serializeMsgPack(doc, p, n) doesn't add terminator anymore (fixes #1545)

src/ArduinoJson/Json/JsonSerializer.hpp

@@ -14,6 +14,8 @@ namespace ARDUINOJSON_NAMESPACE {
 template <typename TWriter>
 class JsonSerializer : public Visitor<size_t> {
  public:
+  static const bool producesText = true;
+
   JsonSerializer(TWriter writer) : _formatter(writer) {}
 
   FORCE_INLINE size_t visitArray(const CollectionData &array) {

src/ArduinoJson/Json/PrettyJsonSerializer.hpp

@@ -16,7 +16,7 @@ class PrettyJsonSerializer : public JsonSerializer<TWriter> {
   typedef JsonSerializer<TWriter> base;
 
  public:
-  PrettyJsonSerializer(TWriter &writer) : base(writer), _nesting(0) {}
+  PrettyJsonSerializer(TWriter writer) : base(writer), _nesting(0) {}
 
   size_t visitArray(const CollectionData &array) {
     VariantSlot *slot = array.head();

src/ArduinoJson/MsgPack/MsgPackSerializer.hpp

@@ -17,6 +17,8 @@ namespace ARDUINOJSON_NAMESPACE {
 template <typename TWriter>
 class MsgPackSerializer : public Visitor<size_t> {
  public:
+  static const bool producesText = false;
+
   MsgPackSerializer(TWriter writer) : _writer(writer) {}
 
   template <typename T>

src/ArduinoJson/Serialization/Writers/StaticStringWriter.hpp

@@ -8,18 +8,14 @@
 
 namespace ARDUINOJSON_NAMESPACE {
 
-// A Print implementation that allows to write in a char[]
 class StaticStringWriter {
  public:
-  StaticStringWriter(char *buf, size_t size) : end(buf + size - 1), p(buf) {
-    *p = '\0';
-  }
+  StaticStringWriter(char *buf, size_t size) : end(buf + size), p(buf) {}
 
   size_t write(uint8_t c) {
     if (p >= end)
       return 0;
     *p++ = static_cast<char>(c);
-    *p = '\0';
     return 1;
   }
 
@@ -29,7 +25,6 @@ class StaticStringWriter {
       *p++ = static_cast<char>(*s++);
       n--;
     }
-    *p = '\0';
     return size_t(p - begin);
   }
 

src/ArduinoJson/Serialization/serialize.hpp

@@ -23,11 +23,23 @@ size_t serialize(const TSource &source, TDestination &destination) {
 }
 
 template <template <typename> class TSerializer, typename TSource>
-size_t serialize(const TSource &source, void *buffer, size_t bufferSize) {
+typename enable_if<!TSerializer<StaticStringWriter>::producesText, size_t>::type
+serialize(const TSource &source, void *buffer, size_t bufferSize) {
   StaticStringWriter writer(reinterpret_cast<char *>(buffer), bufferSize);
   return doSerialize<TSerializer>(source, writer);
 }
 
+template <template <typename> class TSerializer, typename TSource>
+typename enable_if<TSerializer<StaticStringWriter>::producesText, size_t>::type
+serialize(const TSource &source, void *buffer, size_t bufferSize) {
+  StaticStringWriter writer(reinterpret_cast<char *>(buffer), bufferSize);
+  size_t n = doSerialize<TSerializer>(source, writer);
+  // add null-terminator for text output (not counted in the size)
+  if (n < bufferSize)
+    reinterpret_cast<char *>(buffer)[n] = 0;
+  return n;
+}
+
 template <template <typename> class TSerializer, typename TSource,
           typename TChar, size_t N>
 #if defined _MSC_VER && _MSC_VER < 1900
@@ -36,8 +48,7 @@ typename enable_if<sizeof(remove_reference<TChar>::type) == 1, size_t>::type
 typename enable_if<sizeof(TChar) == 1, size_t>::type
 #endif
 serialize(const TSource &source, TChar (&buffer)[N]) {
-  StaticStringWriter writer(reinterpret_cast<char *>(buffer), N);
-  return doSerialize<TSerializer>(source, writer);
+  return serialize<TSerializer>(source, buffer, N);
 }
 
 }  // namespace ARDUINOJSON_NAMESPACE