macros.h

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#ifndef _MACROS_H_
#define _MACROS_H_
 
#define CLAMP(a, l, u) ((a) < l ? l : ((a) > u ? u : (a)))
 
#define MIN(a, b) (((a) < (b)) ? (a) : (b))
 
#define MAX(a, b) (((a) > (b)) ? (a) : (b))
 
#define ABS(a) (((a) < (0)) ? -(a) : (a))
 
#ifdef __APPLE__
    /* Force a compilation error if condition is true, but also produce a
        result (of value 0 and type size_t), so the expression can be used
        e.g. in a structure initializer (or where-ever else comma expressions
        aren't permitted). */
    #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int : -!!(e); }))
 
    #define __must_be_array(a) BUILD_BUG_ON_ZERO(__builtin_types_compatible_p(typeof(a), typeof(&(a)[0])))
 
    #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
#else
    #define IS_ARRAY(arr) ((void*)&(arr) == &(arr)[0])
 
    #define STATIC_EXP(e) (0 * sizeof(struct { int ARRAY_SIZE_FAILED : (2 * (e)-1); }))
 
    #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + STATIC_EXP(IS_ARRAY(arr)))
#endif
 
#define POS_MODULO_ADD(a, b, d) ((a + (b % d) + d) % d)
 
#define RUN_TIMER_EVERY(timer, period, elapsed, timer_code) \
    do                                                      \
    {                                                       \
        timer += elapsed;                                   \
        while (timer > period)                              \
        {                                                   \
            timer -= period;                                \
            {                                               \
                timer_code                                  \
            }                                               \
        }                                                   \
    } while (0)
 
#endif