// Copyright 2016 The SwiftShader Authors. All Rights Reserved.
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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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#include "Resource.hpp"
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#include "Memory.hpp"
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#include "Debug.hpp"
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namespace sw
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{
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Resource::Resource(size_t bytes) : size(bytes)
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{
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blocked = 0;
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accessor = PUBLIC;
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count = 0;
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orphaned = false;
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buffer = allocate(bytes);
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}
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Resource::~Resource()
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{
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deallocate(buffer);
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}
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void *Resource::lock(Accessor claimer)
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{
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criticalSection.lock();
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while(count > 0 && accessor != claimer)
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{
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blocked++;
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criticalSection.unlock();
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unblock.wait();
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criticalSection.lock();
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blocked--;
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}
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accessor = claimer;
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count++;
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criticalSection.unlock();
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return buffer;
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}
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void *Resource::lock(Accessor relinquisher, Accessor claimer)
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{
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criticalSection.lock();
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// Release
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while(count > 0 && accessor == relinquisher)
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{
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count--;
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if(count == 0)
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{
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if(blocked)
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{
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unblock.signal();
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}
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else if(orphaned)
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{
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criticalSection.unlock();
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delete this;
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return 0;
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}
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}
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}
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// Acquire
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while(count > 0 && accessor != claimer)
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{
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blocked++;
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criticalSection.unlock();
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unblock.wait();
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criticalSection.lock();
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blocked--;
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}
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accessor = claimer;
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count++;
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criticalSection.unlock();
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return buffer;
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}
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void Resource::unlock()
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{
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criticalSection.lock();
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ASSERT(count > 0);
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count--;
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if(count == 0)
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{
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if(blocked)
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{
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unblock.signal();
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}
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else if(orphaned)
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{
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criticalSection.unlock();
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delete this;
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return;
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}
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}
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criticalSection.unlock();
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}
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void Resource::unlock(Accessor relinquisher)
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{
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criticalSection.lock();
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ASSERT(count > 0);
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while(count > 0 && accessor == relinquisher)
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{
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count--;
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if(count == 0)
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{
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if(blocked)
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{
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unblock.signal();
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}
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else if(orphaned)
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{
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criticalSection.unlock();
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delete this;
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return;
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}
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}
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}
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criticalSection.unlock();
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}
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void Resource::destruct()
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{
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criticalSection.lock();
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if(count == 0 && !blocked)
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{
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criticalSection.unlock();
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delete this;
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return;
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}
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orphaned = true;
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criticalSection.unlock();
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}
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const void *Resource::data() const
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{
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return buffer;
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}
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}
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