From c8a79d0d0c999997d2ee9cd5b773b5ff6561e130 Mon Sep 17 00:00:00 2001
From: Tevin Zhang <mail2tevin@gmail.com>
Date: Wed, 29 May 2013 10:42:07 +0800
Subject: add String.toFloat

---
 cores/arduino/WString.cpp | 45 +++++++++++++++++++++++++++++++++++++++++++++
 cores/arduino/WString.h   |  7 +++++++
 2 files changed, 52 insertions(+)

(limited to 'cores/arduino')

diff --git a/cores/arduino/WString.cpp b/cores/arduino/WString.cpp
index aab2a54..e19f543 100644
--- a/cores/arduino/WString.cpp
+++ b/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;
+}
diff --git a/cores/arduino/WString.h b/cores/arduino/WString.h
index b587a3d..2d372c5 100644
--- a/cores/arduino/WString.h
+++ b/cores/arduino/WString.h
@@ -68,6 +68,8 @@ public:
 	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 @@ public:
 	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 @@ public:
 	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 @@ public:
 
 	// parsing/conversion
 	long toInt(void) const;
+	float toFloat(void) const;
 
 protected:
 	char *buffer;	        // the actual char array
-- 
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