String purge

src/Devices/PHProbe.cpp

@@ -39,24 +39,26 @@ void PHProbe::clearCalibration() {
 }
 
 void PHProbe::sendSlopeRequest() {
-  Serial1.print("SLOPE,?\r");  // Sending request for Calibration Slope
-  slopeResponse = "       Slope requested!";
+  // Sending request for Calibration Slope
+  Serial1.print("SLOPE,?\r");
+  strncpy(slopeResponse, "       Slope requested!", sizeof(slopeResponse));  // Flawfinder: ignore
 }
 
-String PHProbe::getSlope() {
+void PHProbe::getSlope(char *buffer, int size) {
   // for example "?SLOPE,99.7,100.3, -0.89"
-  if (slopeResponse.length() < 10) {
-    return String("");
+  if (strlen(slopeResponse) > 10) {            // Flawfinder: ignore
+    strncpy(buffer, slopeResponse + 7, size);  // Flawfinder: ignore
+  } else {
+    buffer[0] = '\0';
   }
-  String slope = slopeResponse.substring(7);
-  return slope;
 }
 
 /**
  * interrupt handler for data arriving from probe
  */
 void PHProbe::serialEvent1() {
-  while (Serial1.available() > 0) {                 // if we see that the Atlas Scientific product has sent a character
+  // if we see that the Atlas Scientific product has sent a character
+  while (Serial1.available() > 0) {
     String string = Serial1.readStringUntil('\r');  // read the string until we see a <CR>
     if (string.length() > 0 && string[string.length() - 1] == '\r') {
       // We should not see the CR (https://github.com/Arduino-CI/arduino_ci/pull/302)
@@ -79,7 +81,7 @@ void PHProbe::serialEvent1() {
         serial("PHProbe serialEvent1: \"%s\"", string.c_str());
         if (string.length() > 7 && string.substring(0, 7) == "?SLOPE,") {
           // for example "?SLOPE,16.1,100.0"
-          slopeResponse = string;
+          strncpy(slopeResponse, string.c_str(), sizeof(slopeResponse));  // Flawfinder: ignore
         }
       }
     }
@@ -90,31 +92,30 @@ void PHProbe::serialEvent1() {
 //  water becomes more acidic at higher temperatures."
 // https://www.westlab.com/blog/2017/11/15/how-does-temperature-affect-ph
 void PHProbe::setTemperatureCompensation(float temperature) {
-  const String PARTIAL_COMMAND = "T,";
-  String fullCommand;
+  char buffer[10];
   if (temperature > 0 && temperature < 100) {
-    fullCommand = PARTIAL_COMMAND + String(temperature, 2) + "\r";
+    snprintf(buffer, sizeof(buffer), "T,%.2f\r", temperature);
   } else {
-    fullCommand = PARTIAL_COMMAND + "20\r";
+    snprintf(buffer, sizeof(buffer), "T,20\r");
   }
-  serial("PHProbe::setTemperatureCompensation) - %s", fullCommand.c_str());
-  Serial1.print(fullCommand);  // send that string to the Atlas Scientific product
+  serial("PHProbe::setTemperatureCompensation) - %s", buffer);
+  Serial1.print(buffer);  // send that string to the Atlas Scientific product
 }
 
 void PHProbe::setHighpointCalibration(float highpoint) {
-  String fullCommand;
-  fullCommand = "Cal,High," + String(highpoint, 3) + "\r";
-  Serial1.print(fullCommand);  // send that string to the Atlas Scientific product
+  char buffer[17];
+  snprintf(buffer, sizeof(buffer), "Cal,High,%.3f\r", highpoint);
+  Serial1.print(buffer);  // send that string to the Atlas Scientific product
 }
 
 void PHProbe::setLowpointCalibration(float lowpoint) {
-  String fullCommand;
-  fullCommand = "Cal,low," + String(lowpoint, 3) + "\r";
-  Serial1.print(fullCommand);  // send that string to the Atlas Scientific product
+  char buffer[16];
+  snprintf(buffer, sizeof(buffer), "Cal,low,%.3f\r", lowpoint);
+  Serial1.print(buffer);  // send that string to the Atlas Scientific product
 }
 
 void PHProbe::setMidpointCalibration(float midpoint) {
-  String fullCommand;
-  fullCommand = "Cal,mid," + String(midpoint, 3) + "\r";
-  Serial1.print(fullCommand);  // send that string to the Atlas Scientific product
+  char buffer[16];
+  snprintf(buffer, sizeof(buffer), "Cal,mid,%.3f\r", midpoint);
+  Serial1.print(buffer);  // send that string to the Atlas Scientific product
 }

src/Devices/PHProbe.h

@@ -19,11 +19,11 @@ class PHProbe {
   float getPh() {
     return value;
   }
-  String getSlopeResponse() {
+  const char* getSlopeResponse() const {
     return slopeResponse;
   }
   void clearCalibration();
-  String getSlope();
+  void getSlope(char* buffer, int size);
   void sendSlopeRequest();
   void serialEvent1();
   void setHighpointCalibration(float highpoint);
@@ -36,7 +36,7 @@ class PHProbe {
   static PHProbe* _instance;
   // instance variable
   float value = 0;
-  String slopeResponse = "";
+  char slopeResponse[32] = "";
   // Methods
   PHProbe();
 };

src/Devices/SD_TC.cpp

@@ -34,32 +34,33 @@ SD_TC::SD_TC() {
 /**
  * append data to a data log file
  */
-void SD_TC::appendData(String header, String line) {
-  String path = todaysDataFileName();
-  if (!sd.exists(path.c_str())) {
-    appendDataToPath(header, path.c_str());
+void SD_TC::appendData(const char* header, const char* line) {
+  char path[30];
+  todaysDataFileName(path, sizeof(path));
+  if (!sd.exists(path)) {
+    appendDataToPath(header, path);
     COUT(header);
   }
-  appendDataToPath(line, path.c_str());
+  appendDataToPath(line, path);
   COUT(line);
 }
 
 /**
  * append data to a path
  */
-void SD_TC::appendDataToPath(String line, String path) {
+void SD_TC::appendDataToPath(const char* line, const char* path) {
   COUT(path);
   File file = sd.open(path, O_CREAT | O_WRONLY | O_APPEND);
   if (file) {
-    file.write(line.c_str(), line.length());
+    file.write(line);
     file.write("\n", 1);
     file.close();
     COUT(file);
   } else {
     if (!hasHadError) {
       hasHadError = true;
-      serial("Unable to open file: \"%s\"", path.c_str());
-      COUT("Unable to open file: \"" << path.c_str() << "\"");
+      serial("Unable to open file: \"%s\"", path);
+      COUT("Unable to open file: \"" << path << "\"");
       return;
     }
   }
@@ -68,7 +69,7 @@ void SD_TC::appendDataToPath(String line, String path) {
 /**
  * append data to a serial log file
  */
-void SD_TC::appendToLog(String line) {
+void SD_TC::appendToLog(const char* line) {
   DateTime_TC now = DateTime_TC::now();
   char path[30];
   snprintf(path, sizeof(path), "%4i%02i%02i.log", now.year(), now.month(), now.day());
@@ -98,10 +99,8 @@ void SD_TC::printRootDirectory() {
   // serial("SD_TC::printRootDirectory()");
 }
 
-String SD_TC::todaysDataFileName() {
+void SD_TC::todaysDataFileName(char* path, int size) {
   DateTime_TC now = DateTime_TC::now();
-  char path[30];
-  snprintf(path, sizeof(path), "%4i%02i%02i.csv", now.year(), now.month(), now.day());
+  snprintf(path, size, "%4i%02i%02i.csv", now.year(), now.month(), now.day());
   COUT(path);
-  return String(path);
 }

src/Devices/SD_TC.h

@@ -5,23 +5,20 @@
 #define SS 4
 #include <SdFat.h>
 
-typedef void (*visitor)(File* pEntry, String parentPath);
-
 class SD_TC {
 public:
   // class methods
   static SD_TC* instance();
 
   // instance methods
-  void appendData(String header, String line);
-  void appendToLog(String line);
+  void appendData(const char* header, const char* line);
+  void appendToLog(const char* line);
   bool exists(const char* path);
   bool format();
   bool mkdir(const char* path);
   File open(const char* path, oflag_t oflag = 0x00);
-  String todaysDataFileName();
+  void todaysDataFileName(char* path, int size);
   void printRootDirectory();
-  void visit(visitor pFunction);
 
 private:
   // class variables
@@ -34,5 +31,5 @@ class SD_TC {
 
   // instance methods
   SD_TC();
-  void appendDataToPath(String data, String path);
+  void appendDataToPath(const char* data, const char* path);
 };

src/UIState/SeeLogFile.cpp

@@ -10,5 +10,7 @@
 
 void SeeLogFile::start() {
   LiquidCrystal_TC::instance()->writeLine(prompt(), 0);
-  LiquidCrystal_TC::instance()->writeLine(SD_TC::instance()->todaysDataFileName().c_str(), 1);
+  char path[30];
+  SD_TC::instance()->todaysDataFileName(path, sizeof(path));
+  LiquidCrystal_TC::instance()->writeLine(path, 1);
 }

src/UIState/SeePHSlope.cpp

@@ -8,11 +8,13 @@
 #include "Devices/PHProbe.h"
 
 void SeePHSlope::loop() {
-  LiquidCrystal_TC::instance()->writeLine(PHProbe::instance()->getSlope().c_str(), 1);
+  char buffer[20];
+  PHProbe::instance()->getSlope(buffer, sizeof(buffer));
+  LiquidCrystal_TC::instance()->writeLine(buffer, 1);
 }
 
 void SeePHSlope::start() {
   LiquidCrystal_TC::instance()->writeLine(prompt(), 0);
   LiquidCrystal_TC::instance()->writeLine("requesting slope", 1);
   PHProbe::instance()->sendSlopeRequest();
-}
+}

test/PHProbeTest.cpp

@@ -90,15 +90,16 @@ unittest(getSlope) {
   PHProbe *pPHProbe = PHProbe::instance();
   GODMODE()->serialPort[1].dataIn = "?SLOPE,99.7,100.3,-0.89\r";  // the queue of data waiting to be read
   tc->serialEvent1();                                             // fake interrupt
-  String slope = pPHProbe->getSlope();
-  assertEqual("99.7,100.3,-0.89", slope);
+  char buffer[20];
+  pPHProbe->getSlope(buffer, sizeof(buffer));
+  assertEqual("99.7,100.3,-0.89", buffer);
   COUT(state->serialPort[0].dataOut.length());
   GODMODE()->serialPort[1].dataIn = "?SLOPE,98.7,101.3,-0.89\r";  // the answer to getSlop() waiting to be read
   tc->serialEvent1();                                             // fake interrupt
   COUT(state->serialPort[0].dataOut.length());
   state->serialPort[0].dataOut = "";
-  slope = pPHProbe->getSlope();
-  assertEqual("98.7,101.3,-0.89", slope);
+  pPHProbe->getSlope(buffer, sizeof(buffer));
+  assertEqual("98.7,101.3,-0.89", buffer);
 }
 
 unittest(getPh) {