include/lttng/bitmap.h

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright (C) 2020 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * LTTng Bitmap API
   7  */
   8
   9 #ifndef _LTTNG_BITMAP_H
  10 #define _LTTNG_BITMAP_H
  11
  12 #include <urcu/compiler.h>
  13 #include <urcu/system.h>
  14 #include <urcu/uatomic.h>
  15 #include <stdbool.h>
  16
  17 static inline void lttng_bitmap_index(unsigned int index, unsigned int *word,
  18                 unsigned int *bit)
  19 {
  20         *word = index / CAA_BITS_PER_LONG;
  21         *bit = index % CAA_BITS_PER_LONG;
  22 }
  23
  24 static inline void lttng_bitmap_set_bit(unsigned int index, unsigned long *p)
  25 {
  26         unsigned int word, bit;
  27         unsigned long val;
  28
  29         lttng_bitmap_index(index, &word, &bit);
  30         val = 1U << bit;
  31         uatomic_or(p + word, val);
  32 }
  33
  34 static inline void lttng_bitmap_clear_bit(unsigned int index, unsigned long *p)
  35 {
  36         unsigned int word, bit;
  37         unsigned long val;
  38
  39         lttng_bitmap_index(index, &word, &bit);
  40         val = ~(1U << bit);
  41         uatomic_and(p + word, val);
  42 }
  43
  44 static inline bool lttng_bitmap_test_bit(unsigned int index, unsigned long *p)
  45 {
  46         unsigned int word, bit;
  47
  48         lttng_bitmap_index(index, &word, &bit);
  49         return (CMM_LOAD_SHARED(p[word]) >> bit) & 0x1;
  50 }
  51
  52 #endif /* _LTTNG_BITMAP_H */