AudioTrack.cpp revision 6dbc1359f778575d09d6da722b060a6d72c2e7c5 
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     }
349
350    AutoMutex lock(mLock);
351    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
352    // while we are accessing the cblk
353    sp <IAudioTrack> audioTrack = mAudioTrack;
354    sp <IMemory> iMem = mCblkMemory;
355    audio_track_cblk_t* cblk = mCblk;
356
357    if (!mActive) {
358        mFlushed = false;
359        mActive = true;
360        mNewPosition = cblk->server + mUpdatePeriod;
361        cblk->lock.lock();
362        cblk->bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS;
363        cblk->waitTimeMs = 0;
364        android_atomic_and(~CBLK_DISABLED_ON, &cblk->flags);
365        pid_t tid;
366        if (t != 0) {
367            t->run("AudioTrackThread", ANDROID_PRIORITY_AUDIO);
368            tid = t->getTid();  // pid_t is unknown until run()
369            ALOGV("getTid=%d", tid);
370            if (tid == -1) {
371                tid = 0;
372            }
373        } else {
374            mPreviousPriority = getpriority(PRIO_PROCESS, 0);
375            mPreviousSchedulingGroup = androidGetThreadSchedulingGroup(0);
376            androidSetThreadPriority(0, ANDROID_PRIORITY_AUDIO);
377            tid = 0;    // not gettid()
378        }
379
380        ALOGV("start %p before lock cblk %p", this, mCblk);
381        if (!(cblk->flags & CBLK_INVALID_MSK)) {
382            cblk->lock.unlock();
383            ALOGV("mAudioTrack->start(tid=%d)", tid);
384            status = mAudioTrack->start(tid);
385            cblk->lock.lock();
386            if (status == DEAD_OBJECT) {
387                android_atomic_or(CBLK_INVALID_ON, &cblk->flags);
388            }
389        }
390        if (cblk->flags & CBLK_INVALID_MSK) {
391            status = restoreTrack_l(cblk, true);
392        }
393        cblk->lock.unlock();
394        if (status != NO_ERROR) {
395            ALOGV("start() failed");
396            mActive = false;
397            if (t != 0) {
398                t->requestExit();
399            } else {
400                setpriority(PRIO_PROCESS, 0, mPreviousPriority);
401                androidSetThreadSchedulingGroup(0, mPreviousSchedulingGroup);
402            }
403        }
404    }
405
406}
407
408void AudioTrack::stop()
409{
410    sp<AudioTrackThread> t = mAudioTrackThread;
411
412    ALOGV("stop %p", this);
413
414    AutoMutex lock(mLock);
415    if (mActive) {
416        mActive = false;
417        mCblk->cv.signal();
418        mAudioTrack->stop();
419        // Cancel loops (If we are in the middle of a loop, playback
420        // would not stop until loopCount reaches 0).
421        setLoop_l(0, 0, 0);
422        // the playback head position will reset to 0, so if a marker is set, we need
423        // to activate it again
424        mMarkerReached = false;
425        // Force flush if a shared buffer is used otherwise audioflinger
426        // will not stop before end of buffer is reached.
427        if (mSharedBuffer != 0) {
428            flush_l();
429        }
430        if (t != 0) {
431            t->requestExit();
432        } else {
433            setpriority(PRIO_PROCESS, 0, mPreviousPriority);
434            androidSetThreadSchedulingGroup(0, mPreviousSchedulingGroup);
435        }
436    }
437
438}
439
440bool AudioTrack::stopped() const
441{
442    AutoMutex lock(mLock);
443    return stopped_l();
444}
445
446void AudioTrack::flush()
447{
448    AutoMutex lock(mLock);
449    flush_l();
450}
451
452// must be called with mLock held
453void AudioTrack::flush_l()
454{
455    ALOGV("flush");
456
457    // clear playback marker and periodic update counter
458    mMarkerPosition = 0;
459    mMarkerReached = false;
460    mUpdatePeriod = 0;
461
462    if (!mActive) {
463        mFlushed = true;
464        mAudioTrack->flush();
465        // Release AudioTrack callback thread in case it was waiting for new buffers
466        // in AudioTrack::obtainBuffer()
467        mCblk->cv.signal();
468    }
469}
470
471void AudioTrack::pause()
472{
473    ALOGV("pause");
474    AutoMutex lock(mLock);
475    if (mActive) {
476        mActive = false;
477        mAudioTrack->pause();
478    }
479}
480
481void AudioTrack::mute(bool e)
482{
483    mAudioTrack->mute(e);
484    mMuted = e;
485}
486
487bool AudioTrack::muted() const
488{
489    return mMuted;
490}
491
492status_t AudioTrack::setVolume(float left, float right)
493{
494    if (left < 0.0f || left > 1.0f || right < 0.0f || right > 1.0f) {
495        return BAD_VALUE;
496    }
497
498    AutoMutex lock(mLock);
499    mVolume[LEFT] = left;
500    mVolume[RIGHT] = right;
501
502    mCblk->setVolumeLR((uint32_t(uint16_t(right * 0x1000)) << 16) | uint16_t(left * 0x1000));
503
504    return NO_ERROR;
505}
506
507void AudioTrack::getVolume(float* left, float* right) const
508{
509    if (left != NULL) {
510        *left  = mVolume[LEFT];
511    }
512    if (right != NULL) {
513        *right = mVolume[RIGHT];
514    }
515}
516
517status_t AudioTrack::setAuxEffectSendLevel(float level)
518{
519    ALOGV("setAuxEffectSendLevel(%f)", level);
520    if (level < 0.0f || level > 1.0f) {
521        return BAD_VALUE;
522    }
523    AutoMutex lock(mLock);
524
525    mSendLevel = level;
526
527    mCblk->setSendLevel(level);
528
529    return NO_ERROR;
530}
531
532void AudioTrack::getAuxEffectSendLevel(float* level) const
533{
534    if (level != NULL) {
535        *level  = mSendLevel;
536    }
537}
538
539status_t AudioTrack::setSampleRate(int rate)
540{
541    int afSamplingRate;
542
543    if (AudioSystem::getOutputSamplingRate(&afSamplingRate, mStreamType) != NO_ERROR) {
544        return NO_INIT;
545    }
546    // Resampler implementation limits input sampling rate to 2 x output sampling rate.
547    if (rate <= 0 || rate > afSamplingRate*2 ) return BAD_VALUE;
548
549    AutoMutex lock(mLock);
550    mCblk->sampleRate = rate;
551    return NO_ERROR;
552}
553
554uint32_t AudioTrack::getSampleRate() const
555{
556    AutoMutex lock(mLock);
557    return mCblk->sampleRate;
558}
559
560status_t AudioTrack::setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount)
561{
562    AutoMutex lock(mLock);
563    return setLoop_l(loopStart, loopEnd, loopCount);
564}
565
566// must be called with mLock held
567status_t AudioTrack::setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount)
568{
569    audio_track_cblk_t* cblk = mCblk;
570
571    Mutex::Autolock _l(cblk->lock);
572
573    if (loopCount == 0) {
574        cblk->loopStart = UINT_MAX;
575        cblk->loopEnd = UINT_MAX;
576        cblk->loopCount = 0;
577        mLoopCount = 0;
578        return NO_ERROR;
579    }
580
581    if (loopStart >= loopEnd ||
582        loopEnd - loopStart > cblk->frameCount ||
583        cblk->server > loopStart) {
584        ALOGE("setLoop invalid value: loopStart %d, loopEnd %d, loopCount %d, framecount %d, user %d", loopStart, loopEnd, loopCount, cblk->frameCount, cblk->user);
585        return BAD_VALUE;
586    }
587
588    if ((mSharedBuffer != 0) && (loopEnd > cblk->frameCount)) {
589        ALOGE("setLoop invalid value: loop markers beyond data: loopStart %d, loopEnd %d, framecount %d",
590            loopStart, loopEnd, cblk->frameCount);
591        return BAD_VALUE;
592    }
593
594    cblk->loopStart = loopStart;
595    cblk->loopEnd = loopEnd;
596    cblk->loopCount = loopCount;
597    mLoopCount = loopCount;
598
599    return NO_ERROR;
600}
601
602status_t AudioTrack::getLoop(uint32_t *loopStart, uint32_t *loopEnd, int *loopCount) const
603{
604    AutoMutex lock(mLock);
605    if (loopStart != NULL) {
606        *loopStart = mCblk->loopStart;
607    }
608    if (loopEnd != NULL) {
609        *loopEnd = mCblk->loopEnd;
610    }
611    if (loopCount != NULL) {
612        if (mCblk->loopCount < 0) {
613            *loopCount = -1;
614        } else {
615            *loopCount = mCblk->loopCount;
616        }
617    }
618
619    return NO_ERROR;
620}
621
622status_t AudioTrack::setMarkerPosition(uint32_t marker)
623{
624    if (mCbf == NULL) return INVALID_OPERATION;
625
626    mMarkerPosition = marker;
627    mMarkerReached = false;
628
629    return NO_ERROR;
630}
631
632status_t AudioTrack::getMarkerPosition(uint32_t *marker) const
633{
634    if (marker == NULL) return BAD_VALUE;
635
636    *marker = mMarkerPosition;
637
638    return NO_ERROR;
639}
640
641status_t AudioTrack::setPositionUpdatePeriod(uint32_t updatePeriod)
642{
643    if (mCbf == NULL) return INVALID_OPERATION;
644
645    uint32_t curPosition;
646    getPosition(&curPosition);
647    mNewPosition = curPosition + updatePeriod;
648    mUpdatePeriod = updatePeriod;
649
650    return NO_ERROR;
651}
652
653status_t AudioTrack::getPositionUpdatePeriod(uint32_t *updatePeriod) const
654{
655    if (updatePeriod == NULL) return BAD_VALUE;
656
657    *updatePeriod = mUpdatePeriod;
658
659    return NO_ERROR;
660}
661
662status_t AudioTrack::setPosition(uint32_t position)
663{
664    AutoMutex lock(mLock);
665
666    if (!stopped_l()) return INVALID_OPERATION;
667
668    Mutex::Autolock _l(mCblk->lock);
669
670    if (position > mCblk->user) return BAD_VALUE;
671
672    mCblk->server = position;
673    android_atomic_or(CBLK_FORCEREADY_ON, &mCblk->flags);
674
675    return NO_ERROR;
676}
677
678status_t AudioTrack::getPosition(uint32_t *position)
679{
680    if (position == NULL) return BAD_VALUE;
681    AutoMutex lock(mLock);
682    *position = mFlushed ? 0 : mCblk->server;
683
684    return NO_ERROR;
685}
686
687status_t AudioTrack::reload()
688{
689    AutoMutex lock(mLock);
690
691    if (!stopped_l()) return INVALID_OPERATION;
692
693    flush_l();
694
695    mCblk->stepUser(mCblk->frameCount);
696
697    return NO_ERROR;
698}
699
700audio_io_handle_t AudioTrack::getOutput()
701{
702    AutoMutex lock(mLock);
703    return getOutput_l();
704}
705
706// must be called with mLock held
707audio_io_handle_t AudioTrack::getOutput_l()
708{
709    return AudioSystem::getOutput(mStreamType,
710            mCblk->sampleRate, mFormat, mChannelMask, (audio_policy_output_flags_t)mFlags);
711}
712
713int AudioTrack::getSessionId() const
714{
715    return mSessionId;
716}
717
718status_t AudioTrack::attachAuxEffect(int effectId)
719{
720    ALOGV("attachAuxEffect(%d)", effectId);
721    status_t status = mAudioTrack->attachAuxEffect(effectId);
722    if (status == NO_ERROR) {
723        mAuxEffectId = effectId;
724    }
725    return status;
726}
727
728// -------------------------------------------------------------------------
729
730// must be called with mLock held
731status_t AudioTrack::createTrack_l(
732        audio_stream_type_t streamType,
733        uint32_t sampleRate,
734        audio_format_t format,
735        uint32_t channelMask,
736        int frameCount,
737        uint32_t flags,
738        const sp<IMemory>& sharedBuffer,
739        audio_io_handle_t output,
740        bool enforceFrameCount)
741{
742    status_t status;
743    const sp<IAudioFlinger>& audioFlinger = AudioSystem::get_audio_flinger();
744    if (audioFlinger == 0) {
745       ALOGE("Could not get audioflinger");
746       return NO_INIT;
747    }
748
749    int afSampleRate;
750    if (AudioSystem::getOutputSamplingRate(&afSampleRate, streamType) != NO_ERROR) {
751        return NO_INIT;
752    }
753    int afFrameCount;
754    if (AudioSystem::getOutputFrameCount(&afFrameCount, streamType) != NO_ERROR) {
755        return NO_INIT;
756    }
757    uint32_t afLatency;
758    if (AudioSystem::getOutputLatency(&afLatency, streamType) != NO_ERROR) {
759        return NO_INIT;
760    }
761
762    mNotificationFramesAct = mNotificationFramesReq;
763    if (!audio_is_linear_pcm(format)) {
764        if (sharedBuffer != 0) {
765            frameCount = sharedBuffer->size();
766        }
767    } else {
768        // Ensure that buffer depth covers at least audio hardware latency
769        uint32_t minBufCount = afLatency / ((1000 * afFrameCount)/afSampleRate);
770        if (minBufCount < 2) minBufCount = 2;
771
772        int minFrameCount = (afFrameCount*sampleRate*minBufCount)/afSampleRate;
773
774        if (sharedBuffer == 0) {
775            if (frameCount == 0) {
776                frameCount = minFrameCount;
777            }
778            if (mNotificationFramesAct == 0) {
779                mNotificationFramesAct = frameCount/2;
780            }
781            // Make sure that application is notified with sufficient margin
782            // before underrun
783            if (mNotificationFramesAct > (uint32_t)frameCount/2) {
784                mNotificationFramesAct = frameCount/2;
785            }
786            if (frameCount < minFrameCount) {
787                if (enforceFrameCount) {
788                    ALOGE("Invalid buffer size: minFrameCount %d, frameCount %d", minFrameCount, frameCount);
789                    return BAD_VALUE;
790                } else {
791                    frameCount = minFrameCount;
792                }
793            }
794        } else {
795            // Ensure that buffer alignment matches channelcount
796            int channelCount = popcount(channelMask);
797            if (((uint32_t)sharedBuffer->pointer() & (channelCount | 1)) != 0) {
798                ALOGE("Invalid buffer alignement: address %p, channelCount %d", sharedBuffer->pointer(), channelCount);
799                return BAD_VALUE;
800            }
801            frameCount = sharedBuffer->size()/channelCount/sizeof(int16_t);
802        }
803    }
804
805    sp<IAudioTrack> track = audioFlinger->createTrack(getpid(),
806                                                      streamType,
807                                                      sampleRate,
808                                                      format,
809                                                      channelMask,
810                                                      frameCount,
811                                                      ((uint16_t)flags) << 16,
812                                                      sharedBuffer,
813                                                      output,
814                                                      &mSessionId,
815                                                      &status);
816
817    if (track == 0) {
818        ALOGE("AudioFlinger could not create track, status: %d", status);
819        return status;
820    }
821    sp<IMemory> cblk = track->getCblk();
822    if (cblk == 0) {
823        ALOGE("Could not get control block");
824        return NO_INIT;
825    }
826    mAudioTrack = track;
827    mCblkMemory = cblk;
828    mCblk = static_cast<audio_track_cblk_t*>(cblk->pointer());
829    android_atomic_or(CBLK_DIRECTION_OUT, &mCblk->flags);
830    if (sharedBuffer == 0) {
831        mCblk->buffers = (char*)mCblk + sizeof(audio_track_cblk_t);
832    } else {
833        mCblk->buffers = sharedBuffer->pointer();
834         // Force buffer full condition as data is already present in shared memory
835        mCblk->stepUser(mCblk->frameCount);
836    }
837
838    mCblk->setVolumeLR((uint32_t(uint16_t(mVolume[RIGHT] * 0x1000)) << 16) | uint16_t(mVolume[LEFT] * 0x1000));
839    mCblk->setSendLevel(mSendLevel);
840    mAudioTrack->attachAuxEffect(mAuxEffectId);
841    mCblk->bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS;
842    mCblk->waitTimeMs = 0;
843    mRemainingFrames = mNotificationFramesAct;
844    mLatency = afLatency + (1000*mCblk->frameCount) / sampleRate;
845    return NO_ERROR;
846}
847
848status_t AudioTrack::obtainBuffer(Buffer* audioBuffer, int32_t waitCount)
849{
850    AutoMutex lock(mLock);
851    bool active;
852    status_t result = NO_ERROR;
853    audio_track_cblk_t* cblk = mCblk;
854    uint32_t framesReq = audioBuffer->frameCount;
855    uint32_t waitTimeMs = (waitCount < 0) ? cblk->bufferTimeoutMs : WAIT_PERIOD_MS;
856
857    audioBuffer->frameCount  = 0;
858    audioBuffer->size = 0;
859
860    uint32_t framesAvail = cblk->framesAvailable();
861
862    cblk->lock.lock();
863    if (cblk->flags & CBLK_INVALID_MSK) {
864        goto create_new_track;
865    }
866    cblk->lock.unlock();
867
868    if (framesAvail == 0) {
869        cblk->lock.lock();
870        goto start_loop_here;
871        while (framesAvail == 0) {
872            active = mActive;
873            if (CC_UNLIKELY(!active)) {
874                ALOGV("Not active and NO_MORE_BUFFERS");
875                cblk->lock.unlock();
876                return NO_MORE_BUFFERS;
877            }
878            if (CC_UNLIKELY(!waitCount)) {
879                cblk->lock.unlock();
880                return WOULD_BLOCK;
881            }
882            if (!(cblk->flags & CBLK_INVALID_MSK)) {
883                mLock.unlock();
884                result = cblk->cv.waitRelative(cblk->lock, milliseconds(waitTimeMs));
885                cblk->lock.unlock();
886                mLock.lock();
887                if (!mActive) {
888                    return status_t(STOPPED);
889                }
890                cblk->lock.lock();
891            }
892
893            if (cblk->flags & CBLK_INVALID_MSK) {
894                goto create_new_track;
895            }
896            if (CC_UNLIKELY(result != NO_ERROR)) {
897                cblk->waitTimeMs += waitTimeMs;
898                if (cblk->waitTimeMs >= cblk->bufferTimeoutMs) {
899                    // timing out when a loop has been set and we have already written upto loop end
900                    // is a normal condition: no need to wake AudioFlinger up.
901                    if (cblk->user < cblk->loopEnd) {
902                        ALOGW(   "obtainBuffer timed out (is the CPU pegged?) %p "
903                                "user=%08x, server=%08x", this, cblk->user, cblk->server);
904                        //unlock cblk mutex before calling mAudioTrack->start() (see issue #1617140)
905                        cblk->lock.unlock();
906                        result = mAudioTrack->start(0); // callback thread hasn't changed
907                        cblk->lock.lock();
908                        if (result == DEAD_OBJECT) {
909                            android_atomic_or(CBLK_INVALID_ON, &cblk->flags);
910create_new_track:
911                            result = restoreTrack_l(cblk, false);
912                        }
913                        if (result != NO_ERROR) {
914                            ALOGW("obtainBuffer create Track error %d", result);
915                            cblk->lock.unlock();
916                            return result;
917                        }
918                    }
919                    cblk->waitTimeMs = 0;
920                }
921
922                if (--waitCount == 0) {
923                    cblk->lock.unlock();
924                    return TIMED_OUT;
925                }
926            }
927            // read the server count again
928        start_loop_here:
929            framesAvail = cblk->framesAvailable_l();
930        }
931        cblk->lock.unlock();
932    }
933
934    // restart track if it was disabled by audioflinger due to previous underrun
935    if (mActive && (cblk->flags & CBLK_DISABLED_MSK)) {
936        android_atomic_and(~CBLK_DISABLED_ON, &cblk->flags);
937        ALOGW("obtainBuffer() track %p disabled, restarting", this);
938        mAudioTrack->start(0);  // callback thread hasn't changed
939    }
940
941    cblk->waitTimeMs = 0;
942
943    if (framesReq > framesAvail) {
944        framesReq = framesAvail;
945    }
946
947    uint32_t u = cblk->user;
948    uint32_t bufferEnd = cblk->userBase + cblk->frameCount;
949
950    if (u + framesReq > bufferEnd) {
951        framesReq = bufferEnd - u;
952    }
953
954    audioBuffer->flags = mMuted ? Buffer::MUTE : 0;
955    audioBuffer->channelCount = mChannelCount;
956    audioBuffer->frameCount = framesReq;
957    audioBuffer->size = framesReq * cblk->frameSize;
958    if (audio_is_linear_pcm(mFormat)) {
959        audioBuffer->format = AUDIO_FORMAT_PCM_16_BIT;
960    } else {
961        audioBuffer->format = mFormat;
962    }
963    audioBuffer->raw = (int8_t *)cblk->buffer(u);
964    active = mActive;
965    return active ? status_t(NO_ERROR) : status_t(STOPPED);
966}
967
968void AudioTrack::releaseBuffer(Buffer* audioBuffer)
969{
970    AutoMutex lock(mLock);
971    mCblk->stepUser(audioBuffer->frameCount);
972}
973
974// -------------------------------------------------------------------------
975
976ssize_t AudioTrack::write(const void* buffer, size_t userSize)
977{
978
979    if (mSharedBuffer != 0) return INVALID_OPERATION;
980
981    if (ssize_t(userSize) < 0) {
982        // sanity-check. user is most-likely passing an error code.
983        ALOGE("AudioTrack::write(buffer=%p, size=%u (%d)",
984                buffer, userSize, userSize);
985        return BAD_VALUE;
986    }
987
988    ALOGV("write %p: %d bytes, mActive=%d", this, userSize, mActive);
989
990    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
991    // while we are accessing the cblk
992    mLock.lock();
993    sp <IAudioTrack> audioTrack = mAudioTrack;
994    sp <IMemory> iMem = mCblkMemory;
995    mLock.unlock();
996
997    ssize_t written = 0;
998    const int8_t *src = (const int8_t *)buffer;
999    Buffer audioBuffer;
1000    size_t frameSz = frameSize();
1001
1002    do {
1003        audioBuffer.frameCount = userSize/frameSz;
1004
1005        // Calling obtainBuffer() with a negative wait count causes
1006        // an (almost) infinite wait time.
1007        status_t err = obtainBuffer(&audioBuffer, -1);
1008        if (err < 0) {
1009            // out of buffers, return #bytes written
1010            if (err == status_t(NO_MORE_BUFFERS))
1011                break;
1012            return ssize_t(err);
1013        }
1014
1015        size_t toWrite;
1016
1017        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1018            // Divide capacity by 2 to take expansion into account
1019            toWrite = audioBuffer.size>>1;
1020            memcpy_to_i16_from_u8(audioBuffer.i16, (const uint8_t *) src, toWrite);
1021        } else {
1022            toWrite = audioBuffer.size;
1023            memcpy(audioBuffer.i8, src, toWrite);
1024            src += toWrite;
1025        }
1026        userSize -= toWrite;
1027        written += toWrite;
1028
1029        releaseBuffer(&audioBuffer);
1030    } while (userSize >= frameSz);
1031
1032    return written;
1033}
1034
1035// -------------------------------------------------------------------------
1036
1037bool AudioTrack::processAudioBuffer(const sp<AudioTrackThread>& thread)
1038{
1039    Buffer audioBuffer;
1040    uint32_t frames;
1041    size_t writtenSize;
1042
1043    mLock.lock();
1044    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
1045    // while we are accessing the cblk
1046    sp <IAudioTrack> audioTrack = mAudioTrack;
1047    sp <IMemory> iMem = mCblkMemory;
1048    audio_track_cblk_t* cblk = mCblk;
1049    bool active = mActive;
1050    mLock.unlock();
1051
1052    // Manage underrun callback
1053    if (active && (cblk->framesAvailable() == cblk->frameCount)) {
1054        ALOGV("Underrun user: %x, server: %x, flags %04x", cblk->user, cblk->server, cblk->flags);
1055        if (!(android_atomic_or(CBLK_UNDERRUN_ON, &cblk->flags) & CBLK_UNDERRUN_MSK)) {
1056            mCbf(EVENT_UNDERRUN, mUserData, 0);
1057            if (cblk->server == cblk->frameCount) {
1058                mCbf(EVENT_BUFFER_END, mUserData, 0);
1059            }
1060            if (mSharedBuffer != 0) return false;
1061        }
1062    }
1063
1064    // Manage loop end callback
1065    while (mLoopCount > cblk->loopCount) {
1066        int loopCount = -1;
1067        mLoopCount--;
1068        if (mLoopCount >= 0) loopCount = mLoopCount;
1069
1070        mCbf(EVENT_LOOP_END, mUserData, (void *)&loopCount);
1071    }
1072
1073    // Manage marker callback
1074    if (!mMarkerReached && (mMarkerPosition > 0)) {
1075        if (cblk->server >= mMarkerPosition) {
1076            mCbf(EVENT_MARKER, mUserData, (void *)&mMarkerPosition);
1077            mMarkerReached = true;
1078        }
1079    }
1080
1081    // Manage new position callback
1082    if (mUpdatePeriod > 0) {
1083        while (cblk->server >= mNewPosition) {
1084            mCbf(EVENT_NEW_POS, mUserData, (void *)&mNewPosition);
1085            mNewPosition += mUpdatePeriod;
1086        }
1087    }
1088
1089    // If Shared buffer is used, no data is requested from client.
1090    if (mSharedBuffer != 0) {
1091        frames = 0;
1092    } else {
1093        frames = mRemainingFrames;
1094    }
1095
1096    int32_t waitCount = -1;
1097    if (mUpdatePeriod || (!mMarkerReached && mMarkerPosition) || mLoopCount) {
1098        waitCount = 1;
1099    }
1100
1101    do {
1102
1103        audioBuffer.frameCount = frames;
1104
1105        // Calling obtainBuffer() with a wait count of 1
1106        // limits wait time to WAIT_PERIOD_MS. This prevents from being
1107        // stuck here not being able to handle timed events (position, markers, loops).
1108        status_t err = obtainBuffer(&audioBuffer, waitCount);
1109        if (err < NO_ERROR) {
1110            if (err != TIMED_OUT) {
1111                ALOGE_IF(err != status_t(NO_MORE_BUFFERS), "Error obtaining an audio buffer, giving up.");
1112                return false;
1113            }
1114            break;
1115        }
1116        if (err == status_t(STOPPED)) return false;
1117
1118        // Divide buffer size by 2 to take into account the expansion
1119        // due to 8 to 16 bit conversion: the callback must fill only half
1120        // of the destination buffer
1121        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1122            audioBuffer.size >>= 1;
1123        }
1124
1125        size_t reqSize = audioBuffer.size;
1126        mCbf(EVENT_MORE_DATA, mUserData, &audioBuffer);
1127        writtenSize = audioBuffer.size;
1128
1129        // Sanity check on returned size
1130        if (ssize_t(writtenSize) <= 0) {
1131            // The callback is done filling buffers
1132            // Keep this thread going to handle timed events and
1133            // still try to get more data in intervals of WAIT_PERIOD_MS
1134            // but don't just loop and block the CPU, so wait
1135            usleep(WAIT_PERIOD_MS*1000);
1136            break;
1137        }
1138        if (writtenSize > reqSize) writtenSize = reqSize;
1139
1140        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1141            // 8 to 16 bit conversion, note that source and destination are the same address
1142            memcpy_to_i16_from_u8(audioBuffer.i16, (const uint8_t *) audioBuffer.i8, writtenSize);
1143            writtenSize <<= 1;
1144        }
1145
1146        audioBuffer.size = writtenSize;
1147        // NOTE: mCblk->frameSize is not equal to AudioTrack::frameSize() for
1148        // 8 bit PCM data: in this case,  mCblk->frameSize is based on a sample size of
1149        // 16 bit.
1150        audioBuffer.frameCount = writtenSize/mCblk->frameSize;
1151
1152        frames -= audioBuffer.frameCount;
1153
1154        releaseBuffer(&audioBuffer);
1155    }
1156    while (frames);
1157
1158    if (frames == 0) {
1159        mRemainingFrames = mNotificationFramesAct;
1160    } else {
1161        mRemainingFrames = frames;
1162    }
1163    return true;
1164}
1165
1166// must be called with mLock and cblk.lock held. Callers must also hold strong references on
1167// the IAudioTrack and IMemory in case they are recreated here.
1168// If the IAudioTrack is successfully restored, the cblk pointer is updated
1169status_t AudioTrack::restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart)
1170{
1171    status_t result;
1172
1173    if (!(android_atomic_or(CBLK_RESTORING_ON, &cblk->flags) & CBLK_RESTORING_MSK)) {
1174        ALOGW("dead IAudioTrack, creating a new one from %s TID %d",
1175             fromStart ? "start()" : "obtainBuffer()", gettid());
1176
1177        // signal old cblk condition so that other threads waiting for available buffers stop
1178        // waiting now
1179        cblk->cv.broadcast();
1180        cblk->lock.unlock();
1181
1182        // refresh the audio configuration cache in this process to make sure we get new
1183        // output parameters in getOutput_l() and createTrack_l()
1184        AudioSystem::clearAudioConfigCache();
1185
1186        // if the new IAudioTrack is created, createTrack_l() will modify the
1187        // following member variables: mAudioTrack, mCblkMemory and mCblk.
1188        // It will also delete the strong references on previous IAudioTrack and IMemory
1189        result = createTrack_l(mStreamType,
1190                               cblk->sampleRate,
1191                               mFormat,
1192                               mChannelMask,
1193                               mFrameCount,
1194                               mFlags,
1195                               mSharedBuffer,
1196                               getOutput_l(),
1197                               false);
1198
1199        if (result == NO_ERROR) {
1200            uint32_t user = cblk->user;
1201            uint32_t server = cblk->server;
1202            // restore write index and set other indexes to reflect empty buffer status
1203            mCblk->user = user;
1204            mCblk->server = user;
1205            mCblk->userBase = user;
1206            mCblk->serverBase = user;
1207            // restore loop: this is not guaranteed to succeed if new frame count is not
1208            // compatible with loop length
1209            setLoop_l(cblk->loopStart, cblk->loopEnd, cblk->loopCount);
1210            if (!fromStart) {
1211                mCblk->bufferTimeoutMs = MAX_RUN_TIMEOUT_MS;
1212                // Make sure that a client relying on callback events indicating underrun or
1213                // the actual amount of audio frames played (e.g SoundPool) receives them.
1214                if (mSharedBuffer == 0) {
1215                    uint32_t frames = 0;
1216                    if (user > server) {
1217                        frames = ((user - server) > mCblk->frameCount) ?
1218                                mCblk->frameCount : (user - server);
1219                        memset(mCblk->buffers, 0, frames * mCblk->frameSize);
1220                    }
1221                    // restart playback even if buffer is not completely filled.
1222                    android_atomic_or(CBLK_FORCEREADY_ON, &mCblk->flags);
1223                    // stepUser() clears CBLK_UNDERRUN_ON flag enabling underrun callbacks to
1224                    // the client
1225                    mCblk->stepUser(frames);
1226                }
1227            }
1228            if (mActive) {
1229                result = mAudioTrack->start(0); // callback thread hasn't changed
1230                ALOGW_IF(result != NO_ERROR, "restoreTrack_l() start() failed status %d", result);
1231            }
1232            if (fromStart && result == NO_ERROR) {
1233                mNewPosition = mCblk->server + mUpdatePeriod;
1234            }
1235        }
1236        if (result != NO_ERROR) {
1237            android_atomic_and(~CBLK_RESTORING_ON, &cblk->flags);
1238            ALOGW_IF(result != NO_ERROR, "restoreTrack_l() failed status %d", result);
1239        }
1240        mRestoreStatus = result;
1241        // signal old cblk condition for other threads waiting for restore completion
1242        android_atomic_or(CBLK_RESTORED_ON, &cblk->flags);
1243        cblk->cv.broadcast();
1244    } else {
1245        if (!(cblk->flags & CBLK_RESTORED_MSK)) {
1246            ALOGW("dead IAudioTrack, waiting for a new one TID %d", gettid());
1247            mLock.unlock();
1248            result = cblk->cv.waitRelative(cblk->lock, milliseconds(RESTORE_TIMEOUT_MS));
1249            if (result == NO_ERROR) {
1250                result = mRestoreStatus;
1251            }
1252            cblk->lock.unlock();
1253            mLock.lock();
1254        } else {
1255            ALOGW("dead IAudioTrack, already restored TID %d", gettid());
1256            result = mRestoreStatus;
1257            cblk->lock.unlock();
1258        }
1259    }
1260    ALOGV("restoreTrack_l() status %d mActive %d cblk %p, old cblk %p flags %08x old flags %08x",
1261         result, mActive, mCblk, cblk, mCblk->flags, cblk->flags);
1262
1263    if (result == NO_ERROR) {
1264        // from now on we switch to the newly created cblk
1265        cblk = mCblk;
1266    }
1267    cblk->lock.lock();
1268
1269    ALOGW_IF(result != NO_ERROR, "restoreTrack_l() error %d TID %d", result, gettid());
1270
1271    return result;
1272}
1273
1274status_t AudioTrack::dump(int fd, const Vector<String16>& args) const
1275{
1276
1277    const size_t SIZE = 256;
1278    char buffer[SIZE];
1279    String8 result;
1280
1281    result.append(" AudioTrack::dump\n");
1282    snprintf(buffer, 255, "  stream type(%d), left - right volume(%f, %f)\n", mStreamType, mVolume[0], mVolume[1]);
1283    result.append(buffer);
1284    snprintf(buffer, 255, "  format(%d), channel count(%d), frame count(%d)\n", mFormat, mChannelCount, mCblk->frameCount);
1285    result.append(buffer);
1286    snprintf(buffer, 255, "  sample rate(%d), status(%d), muted(%d)\n", (mCblk == 0) ? 0 : mCblk->sampleRate, mStatus, mMuted);
1287    result.append(buffer);
1288    snprintf(buffer, 255, "  active(%d), latency (%d)\n", mActive, mLatency);
1289    result.append(buffer);
1290    ::write(fd, result.string(), result.size());
1291    return NO_ERROR;
1292}
1293
1294// =========================================================================
1295
1296AudioTrack::AudioTrackThread::AudioTrackThread(AudioTrack& receiver, bool bCanCallJava)
1297    : Thread(bCanCallJava), mReceiver(receiver)
1298{
1299}
1300
1301bool AudioTrack::AudioTrackThread::threadLoop()
1302{
1303    return mReceiver.processAudioBuffer(this);
1304}
1305
1306status_t AudioTrack::AudioTrackThread::readyToRun()
1307{
1308    return NO_ERROR;
1309}
1310
1311void AudioTrack::AudioTrackThread::onFirstRef()
1312{
1313}
1314
1315// =========================================================================
1316
1317
1318audio_track_cblk_t::audio_track_cblk_t()
1319    : lock(Mutex::SHARED), cv(Condition::SHARED), user(0), server(0),
1320    userBase(0), serverBase(0), buffers(NULL), frameCount(0),
1321    loopStart(UINT_MAX), loopEnd(UINT_MAX), loopCount(0), mVolumeLR(0x10001000),
1322    mSendLevel(0), flags(0)
1323{
1324}
1325
1326uint32_t audio_track_cblk_t::stepUser(uint32_t frameCount)
1327{
1328    uint32_t u = user;
1329
1330    u += frameCount;
1331    // Ensure that user is never ahead of server for AudioRecord
1332    if (flags & CBLK_DIRECTION_MSK) {
1333        // If stepServer() has been called once, switch to normal obtainBuffer() timeout period
1334        if (bufferTimeoutMs == MAX_STARTUP_TIMEOUT_MS-1) {
1335            bufferTimeoutMs = MAX_RUN_TIMEOUT_MS;
1336        }
1337    } else if (u > server) {
1338        ALOGW("stepServer occurred after track reset");
1339        u = server;
1340    }
1341
1342    if (u >= userBase + this->frameCount) {
1343        userBase += this->frameCount;
1344    }
1345
1346    user = u;
1347
1348    // Clear flow control error condition as new data has been written/read to/from buffer.
1349    if (flags & CBLK_UNDERRUN_MSK) {
1350        android_atomic_and(~CBLK_UNDERRUN_MSK, &flags);
1351    }
1352
1353    return u;
1354}
1355
1356bool audio_track_cblk_t::stepServer(uint32_t frameCount)
1357{
1358    if (!tryLock()) {
1359        ALOGW("stepServer() could not lock cblk");
1360        return false;
1361    }
1362
1363    uint32_t s = server;
1364
1365    s += frameCount;
1366    if (flags & CBLK_DIRECTION_MSK) {
1367        // Mark that we have read the first buffer so that next time stepUser() is called
1368        // we switch to normal obtainBuffer() timeout period
1369        if (bufferTimeoutMs == MAX_STARTUP_TIMEOUT_MS) {
1370            bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS - 1;
1371        }
1372        // It is possible that we receive a flush()
1373        // while the mixer is processing a block: in this case,
1374        // stepServer() is called After the flush() has reset u & s and
1375        // we have s > u
1376        if (s > user) {
1377            ALOGW("stepServer occurred after track reset");
1378            s = user;
1379        }
1380    }
1381
1382    if (s >= loopEnd) {
1383        ALOGW_IF(s > loopEnd, "stepServer: s %u > loopEnd %u", s, loopEnd);
1384        s = loopStart;
1385        if (--loopCount == 0) {
1386            loopEnd = UINT_MAX;
1387            loopStart = UINT_MAX;
1388        }
1389    }
1390    if (s >= serverBase + this->frameCount) {
1391        serverBase += this->frameCount;
1392    }
1393
1394    server = s;
1395
1396    if (!(flags & CBLK_INVALID_MSK)) {
1397        cv.signal();
1398    }
1399    lock.unlock();
1400    return true;
1401}
1402
1403void* audio_track_cblk_t::buffer(uint32_t offset) const
1404{
1405    return (int8_t *)buffers + (offset - userBase) * frameSize;
1406}
1407
1408uint32_t audio_track_cblk_t::framesAvailable()
1409{
1410    Mutex::Autolock _l(lock);
1411    return framesAvailable_l();
1412}
1413
1414uint32_t audio_track_cblk_t::framesAvailable_l()
1415{
1416    uint32_t u = user;
1417    uint32_t s = server;
1418
1419    if (flags & CBLK_DIRECTION_MSK) {
1420        uint32_t limit = (s < loopStart) ? s : loopStart;
1421        return limit + frameCount - u;
1422    } else {
1423        return frameCount + u - s;
1424    }
1425}
1426
1427uint32_t audio_track_cblk_t::framesReady()
1428{
1429    uint32_t u = user;
1430    uint32_t s = server;
1431
1432    if (flags & CBLK_DIRECTION_MSK) {
1433        if (u < loopEnd) {
1434            return u - s;
1435        } else {
1436            // do not block on mutex shared with client on AudioFlinger side
1437            if (!tryLock()) {
1438                ALOGW("framesReady() could not lock cblk");
1439                return 0;
1440            }
1441            uint32_t frames = UINT_MAX;
1442            if (loopCount >= 0) {
1443                frames = (loopEnd - loopStart)*loopCount + u - s;
1444            }
1445            lock.unlock();
1446            return frames;
1447        }
1448    } else {
1449        return s - u;
1450    }
1451}
1452
1453bool audio_track_cblk_t::tryLock()
1454{
1455    // the code below simulates lock-with-timeout
1456    // we MUST do this to protect the AudioFlinger server
1457    // as this lock is shared with the client.
1458    status_t err;
1459
1460    err = lock.tryLock();
1461    if (err == -EBUSY) { // just wait a bit
1462        usleep(1000);
1463        err = lock.tryLock();
1464    }
1465    if (err != NO_ERROR) {
1466        // probably, the client just died.
1467        return false;
1468    }
1469    return true;
1470}
1471
1472// -------------------------------------------------------------------------
1473
1474}; // namespace android
1475