src/util/math.h

   1 #ifndef EL__UTIL_MATH_H
   2 #define EL__UTIL_MATH_H
   3
   4
   5 /* It's evil to include this directly, elinks.h includes it for you
   6  * at the right time. */
   7
   8
   9 /* These macros will evaluate twice their arguments.
  10  * Ie. MIN(a+b, c+d) will do 3 additions...
  11  * Please prefer to use int_min() and int_max() if possible. */
  12
  13 /* FreeBSD needs this. */
  14 #ifdef MIN
  15 #undef MIN
  16 #endif
  17
  18 #ifdef MAX
  19 #undef MAX
  20 #endif
  21
  22 #define MIN(x, y) ((x) < (y) ? (x) : (y))
  23 #define MAX(x, y) ((x) > (y) ? (x) : (y))
  24
  25
  26 static inline int
  27 int_min(register int x, register int y)
  28 {
  29         if (x < y) return x;
  30         return y;
  31 }
  32
  33 static inline int
  34 int_max(register int x, register int y)
  35 {
  36         if (x > y) return x;
  37         return y;
  38 }
  39
  40
  41 /** Limit @a what pointed value to upper bound @a limit. */
  42 static inline void
  43 int_upper_bound(register int *what, register int limit)
  44 {
  45         if (*what > limit) *what = limit;
  46 }
  47
  48 /** Limit @a what pointed value to lower bound @a limit. */
  49 static inline void
  50 int_lower_bound(register int *what, register int limit)
  51 {
  52         if (*what < limit) *what = limit;
  53 }
  54
  55 /** Limit @a what pointed value to lower bound @a lower_limit and to
  56  * upper bound @a upper_limit. */
  57 static inline void
  58 int_bounds(register int *what, register int lower_limit,
  59            register int upper_limit)
  60 {
  61         if (*what < lower_limit)
  62                 *what = lower_limit;
  63         else if (*what > upper_limit)
  64                 *what = upper_limit;
  65 }
  66
  67
  68 /** Swap values @a a and @a b, both of type @a type.
  69  * This is supposed to evaluate at compile time, giving no performance hit. */
  70 #define swap_values(type, a, b)                 \
  71         do {                                    \
  72                 type swap_register_ = (a);      \
  73                 (a) = (b);                      \
  74                 (b) = (swap_register_);         \
  75         } while (0)
  76
  77 #endif