CodeGeneration

Code generation in C with the pre-processor.

Applied X-Macros

• Based on luser-droog's answer on StackOverflow?
• Code generation with Meta-X-Macros

include

define ERRORS(_) \

_(NO_ERROR, 0x00) \  
/* discontiguous  */ \  
_(EMPTY, 0x02) \  
_(OVERFLOW, 0x03) \  
_(TIMEOUT, 0x04) \  

/** X-Macro to define ERROR_ enum entries */

define AS_ENUM(name, ID) ERROR_##name = ID,

/** X-Macro to define {"ERROR_FOO", ID} struct table entries */

define AS_LIST(name, ID) {#name, ID},

/** Register Enum /
enum ERROR {
/ Generate enum elements with X-Macro */
ERRORS(AS_ENUM)

ERROR_MAX  

};

/**

• Error List Generated by X-Macro @ref AS_LIST.
  
• Works with non-contiguous sets.
  /
  static const struct ErrorEntry {
  char name;
  enum ERROR id;
  } ERROR_LIST[] = {
  ERRORS(AS_LIST)
  };
  

void PrintAll(void)
{
size_t idx = ;

for (idx = ;  
     idx < sizeof(ERROR_LIST)/sizeof(ERROR_LIST[]);  
     idx++)  
{  
    const struct ErrorEntry* reg = &ERROR_LIST[idx];  
    printf("Error message 0x%x is \"%s\"\n", reg->id, reg->name);  
}  

}

int main(void)
{
PrintAll();
}

$[Get Code]4

Method

1. ERRORS(AS_ENUM) expands to enum ERROR {
   /* Generate enum elements with X-Macro */
   AS_ENUM(NO_ERROR, 0x00) \
   AS_ENUM(EMPTY, 0x02) \
   ...

   ERROR_MAX  
   

   };

   $[Get Code]5

2. Each of these is then expanded again by the preprocessor to enum ERROR {
   ERROR_NO_ERROR = 0x00,
   ERROR_EMPTY = 0x02,
   ...

   ERROR_MAX  
   

   };

   $[Get Code]6

3. Similar expansion applies for the ERROR_LIST struct list entries

Protocol Messages

• Generate struct serialization/deserialization routines
• https://github.com/cognomen/C-MsgGen