Merge pull request #2515 from jphickey:fix-2514-msg-api-struct

Fix #2514, change CFE_MSG_Message from union to struct

Author: dzbaker

modules/core_api/fsw/inc/cfe_msg_api_typedefs.h

@@ -99,7 +99,7 @@ typedef enum CFE_MSG_PlaybackFlag
 /**
  * \brief cFS generic base message
  */
-typedef union CFE_MSG_Message CFE_MSG_Message_t;
+typedef struct CFE_MSG_Message CFE_MSG_Message_t;
 
 /**
  * \brief cFS command header

modules/core_api/ut-stubs/src/cfe_sb_handlers.c

@@ -348,7 +348,7 @@ void UT_DefaultHandler_CFE_SB_GetUserData(void *UserObj, UT_EntryKey_t FuncKey,
     if (UT_Stub_CopyToLocal(UT_KEY(CFE_SB_GetUserData), &Result, sizeof(Result)) != sizeof(Result))
     {
         BytePtr = (uint8 *)MsgPtr;
-        if ((MsgPtr->Byte[0] & 0x10) != 0)
+        if ((*BytePtr & 0x10) != 0)
         {
             HdrSize = sizeof(CFE_MSG_CommandHeader_t);
         }

modules/core_private/ut-stubs/src/ut_support.c

@@ -342,13 +342,15 @@ int32 UT_SoftwareBusSnapshotHook(void *UserObj, int32 StubRetcode, uint32 CallCo
 {
     UT_SoftwareBusSnapshot_Entry_t *Snapshot = UserObj;
     const CFE_MSG_Message_t *       MsgPtr   = UT_Hook_GetArgValueByName(Context, "MsgPtr", CFE_MSG_Message_t *);
+    const uint8_t *                 BytePtr;
 
     if (MsgPtr != NULL && Snapshot != NULL)
     {
         ++Snapshot->Count;
         if (Snapshot->SnapshotSize > 0 && Snapshot->SnapshotBuffer != NULL)
         {
-            memcpy(Snapshot->SnapshotBuffer, &MsgPtr->Byte[Snapshot->SnapshotOffset], Snapshot->SnapshotSize);
+            BytePtr = (const uint8 *)MsgPtr;
+            memcpy(Snapshot->SnapshotBuffer, &BytePtr[Snapshot->SnapshotOffset], Snapshot->SnapshotSize);
         }
     }
 
@@ -535,7 +537,7 @@ uint16 UT_GetNumEventsSent(void)
 */
 void UT_DisplayPkt(CFE_MSG_Message_t *MsgPtr, size_t size)
 {
-    uint8 *BytePtr = MsgPtr->Byte;
+    uint8 *BytePtr = (uint8 *)MsgPtr;
     size_t i;
     size_t BufSize = UT_MAX_MESSAGE_LENGTH;
     char   DisplayMsg[UT_MAX_MESSAGE_LENGTH];

modules/msg/fsw/src/cfe_msg_sechdr_checksum.c

@@ -34,7 +34,7 @@
 CFE_MSG_Checksum_t CFE_MSG_ComputeCheckSum(const CFE_MSG_Message_t *MsgPtr)
 {
     CFE_MSG_Size_t     PktLen  = 0;
-    const uint8 *      BytePtr = MsgPtr->Byte;
+    const uint8 *      BytePtr = (const uint8 *)MsgPtr;
     CFE_MSG_Checksum_t chksum  = 0xFF;
 
     /* Message already checked, no error case reachable */

modules/msg/option_inc/default_cfe_msg_hdr_pri.h

@@ -89,10 +89,9 @@ typedef struct
  *
  * This provides the definition of CFE_MSG_Message_t
  */
-union CFE_MSG_Message
+struct CFE_MSG_Message
 {
-    CCSDS_SpacePacket_t CCSDS;                             /**< \brief CCSDS Header (Pri or Pri + Ext) */
-    uint8               Byte[sizeof(CCSDS_SpacePacket_t)]; /**< \brief Byte level access */
+    CCSDS_SpacePacket_t CCSDS; /**< \brief CCSDS Header (Pri or Pri + Ext) */
 };
 
 /**

modules/msg/option_inc/default_cfe_msg_hdr_priext.h

@@ -96,10 +96,9 @@ typedef struct
 /**
  * \brief cFS generic base message
  */
-union CFE_MSG_Message
+struct CFE_MSG_Message
 {
-    CCSDS_SpacePacket_t CCSDS;                             /**< \brief CCSDS Header (Pri or Pri + Ext) */
-    uint8               Byte[sizeof(CCSDS_SpacePacket_t)]; /**< \brief Byte level access */
+    CCSDS_SpacePacket_t CCSDS; /**< \brief CCSDS Header (Pri or Pri + Ext) */
 };
 
 /**