Do proper endian conversions

include/nlohmann/detail/input/binary_reader.hpp

@@ -1853,7 +1853,7 @@ class binary_reader
             }
 
             // reverse byte order prior to conversion if necessary
-            if (is_little_endian && !InputIsLittleEndian)
+            if (is_little_endian != InputIsLittleEndian)
             {
                 vec[sizeof(NumberType) - i - 1] = static_cast<uint8_t>(current);
             }

include/nlohmann/detail/output/binary_writer.hpp

@@ -1278,7 +1278,7 @@ class binary_writer
         std::memcpy(vec.data(), &n, sizeof(NumberType));
 
         // step 2: write array to output (with possible reordering)
-        if (is_little_endian and not OutputIsLittleEndian)
+        if (is_little_endian != OutputIsLittleEndian)
         {
             // reverse byte order prior to conversion if necessary
             std::reverse(vec.begin(), vec.end());

single_include/nlohmann/json.hpp

@@ -8333,7 +8333,7 @@ class binary_reader
             }
 
             // reverse byte order prior to conversion if necessary
-            if (is_little_endian && !InputIsLittleEndian)
+            if (is_little_endian != InputIsLittleEndian)
             {
                 vec[sizeof(NumberType) - i - 1] = static_cast<uint8_t>(current);
             }
@@ -9746,7 +9746,7 @@ class binary_writer
         std::memcpy(vec.data(), &n, sizeof(NumberType));
 
         // step 2: write array to output (with possible reordering)
-        if (is_little_endian and not OutputIsLittleEndian)
+        if (is_little_endian != OutputIsLittleEndian)
         {
             // reverse byte order prior to conversion if necessary
             std::reverse(vec.begin(), vec.end());

test/src/unit-udt.cpp

@@ -599,9 +599,8 @@ struct pod_serializer
     static void to_json(BasicJsonType& j, const  T& t) noexcept
     {
         auto bytes = static_cast< const unsigned char*>(static_cast<const void*>(&t));
-        std::uint64_t value = bytes[0];
-        for (auto i = 1; i < 8; ++i)
-            value |= std::uint64_t{bytes[i]} << 8 * i;
+        std::uint64_t value;
+        std::memcpy(&value, bytes, sizeof(value));
         nlohmann::to_json(j, value);
     }
 };