AudioTrack.cpp revision a5224f319e2ba4b51ddb4287705ccf8d4b8ecc51 
1/* frameworks/base/media/libmedia/AudioTrack.cpp
2**
3** Copyright 2007, The Android Open Source Project
4**
5** Licensed under the Apache License, Version 2.0 (the "License");
6** you may not use this file except in compliance with the License.
7** You may obtain a copy of the License at
8**
9**     http://www.apache.org/licenses/LICENSE-2.0
10**
11** Unless required by applicable law or agreed to in writing, software
12** distributed under the License is distributed on an "AS IS" BASIS,
13** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14** See the License for the specific language governing permissions and
15** limitations under the License.
16*/
17
18
19//#define LOG_NDEBUG 0
20#define LOG_TAG "AudioTrack"
21
22#include <stdint.h>
23#include <sys/types.h>
24#include <limits.h>
25
26#include <sched.h>
27#include <sys/resource.h>
28
29#include <private/media/AudioTrackShared.h>
30
31#include <media/AudioSystem.h>
32#include <media/AudioTrack.h>
33
34#include <utils/Log.h>
35#include <binder/Parcel.h>
36#include <binder/IPCThreadState.h>
37#include <utils/Timers.h>
38#include <utils/Atomic.h>
39
40#include <cutils/bitops.h>
41#include <cutils/compiler.h>
42
43#include <system/audio.h>
44#include <system/audio_policy.h>
45
46#include <audio_utils/primitives.h>
47
48namespace android {
49// ---------------------------------------------------------------------------
50
51// static
52status_t AudioTrack::getMinFrameCount(
53        int* frameCount,
54        audio_stream_type_t streamType,
55        uint32_t sampleRate)
56{
57    int afSampleRate;
58    if (AudioSystem::getOutputSamplingRate(&afSampleRate, streamType) != NO_ERROR) {
59        return NO_INIT;
60    }
61    int afFrameCount;
62    if (AudioSystem::getOutputFrameCount(&afFrameCount, streamType) != NO_ERROR) {
63        return NO_INIT;
64    }
65    uint32_t afLatency;
66    if (AudioSystem::getOutputLatency(&afLatency, streamType) != NO_ERROR) {
67        return NO_INIT;
68    }
69
70    // Ensure that buffer depth covers at least audio hardware latency
71    uint32_t minBufCount = afLatency / ((1000 * afFrameCount) / afSampleRate);
72    if (minBufCount < 2) minBufCount = 2;
73
74    *frameCount = (sampleRate == 0) ? afFrameCount * minBufCount :
75              afFrameCount * minBufCount * sampleRate / afSampleRate;
76    return NO_ERROR;
77}
78
79// ---------------------------------------------------------------------------
80
81AudioTrack::AudioTrack()
82    : mStatus(NO_INIT),
83      mPreviousPriority(ANDROID_PRIORITY_NORMAL), mPreviousSchedulingGroup(ANDROID_TGROUP_DEFAULT)
84{
85}
86
87AudioTrack::AudioTrack(
88        audio_stream_type_t streamType,
89        uint32_t sampleRate,
90        audio_format_t format,
91        int channelMask,
92        int frameCount,
93        uint32_t flags,
94        callback_t cbf,
95        void* user,
96        int notificationFrames,
97        int sessionId)
98    : mStatus(NO_INIT),
99      mPreviousPriority(ANDROID_PRIORITY_NORMAL), mPreviousSchedulingGroup(ANDROID_TGROUP_DEFAULT)
100{
101    mStatus = set(streamType, sampleRate, format, channelMask,
102            frameCount, flags, cbf, user, notificationFrames,
103            0, false, sessionId);
104}
105
106AudioTrack::AudioTrack(
107        int streamType,
108        uint32_t sampleRate,
109        int format,
110        int channelMask,
111        int frameCount,
112        uint32_t flags,
113        callback_t cbf,
114        void* user,
115        int notificationFrames,
116        int sessionId)
117    : mStatus(NO_INIT),
118      mPreviousPriority(ANDROID_PRIORITY_NORMAL), mPreviousSchedulingGroup(ANDROID_TGROUP_DEFAULT)
119{
120    mStatus = set((audio_stream_type_t)streamType, sampleRate, (audio_format_t)format, channelMask,
121            frameCount, flags, cbf, user, notificationFrames,
122            0, false, sessionId);
123}
124
125AudioTrack::AudioTrack(
126        audio_stream_type_t streamType,
127        uint32_t sampleRate,
128        audio_format_t format,
129        int channelMask,
130        const sp<IMemory>& sharedBuffer,
131        uint32_t flags,
132        callback_t cbf,
133        void* user,
134        int notificationFrames,
135        int sessionId)
136    : mStatus(NO_INIT),
137      mPreviousPriority(ANDROID_PRIORITY_NORMAL), mPreviousSchedulingGroup(ANDROID_TGROUP_DEFAULT)
138{
139    mStatus = set(streamType, sampleRate, format, channelMask,
140            0, flags, cbf, user, notificationFrames,
141            sharedBuffer, false, sessionId);
142}
143
144AudioTrack::~AudioTrack()
145{
146    ALOGV_IF(mSharedBuffer != 0, "Destructor sharedBuffer: %p", mSharedBuffer->pointer());
147
148    if (mStatus == NO_ERROR) {
149        // Make sure that callback function exits in the case where
150        // it is looping on buffer full condition in obtainBuffer().
151        // Otherwise the callback thread will never exit.
152        stop();
153        if (mAudioTrackThread != 0) {
154            mAudioTrackThread->requestExitAndWait();
155            mAudioTrackThread.clear();
156        }
157        mAudioTrack.clear();
158        IPCThreadState::self()->flushCommands();
159        AudioSystem::releaseAudioSessionId(mSessionId);
160    }
161}
162
163status_t AudioTrack::set(
164        audio_stream_type_t streamType,
165        uint32_t sampleRate,
166        audio_format_t format,
167        int channelMask,
168        int frameCount,
169        uint32_t flags,
170        callback_t cbf,
171        void* user,
172        int notificationFrames,
173        const sp<IMemory>& sharedBuffer,
174        bool threadCanCallJava,
175        int sessionId)
176{
177
178    ALOGV_IF(sharedBuffer != 0, "sharedBuffer: %p, size: %d", sharedBuffer->pointer(), sharedBuffer->size());
179
180    AutoMutex lock(mLock);
181    if (mAudioTrack != 0) {
182        ALOGE("Track already in use");
183        return INVALID_OPERATION;
184    }
185
186    int afSampleRate;
187    if (AudioSystem::getOutputSamplingRate(&afSampleRate, streamType) != NO_ERROR) {
188        return NO_INIT;
189    }
190    uint32_t afLatency;
191    if (AudioSystem::getOutputLatency(&afLatency, streamType) != NO_ERROR) {
192        return NO_INIT;
193    }
194
195    // handle default values first.
196    if (streamType == AUDIO_STREAM_DEFAULT) {
197        streamType = AUDIO_STREAM_MUSIC;
198    }
199    if (sampleRate == 0) {
200        sampleRate = afSampleRate;
201    }
202    // these below should probably come from the audioFlinger too...
203    if (format == AUDIO_FORMAT_DEFAULT) {
204        format = AUDIO_FORMAT_PCM_16_BIT;
205    }
206    if (channelMask == 0) {
207        channelMask = AUDIO_CHANNEL_OUT_STEREO;
208    }
209
210    // validate parameters
211    if (!audio_is_valid_format(format)) {
212        ALOGE("Invalid format");
213        return BAD_VALUE;
214    }
215
216    // force direct flag if format is not linear PCM
217    if (!audio_is_linear_pcm(format)) {
218        flags |= AUDIO_POLICY_OUTPUT_FLAG_DIRECT;
219    }
220
221    if (!audio_is_output_channel(channelMask)) {
222        ALOGE("Invalid channel mask");
223        return BAD_VALUE;
224    }
225    uint32_t channelCount = popcount(channelMask);
226
227    audio_io_handle_t output = AudioSystem::getOutput(
228                                    streamType,
229                                    sampleRate, format, channelMask,
230                                    (audio_policy_output_flags_t)flags);
231
232    if (output == 0) {
233        ALOGE("Could not get audio output for stream type %d", streamType);
234        return BAD_VALUE;
235    }
236
237    mVolume[LEFT] = 1.0f;
238    mVolume[RIGHT] = 1.0f;
239    mSendLevel = 0.0f;
240    mFrameCount = frameCount;
241    mNotificationFramesReq = notificationFrames;
242    mSessionId = sessionId;
243    mAuxEffectId = 0;
244
245    // create the IAudioTrack
246    status_t status = createTrack_l(streamType,
247                                  sampleRate,
248                                  format,
249                                  (uint32_t)channelMask,
250                                  frameCount,
251                                  flags,
252                                  sharedBuffer,
253                                  output,
254                                  true);
255
256    if (status != NO_ERROR) {
257        return status;
258    }
259
260    if (cbf != NULL) {
261        mAudioTrackThread = new AudioTrackThread(*this, threadCanCallJava);
262    }
263
264    mStatus = NO_ERROR;
265
266    mStreamType = streamType;
267    mFormat = format;
268    mChannelMask = (uint32_t)channelMask;
269    mChannelCount = channelCount;
270    mSharedBuffer = sharedBuffer;
271    mMuted = false;
272    mActive = false;
273    mCbf = cbf;
274    mUserData = user;
275    mLoopCount = 0;
276    mMarkerPosition = 0;
277    mMarkerReached = false;
278    mNewPosition = 0;
279    mUpdatePeriod = 0;
280    mFlushed = false;
281    mFlags = flags;
282    AudioSystem::acquireAudioSessionId(mSessionId);
283    mRestoreStatus = NO_ERROR;
284    return NO_ERROR;
285}
286
287status_t AudioTrack::initCheck() const
288{
289    return mStatus;
290}
291
292// -------------------------------------------------------------------------
293
294uint32_t AudioTrack::latency() const
295{
296    return mLatency;
297}
298
299audio_stream_type_t AudioTrack::streamType() const
300{
301    return mStreamType;
302}
303
304audio_format_t AudioTrack::format() const
305{
306    return mFormat;
307}
308
309int AudioTrack::channelCount() const
310{
311    return mChannelCount;
312}
313
314uint32_t AudioTrack::frameCount() const
315{
316    return mCblk->frameCount;
317}
318
319size_t AudioTrack::frameSize() const
320{
321    if (audio_is_linear_pcm(mFormat)) {
322        return channelCount()*audio_bytes_per_sample(mFormat);
323    } else {
324        return sizeof(uint8_t);
325    }
326}
327
328sp<IMemory>& AudioTrack::sharedBuffer()
329{
330    return mSharedBuffer;
331}
332
333// -------------------------------------------------------------------------
334
335void AudioTrack::start()
336{
337    sp<AudioTrackThread> t = mAudioTrackThread;
338    status_t status = NO_ERROR;
339
340    ALOGV("start %p", this);
341    if (t != 0) {
342        if (t->exitPending()) {
343            if (t->requestExitAndWait() == WOULD_BLOCK) {
344                ALOGE("AudioTrack::start called from thread");
345                return;
346            }
347        }
348        t->mLock.lock();
349     }
350
351    AutoMutex lock(mLock);
352    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
353    // while we are accessing the cblk
354    sp <IAudioTrack> audioTrack = mAudioTrack;
355    sp <IMemory> iMem = mCblkMemory;
356    audio_track_cblk_t* cblk = mCblk;
357
358    if (!mActive) {
359        mFlushed = false;
360        mActive = true;
361        mNewPosition = cblk->server + mUpdatePeriod;
362        cblk->lock.lock();
363        cblk->bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS;
364        cblk->waitTimeMs = 0;
365        android_atomic_and(~CBLK_DISABLED_ON, &cblk->flags);
366        if (t != 0) {
367            t->run("AudioTrackThread", ANDROID_PRIORITY_AUDIO);
368        } else {
369            mPreviousPriority = getpriority(PRIO_PROCESS, 0);
370            mPreviousSchedulingGroup = androidGetThreadSchedulingGroup(0);
371            androidSetThreadPriority(0, ANDROID_PRIORITY_AUDIO);
372        }
373
374        ALOGV("start %p before lock cblk %p", this, mCblk);
375        if (!(cblk->flags & CBLK_INVALID_MSK)) {
376            cblk->lock.unlock();
377            status = mAudioTrack->start();
378            cblk->lock.lock();
379            if (status == DEAD_OBJECT) {
380                android_atomic_or(CBLK_INVALID_ON, &cblk->flags);
381            }
382        }
383        if (cblk->flags & CBLK_INVALID_MSK) {
384            status = restoreTrack_l(cblk, true);
385        }
386        cblk->lock.unlock();
387        if (status != NO_ERROR) {
388            ALOGV("start() failed");
389            mActive = false;
390            if (t != 0) {
391                t->requestExit();
392            } else {
393                setpriority(PRIO_PROCESS, 0, mPreviousPriority);
394                androidSetThreadSchedulingGroup(0, mPreviousSchedulingGroup);
395            }
396        }
397    }
398
399    if (t != 0) {
400        t->mLock.unlock();
401    }
402}
403
404void AudioTrack::stop()
405{
406    sp<AudioTrackThread> t = mAudioTrackThread;
407
408    ALOGV("stop %p", this);
409    if (t != 0) {
410        t->mLock.lock();
411    }
412
413    AutoMutex lock(mLock);
414    if (mActive) {
415        mActive = false;
416        mCblk->cv.signal();
417        mAudioTrack->stop();
418        // Cancel loops (If we are in the middle of a loop, playback
419        // would not stop until loopCount reaches 0).
420        setLoop_l(0, 0, 0);
421        // the playback head position will reset to 0, so if a marker is set, we need
422        // to activate it again
423        mMarkerReached = false;
424        // Force flush if a shared buffer is used otherwise audioflinger
425        // will not stop before end of buffer is reached.
426        if (mSharedBuffer != 0) {
427            flush_l();
428        }
429        if (t != 0) {
430            t->requestExit();
431        } else {
432            setpriority(PRIO_PROCESS, 0, mPreviousPriority);
433            androidSetThreadSchedulingGroup(0, mPreviousSchedulingGroup);
434        }
435    }
436
437    if (t != 0) {
438        t->mLock.unlock();
439    }
440}
441
442bool AudioTrack::stopped() const
443{
444    AutoMutex lock(mLock);
445    return stopped_l();
446}
447
448void AudioTrack::flush()
449{
450    AutoMutex lock(mLock);
451    flush_l();
452}
453
454// must be called with mLock held
455void AudioTrack::flush_l()
456{
457    ALOGV("flush");
458
459    // clear playback marker and periodic update counter
460    mMarkerPosition = 0;
461    mMarkerReached = false;
462    mUpdatePeriod = 0;
463
464    if (!mActive) {
465        mFlushed = true;
466        mAudioTrack->flush();
467        // Release AudioTrack callback thread in case it was waiting for new buffers
468        // in AudioTrack::obtainBuffer()
469        mCblk->cv.signal();
470    }
471}
472
473void AudioTrack::pause()
474{
475    ALOGV("pause");
476    AutoMutex lock(mLock);
477    if (mActive) {
478        mActive = false;
479        mAudioTrack->pause();
480    }
481}
482
483void AudioTrack::mute(bool e)
484{
485    mAudioTrack->mute(e);
486    mMuted = e;
487}
488
489bool AudioTrack::muted() const
490{
491    return mMuted;
492}
493
494status_t AudioTrack::setVolume(float left, float right)
495{
496    if (left < 0.0f || left > 1.0f || right < 0.0f || right > 1.0f) {
497        return BAD_VALUE;
498    }
499
500    AutoMutex lock(mLock);
501    mVolume[LEFT] = left;
502    mVolume[RIGHT] = right;
503
504    mCblk->setVolumeLR((uint32_t(uint16_t(right * 0x1000)) << 16) | uint16_t(left * 0x1000));
505
506    return NO_ERROR;
507}
508
509void AudioTrack::getVolume(float* left, float* right) const
510{
511    if (left != NULL) {
512        *left  = mVolume[LEFT];
513    }
514    if (right != NULL) {
515        *right = mVolume[RIGHT];
516    }
517}
518
519status_t AudioTrack::setAuxEffectSendLevel(float level)
520{
521    ALOGV("setAuxEffectSendLevel(%f)", level);
522    if (level < 0.0f || level > 1.0f) {
523        return BAD_VALUE;
524    }
525    AutoMutex lock(mLock);
526
527    mSendLevel = level;
528
529    mCblk->setSendLevel(level);
530
531    return NO_ERROR;
532}
533
534void AudioTrack::getAuxEffectSendLevel(float* level) const
535{
536    if (level != NULL) {
537        *level  = mSendLevel;
538    }
539}
540
541status_t AudioTrack::setSampleRate(int rate)
542{
543    int afSamplingRate;
544
545    if (AudioSystem::getOutputSamplingRate(&afSamplingRate, mStreamType) != NO_ERROR) {
546        return NO_INIT;
547    }
548    // Resampler implementation limits input sampling rate to 2 x output sampling rate.
549    if (rate <= 0 || rate > afSamplingRate*2 ) return BAD_VALUE;
550
551    AutoMutex lock(mLock);
552    mCblk->sampleRate = rate;
553    return NO_ERROR;
554}
555
556uint32_t AudioTrack::getSampleRate() const
557{
558    AutoMutex lock(mLock);
559    return mCblk->sampleRate;
560}
561
562status_t AudioTrack::setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount)
563{
564    AutoMutex lock(mLock);
565    return setLoop_l(loopStart, loopEnd, loopCount);
566}
567
568// must be called with mLock held
569status_t AudioTrack::setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount)
570{
571    audio_track_cblk_t* cblk = mCblk;
572
573    Mutex::Autolock _l(cblk->lock);
574
575    if (loopCount == 0) {
576        cblk->loopStart = UINT_MAX;
577        cblk->loopEnd = UINT_MAX;
578        cblk->loopCount = 0;
579        mLoopCount = 0;
580        return NO_ERROR;
581    }
582
583    if (loopStart >= loopEnd ||
584        loopEnd - loopStart > cblk->frameCount ||
585        cblk->server > loopStart) {
586        ALOGE("setLoop invalid value: loopStart %d, loopEnd %d, loopCount %d, framecount %d, user %d", loopStart, loopEnd, loopCount, cblk->frameCount, cblk->user);
587        return BAD_VALUE;
588    }
589
590    if ((mSharedBuffer != 0) && (loopEnd > cblk->frameCount)) {
591        ALOGE("setLoop invalid value: loop markers beyond data: loopStart %d, loopEnd %d, framecount %d",
592            loopStart, loopEnd, cblk->frameCount);
593        return BAD_VALUE;
594    }
595
596    cblk->loopStart = loopStart;
597    cblk->loopEnd = loopEnd;
598    cblk->loopCount = loopCount;
599    mLoopCount = loopCount;
600
601    return NO_ERROR;
602}
603
604status_t AudioTrack::getLoop(uint32_t *loopStart, uint32_t *loopEnd, int *loopCount) const
605{
606    AutoMutex lock(mLock);
607    if (loopStart != NULL) {
608        *loopStart = mCblk->loopStart;
609    }
610    if (loopEnd != NULL) {
611        *loopEnd = mCblk->loopEnd;
612    }
613    if (loopCount != NULL) {
614        if (mCblk->loopCount < 0) {
615            *loopCount = -1;
616        } else {
617            *loopCount = mCblk->loopCount;
618        }
619    }
620
621    return NO_ERROR;
622}
623
624status_t AudioTrack::setMarkerPosition(uint32_t marker)
625{
626    if (mCbf == NULL) return INVALID_OPERATION;
627
628    mMarkerPosition = marker;
629    mMarkerReached = false;
630
631    return NO_ERROR;
632}
633
634status_t AudioTrack::getMarkerPosition(uint32_t *marker) const
635{
636    if (marker == NULL) return BAD_VALUE;
637
638    *marker = mMarkerPosition;
639
640    return NO_ERROR;
641}
642
643status_t AudioTrack::setPositionUpdatePeriod(uint32_t updatePeriod)
644{
645    if (mCbf == NULL) return INVALID_OPERATION;
646
647    uint32_t curPosition;
648    getPosition(&curPosition);
649    mNewPosition = curPosition + updatePeriod;
650    mUpdatePeriod = updatePeriod;
651
652    return NO_ERROR;
653}
654
655status_t AudioTrack::getPositionUpdatePeriod(uint32_t *updatePeriod) const
656{
657    if (updatePeriod == NULL) return BAD_VALUE;
658
659    *updatePeriod = mUpdatePeriod;
660
661    return NO_ERROR;
662}
663
664status_t AudioTrack::setPosition(uint32_t position)
665{
666    AutoMutex lock(mLock);
667
668    if (!stopped_l()) return INVALID_OPERATION;
669
670    Mutex::Autolock _l(mCblk->lock);
671
672    if (position > mCblk->user) return BAD_VALUE;
673
674    mCblk->server = position;
675    android_atomic_or(CBLK_FORCEREADY_ON, &mCblk->flags);
676
677    return NO_ERROR;
678}
679
680status_t AudioTrack::getPosition(uint32_t *position)
681{
682    if (position == NULL) return BAD_VALUE;
683    AutoMutex lock(mLock);
684    *position = mFlushed ? 0 : mCblk->server;
685
686    return NO_ERROR;
687}
688
689status_t AudioTrack::reload()
690{
691    AutoMutex lock(mLock);
692
693    if (!stopped_l()) return INVALID_OPERATION;
694
695    flush_l();
696
697    mCblk->stepUser(mCblk->frameCount);
698
699    return NO_ERROR;
700}
701
702audio_io_handle_t AudioTrack::getOutput()
703{
704    AutoMutex lock(mLock);
705    return getOutput_l();
706}
707
708// must be called with mLock held
709audio_io_handle_t AudioTrack::getOutput_l()
710{
711    return AudioSystem::getOutput(mStreamType,
712            mCblk->sampleRate, mFormat, mChannelMask, (audio_policy_output_flags_t)mFlags);
713}
714
715int AudioTrack::getSessionId() const
716{
717    return mSessionId;
718}
719
720status_t AudioTrack::attachAuxEffect(int effectId)
721{
722    ALOGV("attachAuxEffect(%d)", effectId);
723    status_t status = mAudioTrack->attachAuxEffect(effectId);
724    if (status == NO_ERROR) {
725        mAuxEffectId = effectId;
726    }
727    return status;
728}
729
730// -------------------------------------------------------------------------
731
732// must be called with mLock held
733status_t AudioTrack::createTrack_l(
734        audio_stream_type_t streamType,
735        uint32_t sampleRate,
736        audio_format_t format,
737        uint32_t channelMask,
738        int frameCount,
739        uint32_t flags,
740        const sp<IMemory>& sharedBuffer,
741        audio_io_handle_t output,
742        bool enforceFrameCount)
743{
744    status_t status;
745    const sp<IAudioFlinger>& audioFlinger = AudioSystem::get_audio_flinger();
746    if (audioFlinger == 0) {
747       ALOGE("Could not get audioflinger");
748       return NO_INIT;
749    }
750
751    int afSampleRate;
752    if (AudioSystem::getOutputSamplingRate(&afSampleRate, streamType) != NO_ERROR) {
753        return NO_INIT;
754    }
755    int afFrameCount;
756    if (AudioSystem::getOutputFrameCount(&afFrameCount, streamType) != NO_ERROR) {
757        return NO_INIT;
758    }
759    uint32_t afLatency;
760    if (AudioSystem::getOutputLatency(&afLatency, streamType) != NO_ERROR) {
761        return NO_INIT;
762    }
763
764    mNotificationFramesAct = mNotificationFramesReq;
765    if (!audio_is_linear_pcm(format)) {
766        if (sharedBuffer != 0) {
767            frameCount = sharedBuffer->size();
768        }
769    } else {
770        // Ensure that buffer depth covers at least audio hardware latency
771        uint32_t minBufCount = afLatency / ((1000 * afFrameCount)/afSampleRate);
772        if (minBufCount < 2) minBufCount = 2;
773
774        int minFrameCount = (afFrameCount*sampleRate*minBufCount)/afSampleRate;
775
776        if (sharedBuffer == 0) {
777            if (frameCount == 0) {
778                frameCount = minFrameCount;
779            }
780            if (mNotificationFramesAct == 0) {
781                mNotificationFramesAct = frameCount/2;
782            }
783            // Make sure that application is notified with sufficient margin
784            // before underrun
785            if (mNotificationFramesAct > (uint32_t)frameCount/2) {
786                mNotificationFramesAct = frameCount/2;
787            }
788            if (frameCount < minFrameCount) {
789                if (enforceFrameCount) {
790                    ALOGE("Invalid buffer size: minFrameCount %d, frameCount %d", minFrameCount, frameCount);
791                    return BAD_VALUE;
792                } else {
793                    frameCount = minFrameCount;
794                }
795            }
796        } else {
797            // Ensure that buffer alignment matches channelcount
798            int channelCount = popcount(channelMask);
799            if (((uint32_t)sharedBuffer->pointer() & (channelCount | 1)) != 0) {
800                ALOGE("Invalid buffer alignement: address %p, channelCount %d", sharedBuffer->pointer(), channelCount);
801                return BAD_VALUE;
802            }
803            frameCount = sharedBuffer->size()/channelCount/sizeof(int16_t);
804        }
805    }
806
807    sp<IAudioTrack> track = audioFlinger->createTrack(getpid(),
808                                                      streamType,
809                                                      sampleRate,
810                                                      format,
811                                                      channelMask,
812                                                      frameCount,
813                                                      ((uint16_t)flags) << 16,
814                                                      sharedBuffer,
815                                                      output,
816                                                      &mSessionId,
817                                                      &status);
818
819    if (track == 0) {
820        ALOGE("AudioFlinger could not create track, status: %d", status);
821        return status;
822    }
823    sp<IMemory> cblk = track->getCblk();
824    if (cblk == 0) {
825        ALOGE("Could not get control block");
826        return NO_INIT;
827    }
828    mAudioTrack = track;
829    mCblkMemory = cblk;
830    mCblk = static_cast<audio_track_cblk_t*>(cblk->pointer());
831    android_atomic_or(CBLK_DIRECTION_OUT, &mCblk->flags);
832    if (sharedBuffer == 0) {
833        mCblk->buffers = (char*)mCblk + sizeof(audio_track_cblk_t);
834    } else {
835        mCblk->buffers = sharedBuffer->pointer();
836         // Force buffer full condition as data is already present in shared memory
837        mCblk->stepUser(mCblk->frameCount);
838    }
839
840    mCblk->setVolumeLR((uint32_t(uint16_t(mVolume[RIGHT] * 0x1000)) << 16) | uint16_t(mVolume[LEFT] * 0x1000));
841    mCblk->setSendLevel(mSendLevel);
842    mAudioTrack->attachAuxEffect(mAuxEffectId);
843    mCblk->bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS;
844    mCblk->waitTimeMs = 0;
845    mRemainingFrames = mNotificationFramesAct;
846    mLatency = afLatency + (1000*mCblk->frameCount) / sampleRate;
847    return NO_ERROR;
848}
849
850status_t AudioTrack::obtainBuffer(Buffer* audioBuffer, int32_t waitCount)
851{
852    AutoMutex lock(mLock);
853    bool active;
854    status_t result = NO_ERROR;
855    audio_track_cblk_t* cblk = mCblk;
856    uint32_t framesReq = audioBuffer->frameCount;
857    uint32_t waitTimeMs = (waitCount < 0) ? cblk->bufferTimeoutMs : WAIT_PERIOD_MS;
858
859    audioBuffer->frameCount  = 0;
860    audioBuffer->size = 0;
861
862    uint32_t framesAvail = cblk->framesAvailable();
863
864    cblk->lock.lock();
865    if (cblk->flags & CBLK_INVALID_MSK) {
866        goto create_new_track;
867    }
868    cblk->lock.unlock();
869
870    if (framesAvail == 0) {
871        cblk->lock.lock();
872        goto start_loop_here;
873        while (framesAvail == 0) {
874            active = mActive;
875            if (CC_UNLIKELY(!active)) {
876                ALOGV("Not active and NO_MORE_BUFFERS");
877                cblk->lock.unlock();
878                return NO_MORE_BUFFERS;
879            }
880            if (CC_UNLIKELY(!waitCount)) {
881                cblk->lock.unlock();
882                return WOULD_BLOCK;
883            }
884            if (!(cblk->flags & CBLK_INVALID_MSK)) {
885                mLock.unlock();
886                result = cblk->cv.waitRelative(cblk->lock, milliseconds(waitTimeMs));
887                cblk->lock.unlock();
888                mLock.lock();
889                if (!mActive) {
890                    return status_t(STOPPED);
891                }
892                cblk->lock.lock();
893            }
894
895            if (cblk->flags & CBLK_INVALID_MSK) {
896                goto create_new_track;
897            }
898            if (CC_UNLIKELY(result != NO_ERROR)) {
899                cblk->waitTimeMs += waitTimeMs;
900                if (cblk->waitTimeMs >= cblk->bufferTimeoutMs) {
901                    // timing out when a loop has been set and we have already written upto loop end
902                    // is a normal condition: no need to wake AudioFlinger up.
903                    if (cblk->user < cblk->loopEnd) {
904                        ALOGW(   "obtainBuffer timed out (is the CPU pegged?) %p "
905                                "user=%08x, server=%08x", this, cblk->user, cblk->server);
906                        //unlock cblk mutex before calling mAudioTrack->start() (see issue #1617140)
907                        cblk->lock.unlock();
908                        result = mAudioTrack->start();
909                        cblk->lock.lock();
910                        if (result == DEAD_OBJECT) {
911                            android_atomic_or(CBLK_INVALID_ON, &cblk->flags);
912create_new_track:
913                            result = restoreTrack_l(cblk, false);
914                        }
915                        if (result != NO_ERROR) {
916                            ALOGW("obtainBuffer create Track error %d", result);
917                            cblk->lock.unlock();
918                            return result;
919                        }
920                    }
921                    cblk->waitTimeMs = 0;
922                }
923
924                if (--waitCount == 0) {
925                    cblk->lock.unlock();
926                    return TIMED_OUT;
927                }
928            }
929            // read the server count again
930        start_loop_here:
931            framesAvail = cblk->framesAvailable_l();
932        }
933        cblk->lock.unlock();
934    }
935
936    // restart track if it was disabled by audioflinger due to previous underrun
937    if (mActive && (cblk->flags & CBLK_DISABLED_MSK)) {
938        android_atomic_and(~CBLK_DISABLED_ON, &cblk->flags);
939        ALOGW("obtainBuffer() track %p disabled, restarting", this);
940        mAudioTrack->start();
941    }
942
943    cblk->waitTimeMs = 0;
944
945    if (framesReq > framesAvail) {
946        framesReq = framesAvail;
947    }
948
949    uint32_t u = cblk->user;
950    uint32_t bufferEnd = cblk->userBase + cblk->frameCount;
951
952    if (u + framesReq > bufferEnd) {
953        framesReq = bufferEnd - u;
954    }
955
956    audioBuffer->flags = mMuted ? Buffer::MUTE : 0;
957    audioBuffer->channelCount = mChannelCount;
958    audioBuffer->frameCount = framesReq;
959    audioBuffer->size = framesReq * cblk->frameSize;
960    if (audio_is_linear_pcm(mFormat)) {
961        audioBuffer->format = AUDIO_FORMAT_PCM_16_BIT;
962    } else {
963        audioBuffer->format = mFormat;
964    }
965    audioBuffer->raw = (int8_t *)cblk->buffer(u);
966    active = mActive;
967    return active ? status_t(NO_ERROR) : status_t(STOPPED);
968}
969
970void AudioTrack::releaseBuffer(Buffer* audioBuffer)
971{
972    AutoMutex lock(mLock);
973    mCblk->stepUser(audioBuffer->frameCount);
974}
975
976// -------------------------------------------------------------------------
977
978ssize_t AudioTrack::write(const void* buffer, size_t userSize)
979{
980
981    if (mSharedBuffer != 0) return INVALID_OPERATION;
982
983    if (ssize_t(userSize) < 0) {
984        // sanity-check. user is most-likely passing an error code.
985        ALOGE("AudioTrack::write(buffer=%p, size=%u (%d)",
986                buffer, userSize, userSize);
987        return BAD_VALUE;
988    }
989
990    ALOGV("write %p: %d bytes, mActive=%d", this, userSize, mActive);
991
992    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
993    // while we are accessing the cblk
994    mLock.lock();
995    sp <IAudioTrack> audioTrack = mAudioTrack;
996    sp <IMemory> iMem = mCblkMemory;
997    mLock.unlock();
998
999    ssize_t written = 0;
1000    const int8_t *src = (const int8_t *)buffer;
1001    Buffer audioBuffer;
1002    size_t frameSz = frameSize();
1003
1004    do {
1005        audioBuffer.frameCount = userSize/frameSz;
1006
1007        // Calling obtainBuffer() with a negative wait count causes
1008        // an (almost) infinite wait time.
1009        status_t err = obtainBuffer(&audioBuffer, -1);
1010        if (err < 0) {
1011            // out of buffers, return #bytes written
1012            if (err == status_t(NO_MORE_BUFFERS))
1013                break;
1014            return ssize_t(err);
1015        }
1016
1017        size_t toWrite;
1018
1019        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1020            // Divide capacity by 2 to take expansion into account
1021            toWrite = audioBuffer.size>>1;
1022            memcpy_to_i16_from_u8(audioBuffer.i16, (const uint8_t *) src, toWrite);
1023        } else {
1024            toWrite = audioBuffer.size;
1025            memcpy(audioBuffer.i8, src, toWrite);
1026            src += toWrite;
1027        }
1028        userSize -= toWrite;
1029        written += toWrite;
1030
1031        releaseBuffer(&audioBuffer);
1032    } while (userSize >= frameSz);
1033
1034    return written;
1035}
1036
1037// -------------------------------------------------------------------------
1038
1039bool AudioTrack::processAudioBuffer(const sp<AudioTrackThread>& thread)
1040{
1041    Buffer audioBuffer;
1042    uint32_t frames;
1043    size_t writtenSize;
1044
1045    mLock.lock();
1046    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
1047    // while we are accessing the cblk
1048    sp <IAudioTrack> audioTrack = mAudioTrack;
1049    sp <IMemory> iMem = mCblkMemory;
1050    audio_track_cblk_t* cblk = mCblk;
1051    bool active = mActive;
1052    mLock.unlock();
1053
1054    // Manage underrun callback
1055    if (active && (cblk->framesAvailable() == cblk->frameCount)) {
1056        ALOGV("Underrun user: %x, server: %x, flags %04x", cblk->user, cblk->server, cblk->flags);
1057        if (!(android_atomic_or(CBLK_UNDERRUN_ON, &cblk->flags) & CBLK_UNDERRUN_MSK)) {
1058            mCbf(EVENT_UNDERRUN, mUserData, 0);
1059            if (cblk->server == cblk->frameCount) {
1060                mCbf(EVENT_BUFFER_END, mUserData, 0);
1061            }
1062            if (mSharedBuffer != 0) return false;
1063        }
1064    }
1065
1066    // Manage loop end callback
1067    while (mLoopCount > cblk->loopCount) {
1068        int loopCount = -1;
1069        mLoopCount--;
1070        if (mLoopCount >= 0) loopCount = mLoopCount;
1071
1072        mCbf(EVENT_LOOP_END, mUserData, (void *)&loopCount);
1073    }
1074
1075    // Manage marker callback
1076    if (!mMarkerReached && (mMarkerPosition > 0)) {
1077        if (cblk->server >= mMarkerPosition) {
1078            mCbf(EVENT_MARKER, mUserData, (void *)&mMarkerPosition);
1079            mMarkerReached = true;
1080        }
1081    }
1082
1083    // Manage new position callback
1084    if (mUpdatePeriod > 0) {
1085        while (cblk->server >= mNewPosition) {
1086            mCbf(EVENT_NEW_POS, mUserData, (void *)&mNewPosition);
1087            mNewPosition += mUpdatePeriod;
1088        }
1089    }
1090
1091    // If Shared buffer is used, no data is requested from client.
1092    if (mSharedBuffer != 0) {
1093        frames = 0;
1094    } else {
1095        frames = mRemainingFrames;
1096    }
1097
1098    int32_t waitCount = -1;
1099    if (mUpdatePeriod || (!mMarkerReached && mMarkerPosition) || mLoopCount) {
1100        waitCount = 1;
1101    }
1102
1103    do {
1104
1105        audioBuffer.frameCount = frames;
1106
1107        // Calling obtainBuffer() with a wait count of 1
1108        // limits wait time to WAIT_PERIOD_MS. This prevents from being
1109        // stuck here not being able to handle timed events (position, markers, loops).
1110        status_t err = obtainBuffer(&audioBuffer, waitCount);
1111        if (err < NO_ERROR) {
1112            if (err != TIMED_OUT) {
1113                ALOGE_IF(err != status_t(NO_MORE_BUFFERS), "Error obtaining an audio buffer, giving up.");
1114                return false;
1115            }
1116            break;
1117        }
1118        if (err == status_t(STOPPED)) return false;
1119
1120        // Divide buffer size by 2 to take into account the expansion
1121        // due to 8 to 16 bit conversion: the callback must fill only half
1122        // of the destination buffer
1123        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1124            audioBuffer.size >>= 1;
1125        }
1126
1127        size_t reqSize = audioBuffer.size;
1128        mCbf(EVENT_MORE_DATA, mUserData, &audioBuffer);
1129        writtenSize = audioBuffer.size;
1130
1131        // Sanity check on returned size
1132        if (ssize_t(writtenSize) <= 0) {
1133            // The callback is done filling buffers
1134            // Keep this thread going to handle timed events and
1135            // still try to get more data in intervals of WAIT_PERIOD_MS
1136            // but don't just loop and block the CPU, so wait
1137            usleep(WAIT_PERIOD_MS*1000);
1138            break;
1139        }
1140        if (writtenSize > reqSize) writtenSize = reqSize;
1141
1142        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1143            // 8 to 16 bit conversion, note that source and destination are the same address
1144            memcpy_to_i16_from_u8(audioBuffer.i16, (const uint8_t *) audioBuffer.i8, writtenSize);
1145            writtenSize <<= 1;
1146        }
1147
1148        audioBuffer.size = writtenSize;
1149        // NOTE: mCblk->frameSize is not equal to AudioTrack::frameSize() for
1150        // 8 bit PCM data: in this case,  mCblk->frameSize is based on a sample size of
1151        // 16 bit.
1152        audioBuffer.frameCount = writtenSize/mCblk->frameSize;
1153
1154        frames -= audioBuffer.frameCount;
1155
1156        releaseBuffer(&audioBuffer);
1157    }
1158    while (frames);
1159
1160    if (frames == 0) {
1161        mRemainingFrames = mNotificationFramesAct;
1162    } else {
1163        mRemainingFrames = frames;
1164    }
1165    return true;
1166}
1167
1168// must be called with mLock and cblk.lock held. Callers must also hold strong references on
1169// the IAudioTrack and IMemory in case they are recreated here.
1170// If the IAudioTrack is successfully restored, the cblk pointer is updated
1171status_t AudioTrack::restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart)
1172{
1173    status_t result;
1174
1175    if (!(android_atomic_or(CBLK_RESTORING_ON, &cblk->flags) & CBLK_RESTORING_MSK)) {
1176        ALOGW("dead IAudioTrack, creating a new one from %s TID %d",
1177             fromStart ? "start()" : "obtainBuffer()", gettid());
1178
1179        // signal old cblk condition so that other threads waiting for available buffers stop
1180        // waiting now
1181        cblk->cv.broadcast();
1182        cblk->lock.unlock();
1183
1184        // refresh the audio configuration cache in this process to make sure we get new
1185        // output parameters in getOutput_l() and createTrack_l()
1186        AudioSystem::clearAudioConfigCache();
1187
1188        // if the new IAudioTrack is created, createTrack_l() will modify the
1189        // following member variables: mAudioTrack, mCblkMemory and mCblk.
1190        // It will also delete the strong references on previous IAudioTrack and IMemory
1191        result = createTrack_l(mStreamType,
1192                               cblk->sampleRate,
1193                               mFormat,
1194                               mChannelMask,
1195                               mFrameCount,
1196                               mFlags,
1197                               mSharedBuffer,
1198                               getOutput_l(),
1199                               false);
1200
1201        if (result == NO_ERROR) {
1202            uint32_t user = cblk->user;
1203            uint32_t server = cblk->server;
1204            // restore write index and set other indexes to reflect empty buffer status
1205            mCblk->user = user;
1206            mCblk->server = user;
1207            mCblk->userBase = user;
1208            mCblk->serverBase = user;
1209            // restore loop: this is not guaranteed to succeed if new frame count is not
1210            // compatible with loop length
1211            setLoop_l(cblk->loopStart, cblk->loopEnd, cblk->loopCount);
1212            if (!fromStart) {
1213                mCblk->bufferTimeoutMs = MAX_RUN_TIMEOUT_MS;
1214                // Make sure that a client relying on callback events indicating underrun or
1215                // the actual amount of audio frames played (e.g SoundPool) receives them.
1216                if (mSharedBuffer == 0) {
1217                    uint32_t frames = 0;
1218                    if (user > server) {
1219                        frames = ((user - server) > mCblk->frameCount) ?
1220                                mCblk->frameCount : (user - server);
1221                        memset(mCblk->buffers, 0, frames * mCblk->frameSize);
1222                    }
1223                    // restart playback even if buffer is not completely filled.
1224                    android_atomic_or(CBLK_FORCEREADY_ON, &mCblk->flags);
1225                    // stepUser() clears CBLK_UNDERRUN_ON flag enabling underrun callbacks to
1226                    // the client
1227                    mCblk->stepUser(frames);
1228                }
1229            }
1230            if (mActive) {
1231                result = mAudioTrack->start();
1232                ALOGW_IF(result != NO_ERROR, "restoreTrack_l() start() failed status %d", result);
1233            }
1234            if (fromStart && result == NO_ERROR) {
1235                mNewPosition = mCblk->server + mUpdatePeriod;
1236            }
1237        }
1238        if (result != NO_ERROR) {
1239            android_atomic_and(~CBLK_RESTORING_ON, &cblk->flags);
1240            ALOGW_IF(result != NO_ERROR, "restoreTrack_l() failed status %d", result);
1241        }
1242        mRestoreStatus = result;
1243        // signal old cblk condition for other threads waiting for restore completion
1244        android_atomic_or(CBLK_RESTORED_ON, &cblk->flags);
1245        cblk->cv.broadcast();
1246    } else {
1247        if (!(cblk->flags & CBLK_RESTORED_MSK)) {
1248            ALOGW("dead IAudioTrack, waiting for a new one TID %d", gettid());
1249            mLock.unlock();
1250            result = cblk->cv.waitRelative(cblk->lock, milliseconds(RESTORE_TIMEOUT_MS));
1251            if (result == NO_ERROR) {
1252                result = mRestoreStatus;
1253            }
1254            cblk->lock.unlock();
1255            mLock.lock();
1256        } else {
1257            ALOGW("dead IAudioTrack, already restored TID %d", gettid());
1258            result = mRestoreStatus;
1259            cblk->lock.unlock();
1260        }
1261    }
1262    ALOGV("restoreTrack_l() status %d mActive %d cblk %p, old cblk %p flags %08x old flags %08x",
1263         result, mActive, mCblk, cblk, mCblk->flags, cblk->flags);
1264
1265    if (result == NO_ERROR) {
1266        // from now on we switch to the newly created cblk
1267        cblk = mCblk;
1268    }
1269    cblk->lock.lock();
1270
1271    ALOGW_IF(result != NO_ERROR, "restoreTrack_l() error %d TID %d", result, gettid());
1272
1273    return result;
1274}
1275
1276status_t AudioTrack::dump(int fd, const Vector<String16>& args) const
1277{
1278
1279    const size_t SIZE = 256;
1280    char buffer[SIZE];
1281    String8 result;
1282
1283    result.append(" AudioTrack::dump\n");
1284    snprintf(buffer, 255, "  stream type(%d), left - right volume(%f, %f)\n", mStreamType, mVolume[0], mVolume[1]);
1285    result.append(buffer);
1286    snprintf(buffer, 255, "  format(%d), channel count(%d), frame count(%d)\n", mFormat, mChannelCount, mCblk->frameCount);
1287    result.append(buffer);
1288    snprintf(buffer, 255, "  sample rate(%d), status(%d), muted(%d)\n", (mCblk == 0) ? 0 : mCblk->sampleRate, mStatus, mMuted);
1289    result.append(buffer);
1290    snprintf(buffer, 255, "  active(%d), latency (%d)\n", mActive, mLatency);
1291    result.append(buffer);
1292    ::write(fd, result.string(), result.size());
1293    return NO_ERROR;
1294}
1295
1296// =========================================================================
1297
1298AudioTrack::AudioTrackThread::AudioTrackThread(AudioTrack& receiver, bool bCanCallJava)
1299    : Thread(bCanCallJava), mReceiver(receiver)
1300{
1301}
1302
1303bool AudioTrack::AudioTrackThread::threadLoop()
1304{
1305    return mReceiver.processAudioBuffer(this);
1306}
1307
1308status_t AudioTrack::AudioTrackThread::readyToRun()
1309{
1310    return NO_ERROR;
1311}
1312
1313void AudioTrack::AudioTrackThread::onFirstRef()
1314{
1315}
1316
1317// =========================================================================
1318
1319
1320audio_track_cblk_t::audio_track_cblk_t()
1321    : lock(Mutex::SHARED), cv(Condition::SHARED), user(0), server(0),
1322    userBase(0), serverBase(0), buffers(NULL), frameCount(0),
1323    loopStart(UINT_MAX), loopEnd(UINT_MAX), loopCount(0), mVolumeLR(0x10001000),
1324    mSendLevel(0), flags(0)
1325{
1326}
1327
1328uint32_t audio_track_cblk_t::stepUser(uint32_t frameCount)
1329{
1330    uint32_t u = user;
1331
1332    u += frameCount;
1333    // Ensure that user is never ahead of server for AudioRecord
1334    if (flags & CBLK_DIRECTION_MSK) {
1335        // If stepServer() has been called once, switch to normal obtainBuffer() timeout period
1336        if (bufferTimeoutMs == MAX_STARTUP_TIMEOUT_MS-1) {
1337            bufferTimeoutMs = MAX_RUN_TIMEOUT_MS;
1338        }
1339    } else if (u > server) {
1340        ALOGW("stepServer occurred after track reset");
1341        u = server;
1342    }
1343
1344    if (u >= userBase + this->frameCount) {
1345        userBase += this->frameCount;
1346    }
1347
1348    user = u;
1349
1350    // Clear flow control error condition as new data has been written/read to/from buffer.
1351    if (flags & CBLK_UNDERRUN_MSK) {
1352        android_atomic_and(~CBLK_UNDERRUN_MSK, &flags);
1353    }
1354
1355    return u;
1356}
1357
1358bool audio_track_cblk_t::stepServer(uint32_t frameCount)
1359{
1360    if (!tryLock()) {
1361        ALOGW("stepServer() could not lock cblk");
1362        return false;
1363    }
1364
1365    uint32_t s = server;
1366
1367    s += frameCount;
1368    if (flags & CBLK_DIRECTION_MSK) {
1369        // Mark that we have read the first buffer so that next time stepUser() is called
1370        // we switch to normal obtainBuffer() timeout period
1371        if (bufferTimeoutMs == MAX_STARTUP_TIMEOUT_MS) {
1372            bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS - 1;
1373        }
1374        // It is possible that we receive a flush()
1375        // while the mixer is processing a block: in this case,
1376        // stepServer() is called After the flush() has reset u & s and
1377        // we have s > u
1378        if (s > user) {
1379            ALOGW("stepServer occurred after track reset");
1380            s = user;
1381        }
1382    }
1383
1384    if (s >= loopEnd) {
1385        ALOGW_IF(s > loopEnd, "stepServer: s %u > loopEnd %u", s, loopEnd);
1386        s = loopStart;
1387        if (--loopCount == 0) {
1388            loopEnd = UINT_MAX;
1389            loopStart = UINT_MAX;
1390        }
1391    }
1392    if (s >= serverBase + this->frameCount) {
1393        serverBase += this->frameCount;
1394    }
1395
1396    server = s;
1397
1398    if (!(flags & CBLK_INVALID_MSK)) {
1399        cv.signal();
1400    }
1401    lock.unlock();
1402    return true;
1403}
1404
1405void* audio_track_cblk_t::buffer(uint32_t offset) const
1406{
1407    return (int8_t *)buffers + (offset - userBase) * frameSize;
1408}
1409
1410uint32_t audio_track_cblk_t::framesAvailable()
1411{
1412    Mutex::Autolock _l(lock);
1413    return framesAvailable_l();
1414}
1415
1416uint32_t audio_track_cblk_t::framesAvailable_l()
1417{
1418    uint32_t u = user;
1419    uint32_t s = server;
1420
1421    if (flags & CBLK_DIRECTION_MSK) {
1422        uint32_t limit = (s < loopStart) ? s : loopStart;
1423        return limit + frameCount - u;
1424    } else {
1425        return frameCount + u - s;
1426    }
1427}
1428
1429uint32_t audio_track_cblk_t::framesReady()
1430{
1431    uint32_t u = user;
1432    uint32_t s = server;
1433
1434    if (flags & CBLK_DIRECTION_MSK) {
1435        if (u < loopEnd) {
1436            return u - s;
1437        } else {
1438            // do not block on mutex shared with client on AudioFlinger side
1439            if (!tryLock()) {
1440                ALOGW("framesReady() could not lock cblk");
1441                return 0;
1442            }
1443            uint32_t frames = UINT_MAX;
1444            if (loopCount >= 0) {
1445                frames = (loopEnd - loopStart)*loopCount + u - s;
1446            }
1447            lock.unlock();
1448            return frames;
1449        }
1450    } else {
1451        return s - u;
1452    }
1453}
1454
1455bool audio_track_cblk_t::tryLock()
1456{
1457    // the code below simulates lock-with-timeout
1458    // we MUST do this to protect the AudioFlinger server
1459    // as this lock is shared with the client.
1460    status_t err;
1461
1462    err = lock.tryLock();
1463    if (err == -EBUSY) { // just wait a bit
1464        usleep(1000);
1465        err = lock.tryLock();
1466    }
1467    if (err != NO_ERROR) {
1468        // probably, the client just died.
1469        return false;
1470    }
1471    return true;
1472}
1473
1474// -------------------------------------------------------------------------
1475
1476}; // namespace android
1477