diff options
Diffstat (limited to 'media/libmedia/SingleStateQueue.cpp')
-rw-r--r-- | media/libmedia/SingleStateQueue.cpp | 106 |
1 files changed, 0 insertions, 106 deletions
diff --git a/media/libmedia/SingleStateQueue.cpp b/media/libmedia/SingleStateQueue.cpp deleted file mode 100644 index c241184303..0000000000 --- a/media/libmedia/SingleStateQueue.cpp +++ /dev/null @@ -1,106 +0,0 @@ -/* - * Copyright (C) 2012 The Android Open Source Project - * - * Licensed under the Apache License, Version 2.0 (the "License"); - * you may not use this file except in compliance with the License. - * You may obtain a copy of the License at - * - * http://www.apache.org/licenses/LICENSE-2.0 - * - * Unless required by applicable law or agreed to in writing, software - * distributed under the License is distributed on an "AS IS" BASIS, - * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - * See the License for the specific language governing permissions and - * limitations under the License. - */ - -#include <new> -#include <cutils/atomic.h> -#include <media/SingleStateQueue.h> - -namespace android { - -template<typename T> SingleStateQueue<T>::Mutator::Mutator(Shared *shared) - : mSequence(0), mShared((Shared *) shared) -{ - // exactly one of Mutator and Observer must initialize, currently it is Observer - //shared->init(); -} - -template<typename T> int32_t SingleStateQueue<T>::Mutator::push(const T& value) -{ - Shared *shared = mShared; - int32_t sequence = mSequence; - sequence++; - android_atomic_acquire_store(sequence, &shared->mSequence); - shared->mValue = value; - sequence++; - android_atomic_release_store(sequence, &shared->mSequence); - mSequence = sequence; - // consider signalling a futex here, if we know that observer is waiting - return sequence; -} - -template<typename T> bool SingleStateQueue<T>::Mutator::ack() -{ - return mShared->mAck - mSequence == 0; -} - -template<typename T> bool SingleStateQueue<T>::Mutator::ack(int32_t sequence) -{ - // this relies on 2's complement rollover to detect an ancient sequence number - return mShared->mAck - sequence >= 0; -} - -template<typename T> SingleStateQueue<T>::Observer::Observer(Shared *shared) - : mSequence(0), mSeed(1), mShared((Shared *) shared) -{ - // exactly one of Mutator and Observer must initialize, currently it is Observer - shared->init(); -} - -template<typename T> bool SingleStateQueue<T>::Observer::poll(T& value) -{ - Shared *shared = mShared; - int32_t before = shared->mSequence; - if (before == mSequence) { - return false; - } - for (int tries = 0; ; ) { - const int MAX_TRIES = 5; - if (before & 1) { - if (++tries >= MAX_TRIES) { - return false; - } - before = shared->mSequence; - } else { - android_memory_barrier(); - T temp = shared->mValue; - int32_t after = android_atomic_release_load(&shared->mSequence); - if (after == before) { - value = temp; - shared->mAck = before; - mSequence = before; - return true; - } - if (++tries >= MAX_TRIES) { - return false; - } - before = after; - } - } -} - -#if 0 -template<typename T> SingleStateQueue<T>::SingleStateQueue(void /*Shared*/ *shared) -{ - ((Shared *) shared)->init(); -} -#endif - -} // namespace android - -// hack for gcc -#ifdef SINGLE_STATE_QUEUE_INSTANTIATIONS -#include SINGLE_STATE_QUEUE_INSTANTIATIONS -#endif |