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/*
* Copyright (C) 2007 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 "AudioTrackShared"
//#define LOG_NDEBUG 0
#include <private/media/AudioTrackShared.h>
#include <utils/Log.h>
namespace android {
audio_track_cblk_t::audio_track_cblk_t()
: lock(Mutex::SHARED), cv(Condition::SHARED), user(0), server(0),
userBase(0), serverBase(0), frameCount_(0),
loopStart(UINT_MAX), loopEnd(UINT_MAX), loopCount(0), mVolumeLR(0x10001000),
mSampleRate(0), mSendLevel(0), flags(0)
{
}
uint32_t audio_track_cblk_t::stepUser(size_t stepCount, size_t frameCount, bool isOut)
{
ALOGV("stepuser %08x %08x %d", user, server, stepCount);
uint32_t u = user;
u += stepCount;
// Ensure that user is never ahead of server for AudioRecord
if (isOut) {
// If stepServer() has been called once, switch to normal obtainBuffer() timeout period
if (bufferTimeoutMs == MAX_STARTUP_TIMEOUT_MS-1) {
bufferTimeoutMs = MAX_RUN_TIMEOUT_MS;
}
} else if (u > server) {
ALOGW("stepUser occurred after track reset");
u = server;
}
if (u >= frameCount) {
// common case, user didn't just wrap
if (u - frameCount >= userBase ) {
userBase += frameCount;
}
} else if (u >= userBase + frameCount) {
// user just wrapped
userBase += frameCount;
}
user = u;
// Clear flow control error condition as new data has been written/read to/from buffer.
if (flags & CBLK_UNDERRUN) {
android_atomic_and(~CBLK_UNDERRUN, &flags);
}
return u;
}
bool audio_track_cblk_t::stepServer(size_t stepCount, size_t frameCount, bool isOut)
{
ALOGV("stepserver %08x %08x %d", user, server, stepCount);
if (!tryLock()) {
ALOGW("stepServer() could not lock cblk");
return false;
}
uint32_t s = server;
bool flushed = (s == user);
s += stepCount;
if (isOut) {
// Mark that we have read the first buffer so that next time stepUser() is called
// we switch to normal obtainBuffer() timeout period
if (bufferTimeoutMs == MAX_STARTUP_TIMEOUT_MS) {
bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS - 1;
}
// It is possible that we receive a flush()
// while the mixer is processing a block: in this case,
// stepServer() is called After the flush() has reset u & s and
// we have s > u
if (flushed) {
ALOGW("stepServer occurred after track reset");
s = user;
}
}
if (s >= loopEnd) {
ALOGW_IF(s > loopEnd, "stepServer: s %u > loopEnd %u", s, loopEnd);
s = loopStart;
if (--loopCount == 0) {
loopEnd = UINT_MAX;
loopStart = UINT_MAX;
}
}
if (s >= frameCount) {
// common case, server didn't just wrap
if (s - frameCount >= serverBase ) {
serverBase += frameCount;
}
} else if (s >= serverBase + frameCount) {
// server just wrapped
serverBase += frameCount;
}
server = s;
if (!(flags & CBLK_INVALID)) {
cv.signal();
}
lock.unlock();
return true;
}
void* audio_track_cblk_t::buffer(void *buffers, size_t frameSize, uint32_t offset) const
{
return (int8_t *)buffers + (offset - userBase) * frameSize;
}
uint32_t audio_track_cblk_t::framesAvailable(size_t frameCount, bool isOut)
{
Mutex::Autolock _l(lock);
return framesAvailable_l(frameCount, isOut);
}
uint32_t audio_track_cblk_t::framesAvailable_l(size_t frameCount, bool isOut)
{
uint32_t u = user;
uint32_t s = server;
if (isOut) {
uint32_t limit = (s < loopStart) ? s : loopStart;
return limit + frameCount - u;
} else {
return frameCount + u - s;
}
}
uint32_t audio_track_cblk_t::framesReady(bool isOut)
{
uint32_t u = user;
uint32_t s = server;
if (isOut) {
if (u < loopEnd) {
return u - s;
} else {
// do not block on mutex shared with client on AudioFlinger side
if (!tryLock()) {
ALOGW("framesReady() could not lock cblk");
return 0;
}
uint32_t frames = UINT_MAX;
if (loopCount >= 0) {
frames = (loopEnd - loopStart)*loopCount + u - s;
}
lock.unlock();
return frames;
}
} else {
return s - u;
}
}
bool audio_track_cblk_t::tryLock()
{
// the code below simulates lock-with-timeout
// we MUST do this to protect the AudioFlinger server
// as this lock is shared with the client.
status_t err;
err = lock.tryLock();
if (err == -EBUSY) { // just wait a bit
usleep(1000);
err = lock.tryLock();
}
if (err != NO_ERROR) {
// probably, the client just died.
return false;
}
return true;
}
} // namespace android
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