MonoPipe.cpp revision 010662326b9c43c703725f933e95e0897f8a6bdd
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 "MonoPipe" 18010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten//#define LOG_NDEBUG 0 19010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 20010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#include <cutils/atomic.h> 21010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#include <cutils/compiler.h> 22010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#include <utils/Log.h> 23010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#include "MonoPipe.h" 24010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#include "roundup.h" 25010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 26010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastennamespace android { 27010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 28010662326b9c43c703725f933e95e0897f8a6bddGlenn KastenMonoPipe::MonoPipe(size_t maxFrames, NBAIO_Format format, bool writeCanBlock) : 29010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten NBAIO_Sink(format), 30010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten mMaxFrames(roundup(maxFrames)), 31010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten mBuffer(malloc(mMaxFrames * Format_frameSize(format))), 32010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten mFront(0), 33010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten mRear(0), 34010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten mWriteCanBlock(writeCanBlock) 35010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten{ 36010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (writeCanBlock) { 37010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // compute sleep time to be about 2/3 of a full pipe; 38010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // this gives a balance between risk of underrun vs. too-frequent wakeups 39010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten mSleep.tv_sec = 0; 40010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten uint64_t ns = mMaxFrames * (666666667 / Format_sampleRate(format)); 41010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (ns > 999999999) { 42010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten ns = 999999999; 43010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 44010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten mSleep.tv_nsec = ns; 45010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 46010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten} 47010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 48010662326b9c43c703725f933e95e0897f8a6bddGlenn KastenMonoPipe::~MonoPipe() 49010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten{ 50010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten free(mBuffer); 51010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten} 52010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 53010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastenssize_t MonoPipe::availableToWrite() const 54010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten{ 55010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (CC_UNLIKELY(!mNegotiated)) { 56010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten return NEGOTIATE; 57010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 58010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten ssize_t ret = mMaxFrames - (mRear - android_atomic_acquire_load(&mFront)); 59010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten ALOG_ASSERT((0 <= ret) && (ret <= mMaxFrames)); 60010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten return ret; 61010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten} 62010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 63010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastenssize_t MonoPipe::write(const void *buffer, size_t count) 64010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten{ 65010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // count == 0 is unlikely and not worth checking for explicitly; will be handled automatically 66010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (CC_UNLIKELY(!mNegotiated)) { 67010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten return NEGOTIATE; 68010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 69010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten size_t totalFramesWritten = 0; 70010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten for (;;) { 71010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten size_t written = availableToWrite(); 72010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (CC_LIKELY(written > count)) { 73010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten written = count; 74010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 75010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten size_t rear = mRear & (mMaxFrames - 1); 76010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten size_t part1 = mMaxFrames - rear; 77010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (part1 > written) { 78010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten part1 = written; 79010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 80010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (CC_LIKELY(part1 > 0)) { 81010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten memcpy((char *) mBuffer + (rear << mBitShift), buffer, part1 << mBitShift); 82010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (CC_UNLIKELY(rear + part1 == mMaxFrames)) { 83010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten size_t part2 = written - part1; 84010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (CC_LIKELY(part2 > 0)) { 85010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten memcpy(mBuffer, (char *) buffer + (part1 << mBitShift), part2 << mBitShift); 86010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 87010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 88010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten android_atomic_release_store(written + mRear, &mRear); 89010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten totalFramesWritten += written; 90010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 91010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if ((count -= written) == 0 || !mWriteCanBlock) { 92010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten break; 93010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 94010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten buffer = (char *) buffer + (written << mBitShift); 95010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten // simulate blocking I/O by sleeping 96010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten nanosleep(&mSleep, NULL); 97010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 98010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten mFramesWritten += totalFramesWritten; 99010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten return totalFramesWritten; 100010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten} 101010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 102010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten} // namespace android 103