Added support for custom reader classes

CHANGELOG.md

@@ -4,7 +4,7 @@ ArduinoJson: change log
 HEAD
 ----
 
-* Added support for custom writer classes (issue #1088)
+* Added support for custom writer/reader classes (issue #1088)
 * Added conversion from `JsonArray` and `JsonObject` to `bool`, to be consistent with `JsonVariant`
 * Fixed `deserializeJson()` when input contains duplicate keys (issue #1095)
 * Improved `deserializeMsgPack()` speed by reading several bytes at once

extras/tests/CMakeLists.txt

@@ -72,6 +72,7 @@ if(MSVC)
 	)
 endif()
 
+include_directories(Helpers)
 add_subdirectory(ElementProxy)
 add_subdirectory(IntegrationTests)
 add_subdirectory(JsonArray)

extras/tests/Helpers/CustomReader.hpp

@@ -0,0 +1,26 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2019
+// MIT License
+
+#pragma once
+
+#include <sstream>
+
+class CustomReader {
+  std::stringstream _stream;
+
+ public:
+  CustomReader(const char* input) : _stream(input) {}
+
+  int read() {
+    return _stream.get();
+  }
+
+  size_t readBytes(char* buffer, size_t length) {
+    _stream.read(buffer, static_cast<std::streamsize>(length));
+    return static_cast<size_t>(_stream.gcount());
+  }
+
+ private:
+  CustomReader(const CustomReader&);
+};

extras/tests/JsonDeserializer/input_types.cpp

@@ -6,6 +6,8 @@
 #include <catch.hpp>
 #include <sstream>
 
+#include "CustomReader.hpp"
+
 TEST_CASE("deserializeJson(const std::string&)") {
   DynamicJsonDocument doc(4096);
 
@@ -113,3 +115,14 @@ TEST_CASE("deserializeJson(VLA)") {
   REQUIRE(err == DeserializationError::Ok);
 }
 #endif
+
+TEST_CASE("deserializeJson(CustomReader)") {
+  DynamicJsonDocument doc(4096);
+  CustomReader reader("[4,2]");
+  DeserializationError err = deserializeJson(doc, reader);
+
+  REQUIRE(err == DeserializationError::Ok);
+  REQUIRE(doc.size() == 2);
+  REQUIRE(doc[0] == 4);
+  REQUIRE(doc[1] == 2);
+}

extras/tests/Misc/Readers.cpp

@@ -2,15 +2,15 @@
 // Copyright Benoit Blanchon 2014-2019
 // MIT License
 
-#include <ArduinoJson.h>
+#include <ArduinoJson/Deserialization/Reader.hpp>
 #include <catch.hpp>
 
 using namespace ARDUINOJSON_NAMESPACE;
 
-TEST_CASE("StdStreamReader") {
+TEST_CASE("Reader<std::istringstream>") {
   SECTION("read()") {
     std::istringstream src("\x01\xFF");
-    StdStreamReader reader(src);
+    Reader<std::istringstream> reader(src);
 
     REQUIRE(reader.read() == 0x01);
     REQUIRE(reader.read() == 0xFF);
@@ -19,7 +19,7 @@ TEST_CASE("StdStreamReader") {
 
   SECTION("readBytes() all at once") {
     std::istringstream src("ABC");
-    StdStreamReader reader(src);
+    Reader<std::istringstream> reader(src);
 
     char buffer[8] = "abcd";
     REQUIRE(reader.readBytes(buffer, 4) == 3);
@@ -32,7 +32,7 @@ TEST_CASE("StdStreamReader") {
 
   SECTION("readBytes() in two parts") {
     std::istringstream src("ABCDEF");
-    StdStreamReader reader(src);
+    Reader<std::istringstream> reader(src);
 
     char buffer[12] = "abcdefg";
     REQUIRE(reader.readBytes(buffer, 4) == 4);
@@ -48,17 +48,17 @@ TEST_CASE("StdStreamReader") {
   }
 }
 
-TEST_CASE("SafeCharPointerReader") {
+TEST_CASE("BoundedReader<const char*>") {
   SECTION("read") {
-    SafeCharPointerReader reader("\x01\xFF", 2);
+    BoundedReader<const char*> reader("\x01\xFF", 2);
     REQUIRE(reader.read() == 0x01);
     REQUIRE(reader.read() == 0xFF);
     REQUIRE(reader.read() == -1);
     REQUIRE(reader.read() == -1);
   }
 
   SECTION("readBytes() all at once") {
-    SafeCharPointerReader reader("ABCD", 3);
+    BoundedReader<const char*> reader("ABCD", 3);
 
     char buffer[8] = "abcd";
     REQUIRE(reader.readBytes(buffer, 4) == 3);
@@ -70,7 +70,7 @@ TEST_CASE("SafeCharPointerReader") {
   }
 
   SECTION("readBytes() in two parts") {
-    SafeCharPointerReader reader("ABCDEF", 6);
+    BoundedReader<const char*> reader("ABCDEF", 6);
 
     char buffer[8] = "abcdefg";
     REQUIRE(reader.readBytes(buffer, 4) == 4);
@@ -86,17 +86,17 @@ TEST_CASE("SafeCharPointerReader") {
   }
 }
 
-TEST_CASE("UnsafeCharPointerReader") {
+TEST_CASE("Reader<const char*>") {
   SECTION("read()") {
-    UnsafeCharPointerReader reader("\x01\xFF\x00\x12");
+    Reader<const char*> reader("\x01\xFF\x00\x12");
     REQUIRE(reader.read() == 0x01);
     REQUIRE(reader.read() == 0xFF);
     REQUIRE(reader.read() == 0);
     REQUIRE(reader.read() == 0x12);
   }
 
   SECTION("readBytes() all at once") {
-    UnsafeCharPointerReader reader("ABCD");
+    Reader<const char*> reader("ABCD");
 
     char buffer[8] = "abcd";
     REQUIRE(reader.readBytes(buffer, 3) == 3);
@@ -108,7 +108,7 @@ TEST_CASE("UnsafeCharPointerReader") {
   }
 
   SECTION("readBytes() in two parts") {
-    UnsafeCharPointerReader reader("ABCDEF");
+    Reader<const char*> reader("ABCDEF");
 
     char buffer[8] = "abcdefg";
     REQUIRE(reader.readBytes(buffer, 4) == 4);

extras/tests/MixedConfiguration/enable_progmem_1.cpp

@@ -86,19 +86,19 @@ TEST_CASE("memcpy_P") {
   CHECK(dst[3] == 0);
 }
 
-TEST_CASE("SafeCharPointerReader") {
-  using ARDUINOJSON_NAMESPACE::SafeFlashStringReader;
+TEST_CASE("BoundedReader<const __FlashStringHelper*>") {
+  using namespace ARDUINOJSON_NAMESPACE;
 
   SECTION("read") {
-    SafeFlashStringReader reader(F("\x01\xFF"), 2);
+    BoundedReader<const __FlashStringHelper*> reader(F("\x01\xFF"), 2);
     REQUIRE(reader.read() == 0x01);
     REQUIRE(reader.read() == 0xFF);
     REQUIRE(reader.read() == -1);
     REQUIRE(reader.read() == -1);
   }
 
   SECTION("readBytes() all at once") {
-    SafeFlashStringReader reader(F("ABCD"), 3);
+    BoundedReader<const __FlashStringHelper*> reader(F("ABCD"), 3);
 
     char buffer[8] = "abcd";
     REQUIRE(reader.readBytes(buffer, 4) == 3);
@@ -110,7 +110,7 @@ TEST_CASE("SafeCharPointerReader") {
   }
 
   SECTION("readBytes() in two parts") {
-    SafeFlashStringReader reader(F("ABCDEF"), 6);
+    BoundedReader<const __FlashStringHelper*> reader(F("ABCDEF"), 6);
 
     char buffer[8] = "abcdefg";
     REQUIRE(reader.readBytes(buffer, 4) == 4);
@@ -126,19 +126,19 @@ TEST_CASE("SafeCharPointerReader") {
   }
 }
 
-TEST_CASE("UnsafeFlashStringReader") {
-  using ARDUINOJSON_NAMESPACE::UnsafeFlashStringReader;
+TEST_CASE("Reader<const __FlashStringHelper*>") {
+  using namespace ARDUINOJSON_NAMESPACE;
 
   SECTION("read()") {
-    UnsafeFlashStringReader reader(F("\x01\xFF\x00\x12"));
+    Reader<const __FlashStringHelper*> reader(F("\x01\xFF\x00\x12"));
     REQUIRE(reader.read() == 0x01);
     REQUIRE(reader.read() == 0xFF);
     REQUIRE(reader.read() == 0);
     REQUIRE(reader.read() == 0x12);
   }
 
   SECTION("readBytes() all at once") {
-    UnsafeFlashStringReader reader(F("ABCD"));
+    Reader<const __FlashStringHelper*> reader(F("ABCD"));
 
     char buffer[8] = "abcd";
     REQUIRE(reader.readBytes(buffer, 3) == 3);
@@ -150,7 +150,7 @@ TEST_CASE("UnsafeFlashStringReader") {
   }
 
   SECTION("readBytes() in two parts") {
-    UnsafeFlashStringReader reader(F("ABCDEF"));
+    Reader<const __FlashStringHelper*> reader(F("ABCDEF"));
 
     char buffer[8] = "abcdefg";
     REQUIRE(reader.readBytes(buffer, 4) == 4);

extras/tests/MsgPackDeserializer/input_types.cpp

@@ -5,6 +5,8 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
+#include "CustomReader.hpp"
+
 TEST_CASE("deserializeMsgPack(const std::string&)") {
   DynamicJsonDocument doc(4096);
 
@@ -80,3 +82,14 @@ TEST_CASE("deserializeMsgPack(VLA)") {
   REQUIRE(err == DeserializationError::Ok);
 }
 #endif
+
+TEST_CASE("deserializeMsgPack(CustomReader)") {
+  DynamicJsonDocument doc(4096);
+  CustomReader reader("\x92\xA5Hello\xA5world");
+  DeserializationError err = deserializeMsgPack(doc, reader);
+
+  REQUIRE(err == DeserializationError::Ok);
+  REQUIRE(doc.size() == 2);
+  REQUIRE(doc[0] == "Hello");
+  REQUIRE(doc[1] == "world");
+}

src/ArduinoJson/Deserialization/Reader.hpp

@@ -0,0 +1,55 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2019
+// MIT License
+
+#pragma once
+
+#include <ArduinoJson/Namespace.hpp>
+
+#include <stdlib.h>  // for size_t
+
+namespace ARDUINOJSON_NAMESPACE {
+
+// The default reader is a simple wrapper for Readers that are not copiable
+template <typename TSource, typename Enable = void>
+struct Reader {
+ public:
+  Reader(TSource& source) : _source(&source) {}
+
+  int read() {
+    return _source->read();
+  }
+
+  size_t readBytes(char* buffer, size_t length) {
+    return _source->readBytes(buffer, length);
+  }
+
+ private:
+  TSource* _source;
+};
+
+template <typename TSource, typename Enable = void>
+struct BoundedReader {
+  // no default implementation because we need to pass the size to the
+  // constructor
+};
+}  // namespace ARDUINOJSON_NAMESPACE
+
+#include <ArduinoJson/Deserialization/Readers/IteratorReader.hpp>
+#include <ArduinoJson/Deserialization/Readers/RamReader.hpp>
+
+#if ARDUINOJSON_ENABLE_ARDUINO_STREAM
+#include <ArduinoJson/Deserialization/Readers/ArduinoStreamReader.hpp>
+#endif
+
+#if ARDUINOJSON_ENABLE_ARDUINO_STRING
+#include <ArduinoJson/Deserialization/Readers/ArduinoStringReader.hpp>
+#endif
+
+#if ARDUINOJSON_ENABLE_PROGMEM
+#include <ArduinoJson/Deserialization/Readers/FlashReader.hpp>
+#endif
+
+#if ARDUINOJSON_ENABLE_STD_STREAM
+#include <ArduinoJson/Deserialization/Readers/StdStreamReader.hpp>
+#endif