#include <stddef.h>
#include <limits.h>
+#include <stdint.h>
+#include <side/endian.h>
/* Helper macros */
#define SIDE_PARAM(...) __VA_ARGS__
+#define side_offsetofend(type, member) \
+ (offsetof(type, member) + sizeof(((type *)0)->member))
+
+/*
+ * 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
+
+/*
+ * Compile time assertion.
+ * - predicate: boolean expression to evaluate,
+ * - msg: string to print to the user on failure when `static_assert()` is
+ * supported,
+ * - c_identifier_msg: message to be included in the typedef to emulate a
+ * static assertion. This parameter must be a valid C identifier as it will
+ * be used as a typedef name.
+ */
+#ifdef __cplusplus
+#define side_static_assert(predicate, msg, c_identifier_msg) \
+ static_assert(predicate, msg)
+#elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L)
+#define side_static_assert(predicate, msg, c_identifier_msg) \
+ _Static_assert(predicate, msg)
+#else
+/*
+ * Evaluates the predicate and emit a compilation error on failure.
+ *
+ * If the predicate evaluates to true, this macro emits a function
+ * prototype with an argument type which is an array of size 0.
+ *
+ * If the predicate evaluates to false, this macro emits a function
+ * prototype with an argument type which is an array of negative size
+ * which is invalid in C and forces a compiler error. The
+ * c_identifier_msg parameter is used as the argument identifier so it
+ * is printed to the user when the error is reported.
+ */
+#define side_static_assert(predicate, msg, c_identifier_msg) \
+ void side_static_assert_proto(char c_identifier_msg[2*!!(predicate)-1])
+#endif
+
/*
* side_container_of - Get the address of an object containing a field.
*
(type *)((char *)__ptr - offsetof(type, member)); \
})
-#define side_struct_field_sizeof_bit(_struct, _field) \
- (sizeof(((_struct * )NULL)->_field) * CHAR_BIT)
+#define side_struct_field_sizeof(_struct, _field) \
+ sizeof(((_struct * )NULL)->_field)
+
+#define SIDE_PACKED __attribute__((packed))
-#if defined(__SIZEOF_LONG__)
-#define SIDE_BITS_PER_LONG (__SIZEOF_LONG__ * 8)
-#elif defined(_LP64)
-#define SIDE_BITS_PER_LONG 64
+#define side_padding(bytes) char padding[bytes]
+
+#define side_check_size(_type, _len) \
+ side_static_assert(sizeof(_type) == (_len), \
+ "Unexpected size for type: `" #_type "`", \
+ unexpected_size_for_type_##_type)
+
+#if (SIDE_BYTE_ORDER == SIDE_LITTLE_ENDIAN)
+#define SIDE_ENDIAN_ORDER(_low, _high) _low, _high
+#else
+#define SIDE_ENDIAN_ORDER(_low, _high) _high, _low
+#endif
+
+/*
+ * The side_ptr macros allow defining a pointer type which is suitable
+ * for use by 32-bit, 64-bit and 128-bit kernels without compatibility
+ * code, while preserving information about the pointer type.
+ *
+ * Those pointers are stored as 128-bit integers, and the type of the
+ * actual pointer is kept alongside with the 128-bit pointer value in a
+ * 0-len array within a union.
+ */
+#if (__SIZEOF_POINTER__ <= 8)
+# define side_raw_ptr_t(_type) \
+ union { \
+ struct { \
+ uint64_t SIDE_ENDIAN_ORDER(low, high); \
+ } v; \
+ struct { \
+ _type t[0]; \
+ } SIDE_PACKED s; \
+ side_padding(16); \
+ }
+# define side_ptr_get(_field) \
+ ((__typeof__((_field).s.t[0]))(uintptr_t)(_field).v.low)
+# define side_ptr_set(_field, _ptr) \
+ do { \
+ (_field).v.low = (uint64_t)(uintptr_t)(_ptr); \
+ (_field).v.high = 0; \
+ } while (0)
+
+/* Keep the correct field init order to make old g++ happy. */
+# if (SIDE_BYTE_ORDER == SIDE_LITTLE_ENDIAN)
+# define SIDE_PTR_INIT(...) \
+ { \
+ .v = { \
+ .low = (uintptr_t) (__VA_ARGS__), \
+ .high = 0, \
+ }, \
+ }
+# else
+# define SIDE_PTR_INIT(...) \
+ { \
+ .v = { \
+ .high = 0, \
+ .low = (uintptr_t) (__VA_ARGS__), \
+ }, \
+ }
+# endif
+#elif (__SIZEOF_POINTER__ == 16)
+# define side_raw_ptr_t(_type) \
+ union { \
+ uintptr_t v; \
+ struct { \
+ _type t[0]; \
+ } SIDE_PACKED s; \
+ side_padding(16); \
+ }
+# define side_ptr_get(_field) \
+ ((__typeof__((_field).s.t[0]))(_field).v)
+# define side_ptr_set(_field, _ptr) \
+ do { \
+ (_field).v = (uintptr_t)(_ptr); \
+ } while (0)
+# define SIDE_PTR_INIT(...) { .v = (uintptr_t) (__VA_ARGS__) }
#else
-#define SIDE_BITS_PER_LONG 32
+# error "Unsupported pointer size"
#endif
+#define side_ptr_t(_type) side_raw_ptr_t(_type *)
+#define side_func_ptr_t(_type) side_raw_ptr_t(_type)
+
+side_static_assert(sizeof(side_ptr_t(int)) == 16,
+ "Unexpected size for side_ptr_t",
+ unexpected_size_side_ptr_t);
+
+/*
+ * side_enum_t allows defining fixed-sized enumerations while preserving
+ * typing information.
+ */
+#define side_enum_t(_enum_type, _size_type) \
+ union { \
+ _size_type v; \
+ struct { \
+ _enum_type t[0]; \
+ } SIDE_PACKED s; \
+ }
+
+#define side_enum_get(_field) \
+ ((__typeof__((_field).s.t[0]))(_field).v)
+
+#define side_enum_set(_field, _v) \
+ do { \
+ (_field).v = (_v); \
+ } while (0)
+
+#define SIDE_ENUM_INIT(...) { .v = (__VA_ARGS__) }
+
#endif /* _SIDE_MACROS_H */
projects / libside.git / blobdiff