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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.
*/
#include <inttypes.h>
#define LOG_TAG "MonoPipe"
//#define LOG_NDEBUG 0
#include <cutils/atomic.h>
#include <cutils/compiler.h>
#include <utils/Log.h>
#include <utils/Trace.h>
#include <media/AudioBufferProvider.h>
#include <media/nbaio/MonoPipe.h>
#include <audio_utils/roundup.h>
namespace android {
MonoPipe::MonoPipe(size_t reqFrames, const NBAIO_Format& format, bool writeCanBlock) :
NBAIO_Sink(format),
mReqFrames(reqFrames),
mMaxFrames(roundup(reqFrames)),
mBuffer(malloc(mMaxFrames * Format_frameSize(format))),
mFront(0),
mRear(0),
mWriteTsValid(false),
// mWriteTs
mSetpoint((reqFrames * 11) / 16),
mWriteCanBlock(writeCanBlock),
mIsShutdown(false),
// mTimestampShared
mTimestampMutator(&mTimestampShared),
mTimestampObserver(&mTimestampShared)
{
}
MonoPipe::~MonoPipe()
{
free(mBuffer);
}
ssize_t MonoPipe::availableToWrite() const
{
if (CC_UNLIKELY(!mNegotiated)) {
return NEGOTIATE;
}
// uses mMaxFrames not mReqFrames, so allows "over-filling" the pipe beyond requested limit
ssize_t ret = mMaxFrames - (mRear - android_atomic_acquire_load(&mFront));
ALOG_ASSERT((0 <= ret) && (ret <= mMaxFrames));
return ret;
}
ssize_t MonoPipe::write(const void *buffer, size_t count)
{
if (CC_UNLIKELY(!mNegotiated)) {
return NEGOTIATE;
}
size_t totalFramesWritten = 0;
while (count > 0) {
// can't return a negative value, as we already checked for !mNegotiated
size_t avail = availableToWrite();
size_t written = avail;
if (CC_LIKELY(written > count)) {
written = count;
}
size_t rear = mRear & (mMaxFrames - 1);
size_t part1 = mMaxFrames - rear;
if (part1 > written) {
part1 = written;
}
if (CC_LIKELY(part1 > 0)) {
memcpy((char *) mBuffer + (rear * mFrameSize), buffer, part1 * mFrameSize);
if (CC_UNLIKELY(rear + part1 == mMaxFrames)) {
size_t part2 = written - part1;
if (CC_LIKELY(part2 > 0)) {
memcpy(mBuffer, (char *) buffer + (part1 * mFrameSize), part2 * mFrameSize);
}
}
android_atomic_release_store(written + mRear, &mRear);
totalFramesWritten += written;
}
if (!mWriteCanBlock || mIsShutdown) {
break;
}
count -= written;
buffer = (char *) buffer + (written * mFrameSize);
// Simulate blocking I/O by sleeping at different rates, depending on a throttle.
// The throttle tries to keep the mean pipe depth near the setpoint, with a slight jitter.
uint32_t ns;
if (written > 0) {
size_t filled = (mMaxFrames - avail) + written;
// FIXME cache these values to avoid re-computation
if (filled <= mSetpoint / 2) {
// pipe is (nearly) empty, fill quickly
ns = written * ( 500000000 / Format_sampleRate(mFormat));
} else if (filled <= (mSetpoint * 3) / 4) {
// pipe is below setpoint, fill at slightly faster rate
ns = written * ( 750000000 / Format_sampleRate(mFormat));
} else if (filled <= (mSetpoint * 5) / 4) {
// pipe is at setpoint, fill at nominal rate
ns = written * (1000000000 / Format_sampleRate(mFormat));
} else if (filled <= (mSetpoint * 3) / 2) {
// pipe is above setpoint, fill at slightly slower rate
ns = written * (1150000000 / Format_sampleRate(mFormat));
} else if (filled <= (mSetpoint * 7) / 4) {
// pipe is overflowing, fill slowly
ns = written * (1350000000 / Format_sampleRate(mFormat));
} else {
// pipe is severely overflowing
ns = written * (1750000000 / Format_sampleRate(mFormat));
}
} else {
ns = count * (1350000000 / Format_sampleRate(mFormat));
}
if (ns > 999999999) {
ns = 999999999;
}
struct timespec nowTs;
bool nowTsValid = !clock_gettime(CLOCK_MONOTONIC, &nowTs);
// deduct the elapsed time since previous write() completed
if (nowTsValid && mWriteTsValid) {
time_t sec = nowTs.tv_sec - mWriteTs.tv_sec;
long nsec = nowTs.tv_nsec - mWriteTs.tv_nsec;
ALOGE_IF(sec < 0 || (sec == 0 && nsec < 0),
"clock_gettime(CLOCK_MONOTONIC) failed: was %ld.%09ld but now %ld.%09ld",
mWriteTs.tv_sec, mWriteTs.tv_nsec, nowTs.tv_sec, nowTs.tv_nsec);
if (nsec < 0) {
--sec;
nsec += 1000000000;
}
if (sec == 0) {
if ((long) ns > nsec) {
ns -= nsec;
} else {
ns = 0;
}
}
}
if (ns > 0) {
const struct timespec req = {0, static_cast<long>(ns)};
nanosleep(&req, NULL);
}
// record the time that this write() completed
if (nowTsValid) {
mWriteTs = nowTs;
if ((mWriteTs.tv_nsec += ns) >= 1000000000) {
mWriteTs.tv_nsec -= 1000000000;
++mWriteTs.tv_sec;
}
}
mWriteTsValid = nowTsValid;
}
mFramesWritten += totalFramesWritten;
return totalFramesWritten;
}
void MonoPipe::setAvgFrames(size_t setpoint)
{
mSetpoint = setpoint;
}
void MonoPipe::shutdown(bool newState)
{
mIsShutdown = newState;
}
bool MonoPipe::isShutdown()
{
return mIsShutdown;
}
status_t MonoPipe::getTimestamp(ExtendedTimestamp &timestamp)
{
ExtendedTimestamp ets;
if (mTimestampObserver.poll(ets)) {
timestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL] =
ets.mPosition[ExtendedTimestamp::LOCATION_KERNEL];
timestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL] =
ets.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL];
return OK;
}
return INVALID_OPERATION;
}
} // namespace android