo <> 0 THEN //Add the channel to the end of the list elem := ulintFactory.Create(TO_ULINT(channelInfo)); _tmpConnList.AddElement(elem); END_IF END_FOR //Iterate temporary list and add the channels to the input or output list lastE := TO_DINT(_tmpConnList.CountElements()) - 1; FOR i := 0 TO lastE DO _tmpConnList.GetElementAt(udiPosition := TO_UDINT(i), itfElement => itf); __QUERYINTERFACE(itf, elem); {warning disable C0033} tmpCh := TO___UXINT(elem.UlintValue); {warning restire C0033} //If type is input, add the channel to the input list IF tType = TaskMapTypes.TMT_INPUTS THEN e := inputChannels.AddElement(ulintFactory.Create(TO_ULINT(tmpCh))); //If type is output, add the channel to the output list ELSIF tType = TaskMapTypes.TMT_OUTPUTS THEN e := outputChannels.AddElement(ulintFactory.Create(TO_ULINT(tmpCh))); ELSE __DELETE(tmpCh); END_IF END_FOR //Clear the temporary list _tmpConnList.RemoveAllElements(); END_FOR END_FOR END_METHOD
Last updated: 2024-02-13

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