81 lines
2.0 KiB
C++
81 lines
2.0 KiB
C++
/* -*- C -*-
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// -------------------------------------------------------------------
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// MiniLock - a quick mostly user space lock
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// Copyright (c) 2008 Leon Bottou. All rights reserved
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//
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// Permission is hereby granted, free of charge, to any person obtaining
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// a copy of this software and associated documentation files (the
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// "Software"), to deal in the Software without restriction, including
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// without limitation the rights to use, copy, modify, merge, publish,
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// distribute, sublicense, and/or sell copies of the Software, and to
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// permit persons to whom the Software is furnished to do so, subject to
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// the following conditions:
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//
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// The above copyright notice and this permission notice shall be
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// included in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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//
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// ------------------------------------------------------------------- */
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include "../../libdjvu/atomic.h"
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int
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atomicAcquire(int volatile *lock)
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{
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int tmp;
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if ((tmp = !*lock))
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*lock = 1;
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return tmp;
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}
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void
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atomicAcquireOrSpin(int volatile *lock)
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{
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while (*lock)
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;
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*lock = 1;
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}
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void
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atomicRelease(int volatile *lock)
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{
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*lock = 0;
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}
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int
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atomicIncrement(int volatile *var)
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{
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int res;
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res = ++(*var);
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return res;
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}
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int
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atomicDecrement(int volatile *var)
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{
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int res;
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res = --(*var);
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return res;
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}
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int
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atomicCompareAndSwap(int volatile *var, int oldval, int newval)
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{
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int ret;
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ret = *var;
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if (ret == oldval)
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*var = newval;
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return (ret == oldval);
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}
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