The state tracker and winsys driver support a rather limited number of
platforms. However, the pipe drivers are meant to run in a wide number of
platforms. Hence the pipe drivers, the auxiliary modules, and all public
-headers in general, should stricly follow these guidelines to ensure
+headers in general, should strictly follow these guidelines to ensure
= Compiler Support =
* Don't use variable number of macro arguments. Use static inline functions
instead.
+* Don't use C99 features.
= Standard Library =
* Use MALLOC, CALLOC, FREE instead of the malloc, calloc, free functions.
-* Use align_pointer() function defined in p_util.h for aligning pointers in a
-portable way.
+* Use align_pointer() function defined in u_memory.h for aligning pointers
+ in a portable way.
== Debugging ==
-TODO
+* Use the functions/macros in p_debug.h.
+* Don't include assert.h, call abort, printf, etc.
+
+
+= Code Style =
+
+== Inherantice in C ==
+
+The main thing we do is mimic inheritance by structure containment.
+
+Here's a silly made-up example:
+
+/* base class */
+struct buffer
+{
+ int size;
+ void (*validate)(struct buffer *buf);
+};
+
+/* sub-class of bufffer */
+struct texture_buffer
+{
+ struct buffer base; /* the base class, MUST COME FIRST! */
+ int format;
+ int width, height;
+};
+
+
+Then, we'll typically have cast-wrapper functions to convert base-class
+pointers to sub-class pointers where needed:
+
+static inline struct vertex_buffer *vertex_buffer(struct buffer *buf)
+{
+ return (struct vertex_buffer *) buf;
+}
+
+
+To create/init a sub-classed object:
+
+struct buffer *create_texture_buffer(int w, int h, int format)
+{
+ struct texture_buffer *t = malloc(sizeof(*t));
+ t->format = format;
+ t->width = w;
+ t->height = h;
+ t->base.size = w * h;
+ t->base.validate = tex_validate;
+ return &t->base;
+}
+
+Example sub-class method:
+
+void tex_validate(struct buffer *buf)
+{
+ struct texture_buffer *tb = texture_buffer(buf);
+ assert(tb->format);
+ assert(tb->width);
+ assert(tb->height);
+}
+
+
+Note that we typically do not use typedefs to make "class names"; we use
+'struct whatever' everywhere.
+
+Gallium's pipe_context and the subclassed psb_context, etc are prime examples
+of this. There's also many examples in Mesa and the Mesa state tracker.