demos/ansi-c/objects-c.c

   1 #include <stdio.h>
   2 #include <malloc.h>
   3
   4 #define CONFEDERATION(IFACE,TYPE) struct IFACE *interface;struct TYPE *next
   5 #define CREATE(TYPE) (struct TYPE *)malloc(sizeof(struct TYPE))
   6 #define APPEND(TYPE,MEMBER,LIST) (MEMBER?MEMBER->next=(struct TYPE *)LIST:0,LIST=(struct TYPE *)MEMBER)
   7
   8 struct Drawable_data
   9 {
  10  CONFEDERATION(Drawable_interface,Drawable_data);
  11 };
  12
  13 struct Drawable_interface
  14 {
  15  void (*draw)(void *self);
  16 };
  17
  18 struct Tri
  19 {
  20  CONFEDERATION(Drawable_interface,Drawable_data);
  21  int x1; int y1; int x2; int y2; int x3; int y3;
  22 };
  23
  24 struct Rect
  25 {
  26  CONFEDERATION(Drawable_interface,Drawable_data);
  27  int x1; int y1; int x2; int y2;
  28 };
  29
  30 void draw_tri(void *_self)
  31 {
  32  struct Tri *self=(struct Tri *)_self;
  33  printf("%d,%d - %d,%d - %d,%d\n",self->x1,self->y1,self->x2,self->y2,self->x3,self->y3);
  34 };
  35
  36 void draw_rect(void *self)
  37 {
  38  struct Rect *r=(struct Rect *)self;
  39  printf("%d,%d - %d,%d\n",r->x1,r->y1,r->x2,r->y2);
  40 };
  41
  42 struct Drawable_interface *init_tri_interface(void)
  43 {
  44  struct Drawable_interface *i=CREATE(Drawable_interface);
  45  /* vsechny metody je bohuzel potreba bindnout rucne, neda se svitit... */
  46  if(i) i->draw=draw_tri;
  47  return i;
  48 }
  49
  50 struct Drawable_interface *init_rect_interface(void)
  51 {
  52  struct Drawable_interface *i=CREATE(Drawable_interface);
  53  /* vsechny metody je bohuzel potreba bindnout rucne, neda se svitit... */
  54  if(i) i->draw=draw_rect;
  55  return i;
  56 }
  57
  58 struct Tri *create_tri(struct Drawable_interface *i, int x1, int y1, int x2, int y2, int x3, int y3)
  59 {
  60  struct Tri *t=CREATE(Tri);
  61  if(i && t)
  62  {
  63   t->interface=i;
  64   t->x1=x1;t->y1=y1;t->x2=x2;t->y2=y2;t->x3=x3;t->y3=y3;
  65  }
  66  return t;
  67 }
  68
  69 struct Rect *create_rect(struct Drawable_interface *i, int x1, int y1, int x2, int y2)
  70 {
  71  struct Rect *r=CREATE(Rect);
  72  if(i && r)
  73  {
  74   r->interface=i;
  75   r->x1=x1;r->y1=y1;r->x2=x2;r->y2=y2;
  76  }
  77  return r;
  78 }
  79
  80 int main(void)
  81 {
  82  struct Drawable_interface *tri_interface=init_tri_interface();
  83  struct Drawable_interface *rect_interface=init_rect_interface();
  84  struct Drawable_data *all=NULL,*one;
  85  struct Tri *t;
  86  struct Rect *r;
  87
  88  r=create_rect(rect_interface,0,10,1,11);
  89  APPEND(Drawable_data,r,all);
  90  t=create_tri(tri_interface,0,0,0,4,3,0);
  91  APPEND(Drawable_data,t,all);
  92  r=create_rect(rect_interface,10,0,11,1);
  93  APPEND(Drawable_data,r,all);
  94
  95  /* a nyni ... bylo to hodne prace, ale povedlo se ... ! */
  96
  97  for(one=all;one;one=one->next) (*(one->interface->draw))(one);
  98
  99  /* a nyni pro efekt jeste instatni nudlovy kod s kanci prichuti: */
 100
 101 #define _(OBJECT,METHOD) OBJECT==NULL)?0:(*(OBJECT->interface->METHOD))(OBJECT
 102 #define FOR_EACH(ONE,ALL)  for(ONE=ALL;ONE;ONE=ONE->next)
 103
 104  FOR_EACH(one,all) (_(one,draw));
 105
 106  return 0;
 107 }