73 lines
2.2 KiB
C++
73 lines
2.2 KiB
C++
/*
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* Copyright (C) 2012 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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#define LOG_TAG "Pipe"
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//#define LOG_NDEBUG 0
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#include <cutils/atomic.h>
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#include <cutils/compiler.h>
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#include <utils/Log.h>
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#include <media/nbaio/Pipe.h>
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#include <audio_utils/roundup.h>
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namespace android {
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Pipe::Pipe(size_t maxFrames, const NBAIO_Format& format, void *buffer) :
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NBAIO_Sink(format),
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mMaxFrames(roundup(maxFrames)),
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mBuffer(buffer == NULL ? malloc(mMaxFrames * Format_frameSize(format)) : buffer),
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mRear(0),
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mReaders(0),
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mFreeBufferInDestructor(buffer == NULL)
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{
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}
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Pipe::~Pipe()
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{
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ALOG_ASSERT(android_atomic_acquire_load(&mReaders) == 0);
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if (mFreeBufferInDestructor) {
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free(mBuffer);
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}
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}
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ssize_t Pipe::write(const void *buffer, size_t count)
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{
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// count == 0 is unlikely and not worth checking for
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if (CC_UNLIKELY(!mNegotiated)) {
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return NEGOTIATE;
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}
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// write() is not multi-thread safe w.r.t. itself, so no mutex or atomic op needed to read mRear
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size_t rear = mRear & (mMaxFrames - 1);
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size_t written = mMaxFrames - rear;
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if (CC_LIKELY(written > count)) {
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written = count;
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}
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memcpy((char *) mBuffer + (rear * mFrameSize), buffer, written * mFrameSize);
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if (CC_UNLIKELY(rear + written == mMaxFrames)) {
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if (CC_UNLIKELY((count -= written) > rear)) {
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count = rear;
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}
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if (CC_LIKELY(count > 0)) {
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memcpy(mBuffer, (char *) buffer + (written * mFrameSize), count * mFrameSize);
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written += count;
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}
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}
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android_atomic_release_store(written + mRear, &mRear);
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mFramesWritten += written;
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return written;
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}
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} // namespace android
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