Add Print::printf() method for sanity

Author: earlephilhower

api/Print.cpp

@@ -16,6 +16,7 @@
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
 
+#include <stdarg.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
@@ -235,6 +236,53 @@ size_t Print::println(const Printable& x)
   return n;
 }
 
+size_t Print::printf(const char *format, ...) {
+    va_list arg;
+    va_start(arg, format);
+    char temp[64];
+    char* buffer = temp;
+    size_t len = vsnprintf(temp, sizeof(temp), format, arg);
+    va_end(arg);
+    if (len > sizeof(temp) - 1) {
+        buffer = new char[len + 1];
+        if (!buffer) {
+            return 0;
+        }
+        va_start(arg, format);
+        vsnprintf(buffer, len + 1, format, arg);
+        va_end(arg);
+    }
+    len = write((const uint8_t*) buffer, len);
+    if (buffer != temp) {
+        delete[] buffer;
+    }
+    return len;
+}
+
+// TODO - must be better way than cut-n-paste!
+size_t Print::printf_P(const char *format, ...) {
+    va_list arg;
+    va_start(arg, format);
+    char temp[64];
+    char* buffer = temp;
+    size_t len = vsnprintf(temp, sizeof(temp), format, arg);
+    va_end(arg);
+    if (len > sizeof(temp) - 1) {
+        buffer = new char[len + 1];
+        if (!buffer) {
+            return 0;
+        }
+        va_start(arg, format);
+        vsnprintf(buffer, len + 1, format, arg);
+        va_end(arg);
+    }
+    len = write((const uint8_t*) buffer, len);
+    if (buffer != temp) {
+        delete[] buffer;
+    }
+    return len;
+}
+
 // Private Methods /////////////////////////////////////////////////////////////
 
 size_t Print::printNumber(unsigned long n, uint8_t base)

api/Print.h

@@ -89,8 +89,12 @@ class Print
     size_t println(const Printable&);
     size_t println(void);
 
+    // EFP3 - Add printf() to make life so much easier...
+    size_t printf(const char *format, ...);
+    size_t printf_P(const char *format, ...);
+
     virtual void flush() { /* Empty implementation for backward compatibility */ }
 };
 
 }
-using namespace arduino;
+using namespace arduino;