From d20c3c65c89949e149e76151d7dc3150a191cfd0 Mon Sep 17 00:00:00 2001
From: Benoit Blanchon <git@benoitblanchon.fr>
Date: Fri, 31 Dec 2021 13:13:51 +0100
Subject: [PATCH] Add a polyfill for `pgm_read_dword()` (issue #1433)

---
 extras/tests/Helpers/progmem_emulation.hpp |  4 ----
 src/ArduinoJson/Polyfills/pgmspace.hpp     | 10 +++++++++-
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/extras/tests/Helpers/progmem_emulation.hpp b/extras/tests/Helpers/progmem_emulation.hpp
index 7ca5f158..7a977db8 100644
--- a/extras/tests/Helpers/progmem_emulation.hpp
+++ b/extras/tests/Helpers/progmem_emulation.hpp
@@ -31,10 +31,6 @@ inline float pgm_read_float(const void* p) {
   return *reinterpret_cast<const float*>(convertFlashToPtr(p));
 }
 
-inline uint32_t pgm_read_dword(const void* p) {
-  return *reinterpret_cast<const uint32_t*>(convertFlashToPtr(p));
-}
-
 #define ARDUINOJSON_DEFINE_PROGMEM_ARRAY(type, name, value)        \
   static type const ARDUINOJSON_CONCAT2(name, _progmem)[] = value; \
   static type const* name = reinterpret_cast<type const*>(         \
diff --git a/src/ArduinoJson/Polyfills/pgmspace.hpp b/src/ArduinoJson/Polyfills/pgmspace.hpp
index b4c56fce..28ce4f8b 100644
--- a/src/ArduinoJson/Polyfills/pgmspace.hpp
+++ b/src/ArduinoJson/Polyfills/pgmspace.hpp
@@ -14,7 +14,7 @@ namespace ARDUINOJSON_NAMESPACE {
 // Wraps a const char* so that the our functions are picked only if the
 // originals are missing
 struct pgm_p {
-  pgm_p(const char* p) : address(p) {}
+  pgm_p(const void* p) : address(reinterpret_cast<const char*>(p)) {}
   const char* address;
 };
 }  // namespace ARDUINOJSON_NAMESPACE
@@ -95,3 +95,11 @@ inline void* memcpy_P(void* dst, ARDUINOJSON_NAMESPACE::pgm_p src, size_t n) {
   return dst;
 }
 #endif
+
+#ifndef pgm_read_dword
+inline uint32_t pgm_read_dword(ARDUINOJSON_NAMESPACE::pgm_p p) {
+  uint32_t result;
+  memcpy_P(&result, p, 4);
+  return result;
+}
+#endif