Extracted class StringBuilder

JsonGeneratorTests/StringBuilder.h

@@ -0,0 +1,27 @@
+/*
+ * Arduino JSON library
+ * Benoit Blanchon 2014 - MIT License
+ */
+
+#pragma once
+
+#include <cstdarg>
+#include <cstdio>
+#include <cstring>
+
+class StringBuilder
+{
+public:
+    StringBuilder(char* buf, size_t size)
+        : buffer(buf), capacity(size), length(0)
+    {
+    }
+
+    void append(const char* format, ...);
+
+private:
+    char* buffer;
+    int capacity;
+    int length;
+};
+