Init commit.HEADmaster

5 files changed, 142 insertions, 0 deletions

diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..4386a05
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,24 @@
+#include <stdio.h>
+#include "square.h"
+
+void print_square(struct square *square)
+{
+    double area = square_area(square);
+    printf("square_area=%f\n", area);
+}
+
+void print_shape(struct shape *shape)
+{
+    double area = shape_area(shape);
+    printf("shape_area=%f\n", area);
+}
+
+int main(int argc, char **argv)
+{
+    struct square *square = square_create(5);
+    print_square(square);
+
+    print_shape(square_as_shape(square));
+    
+    shape_destroy(square_as_shape(square));
+}
diff --git a/src/shape.c b/src/shape.c
new file mode 100644
index 0000000..cb72c05
--- /dev/null
+++ b/src/shape.c
@@ -0,0 +1,32 @@
+#include <stdlib.h>
+#include "shape.h"
+
+struct shape
+{
+    shape_area_t area;
+    shape_destroy_t destroy;
+};
+
+double shape_area(struct shape *shape)
+{
+    return shape->area(shape);
+}
+
+void shape_destroy(struct shape *shape)
+{
+    shape->destroy(shape);
+}
+
+void shape_init(
+    struct shape *shape,
+    shape_area_t area,
+    shape_destroy_t destroy)
+{
+    shape->area = area;
+    shape->destroy = destroy;
+}
+
+int shape_sizeof()
+{
+    return sizeof(struct shape);
+}
\ No newline at end of file
diff --git a/src/shape.h b/src/shape.h
new file mode 100644
index 0000000..641b440
--- /dev/null
+++ b/src/shape.h
@@ -0,0 +1,21 @@
+#ifndef POC__SHAPE_H
+#define POC__SHAPE_H
+
+struct shape;
+
+/* Calculates the area of the shape and returns the value. */
+double shape_area(struct shape *shape);
+typedef double (*shape_area_t)(struct shape *);
+
+/* Deallocates the object. */
+void shape_destroy(struct shape *shape);
+typedef void (*shape_destroy_t)(struct shape *);
+
+void shape_init(
+    struct shape *shape,
+    shape_area_t area,
+    shape_destroy_t destroy);
+
+int shape_sizeof();
+
+#endif
diff --git a/src/square.c b/src/square.c
new file mode 100644
index 0000000..8aef283
--- /dev/null
+++ b/src/square.c
@@ -0,0 +1,49 @@
+#include <stdlib.h>
+#include <stddef.h>
+#include "square.h"
+
+struct square
+{
+    double width;
+};
+
+/* Shape interface */
+
+double shape_area_impl(struct shape *shape)
+{
+    struct square *square = ((void *)shape) + shape_sizeof();
+    return square_area(square);
+}
+
+void shape_destroy_impl(struct shape *shape)
+{
+    struct square *square = ((void *)shape) + shape_sizeof();
+    square_destroy(square);
+}
+
+struct shape *square_as_shape(struct square *square)
+{
+    return ((void *)square) - shape_sizeof();
+}
+
+/* End of shape interface */
+
+struct square *square_create(double width)
+{
+    struct shape *shape = malloc(shape_sizeof() + sizeof(struct square));
+    struct square *square = ((void *)shape) + shape_sizeof();
+    square->width = width;
+
+    shape_init(shape, shape_area_impl, shape_destroy_impl);
+    return square;
+}
+
+double square_area(struct square *square)
+{
+    return square->width * square->width;
+}
+
+void square_destroy(struct square *square)
+{
+    free(((void *)square) - shape_sizeof());
+}
\ No newline at end of file
diff --git a/src/square.h b/src/square.h
new file mode 100644
index 0000000..177c9c7
--- /dev/null
+++ b/src/square.h
@@ -0,0 +1,16 @@
+#ifndef POC__SQUARE_H
+#define POC__SQUARE_H
+
+#include "shape.h"
+
+struct square;
+
+struct square *square_create(double width);
+
+double square_area(struct square *square);
+
+void square_destroy(struct square *square);
+
+struct shape *square_as_shape(struct square *square);
+
+#endif