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