Merge branch 'pull-request/#989-Packed-unaligned_type' into development

ETLCPP · Dec 16, 2024 · f9b2494 · f9b2494
2 parents d6f7d28 + 0568293
commit f9b2494
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Showing 4 changed files with 48 additions and 4 deletions.
diff --git a/include/etl/platform.h b/include/etl/platform.h
@@ -460,6 +460,22 @@ SOFTWARE.
   #define ETL_HAS_INITIALIZER_LIST 0
 #endif
 
+//*************************************
+// Determine if the ETL should use __attribute__((packed).
+#if defined(ETL_COMPILER_CLANG) || defined(ETL_COMPILER_GCC) || defined(ETL_COMPILER_INTEL) || defined(ETL_COMPILER_ARM6)
+  #define ETL_PACKED     __attribute__((packed))
+  #define ETL_END_PACKED
+  #define ETL_HAS_PACKED 1
+#elif defined(ETL_COMPILER_MICROSOFT)
+  #define ETL_PACKED     __pragma(pack(push, 1))
+  #define ETL_END_PACKED __pragma(pack(pop))
+  #define ETL_HAS_PACKED 1
+#else
+  #define ETL_PACKED
+  #define ETL_END_PACKED
+  #define ETL_HAS_PACKED 0
+#endif
+
 //*************************************
 // Check for availability of certain builtins
 #include "profiles/determine_builtin_support.h"
@@ -518,6 +534,7 @@ namespace etl
     static ETL_CONSTANT bool has_mutable_array_view           = (ETL_HAS_MUTABLE_ARRAY_VIEW == 1);
     static ETL_CONSTANT bool has_ideque_repair                = (ETL_HAS_IDEQUE_REPAIR == 1);
     static ETL_CONSTANT bool has_virtual_messages             = (ETL_HAS_VIRTUAL_MESSAGES == 1);
+    static ETL_CONSTANT bool has_packed                       = (ETL_HAS_PACKED == 1);
 
     // Is...
     static ETL_CONSTANT bool is_debug_build                   = (ETL_IS_DEBUG_BUILD == 1);

diff --git a/include/etl/unaligned_type.h b/include/etl/unaligned_type.h
@@ -53,7 +53,7 @@ namespace etl
     /// Contains all functionality that doesn't require the type.
     //*************************************************************************
     template <size_t Size_>
-    class unaligned_type_common
+    class ETL_PACKED unaligned_type_common
     {
     public:
 
@@ -214,7 +214,7 @@ namespace etl
     protected:
 
       unsigned char storage[Size];
-    };
+    }; ETL_END_PACKED
 
     template <size_t Size_>
     ETL_CONSTANT size_t unaligned_type_common<Size_>::Size;
@@ -227,7 +227,7 @@ namespace etl
   ///\tparam Endian The endianness of the arithmetic type.
   //*************************************************************************
   template <typename T, int Endian_>
-  class unaligned_type : public private_unaligned_type::unaligned_type_common<sizeof(T)>
+  class ETL_PACKED unaligned_type : public private_unaligned_type::unaligned_type_common<sizeof(T)>
   {
   public:
 
@@ -729,7 +729,7 @@ namespace etl
         }
       }
     };
-  };
+  }; ETL_END_PACKED
 
   template <typename T, int Endian_>
   ETL_CONSTANT int unaligned_type<T, Endian_>::Endian;

diff --git a/test/test_etl_traits.cpp b/test/test_etl_traits.cpp
@@ -77,6 +77,7 @@ namespace
       CHECK_EQUAL((ETL_HAS_IDEQUE_REPAIR == 1),                etl::traits::has_ideque_repair);
       CHECK_EQUAL((ETL_HAS_MUTABLE_ARRAY_VIEW == 1),           etl::traits::has_mutable_array_view);
       CHECK_EQUAL((ETL_HAS_VIRTUAL_MESSAGES == 1),             etl::traits::has_virtual_messages);
+      CHECK_EQUAL((ETL_HAS_PACKED == 1),                       etl::traits::has_packed);
 
       CHECK_EQUAL((ETL_IS_DEBUG_BUILD == 1),                   etl::traits::is_debug_build);
       CHECK_EQUAL(__cplusplus,                                 etl::traits::cplusplus);

diff --git a/test/test_utility.cpp b/test/test_utility.cpp
@@ -718,5 +718,31 @@ namespace
       CHECK_EQUAL(forward_like_call_type::ConstRValue, template_function_fl<TFL&&>(etl::move(u4)));
       CHECK_EQUAL(forward_like_call_type::ConstRValue, template_function_fl<const TFL&&>(etl::move(u4)));
     }
+
+#if ETL_HAS_PACKED
+    //*********************************
+    TEST(test_packed)
+    {
+      struct Unpacked
+      {
+        uint32_t a = 0x12345678;
+        uint8_t  b = 0x9A;
+        uint32_t c = 0x87654321;
+      };
+
+      struct ETL_PACKED Packed
+      {
+        uint32_t a = 0x12345678;
+        uint8_t  b = 0x9A;
+        uint32_t c = 0x87654321;
+      }; ETL_END_PACKED
+
+      Unpacked unpacked;
+      Packed   packed;
+
+      CHECK_TRUE(sizeof(unpacked) > sizeof(packed));
+      CHECK_EQUAL(9U, sizeof(packed));
+    }
+#endif
   };
 }