通过 c++ DLL 将 Arduino 字符串转换为 Excel BSTR 的随机字符答案

【问题标题】：Random characters from casting Arduino string to Excel BSTR through c++ DLL通过 c++ DLL 将 Arduino 字符串转换为 Excel BSTR 的随机字符
【发布时间】：2017-08-04 22:09:01
【问题描述】：

所以在一些 Arduino 代码中，我是 Serial.print 一些这样的数字 (var1=##,var2=##,var3=##)。我有一个 C++ DLL，我正在制作它来获取此信息并将其解析为这样的变体数组 ("var1=",##.##,"var2=",##.##,"var3=",##.##)，将字符串部分存储为变体 BSTR，将 #s 存储为变体双精度数。这个变体数组来自 Excel，我的 C++ DLL 的目的是允许与 Excel 和 Arduino 板进行串行通信。

我的问题是，我没有像我想要的那样获取信息，而是在最后得到了很多额外的胡言乱语，无法弄清楚它来自哪里。我之前包含了我的相关代码，省略了串行通信，因为我知道那部分肯定可以工作。目前，Arduino 代码只是发送 (##,##,##) 然后发送 Serial.println(); 以使事情变得更简单，因为没有字符串，只有数字。

VBA 代码：

'collects all rows available currently up to 1000(global numRows) lines each time, stores result in dataArray
Public Function getAllData()
    Dim stringArray() As Variant
    Dim variantArray() As Variant

    ReDim stringArray(0 To 3000) As Variant
    ReDim variantArray(0 To 3000) As Variant


    If Main.dataCollectionActive Then
        Dim staringDataRow As Integer
        staringDataRow = currentDataRow

        Dim returnValue As Long

        returnValue = GetAllDataTypes(stringArray(), variantArray(), currentDataRow)
        If Not (returnValue = 0) Then
            If Not (returnValue = -1) Then
                If printWhileCollectingData = True Then
                    ' Call printVariantData
                    Dim row As Integer
                    Dim col As Integer
                    For row = startingDataRow To (currentDataRow - 1)
                        Main.dataBox.Text = Main.dataBox.Text & stringArray(row)
                        For col = 0 To (getNumColumns() - 1)
                             Main.Cells(row + startingRow, col + startingCol).Value = variantArray(col + (row * getNumColumns()))
                        Next col
                    Next row
                End If
            End If
        End If

        'only stoped in Main sheets code for stopDataButton or if the array has reached its limit
        If Not ((currentDataRow * getNumColumns) = UBound(variantArray())) Then
            Application.OnTime Now + TimeValue("00:00:01"), "getAllData"
        End If
        Main.Range("$L$4").Value = currentDataRow
    End If
End Function

C++ DLL 代码：

//end1 comes before end2, so end1 = i-1 and end2 = i characters
DLL_EXPORT bool WINAPI isEndLine(char end1, char end2){
    //check for CRLF
    if (end1 == '\r') {
        if (end2 == '\n') {
            return true;
        }
    }

    //check for normal endLine \0
    else if ((end1 == '\0')) {
        return true;
    }

    //check for users own endLine character
    else{
        for(int i = 0; i < MAX_ENDLINE_LENGTH; i++){
            if (end1 == endLine[i]){
                return true;
            }
        }
    }
    return false;
}

//reads a single character from buffer, if there is nothing returned then the global, bufferAvailable is set to false, so that no more characters are asked for, for now
DLL_EXPORT char WINAPI readCharFromSerial() {
    char dataChar[1];
    DWORD dwBytesRead = 0; //number of data bytes read in
    if(!ReadFile(hSerial, dataChar, 1, &dwBytesRead, NULL)) { //gets data if successful, if not then notifies user
        ErrorExit("ReadFile, reading a character");
    }
    if (dwBytesRead == 0) {
        bufferAvailable = false;
    }
    return dataChar[0]; //returns read in data
}

//reads a single line by pulling one character at a time until it finds the end of line character, if the buffer has characters in it
DLL_EXPORT void WINAPI readLineFromSerialPort(char* line, int length) {
    bufferAvailable = true;
    int i = 0;
    line[i] = readCharFromSerial();
    i++;
    if (bufferAvailable){
        do{
            line[i] = readCharFromSerial();
            i++;
        }while((!isEndLine(line[i-2], line[i-1])) && (i < length));

        if(line[i-2] == '\r') {
            line[i-2] = '\n';
            line[i-1] = '\0';
        }

        if(!(i<length)){
            MessageBoxA(NULL, (LPCSTR)("string length not long enough"), TEXT("readLineFromSerialPort"), MB_OK);
        }
    }
}


DLL_EXPORT void WINAPI PlaceDblInVarDbl(varArr* VD, double data) {
    (VD->ptr[VD->index]).vt = VT_R8; //FIXME add function to do this
    (VD->ptr[VD->index]).dblVal = data;
    VD->index++;
}

DLL_EXPORT void WINAPI PlaceCharPtrInVarBstr(varArr* VD, char* cString) {
    BSTR bstr = new OLECHAR[MAX_DATA_LENGTH];
    const char* Cstring = (const char*)cString;
    mbstowcs(bstr, Cstring, MAX_DATA_LENGTH);
    VD->ptr[VD->index].vt = VT_BSTR;
    SysReAllocString(&((VD->ptr[VD->index]).bstrVal), bstr);
    VD->index++;
}

DLL_EXPORT int  WINAPI ParseCharPtrToVarBstrAndVarDbl(varArr* VD, char* dataString) {
    //FIXME perhaps make an array of chars for strings that are allowed without being coppied, this would be added to the if begging with !isdigit (like the '.')
    bool hasLetters = false;
    int endIndex = 0;
    int startIndex = 0;
    //    MessageBoxA(NULL, (LPCSTR)("entered"), TEXT("ParseCharPtrToVarBstrAndVarDbl"), MB_OK);
    while (!(isEndLine(dataString[endIndex], dataString[endIndex+1]))) {
        hasLetters = false;
        startIndex = endIndex;
        while (!isDelim(dataString[endIndex]) && (!(isEndLine(dataString[endIndex-1], dataString[endIndex])))) {
            if (!(isdigit(dataString[endIndex])) && !(dataString[endIndex] == ' ') && !(dataString[endIndex] == '.')) {
                hasLetters = true;
            }
            endIndex++;
        }
       // MessageBoxA(NULL, (LPCSTR)("delimeter found"), TEXT("ParseCharPtrToVarBstrAndVarDbl"), MB_OK);
        if((startIndex + 1 == endIndex) || (startIndex == endIndex)/* && !(isEndLine(dataString[endIndex-1], dataString[endIndex]))*/) {
            //FIXME odd way to fix CRLF problem
           // MessageBoxA(NULL, (LPCSTR)("triggered if"), TEXT("ParseCharPtrToVarBstrAndVarDbl"), MB_OK);
        }
        else if (hasLetters) { //string
            char smallerString[MAX_DATA_LENGTH];
            const char* DStr = (const char*)(&(dataString[startIndex]));
            strncpy(smallerString, DStr, endIndex-startIndex+1);
            smallerString[endIndex-startIndex+1] = '\0';
            PlaceCharPtrInVarBstr(VD, smallerString);
           // MessageBoxA(NULL, (LPCSTR)("triggered hasLetters"), TEXT("ParseCharPtrToVarBstrAndVarDbl"), MB_OK);
        }
        else { //double
            //FIXME remove whitespace
            char* start = &dataString[startIndex];
            char* eOS = &(dataString[endIndex]);
            char** endOfString = &eOS;

            double data = strtod(start, endOfString);
            //FIXME do some error checking
            PlaceDblInVarDbl(VD, data);
           // MessageBoxA(NULL, (LPCSTR)("triggered does not hasLetters"), TEXT("ParseCharPtrToVarBstrAndVarDbl"), MB_OK);
        }
        endIndex++;
    }
   //, MessageBoxA(NULL, (LPCSTR)("exited"), TEXT("ParseCharPtrToVarBstrAndVarDbl"), MB_OK);
    return VD->startingIndex - VD->index;
}

//first read a lines from the serial port and then parse it into dataArray, does this until there is no data in buffer or array is full
//returns how many rows that it read
DLL_EXPORT int WINAPI GetAllDataTypes(LPSAFEARRAY* unparsedData, LPSAFEARRAY* parsedData, int* currentDataRow) {
    bufferAvailable = true;
    varArr UPD;
    OpenVariantSafeArray(&UPD, unparsedData, *currentDataRow); if (UPD.failed) { return -1; }
    varArr PD;
    OpenVariantSafeArray(&PD, parsedData, *currentDataRow);    if (PD.failed)  { return -1; }

    while (bufferAvailable && ((PD.index + 10) < PD.uBound)) {
        char dataString[MAX_DATA_LENGTH];
        readLineFromSerialPort(dataString, MAX_DATA_LENGTH);
        if (bufferAvailable) {
            PlaceCharPtrInVarBstr(&UPD, dataString);
            ParseCharPtrToVarBstrAndVarDbl(&PD, dataString);
        }
    }

    CloseVariantSafeArray(&UPD, unparsedData); if (UPD.failed) { return -1; }
    CloseVariantSafeArray(&PD, parsedData);    if (PD.failed)  { return -1; }
    *currentDataRow +=  UPD.index - UPD.startingIndex;
    bufferAvailable = true;
    return UPD.index - UPD.startingIndex;
}

产生的错误：

这是在 Excel 的文本框中打印时返回的未解析字符串。

0.00,0.01,0.00 0.10,0.02,0.01 0.20,0.03,0.02 0.30,0.04,0.03 0.40,0.05,0.04 0.50,0.06,0.05 0.60,0.07,0.06 0.70,0.08,0.07 0.80,0.09,0.08 0.90,0.10,0.09 1.00,0.10,0.10

但是，VBA for 循环在单元格中打印的解析字符串。仍然有随机字符。看来我在 DLL 中的解析有问题，因为最后一个 double 总是最终是一个字符串，然后它总是有随机字符串。

0.000 0.010 "0.00 " - 0.100 0.020 "0.01 " - 0.200 0.030 "0.02 “—— 0.300 0.040 "0.03 " - 0.400 0.050 0.900 0.100 "0.09 " - 0.000 0.100 "0.10 " - 0.100 0.110"0.11 “—— 0.200 0.120 "0.12 " - 0.300 0.130 "0.13 " - 0.400 0.140"0.14 “—— 0.500 0.150 "0.15 " - 0.600 0.160 "0.16 “—— "0.25 " - 0.600 0.240"0.26 “—— 0.700 0.250 "0.27 " -

【问题讨论】：

'/r' 和 '/0' 与 '\0' 和 '\r' 不同。在编译器中打开警告。
没有实际答案就无法将其标记为已回答。可能最好只是删除问题并在需要时发布一个新问题。
我已经更新了这个问题。我现在已将其范围缩小为 DLL 中的解析问题
我从 excel 中获取的特定示例有一个可见的“-”字符，但它仍然会做随机的东西，而不仅仅是“-”。
我相信问题出在 ParseCharPtrToVarBstrAndVarDbl() 及其 while 循环和 if 语句条件中，但我似乎无法弄清楚。

标签： c++ excel vba memory bstr

【解决方案1】：

在 DLL 代码中 ParseCharPtrToVarBstrAndVarDbl() 中的最终 endIndex++ 跳过了分隔符，跳过了字符串中的空终止符。解决方法是在字符串末尾添加一个最终 if 语句，如果它是则返回。

【讨论】：