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/*
* Copyright 2013 Marek Olšák <maraeo@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* on the rights to use, copy, modify, merge, publish, distribute, sub
* license, and/or sell copies of the Software, and to permit persons to whom
* the Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
* THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
* USE OR OTHER DEALINGS IN THE SOFTWARE. */
/**
* @file
* 1D integer range, capable of the union and intersection operations.
*
* It only maintains a single interval which is extended when the union is
* done. This implementation is partially thread-safe (readers are not
* protected by a lock).
*
* @author Marek Olšák
*/
#ifndef U_RANGE_H
#define U_RANGE_H
#include "os/os_thread.h"
#include "util/u_math.h"
struct util_range {
unsigned start; /* inclusive */
unsigned end; /* exclusive */
/* for the range to be consistent with multiple contexts: */
mtx_t write_mutex;
};
static inline void
util_range_set_empty(struct util_range *range)
{
range->start = ~0;
range->end = 0;
}
/* This is like a union of two sets. */
static inline void
util_range_add(struct util_range *range, unsigned start, unsigned end)
{
if (start < range->start || end > range->end) {
mtx_lock(&range->write_mutex);
range->start = MIN2(start, range->start);
range->end = MAX2(end, range->end);
mtx_unlock(&range->write_mutex);
}
}
static inline boolean
util_ranges_intersect(const struct util_range *range,
unsigned start, unsigned end)
{
return MAX2(start, range->start) < MIN2(end, range->end);
}
/* Init/deinit */
static inline void
util_range_init(struct util_range *range)
{
(void) mtx_init(&range->write_mutex, mtx_plain);
util_range_set_empty(range);
}
static inline void
util_range_destroy(struct util_range *range)
{
mtx_destroy(&range->write_mutex);
}
#endif
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