[Morse] Added support for Arduino flash strings

examples/Morse/Morse_Transmit/Morse_Transmit.ino

@@ -74,6 +74,9 @@ void loop() {
   // character array (C-String)
   morse.print("C-String");
 
+  // string saved in flash
+  morse.print(F("Flash String"));
+
   // character
   morse.print('c');
 

src/protocols/Morse.cpp

@@ -85,6 +85,10 @@ int16_t MorseClient::begin(float base, uint8_t speed) {
   return(state);
 }
 
+size_t MorseClient::startSignal() {
+  return(MorseClient::write(0x01));
+}
+
 size_t MorseClient::write(const char* str) {
   if(str == NULL) {
     return(0);
@@ -147,8 +151,17 @@ size_t MorseClient::write(uint8_t b) {
   return(0);
 }
 
-size_t MorseClient::startSignal() {
-  return(MorseClient::write(0x01));
+size_t MorseClient::print(__FlashStringHelper* fstr) {
+  PGM_P p = reinterpret_cast<PGM_P>(fstr);
+  size_t n = 0;
+  while(true) {
+    char c = pgm_read_byte(p++);
+    if(c == '\0') {
+      break;
+    }
+    n += MorseClient::write(c);
+  }
+  return n;
 }
 
 size_t MorseClient::print(const String& str) {
@@ -206,6 +219,12 @@ size_t MorseClient::println(void) {
   return(MorseClient::write(0x02));
 }
 
+size_t MorseClient::println(__FlashStringHelper* fstr) {
+  size_t n = MorseClient::print(fstr);
+  n += MorseClient::println();
+  return(n);
+}
+
 size_t MorseClient::println(const String& str) {
   size_t n = MorseClient::print(str);
   n += MorseClient::println();

src/protocols/Morse.h

@@ -44,6 +44,7 @@ class MorseClient {
     size_t write(uint8_t* buff, size_t len);
     size_t write(uint8_t b);
 
+    size_t print(__FlashStringHelper*);
     size_t print(const String &);
     size_t print(const char[]);
     size_t print(char);
@@ -55,6 +56,7 @@ class MorseClient {
     size_t print(double, int = 2);
 
     size_t println(void);
+    size_t println(__FlashStringHelper*);
     size_t println(const String &s);
     size_t println(const char[]);
     size_t println(char);