Files
libucore/include/ucore/utils.h
T
2013-12-08 00:43:22 +01:00

122 lines
3.1 KiB
C

#ifndef UC_UTILS_H_
#define UC_UTILS_H_
#include <stddef.h>
#include <stdio.h>
//Gnerate a compiler error if the compile time
//constant expression fails
#define UC_STATIC_ASSERT(expr) \
enum { assert_static__ = 1/(expr) };
//MAX of a and b
#define UC_MAX(a,b) \
({ __typeof__ (a) _amx = (a); \
__typeof__ (b) _bmx = (b); \
_amx > _bmx ? _amx : _bmx; })
//min of a and b
#define UC_MIN(a,b) \
({ __typeof__ (a) _amn = (a); \
__typeof__ (b) _bmn = (b); \
_amn < _bmn ? _amn : _bmn; })
#define ARRAY_SIZE(a) (sizeof(a) / sizeof(*a))
//given 'ptr' as a pointer to a struct 'member',
//find the struct that ptr is the member of, where
//'type' is the type of the containing struct
//e.g.
//struct foo {
// int i;
// struct bar zap;
//};
// ...
//struct bar *p = ..; //the local p is a pointer to
//a 'zap' member inside a struct foo.
//give us the struct foo*:
//struct foo *f = CONTAINER_OF(p, struct foo, zap);
#define UC_CONTAINER_OF(ptr, type, member) ({ \
typeof( ((type *)0)->member ) *__mptr = (ptr); \
(type *)((void *)(unsigned char *)__mptr - offsetof(type, member) ); })
//the void* cast is to suppress alignment warnings
//Same as UC_CONTAINER_OF, but for a const pointer to avoid gcc warnings..
#define UC_CONST_CONTAINER_OF(ptr, type, member) ({ \
const typeof( ((const type *)0)->member ) *__mptr = (ptr); \
(const type *)((const void *)(const unsigned char *)__mptr - offsetof(const type, member) ); })
/** Align a value.
* @param val value to align
* @param align alignment, must be power of 2
* @return the aligned val
*/
#define UC_ALIGN(val,align) (((val)+(align)-1UL)&~((align)-1UL))
/**
* Test if x is a power of 2
*
* @param x value, must be an unsigned type
* @return 1 if x is a power of 20, 0 if it is not
*/
#define UC_IS_POW2(x) ((x) && !((x) & (x) - 1))
/**
* Expands @x and turns it into a string.
*/
#define UC_STRINGIFY(x) UC_STRINGIFY_HLP(x)
#define UC_STRINGIFY_HLP(x) #x
/** Macro that expands to a string for the current file:line
*/
#define UC_SRC_LOCATION __FILE__ ":" UC_STRINGIFY(__LINE__)
#ifdef DEBUG
#define TRACEF(fmt, ...)\
do { \
fprintf(stdout, "%s (%s)\t" fmt, UC_SRC_LOCATION, __FUNCTION__, ##__VA_ARGS__);\
fflush(stdout);\
} while(0)
#else
#define TRACEF(fmt, ...) do {} while(0)
#endif
/**
* Round up x / y
* (e.g 100/9 == 12, 3/2 == 2)
* x + y must not overflow.
*
* @param x numerator, must be positive
* @param y denominator
* @return x/y rounded up
*/
#define UC_DIV_ROUND_UP(x, y) (((x) + ((y) - 1))/(y))
/**
* Round x down to nearest multiple of y
*
* @param x numerator, must be positive
* @param y denominator
* @return x rounded to nearest multiple of y
*/
#define UC_ROUND_UP(x, y) (((x) / (y)) * (y))
/**
* Round x down to nearest multiple of y
*
* @param x numerator, must be positive
* @param y denominator
* @return x rounded to nearest multiple of y
*/
#define UC_ROUND_DOWN(x, y) ((x) / (y) * (y))
/** Indicate the variable is unused.
*/
#define UC_UNUSED(x) x __attribute__((unused))
#endif