Fixed ignored Stream timeout and made sure we don't read more that necessary (issue #422)

include/ArduinoJson/StringTraits/ArduinoStream.hpp

@@ -17,15 +17,35 @@ namespace ArduinoJson {
 namespace Internals {
 
 struct ArduinoStreamTraits {
-  class Iterator {
+  class Reader {
     Stream& _stream;
+    char _current, _next;
 
    public:
-    Iterator(Stream& stream) : _stream(stream) {}
+    Reader(Stream& stream) : _stream(stream), _current(0), _next(0) {}
+
+    void move() {
+      _current = _next;
+      _next = 0;
+    }
+
+    char current() {
+      if (!_current) _current = read();
+      return _current;
+    }
 
     char next() {
-      int n = _stream.read();
-      return n >= 0 ? static_cast<char>(n) : '\0';
+      // assumes that current() has been called
+      if (!_next) _next = read();
+      return _next;
+    }
+
+   private:
+    char read() {
+      // don't use _stream.read() as it ignores the timeout
+      char c = 0;
+      _stream.readBytes(&c, 1);
+      return c;
     }
   };
 };

include/ArduinoJson/StringTraits/CharPointer.hpp

@@ -11,16 +11,22 @@ namespace ArduinoJson {
 namespace Internals {
 
 struct CharPointerTraits {
-  class Iterator {
+  class Reader {
     const char* _ptr;
 
    public:
-    Iterator(const char* ptr) : _ptr(ptr ? ptr : "") {}
+    Reader(const char* ptr) : _ptr(ptr ? ptr : "") {}
 
-    char next() {
-      char c = *_ptr;
-      if (c) ++_ptr;
-      return c;
+    void move() {
+      ++_ptr;
+    }
+
+    char current() const {
+      return _ptr[0];
+    }
+
+    char next() const {
+      return _ptr[1];
     }
   };
 

include/ArduinoJson/StringTraits/FlashString.hpp

@@ -11,15 +11,23 @@ namespace ArduinoJson {
 namespace Internals {
 template <>
 struct StringTraits<const __FlashStringHelper*, void> {
-  class Iterator {
+  class Reader {
     const char* _ptr;
 
    public:
-    Iterator(const __FlashStringHelper* ptr)
+    Reader(const __FlashStringHelper* ptr)
         : _ptr(reinterpret_cast<const char*>(ptr)) {}
 
-    char next() {
-      return pgm_read_byte_near(_ptr++);
+    void move() {
+      _ptr++;
+    }
+
+    char current() const {
+      return pgm_read_byte_near(_ptr);
+    }
+
+    char next() const {
+      return pgm_read_byte_near(_ptr + 1);
     }
   };
 

include/ArduinoJson/StringTraits/StdStream.hpp

@@ -16,18 +16,35 @@ namespace ArduinoJson {
 namespace Internals {
 
 struct StdStreamTraits {
-  class Iterator {
+  class Reader {
     std::istream& _stream;
+    char _current, _next;
 
    public:
-    Iterator(std::istream& stream) : _stream(stream) {}
+    Reader(std::istream& stream) : _stream(stream), _current(0), _next(0) {}
+
+    void move() {
+      _current = _next;
+      _next = 0;
+    }
+
+    char current() {
+      if (!_current) _current = read();
+      return _current;
+    }
 
     char next() {
-      return _stream.eof() ? '\0' : static_cast<char>(_stream.get());
+      // assumes that current() has been called
+      if (!_next) _next = read();
+      return _next;
     }
 
    private:
-    Iterator& operator=(const Iterator&);  // Visual Studio C4512
+    Reader& operator=(const Reader&);  // Visual Studio C4512
+
+    char read() {
+      return _stream.eof() ? '\0' : static_cast<char>(_stream.get());
+    }
   };
 };
 

include/ArduinoJson/StringTraits/StdString.hpp

@@ -29,8 +29,8 @@ struct StdStringTraits {
     return static_cast<char*>(dup);
   }
 
-  struct Iterator : CharPointerTraits::Iterator {
-    Iterator(const TString& str) : CharPointerTraits::Iterator(str.c_str()) {}
+  struct Reader : CharPointerTraits::Reader {
+    Reader(const TString& str) : CharPointerTraits::Reader(str.c_str()) {}
   };
 
   static bool equals(const TString& str, const char* expected) {