include/lttng/bitmap.h

   1 /*
   2  * lttng/bitmap.h
   3  *
   4  * LTTng Bitmap API
   5  *
   6  * Copyright (C) 2020 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a copy
   9  * of this software and associated documentation files (the "Software"), to deal
  10  * in the Software without restriction, including without limitation the rights
  11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12  * copies of the Software, and to permit persons to whom the Software is
  13  * furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  21  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  24  * SOFTWARE.
  25  */
  26
  27 #ifndef _LTTNG_BITMAP_H
  28 #define _LTTNG_BITMAP_H
  29
  30 #include <urcu/compiler.h>
  31 #include <urcu/system.h>
  32 #include <urcu/uatomic.h>
  33 #include <stdbool.h>
  34
  35 static inline void lttng_bitmap_index(unsigned int index, unsigned int *word,
  36                 unsigned int *bit)
  37 {
  38         *word = index / CAA_BITS_PER_LONG;
  39         *bit = index % CAA_BITS_PER_LONG;
  40 }
  41
  42 static inline void lttng_bitmap_set_bit(unsigned int index, unsigned long *p)
  43 {
  44         unsigned int word, bit;
  45         unsigned long val;
  46
  47         lttng_bitmap_index(index, &word, &bit);
  48         val = 1U << bit;
  49         uatomic_or(p + word, val);
  50 }
  51
  52 static inline void lttng_bitmap_clear_bit(unsigned int index, unsigned long *p)
  53 {
  54         unsigned int word, bit;
  55         unsigned long val;
  56
  57         lttng_bitmap_index(index, &word, &bit);
  58         val = ~(1U << bit);
  59         uatomic_and(p + word, val);
  60 }
  61
  62 static inline bool lttng_bitmap_test_bit(unsigned int index, unsigned long *p)
  63 {
  64         unsigned int word, bit;
  65
  66         lttng_bitmap_index(index, &word, &bit);
  67         return (CMM_LOAD_SHARED(p[word]) >> bit) & 0x1;
  68 }
  69
  70 #endif /* _LTTNG_BITMAP_H */