Don't use JsonBuffer to create or parse objects and arrays.

* Added DynamicJsonArray and StaticJsonArray
* Added DynamicJsonObject and StaticJsonObject
* Added DynamicJsonVariant and StaticJsonVariant
* Added deserializeJson()
* Removed JsonBuffer::parseArray(), parseObject() and parse()
* Removed JsonBuffer::createArray() and createObject()

test/JsonParser/JsonVariant.cpp

@@ -0,0 +1,90 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2018
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+using namespace Catch::Matchers;
+
+TEST_CASE("deserializeJson(JsonVariant&)") {
+  DynamicJsonVariant variant;
+
+  SECTION("EmptyObject") {
+    bool success = deserializeJson(variant, "{}");
+
+    REQUIRE(success == true);
+    REQUIRE(variant.is<JsonObject>());
+  }
+
+  SECTION("EmptyArray") {
+    bool success = deserializeJson(variant, "[]");
+
+    REQUIRE(success == true);
+    REQUIRE(variant.is<JsonArray>());
+  }
+
+  SECTION("Integer") {
+    bool success = deserializeJson(variant, "-42");
+
+    REQUIRE(success == true);
+    REQUIRE(variant.is<int>());
+    REQUIRE_FALSE(variant.is<bool>());
+    REQUIRE(variant == -42);
+  }
+
+  SECTION("Double") {
+    bool success = deserializeJson(variant, "-1.23e+4");
+
+    REQUIRE(success == true);
+    REQUIRE_FALSE(variant.is<int>());
+    REQUIRE(variant.is<double>());
+    REQUIRE(variant.as<double>() == Approx(-1.23e+4));
+  }
+
+  SECTION("Double quoted string") {
+    bool success = deserializeJson(variant, "\"hello world\"");
+
+    REQUIRE(success == true);
+    REQUIRE(variant.is<char*>());
+    REQUIRE_THAT(variant.as<char*>(), Equals("hello world"));
+  }
+
+  SECTION("Single quoted string") {
+    bool success = deserializeJson(variant, "\'hello world\'");
+
+    REQUIRE(success == true);
+    REQUIRE(variant.is<char*>());
+    REQUIRE_THAT(variant.as<char*>(), Equals("hello world"));
+  }
+
+  SECTION("True") {
+    bool success = deserializeJson(variant, "true");
+
+    REQUIRE(success == true);
+    REQUIRE(variant.is<bool>());
+    REQUIRE(variant == true);
+  }
+
+  SECTION("False") {
+    bool success = deserializeJson(variant, "false");
+
+    REQUIRE(success == true);
+    REQUIRE(variant.is<bool>());
+    REQUIRE(variant == false);
+  }
+
+  SECTION("OpenBrace") {
+    bool success = deserializeJson(variant, "{");
+
+    REQUIRE(success == false);
+  }
+
+  SECTION("Incomplete string") {
+    bool success = deserializeJson(variant, "\"hello");
+
+    REQUIRE(success == true);
+    REQUIRE(variant.is<char*>());
+    REQUIRE_THAT(variant.as<char*>(), Equals("hello"));
+  }
+}