Reduced memory consumption by not duplicating spaces and comments

include/ArduinoJson/Deserialization/StringReader.hpp

@@ -13,24 +13,29 @@ namespace Internals {
 // Parse JSON string to create JsonArrays and JsonObjects
 // This internal class is not indended to be used directly.
 // Instead, use JsonBuffer.parseArray() or .parseObject()
+template <typename TIterator>
 class StringReader {
+  TIterator _input;
+  char _current, _next;
+
  public:
-  StringReader(const char *input) : _ptr(input ? input : "") {}
-
-  void skip() {
-    _ptr++;
+  StringReader(const TIterator& input) : _input(input) {
+    _current = _input.next();
+    _next = _input.next();
   }
 
-  char peek() const {
-    return _ptr[0];
+  void move() {
+    _current = _next;
+    _next = _input.next();
   }
 
-  char peekNext() const {
-    return _ptr[1];
+  char current() const {
+    return _current;
   }
 
- private:
-  const char *_ptr;
+  char next() const {
+    return _next;
+  }
 };
 }
 }