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// example: https://doc.rust-lang.org/rust-by-example/std/box.html
#include <stdio.h>
typedef struct {
double x;
double y;
} Point;
// A Rectangle can be specified by where its top left and bottom right
// corners are in space
typedef struct {
Point top_left;
Point bottom_right;
} Rectangle;
#define i_key Point
#include <stc/cbox.h> // cbox_Point
#define i_key Rectangle
#include <stc/cbox.h> // cbox_Rectangle
// Box in box:
#define i_type BoxBoxPoint
#define i_keyboxed cbox_Point // NB: use i_keyboxed when value is a cbox or carc!
#define i_no_cmp
#include <stc/cbox.h> // BoxBoxPoint
Point origin(void) {
return c_LITERAL(Point){ .x=1.0, .y=2.0 };
}
cbox_Point boxed_origin(void) {
// Allocate this point on the heap, and return a pointer to it
return cbox_Point_make(c_LITERAL(Point){ .x=1.0, .y=2.0 });
}
int main(void) {
// Stack allocated variables
Point point = origin();
Rectangle rectangle = {
.top_left = origin(),
.bottom_right = { .x=3.0, .y=-4.0 }
};
// Heap allocated rectangle
cbox_Rectangle boxed_rectangle = cbox_Rectangle_make(c_LITERAL(Rectangle){
.top_left = origin(),
.bottom_right = { .x=3.0, .y=-4.0 }
});
// The output of functions can be boxed
cbox_Point boxed_point = cbox_Point_make(origin());
// Can use from(raw) and toraw instead:
BoxBoxPoint box_in_a_box = BoxBoxPoint_from(origin());
c_defer(
BoxBoxPoint_drop(&box_in_a_box),
cbox_Point_drop(&boxed_point),
cbox_Rectangle_drop(&boxed_rectangle)
){
printf("box_in_a_box: x = %g\n", BoxBoxPoint_toraw(&box_in_a_box).x);
printf("Point occupies %d bytes on the stack\n",
(int)sizeof(point));
printf("Rectangle occupies %d bytes on the stack\n",
(int)sizeof(rectangle));
// box size == pointer size
printf("Boxed point occupies %d bytes on the stack\n",
(int)sizeof(boxed_point));
printf("Boxed rectangle occupies %d bytes on the stack\n",
(int)sizeof(boxed_rectangle));
printf("Boxed box occupies %d bytes on the stack\n",
(int)sizeof(box_in_a_box));
// Copy the data contained in `boxed_point` into `unboxed_point`
Point unboxed_point = *boxed_point.get;
printf("Unboxed point occupies %d bytes on the stack\n",
(int)sizeof(unboxed_point));
}
}
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