1010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten/* 2010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * Copyright (C) 2012 The Android Open Source Project 3010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * 4010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * Licensed under the Apache License, Version 2.0 (the "License"); 5010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * you may not use this file except in compliance with the License. 6010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * You may obtain a copy of the License at 7010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * 8010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * http://www.apache.org/licenses/LICENSE-2.0 9010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * 10010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * Unless required by applicable law or agreed to in writing, software 11010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * distributed under the License is distributed on an "AS IS" BASIS, 12010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * See the License for the specific language governing permissions and 14010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * limitations under the License. 15010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten */ 16010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 17010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#define LOG_TAG "MonoPipeReader" 18010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten//#define LOG_NDEBUG 0 19010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 20010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#include <cutils/compiler.h> 21010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#include <utils/Log.h> 222dd4bdd715f586d4d30cf90cc6fc2bbfbce60fe0Glenn Kasten#include <media/nbaio/MonoPipeReader.h> 23010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 24010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastennamespace android { 25010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 26010662326b9c43c703725f933e95e0897f8a6bddGlenn KastenMonoPipeReader::MonoPipeReader(MonoPipe* pipe) : 27010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten NBAIO_Source(pipe->mFormat), 28010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten mPipe(pipe) 29010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten{ 30010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten} 31010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 32010662326b9c43c703725f933e95e0897f8a6bddGlenn KastenMonoPipeReader::~MonoPipeReader() 33010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten{ 34010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten} 35010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 36010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastenssize_t MonoPipeReader::availableToRead() 37010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten{ 38010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (CC_UNLIKELY(!mNegotiated)) { 39010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten return NEGOTIATE; 40010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 41010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten ssize_t ret = android_atomic_acquire_load(&mPipe->mRear) - mPipe->mFront; 42010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten ALOG_ASSERT((0 <= ret) && (ret <= mMaxFrames)); 43010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten return ret; 44010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten} 45010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 462c3b2da3049627264b7c6b449a1622f002210f03John Grossmanssize_t MonoPipeReader::read(void *buffer, size_t count, int64_t readPTS) 47010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten{ 482c3b2da3049627264b7c6b449a1622f002210f03John Grossman // Compute the "next read PTS" and cache it. Callers of read pass a read 492c3b2da3049627264b7c6b449a1622f002210f03John Grossman // PTS indicating the local time for which they are requesting data along 502c3b2da3049627264b7c6b449a1622f002210f03John Grossman // with a count (which is the number of audio frames they are going to 512c3b2da3049627264b7c6b449a1622f002210f03John Grossman // ultimately pass to the next stage of the pipeline). Offsetting readPTS 522c3b2da3049627264b7c6b449a1622f002210f03John Grossman // by the duration of count will give us the readPTS which will be passed to 532c3b2da3049627264b7c6b449a1622f002210f03John Grossman // us next time, assuming they system continues to operate in steady state 542c3b2da3049627264b7c6b449a1622f002210f03John Grossman // with no discontinuities. We stash this value so it can be used by the 552c3b2da3049627264b7c6b449a1622f002210f03John Grossman // MonoPipe writer to imlement getNextWriteTimestamp. 562c3b2da3049627264b7c6b449a1622f002210f03John Grossman int64_t nextReadPTS; 572c3b2da3049627264b7c6b449a1622f002210f03John Grossman nextReadPTS = mPipe->offsetTimestampByAudioFrames(readPTS, count); 582c3b2da3049627264b7c6b449a1622f002210f03John Grossman 59010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // count == 0 is unlikely and not worth checking for explicitly; will be handled automatically 60010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten ssize_t red = availableToRead(); 61010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (CC_UNLIKELY(red <= 0)) { 622c3b2da3049627264b7c6b449a1622f002210f03John Grossman // Uh-oh, looks like we are underflowing. Update the next read PTS and 632c3b2da3049627264b7c6b449a1622f002210f03John Grossman // get out. 642c3b2da3049627264b7c6b449a1622f002210f03John Grossman mPipe->updateFrontAndNRPTS(mPipe->mFront, nextReadPTS); 65010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten return red; 66010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 67010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (CC_LIKELY((size_t) red > count)) { 68010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten red = count; 69010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 70010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten size_t front = mPipe->mFront & (mPipe->mMaxFrames - 1); 71010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten size_t part1 = mPipe->mMaxFrames - front; 72010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (part1 > (size_t) red) { 73010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten part1 = red; 74010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 75010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (CC_LIKELY(part1 > 0)) { 76010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten memcpy(buffer, (char *) mPipe->mBuffer + (front << mBitShift), part1 << mBitShift); 77010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (CC_UNLIKELY(front + part1 == mPipe->mMaxFrames)) { 78010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten size_t part2 = red - part1; 79010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (CC_LIKELY(part2 > 0)) { 80010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten memcpy((char *) buffer + (part1 << mBitShift), mPipe->mBuffer, part2 << mBitShift); 81010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 82010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 832c3b2da3049627264b7c6b449a1622f002210f03John Grossman mPipe->updateFrontAndNRPTS(red + mPipe->mFront, nextReadPTS); 84010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten mFramesRead += red; 85010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 86010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten return red; 87010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten} 88010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 89010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten} // namespace android 90