From c711fe592db35e57c9273bdd2f1bdc60f609edf6 Mon Sep 17 00:00:00 2001
From: Benoit Blanchon <git@benoitblanchon.fr>
Date: Wed, 28 Oct 2020 09:23:26 +0100
Subject: [PATCH] Allowed more than 32767 values in non-embedded mode (fixes
 #1414)

---
 CHANGELOG.md                            |  1 +
 src/ArduinoJson/Configuration.hpp       | 17 ++++++++++++++
 src/ArduinoJson/Polyfills/integer.hpp   | 30 +++++++++++++++++++++++++
 src/ArduinoJson/Variant/VariantSlot.hpp |  9 ++++----
 4 files changed, 52 insertions(+), 5 deletions(-)
 create mode 100644 src/ArduinoJson/Polyfills/integer.hpp

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 98254812..15e20f43 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@ HEAD
 
 * Fixed error `ambiguous overload for 'operator|'` (issue #1411)
 * Fixed `operator|(MemberProxy, JsonObject)` (issue #1415)
+* Allowed more than 32767 values in non-embedded mode (issue #1414)
 
 v6.17.0 (2020-10-19)
 -------
diff --git a/src/ArduinoJson/Configuration.hpp b/src/ArduinoJson/Configuration.hpp
index 42ba498e..32a6f339 100644
--- a/src/ArduinoJson/Configuration.hpp
+++ b/src/ArduinoJson/Configuration.hpp
@@ -83,6 +83,18 @@
 #define ARDUINOJSON_DEFAULT_NESTING_LIMIT 10
 #endif
 
+// Number of bits to store the pointer to next node
+// (saves RAM but limits the number of values in a document)
+#ifndef ARDUINOJSON_SLOT_OFFSET_SIZE
+#if defined(__SIZEOF_POINTER__) && __SIZEOF_POINTER__ == 2
+// Address space == 16-bit => max 127 values
+#define ARDUINOJSON_SLOT_OFFSET_SIZE 1
+#else
+// Address space > 16-bit => max 32767 values
+#define ARDUINOJSON_SLOT_OFFSET_SIZE 2
+#endif
+#endif
+
 #else  // ARDUINOJSON_EMBEDDED_MODE
 
 // On a computer we have plenty of memory so we can use doubles
@@ -114,6 +126,11 @@
 #define ARDUINOJSON_DEFAULT_NESTING_LIMIT 50
 #endif
 
+// Number of bits to store the pointer to next node
+#ifndef ARDUINOJSON_SLOT_OFFSET_SIZE
+#define ARDUINOJSON_SLOT_OFFSET_SIZE 4
+#endif
+
 #endif  // ARDUINOJSON_EMBEDDED_MODE
 
 #ifdef ARDUINO
diff --git a/src/ArduinoJson/Polyfills/integer.hpp b/src/ArduinoJson/Polyfills/integer.hpp
new file mode 100644
index 00000000..8dfebb09
--- /dev/null
+++ b/src/ArduinoJson/Polyfills/integer.hpp
@@ -0,0 +1,30 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2020
+// MIT License
+
+#pragma once
+
+#include <stdint.h>  // int8_t, int16_t
+
+#include <ArduinoJson/Namespace.hpp>
+
+namespace ARDUINOJSON_NAMESPACE {
+
+template <int Bits>
+struct int_t;
+
+template <>
+struct int_t<8> {
+  typedef int8_t type;
+};
+
+template <>
+struct int_t<16> {
+  typedef int16_t type;
+};
+
+template <>
+struct int_t<32> {
+  typedef int32_t type;
+};
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Variant/VariantSlot.hpp b/src/ArduinoJson/Variant/VariantSlot.hpp
index 9a62954d..38494f3b 100644
--- a/src/ArduinoJson/Variant/VariantSlot.hpp
+++ b/src/ArduinoJson/Variant/VariantSlot.hpp
@@ -4,8 +4,7 @@
 
 #pragma once
 
-#include <stdint.h>  // int8_t, int16_t
-
+#include <ArduinoJson/Polyfills/integer.hpp>
 #include <ArduinoJson/Polyfills/limits.hpp>
 #include <ArduinoJson/Polyfills/type_traits.hpp>
 #include <ArduinoJson/Strings/StoragePolicy.hpp>
@@ -13,7 +12,7 @@
 
 namespace ARDUINOJSON_NAMESPACE {
 
-typedef conditional<sizeof(void*) <= 2, int8_t, int16_t>::type VariantSlotDiff;
+typedef int_t<ARDUINOJSON_SLOT_OFFSET_SIZE * 8>::type VariantSlotDiff;
 
 class VariantSlot {
   // CAUTION: same layout as VariantData
@@ -63,9 +62,9 @@ class VariantSlot {
 
   void setNext(VariantSlot* slot) {
     ARDUINOJSON_ASSERT(!slot || slot - this >=
-                       numeric_limits<VariantSlotDiff>::lowest());
+                                    numeric_limits<VariantSlotDiff>::lowest());
     ARDUINOJSON_ASSERT(!slot || slot - this <=
-                       numeric_limits<VariantSlotDiff>::highest());
+                                    numeric_limits<VariantSlotDiff>::highest());
     _next = VariantSlotDiff(slot ? slot - this : 0);
   }