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