C++ SdFat::open方法代码示例

void SDcard::writefile(uint64_t timestamp_sd, int eeprom){
  
    myfile = SD.open("data.txt", FILE_WRITE);
    
    if (myfile) {
      myfile.print("G|");
      uint64_t xx = timestamp_sd/1000000000ULL;
      if (xx >0) myfile.print((long)xx);
      myfile.print((long)(timestamp_sd-xx*1000000000));
      myfile.print("|");
      myfile.print(eeprom);
      myfile.print("|");
      for(int i = 0; i<3;i++){ // nombre de capteurs = 3
        String data = this->mem->getNext();
        myfile.print(data);
        if (i!=2)
        myfile.print("|");
      }
      myfile.write('\n');
      //myfile.print("|H,");
      //myfile.println(value);
      myfile.close();
    }
    else {
      Serial.println("error opening data.txt");
    }
  }

// Get the full path/filename of the GIF file with specified index
void getGIFFilenameByIndex(const char *directoryName, int index, char *pnBuffer) {

	char fname[30];

    // Make sure index is in range
    if ((index < 0) || (index >= numberOfFiles))
        return;

    File directory = sd.open(directoryName);
    if (!directory)
        return;

    File file = directory.openNextFile();
    while (file && (index >= 0)) {
        file.getName(fname, sizeof(fname));

        if (isAnimationFile(fname)) {
            index--;

            // Copy the directory name into the pathname buffer
            strcpy(pnBuffer, directoryName);

            // Append the filename to the pathname
            strcat(pnBuffer, fname);
        }

        file.close();
        file = directory.openNextFile();
    }

    file.close();
    directory.close();
}

// Enumerate and possibly display the animated GIF filenames in GIFS directory
int enumerateGIFFiles(const char *directoryName, boolean displayFilenames) {

	char fname[30];
	numberOfFiles = 0;

    File directory = sd.open(directoryName);
    if (!directory) {
        return -1;
    }

    File file = directory.openNextFile();
    while (file) {
		file.getName(fname, sizeof(fname));
  		Serial.println(fname);
        if (isAnimationFile(fname)) {
            numberOfFiles++;
            if (displayFilenames) {
                Serial.println(fname);
            }
        }
        file.close();
        file = directory.openNextFile();
    }

    file.close();
    directory.close();

    return numberOfFiles;
}

/**
 * Function starts the SD card service and makes sure that the appropriate directory
 * structure exists, then creates the file to use for logging data. Data will be logged
 * to a file called fileNamePrefix_0.csv or fileNamePrefix_0.bin (number will be incremented
 * for each new log file)
 *
 * @param chipSelectPin Arduino pin SD card reader CS pin is attached to
 * @param fileNamePrefix string to prefix at beginning of data file
 * @param csvData boolean flag whether we are writing csv data or binary data (used for filename)
 *
 * @return true if successful, false if failed
 */
bool beginDataLog(int chipSelectPin, const char *fileNamePrefix, bool csvData)
{
  bool ret;
  int i = 0;
  int max_len;
  char fileName[19];
  char prefix[8];
  char rootPath[] = "/data";


  if (_output_buffer != NULL) {
    delete []_output_buffer;
  }
  OUTPUT_BUF_SIZE = 512;
  _output_buffer = vol.cacheAddress()->output_buf;

  if (freeMemory() < 400) {
    strcpy_P(_getOutBuf(), sd_card_error);
    Serial.print(_getOutBuf());
    Serial.print(freeMemory());
    Serial.println(", need 400)");
    ret = false;
  } else {
    ret = sd.begin(chipSelectPin, SPI_FULL_SPEED);
  }

  //Filenames need to fit the 8.3 filename convention, so truncate down the
  //given filename if it is too long.
  memcpy(prefix, fileNamePrefix, 7);
  prefix[7] = '\0';

  if (ret) {
    if (!sd.exists(rootPath))
      ret = sd.mkdir(rootPath);
    if (ret) {
      while (true) {
	if (i < 10) {
	  max_len = 7;
	} else if (i < 100) {
	  max_len = 6;
	} else if (i < 1000) {
	  max_len = 5;
	} else {
	  break;
	}

	prefix[max_len - 1] = '\0';
	sprintf(fileName, "%s/%s%d.%s", rootPath, prefix, i,
		csvData ? "csv" : "bin");
	if (!sd.exists(fileName)) {
	  file = sd.open(fileName, FILE_WRITE);
	  break;
	}
	i++;
      }
    }
  }
  return file.isOpen();
}

void TicketflySDBeacon::writeToSD (String writeThisString, String fileName, SdFat& SD) { 
	File myFile;
	const char* conversion = fileName.c_str();
	Serial.println (conversion);
	myFile = SD.open(conversion);
  if (myFile) {
    myFile.println(writeThisString);
    myFile.close();
  } 
	else {
    Serial.println(F("error opening example.txt"));
  }
}

void SDcard::readfile(){

  // re-open the file for reading:
  myfile = SD.open("data.txt");
  if (myfile) {
    // read from the file until there's nothing else in it:
    while (myfile.available()) {
      Serial.write(myfile.read());
    }
    // close the file:
    myfile.close();
  } else {
    Serial.println("error opening data.txt");
  }
}

void TicketflySDBeacon::simpleReadSD (String fileName, SdFat& SD){ 
	File myFile;
	const char* conversion = fileName.c_str();
	myFile = SD.open(conversion, FILE_READ);
	if (myFile) {
	  while (myFile.available()) {
	    Serial.write(myFile.read());
	  }
	  myFile.close();
	} 
	else 
	{
	    Serial.print(F("Error opening "));
			Serial.println (fileName);
	 }
}

bool TicketflySDBeacon::searchDatabaseForTicket(String TicketString, SdFat& SD){ 
		File myFile;
		const char* TicketNo = TicketString.c_str();
		myFile = SD.open("example.txt");  
		if (myFile) {
    	char buf[16];
    	myFile.read(buf, 16);
    	if (strncmp(buf, TicketNo, 14) == 0)
    	{
      	Serial.println(F("Match!"));
      	return true;
    	}
    	else {
				Serial.println (F("No Match"));
      	return false;
    	}
    myFile.close();
  }
	else {
	Serial.println(F("error opening file"));
  }
}

void TicketflySDBeacon::fileRemove (String fileName, SdFat& SD) { 
	File myFile;
	const char* conversion = fileName.c_str();
  myFile = SD.open(conversion);
  SD.remove(conversion);
}