src/core/trigger.h

   1 /*!@file
   2   \brief   Trigger Mechanism
   3   \details includes a small, 15 (by default) element list of function pointers
   4            that may be registered and triggered like a stack of functions.
   5            Useful for synchronizing function calls.
   6
   7            Usage example:
   8            #include <trigger.h>
   9
  10            void trigger_test(void);
  11
  12            extern void hack_the_planet(void);
  13            extern void hack_the_plants(void);
  14            extern void hack_robert_plant(void);
  15
  16            void
  17            trigger_test()
  18            { TRIGGER_SET(hack_the_planet);
  19              TRIGGER_SET(hack_the_plants);
  20              TRIGGER_SET(hack_robert_plant);
  21
  22              //Don't worry robert!
  23              TRIGGER_POP();
  24
  25              TRIGGER();
  26            }
  27
  28            Advanced Usage Example:
  29            #define MAX_TRIGGER_FUNCS 2
  30            #define TRIGGERS kill_trigger flush_trigger
  31            #include <trigger.h>
  32            #include <hack_functions.h>
  33
  34            void
  35            advanced_trigger_test()
  36            { TRIGGER_SET(kill_trigger, hack_the_planet);
  37              TRIGGER_SET(kill_trigger, hack_the_missiles);
  38              TRIGGER_SET(flush_trigger, hack_the_government);
  39              TRIGGER_SET(flush trigger, hack_my_tax_bill);
  40
  41              if (robert_plant_hacked())
  42                { TRIGGER(kill_trigger);
  43
  44                  TRIGGER_POP(flush_trigger);
  45                  TRIGGER_SET(flush_trigger, hack_the_missile_defenses);
  46                }
  47              TRIGGER(flush_trigger);
  48            }
  49
  50
  51   \author  K
  52   \date    2016
  53   -----------------------------------------------------------------------------*/
  54
  55 #ifndef _TRIGGER_H_
  56 #define _TRIGGER_H_
  57
  58 /** The number of trigger functions per trigger */
  59 #ifndef MAX_TRIGGER_FUNCS
  60 #define MAX_TRIGGER_FUNCS 15
  61 #endif
  62
  63 /* Internal macro prototypes */
  64 #define _TRIGGER_DEL(TARG) --TARG.num_funcs
  65 #define _TRIGGER_POP(TARG) (TARG.func[_TRIGGER_DEL(TARG)])()
  66 #define _TRIGGER_SET(TARG, FUNC) TARG.func[TARG.num_funcs++] = FUNC
  67 #define _TRIGGER(TARG) while(TARG.num_funcs) TRIGGER_POP(TARG)
  68
  69 /* If TRIGGERS is not defined, use only a default trigger and define shorthand
  70    functions for easy use. */
  71 #ifndef TRIGGERS
  72 #define TRIGGERS default_trigger
  73 #define TRIGGER_DEL() _TRIGGER_DEL(default_trigger)
  74 #define TRIGGER_POP() _TRIGGER_POP(default_trigger)
  75 #define TRIGGER_SET(FUNC) _TRIGGER_SET(default_trigger, FUNC)
  76 #define TRIGGER() _TRIGGER(default_trigger)
  77 #else
  78 #define TRIGGER_DEL(TARG) _TRIGGER_DEL(TARG)
  79 #define TRIGGER_POP(TARG) _TRIGGER_POP(TARG)
  80 #define TRIGGER_SET(TARG,FUNC) _TRIGGER_SET(TARG,FUNC)
  81 #define TRIGGER(TARG) _TRIGGER(TARG)
  82 #endif
  83
  84 static struct call_trigger
  85 { int num_funcs;
  86   void (*func[MAX_TRIGGER_FUNCS])(void);
  87 } TRIGGERS;
  88
  89 #endif //_TRIGGER_H_