Subversion Repositories Kolibri OS

Rev

Go to most recent revision | Blame | Last modification | View Log | RSS feed

  1. /*
  2.  * Copyright 2013 Marek Olšák <maraeo@gmail.com>
  3.  *
  4.  * Permission is hereby granted, free of charge, to any person obtaining a
  5.  * copy of this software and associated documentation files (the "Software"),
  6.  * to deal in the Software without restriction, including without limitation
  7.  * on the rights to use, copy, modify, merge, publish, distribute, sub
  8.  * license, and/or sell copies of the Software, and to permit persons to whom
  9.  * the Software is furnished to do so, subject to the following conditions:
  10.  *
  11.  * The above copyright notice and this permission notice (including the next
  12.  * paragraph) shall be included in all copies or substantial portions of the
  13.  * Software.
  14.  *
  15.  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16.  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17.  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  18.  * THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
  19.  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  20.  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  21.  * USE OR OTHER DEALINGS IN THE SOFTWARE. */
  22.  
  23. /**
  24.  * @file
  25.  * 1D integer range, capable of the union and intersection operations.
  26.  *
  27.  * It only maintains a single interval which is extended when the union is
  28.  * done. This implementation is partially thread-safe (readers are not
  29.  * protected by a lock).
  30.  *
  31.  * @author Marek Olšák
  32.  */
  33.  
  34. #ifndef U_RANGE_H
  35. #define U_RANGE_H
  36.  
  37. #include "os/os_thread.h"
  38.  
  39. struct util_range {
  40.    unsigned start; /* inclusive */
  41.    unsigned end; /* exclusive */
  42.  
  43.    /* for the range to be consistent with multiple contexts: */
  44.    pipe_mutex write_mutex;
  45. };
  46.  
  47.  
  48. static INLINE void
  49. util_range_set_empty(struct util_range *range)
  50. {
  51.    range->start = ~0;
  52.    range->end = 0;
  53. }
  54.  
  55. /* This is like a union of two sets. */
  56. static INLINE void
  57. util_range_add(struct util_range *range, unsigned start, unsigned end)
  58. {
  59.    if (start < range->start || end > range->end) {
  60.       pipe_mutex_lock(range->write_mutex);
  61.       range->start = MIN2(start, range->start);
  62.       range->end = MAX2(end, range->end);
  63.       pipe_mutex_unlock(range->write_mutex);
  64.    }
  65. }
  66.  
  67. static INLINE boolean
  68. util_ranges_intersect(struct util_range *range, unsigned start, unsigned end)
  69. {
  70.    return MAX2(start, range->start) < MIN2(end, range->end);
  71. }
  72.  
  73.  
  74. /* Init/deinit */
  75.  
  76. static INLINE void
  77. util_range_init(struct util_range *range)
  78. {
  79.    pipe_mutex_init(range->write_mutex);
  80.    util_range_set_empty(range);
  81. }
  82.  
  83. static INLINE void
  84. util_range_destroy(struct util_range *range)
  85. {
  86.    pipe_mutex_destroy(range->write_mutex);
  87. }
  88.  
  89. #endif
  90.