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62 lines
1.8 KiB
62 lines
1.8 KiB
/*-------------------------------------------------------------------------
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* drawElements Thread Library
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* ---------------------------
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*
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* Copyright 2014 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*//*!
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* \file
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* \brief Thread-safe singleton.
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*//*--------------------------------------------------------------------*/
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#include "deSingleton.h"
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#include "deAtomic.h"
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#include "deThread.h"
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DE_STATIC_ASSERT(sizeof(deSingletonState) == sizeof(deUint32));
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void deInitSingleton (volatile deSingletonState* singletonState, deSingletonConstructorFunc constructor, void* arg)
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{
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if (*singletonState != DE_SINGLETON_STATE_INITIALIZED)
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{
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deSingletonState curState = (deSingletonState)deAtomicCompareExchange32((volatile deUint32*)singletonState, (deUint32)DE_SINGLETON_STATE_NOT_INITIALIZED, (deUint32)DE_SINGLETON_STATE_INITIALIZING);
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if (curState == DE_SINGLETON_STATE_NOT_INITIALIZED)
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{
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constructor(arg);
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deMemoryReadWriteFence();
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*singletonState = DE_SINGLETON_STATE_INITIALIZED;
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deMemoryReadWriteFence();
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}
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else if (curState == DE_SINGLETON_STATE_INITIALIZING)
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{
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for (;;)
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{
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deMemoryReadWriteFence();
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if (*singletonState == DE_SINGLETON_STATE_INITIALIZED)
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break;
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else
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deYield();
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}
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}
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DE_ASSERT(*singletonState == DE_SINGLETON_STATE_INITIALIZED);
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}
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}
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