Fix #1 by using dtostrf on ESP8266.

Author: tdicola

Adafruit_IO_Arduino.cpp

@@ -99,7 +99,7 @@ bool FeedData::ulongValue(unsigned long* value) {
     #else
         *value = strtoul(_value, &endptr, 10);
     #endif
-    return (*_value != 0 && *endptr == 0);  
+    return (*_value != 0 && *endptr == 0);
 }
 
 bool FeedData::floatValue(float* value) {
@@ -149,27 +149,35 @@ bool Adafruit_IO_Feed::send(unsigned long value) {
     return _adapter->send(_name, _converted, _key, false);
 }
 
-bool Adafruit_IO_Feed::send(float value) {
-    // Convert float to string using scientific notation, then send the value 
+bool Adafruit_IO_Feed::send(float value, int precision) {
+    // Convert float to string using scientific notation, then send the value
     // (being careful not to quote it).
     memset(_converted, 0, sizeof(_converted));
     #if defined(ARDUINO_ARCH_AVR)
         // Use avrlibc dtostre function on AVR platforms.
         dtostre(value, _converted, 10, 0);
+    #elif defined(ESP8266)
+        // ESP8266 Arduino only implements dtostrf and not dtostre.  Use dtostrf
+        // but accept a hint as to how many decimals of precision are desired.
+        dtostrf(value, 0, precision, _converted);
     #else
         // Otherwise fall back to snprintf on other platforms.
         snprintf(_converted, sizeof(_converted)-1, "%f", value);
     #endif
     return _adapter->send(_name, _converted, _key, false);
 }
 
-bool Adafruit_IO_Feed::send(double value) {
-    // Convert double to string using scientific notation, then send the value 
+bool Adafruit_IO_Feed::send(double value, int precision) {
+    // Convert double to string using scientific notation, then send the value
     // (being careful not to quote it).
     memset(_converted, 0, sizeof(_converted));
     #if defined(ARDUINO_ARCH_AVR)
         // Use avrlibc dtostre function on AVR platforms.
         dtostre(value, _converted, 10, 0);
+    #elif defined(ESP8266)
+        // ESP8266 Arduino only implements dtostrf and not dtostre.  Use dtostrf
+        // but accept a hint as to how many decimals of precision are desired.
+        dtostrf(value, 0, precision, _converted);
     #else
         // Otherwise fall back to snprintf on other platforms.
         snprintf(_converted, sizeof(_converted)-1, "%f", value);

Adafruit_IO_Arduino.h

@@ -26,8 +26,8 @@
 #include "Arduino.h"
 
 // Control how big the buffer is for storing a data instance's value.
-// Keep at least a value of ~33 to store large numeric and float values.
-#define FEEDDATA_LENGTH 33
+// Keep at least a value of ~41 to store large numeric and float values.
+#define FEEDDATA_LENGTH 41
 
 // How large the received data buffer is in bytes.  This is used for reading
 // the response of HTTP requests like header names and response codes.
@@ -96,16 +96,16 @@ class Adafruit_IO_Feed {
     Adafruit_IO_Feed(const char* name, const char* key, AIOService* adapter):
         _name(name), _key(key), _adapter(adapter)
     {}
-    
-    bool send(const char* value) { 
+
+    bool send(const char* value) {
         return _adapter->send(_name, value, _key, true);
     }
     bool send(int value);
     bool send(unsigned int value);
     bool send(long value);
     bool send(unsigned long value);
-    bool send(float value);
-    bool send(double value);
+    bool send(float value, int precision=6);
+    bool send(double value, int precision=6);
 
     FeedData receive() {
         return _adapter->receive(_name, _key);

library.properties

@@ -1,5 +1,5 @@
 name=Adafruit IO Arduino
-version=1.0.0
+version=1.0.1
 author=Adafruit
 maintainer=Adafruit <info@adafruit.com>
 sentence=Arduino library to access the Adafruit IO REST API.