// Read a two dimensional array from a CSV file. // #include #include #define CS_PIN SS // 5 X 4 array #define ROW_DIM 5 #define COL_DIM 4 SdFat SD; File file; /* * Read a file one field at a time. * * file - File to read. * * str - Character array for the field. * * size - Size of str array. * * delim - String containing field delimiters. * * return - length of field including terminating delimiter. * * Note, the last character of str will not be a delimiter if * a read error occurs, the field is too long, or the file * does not end with a delimiter. Consider this an error * if not at end-of-file. * */ size_t readField(File* file, char* str, size_t size, const char* delim) { char ch; size_t n = 0; while ((n + 1) < size && file->read(&ch, 1) == 1) { // Delete CR. if (ch == '\r') { continue; } str[n++] = ch; if (strchr(delim, ch)) { break; } } str[n] = '\0'; return n; } //------------------------------------------------------------------------------ #define errorHalt(msg) {Serial.println(F(msg)); SysCall::halt();} //------------------------------------------------------------------------------ void setup() { Serial.begin(9600); // Wait for USB Serial while (!Serial) { SysCall::yield(); } Serial.println("Type any character to start"); while (!Serial.available()) { SysCall::yield(); } // Initialize the SD. if (!SD.begin(CS_PIN)) { errorHalt("begin failed"); } // Create or open the file. file = SD.open("READNUM.TXT", FILE_WRITE); if (!file) { errorHalt("open failed"); } // Rewind file so test data is not appended. file.rewind(); // Write test data. file.print(F( "11,12,13,14\r\n" "21,22,23,24\r\n" "31,32,33,34\r\n" "41,42,43,44\r\n" "51,52,53,54" // Allow missing endl at eof. )); // Rewind the file for read. file.rewind(); // Array for data. int array[ROW_DIM][COL_DIM]; int i = 0; // First array index. int j = 0; // Second array index size_t n; // Length of returned field with delimiter. char str[20]; // Must hold longest field with delimiter and zero byte. char *ptr; // Test for valid field. // Read the file and store the data. for (i = 0; i < ROW_DIM; i++) { for (j = 0; j < COL_DIM; j++) { n = readField(&file, str, sizeof(str), ",\n"); if (n == 0) { errorHalt("Too few lines"); } array[i][j] = strtol(str, &ptr, 10); if (ptr == str) { errorHalt("bad number"); } while (*ptr == ' ') { ptr++; } if (*ptr != ',' && *ptr != '\n' && *ptr != '\0') { errorHalt("extra characters in field"); } if (j < (COL_DIM-1) && str[n-1] != ',') { errorHalt("line with too few fields"); } } // Allow missing endl at eof. if (str[n-1] != '\n' && file.available()) { errorHalt("missing endl"); } } // Print the array. for (i = 0; i < ROW_DIM; i++) { for (j = 0; j < COL_DIM; j++) { if (j) { Serial.print(' '); } Serial.print(array[i][j]); } Serial.println(); } Serial.println("Done"); file.close(); } //------------------------------------------------------------------------------ void loop() { }