add String.toFloat

Author: tevino

arduino/cores/arduino/WString.cpp

@@ -100,6 +100,19 @@ String::String(unsigned long value, unsigned char base)
 	*this = buf;
 }
 
+String::String(float value, int decimalPlaces)
+{
+	init();
+	char buf[33];
+	*this = dtostrf(value, (decimalPlaces + 2), decimalPlaces, buf);
+}
+
+String::String(double value, int decimalPlaces)
+{
+	init();
+	char buf[33];
+	*this = dtostrf(value, (decimalPlaces + 2), decimalPlaces, buf);
+}
 String::~String()
 {
 	free(buffer);
@@ -283,6 +296,20 @@ unsigned char String::concat(unsigned long num)
 	return concat(buf, strlen(buf));
 }
 
+unsigned char String::concat(float num)
+{
+	char buf[20];
+	char* string = dtostrf(num, 8, 6, buf);
+	return concat(string, strlen(string));
+}
+
+unsigned char String::concat(double num)
+{
+	char buf[20];
+	char* string = dtostrf(num, 8, 6, buf);
+	return concat(string, strlen(string));
+}
+
 /*********************************************/
 /*  Concatenate                              */
 /*********************************************/
@@ -343,6 +370,19 @@ StringSumHelper & operator + (const StringSumHelper &lhs, unsigned long num)
 	return a;
 }
 
+StringSumHelper & operator + (const StringSumHelper &lhs, float num)
+{
+	StringSumHelper &a = const_cast<StringSumHelper&>(lhs);
+	if (!a.concat(num)) a.invalidate();
+	return a;
+}
+
+StringSumHelper & operator + (const StringSumHelper &lhs, double num)
+{
+	StringSumHelper &a = const_cast<StringSumHelper&>(lhs);
+	if (!a.concat(num)) a.invalidate();
+	return a;
+}
 /*********************************************/
 /*  Comparison                               */
 /*********************************************/
@@ -659,3 +699,8 @@ long String::toInt(void) const
 }
 
 
+float String::toFloat(void) const
+{
+	if (buffer) return float(atof(buffer));
+	return 0;
+}

arduino/cores/arduino/WString.h

@@ -68,6 +68,8 @@ class String
 	explicit String(unsigned int, unsigned char base=10);
 	explicit String(long, unsigned char base=10);
 	explicit String(unsigned long, unsigned char base=10);
+    explicit String(float, int decimalPlaces=6);
+    explicit String(double, int decimalPlaces=6);
 	~String(void);
 
 	// memory management
@@ -100,6 +102,8 @@ class String
 	unsigned char concat(unsigned int num);
 	unsigned char concat(long num);
 	unsigned char concat(unsigned long num);
+	unsigned char concat(float num);
+	unsigned char concat(double num);
 
 	// if there's not enough memory for the concatenated value, the string
 	// will be left unchanged (but this isn't signalled in any way)
@@ -120,6 +124,8 @@ class String
 	friend StringSumHelper & operator + (const StringSumHelper &lhs, unsigned int num);
 	friend StringSumHelper & operator + (const StringSumHelper &lhs, long num);
 	friend StringSumHelper & operator + (const StringSumHelper &lhs, unsigned long num);
+	friend StringSumHelper & operator + (const StringSumHelper &lhs, float num);
+	friend StringSumHelper & operator + (const StringSumHelper &lhs, double num);
 
 	// comparison (only works w/ Strings and "strings")
 	operator StringIfHelperType() const { return buffer ? &String::StringIfHelper : 0; }
@@ -172,6 +178,7 @@ class String
 
 	// parsing/conversion
 	long toInt(void) const;
+	float toFloat(void) const;
 
 protected:
 	char *buffer;	        // the actual char array