#ifndef _SIDE_MACROS_H
#define _SIDE_MACROS_H
+#include <stddef.h>
+#include <limits.h>
+
/* Helper macros */
#define SIDE_ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
#define SIDE_PARAM(...) __VA_ARGS__
+/*
+ * SIDE_PARAM_SELECT_ARG1
+ *
+ * Select second argument. Use inside macros to implement optional last
+ * macro argument, such as:
+ *
+ * #define macro(_a, _b, _c, _optional...) \
+ * SIDE_PARAM_SELECT_ARG1(_, ##_optional, do_default_macro())
+ *
+ * This macro is far from pretty, but attempts to create a cleaner layer
+ * on top fails for various reasons:
+ *
+ * - The libside API needs to use the default argument selection as an
+ * argument to itself (recursively), e.g. for fields and for types, so
+ * using the argument selection within an extra layer of macro fails
+ * because the extra layer cannot expand recursively.
+ * - Attempts to make the extra layer of macro support recursion through
+ * another layer of macros which expands all arguments failed because
+ * the optional argument may contain commas, and is therefore expanded
+ * into multiple arguments before argument selection, which fails to
+ * select the optional argument content after its first comma.
+ */
+#define SIDE_PARAM_SELECT_ARG1(_arg0, _arg1, ...) _arg1
+
/*
* side_container_of - Get the address of an object containing a field.
*
(type *)((char *)__ptr - offsetof(type, member)); \
})
+#define side_struct_field_sizeof(_struct, _field) \
+ sizeof(((_struct * )NULL)->_field)
+
+#if defined(__SIZEOF_LONG__)
+# define SIDE_BITS_PER_LONG (__SIZEOF_LONG__ * 8)
+#elif defined(_LP64)
+# define SIDE_BITS_PER_LONG 64
+#else
+# define SIDE_BITS_PER_LONG 32
+#endif
+
+#define SIDE_PACKED __attribute__((packed))
+
+/*
+ * The side_ptr macros allow defining a pointer type which is suitable
+ * for use by 32-bit and 64-bit kernels without compatibility code,
+ * while preserving information about the pointer type.
+ *
+ * Those pointers are stored as 64-bit integers, and the type of the
+ * actual pointer is kept alongside with the 64-bit pointer value in a
+ * 0-len array within a union.
+ *
+ * uintptr_t will fit within a uint64_t except on architectures with
+ * 128-bit pointers. This provides fixed-size pointers on architectures
+ * with pointer size of 64-bit or less. Architectures with larger
+ * pointer size will have to handle the ABI offset specifics explicitly.
+ */
+#if (__SIZEOF_POINTER__ <= 8)
+# define side_ptr_t(_type) \
+ union { \
+ uint64_t v; \
+ _type *t[0]; \
+ }
+# define side_ptr_get(_field) \
+ ((__typeof__((_field).t[0]))(uintptr_t)(_field).v)
+# define side_ptr_set(_field, _ptr) \
+ do { \
+ (_field).v = (uint64_t)(uintptr_t)(_ptr); \
+ } while (0)
+#else
+# define side_ptr_t(_type) \
+ union { \
+ uintptr_t v; \
+ _type *t[0]; \
+ }
+# define side_ptr_get(_field) \
+ ((__typeof__((_field).t[0]))(_field).v)
+# define side_ptr_set(_field, _ptr) \
+ do { \
+ (_field).v = (uintptr_t)(_ptr); \
+ } while (0)
+#endif
+
+#define SIDE_PTR_INIT(...) { .v = (uintptr_t) (__VA_ARGS__) }
+
#endif /* _SIDE_MACROS_H */