src/main/common/utils.h

   1 /*
   2  * This file is part of Cleanflight.
   3  *
   4  * Cleanflight is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * Cleanflight is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with Cleanflight.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #pragma once
  19
  20 #include <stddef.h>
  21 #include <stdint.h>
  22
  23 #define ARRAYLEN(x) (sizeof(x) / sizeof((x)[0]))
  24 #define ARRAYEND(x) (&(x)[ARRAYLEN(x)])
  25 #define ZERO_FARRAY(a) memset(a, 0, sizeof(a))
  26
  27 #define CONST_CAST(type, value) ((type)(value))
  28
  29 #define CONCAT_HELPER(x,y) x ## y
  30 #define CONCAT(x,y) CONCAT_HELPER(x, y)
  31
  32 #define CONCAT3_HELPER(x, y, z) x ## y ## z
  33 #define CONCAT3(x, y, z) CONCAT3_HELPER(x, y, z)
  34
  35 #define CONCAT4_HELPER(x, y, z, w) x ## y ## z ## w
  36 #define CONCAT4(x, y, z, w) CONCAT4_HELPER(x, y, z, w)
  37
  38 #define STR_HELPER(x) #x
  39 #define STR(x) STR_HELPER(x)
  40
  41 #define EXPAND_I(x) x
  42 #define EXPAND(x) EXPAND_I(x)
  43
  44 // Expand all argumens and call macro with them. When expansion of some argument contains ',', it will be passed as multiple arguments
  45 // #define TAKE3(_1,_2,_3) CONCAT3(_1,_2,_3)
  46 // #define MULTI2 A,B
  47 // PP_CALL(TAKE3, MULTI2, C) expands to ABC
  48 #define PP_CALL(macro, ...) macro(__VA_ARGS__)
  49
  50 #if !defined(UNUSED)
  51 #define UNUSED(x) (void)(x)
  52 #endif
  53
  54 #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
  55
  56 #define BIT(x) (1 << (x))
  57 #define GET_BIT(value, bit) ((value >> bit) & 1)
  58
  59 #define STATIC_ASSERT(condition, name) \
  60     typedef char assert_failed_ ## name [(condition) ? 1 : -1 ] __attribute__((unused))
  61
  62 /*
  63 http://resnet.uoregon.edu/~gurney_j/jmpc/bitwise.html
  64 */
  65 #define BITCOUNT(x) (((BX_(x)+(BX_(x)>>4)) & 0x0F0F0F0F) % 255)
  66 #define BX_(x) ((x) - (((x)>>1)&0x77777777) - (((x)>>2)&0x33333333) - (((x)>>3)&0x11111111))
  67
  68
  69 /*
  70  * https://groups.google.com/forum/?hl=en#!msg/comp.lang.c/attFnqwhvGk/sGBKXvIkY3AJ
  71  * Return (v ? floor(log2(v)) : 0) when 0 <= v < 1<<[8, 16, 32, 64].
  72  * Inefficient algorithm, intended for compile-time constants.
  73  */
  74 #define LOG2_8BIT(v)  (8 - 90/(((v)/4+14)|1) - 2/((v)/2+1))
  75 #define LOG2_16BIT(v) (8*((v)>255) + LOG2_8BIT((v) >>8*((v)>255)))
  76 #define LOG2_32BIT(v) (16*((v)>65535L) + LOG2_16BIT((v)*1L >>16*((v)>65535L)))
  77 #define LOG2_64BIT(v) \
  78     (32*((v)/2L>>31 > 0) \
  79      + LOG2_32BIT((v)*1L >>16*((v)/2L>>31 > 0) \
  80                          >>16*((v)/2L>>31 > 0)))
  81
  82 // non ISO variant from linux kernel; checks ptr type, but triggers 'ISO C forbids braced-groups within expressions [-Wpedantic]'
  83 //  __extension__ is here to disable this warning
  84 #define container_of(ptr, type, member)  ( __extension__ ({     \
  85         const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
  86         (type *)( (char *)__mptr - offsetof(type,member) );}))
  87
  88 static inline int16_t cmp16(uint16_t a, uint16_t b) { return a-b; }
  89 static inline int32_t cmp32(uint32_t a, uint32_t b) { return a-b; }
  90
  91 // using memcpy_fn will force memcpy function call, instead of inlining it. In most cases function call takes fewer instructions
  92 //  than inlined version (inlining is cheaper for very small moves < 8 bytes / 2 store instructions)
  93 #if defined(UNIT_TEST) || defined(SITL_BUILD)
  94 #include <string.h>
  95 #define memcpy_fn(destination, source, num) memcpy(destination, source, num)
  96 #else
  97 void *memcpy_fn(void *destination, const void *source, size_t num) asm("memcpy");
  98 #endif
  99
 100 #if __GNUC__ > 6
 101 #define FALLTHROUGH __attribute__ ((fallthrough))
 102 #else
 103 #define FALLTHROUGH do {} while(0)
 104 #endif
 105
 106 #define UNREACHABLE() __builtin_unreachable()
 107
 108 #define ALIGNED(x) __attribute__ ((aligned(x)))
 109
 110 #define PACKED __attribute__((packed))