This patch improves the parsing capabilites of

Stream::parseFloat()

The function will now accept decimals starting with an '.' character
not just '0.'.

This commit also fixes an error in the function where 1.23.45 is
parsed as 1.2345 rather than 1.23 and subsequent calls reading 0.45

Author: Chris--A

hardware/arduino/avr/cores/arduino/Stream.cpp

@@ -54,14 +54,17 @@ int Stream::timedPeek()
 
 // returns peek of the next digit in the stream or -1 if timeout
 // discards non-numeric characters
-int Stream::peekNextDigit()
+int Stream::peekNextDigit( bool detectDecimal )
 {
   int c;
   while (1) {
     c = timedPeek();
-    if (c < 0) return c;  // timeout
-    if (c == '-') return c;
-    if (c >= '0' && c <= '9') return c;
+
+    if( c < 0 ||
+        c == '-' ||
+        c >= '0' && c <= '9' ||
+        detectDecimal && c == '.') return c;
+
     read();  // discard non-numeric
   }
 }
@@ -124,7 +127,7 @@ long Stream::parseInt(char skipChar)
   long value = 0;
   int c;
 
-  c = peekNextDigit();
+  c = peekNextDigit(false);
   // ignore non numeric leading characters
   if(c < 0)
     return 0; // zero returned if timeout
@@ -162,7 +165,7 @@ float Stream::parseFloat(char skipChar){
   char c;
   float fraction = 1.0;
 
-  c = peekNextDigit();
+  c = peekNextDigit(true);
     // ignore non numeric leading characters
   if(c < 0)
     return 0; // zero returned if timeout
@@ -182,7 +185,7 @@ float Stream::parseFloat(char skipChar){
     read();  // consume the character we got with peek
     c = timedPeek();
   }
-  while( (c >= '0' && c <= '9')  || c == '.' || c == skipChar );
+  while( (c >= '0' && c <= '9')  || c == '.' && !isFraction || c == skipChar );
 
   if(isNegative)
     value = -value;

hardware/arduino/avr/cores/arduino/Stream.h

@@ -42,7 +42,7 @@ class Stream : public Print
     unsigned long _startMillis;  // used for timeout measurement
     int timedRead();    // private method to read stream with timeout
     int timedPeek();    // private method to peek stream with timeout
-    int peekNextDigit(); // returns the next numeric digit in the stream or -1 if timeout
+    int peekNextDigit( bool detectDecimal ); // returns the next numeric digit in the stream or -1 if timeout
 
   public:
     virtual int available() = 0;

hardware/arduino/sam/cores/arduino/Stream.cpp

@@ -54,14 +54,17 @@ int Stream::timedPeek()
 
 // returns peek of the next digit in the stream or -1 if timeout
 // discards non-numeric characters
-int Stream::peekNextDigit()
+int Stream::peekNextDigit( bool detectDecimal )
 {
   int c;
   while (1) {
     c = timedPeek();
-    if (c < 0) return c;  // timeout
-    if (c == '-') return c;
-    if (c >= '0' && c <= '9') return c;
+
+    if( c < 0 ||
+        c == '-' ||
+        c >= '0' && c <= '9' ||
+        detectDecimal && c == '.') return c;
+
     read();  // discard non-numeric
   }
 }
@@ -124,7 +127,7 @@ long Stream::parseInt(char skipChar)
   long value = 0;
   int c;
 
-  c = peekNextDigit();
+  c = peekNextDigit(false);
   // ignore non numeric leading characters
   if(c < 0)
     return 0; // zero returned if timeout
@@ -162,7 +165,7 @@ float Stream::parseFloat(char skipChar){
   char c;
   float fraction = 1.0;
 
-  c = peekNextDigit();
+  c = peekNextDigit(true);
     // ignore non numeric leading characters
   if(c < 0)
     return 0; // zero returned if timeout
@@ -182,7 +185,7 @@ float Stream::parseFloat(char skipChar){
     read();  // consume the character we got with peek
     c = timedPeek();
   }
-  while( (c >= '0' && c <= '9')  || c == '.' || c == skipChar );
+  while( (c >= '0' && c <= '9')  || c == '.' && !isFraction || c == skipChar );
 
   if(isNegative)
     value = -value;

hardware/arduino/sam/cores/arduino/Stream.h

@@ -42,7 +42,7 @@ class Stream : public Print
     unsigned long _startMillis;  // used for timeout measurement
     int timedRead();    // private method to read stream with timeout
     int timedPeek();    // private method to peek stream with timeout
-    int peekNextDigit(); // returns the next numeric digit in the stream or -1 if timeout
+    int peekNextDigit( bool detectDecimal ); // returns the next numeric digit in the stream or -1 if timeout
 
   public:
     virtual int available() = 0;