src/gallium/auxiliary/util/u_range.h

   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 #include "util/u_math.h"
  40
  41 struct util_range {
  42    unsigned start; /* inclusive */
  43    unsigned end; /* exclusive */
  44
  45    /* for the range to be consistent with multiple contexts: */
  46    mtx_t write_mutex;
  47 };
  48
  49
  50 static inline void
  51 util_range_set_empty(struct util_range *range)
  52 {
  53    range->start = ~0;
  54    range->end = 0;
  55 }
  56
  57 /* This is like a union of two sets. */
  58 static inline void
  59 util_range_add(struct util_range *range, unsigned start, unsigned end)
  60 {
  61    if (start < range->start || end > range->end) {
  62       mtx_lock(&range->write_mutex);
  63       range->start = MIN2(start, range->start);
  64       range->end = MAX2(end, range->end);
  65       mtx_unlock(&range->write_mutex);
  66    }
  67 }
  68
  69 static inline boolean
  70 util_ranges_intersect(const struct util_range *range,
  71                       unsigned start, unsigned end)
  72 {
  73    return MAX2(start, range->start) < MIN2(end, range->end);
  74 }
  75
  76
  77 /* Init/deinit */
  78
  79 static inline void
  80 util_range_init(struct util_range *range)
  81 {
  82    (void) mtx_init(&range->write_mutex, mtx_plain);
  83    util_range_set_empty(range);
  84 }
  85
  86 static inline void
  87 util_range_destroy(struct util_range *range)
  88 {
  89    mtx_destroy(&range->write_mutex);
  90 }
  91
  92 #endif