1/* 2 * Copyright (C) 2010 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "include/ThrottledSource.h" 18 19#include <media/stagefright/foundation/ADebug.h> 20#include <media/stagefright/foundation/ALooper.h> 21 22namespace android { 23 24ThrottledSource::ThrottledSource( 25 const sp<DataSource> &source, 26 int32_t bandwidthLimitBytesPerSecond) 27 : mSource(source), 28 mBandwidthLimitBytesPerSecond(bandwidthLimitBytesPerSecond), 29 mStartTimeUs(-1), 30 mTotalTransferred(0) { 31 CHECK(mBandwidthLimitBytesPerSecond > 0); 32} 33 34status_t ThrottledSource::initCheck() const { 35 return mSource->initCheck(); 36} 37 38ssize_t ThrottledSource::readAt(off64_t offset, void *data, size_t size) { 39 Mutex::Autolock autoLock(mLock); 40 41 ssize_t n = mSource->readAt(offset, data, size); 42 43 if (n <= 0) { 44 return n; 45 } 46 47 mTotalTransferred += n; 48 49 int64_t nowUs = ALooper::GetNowUs(); 50 51 if (mStartTimeUs < 0) { 52 mStartTimeUs = nowUs; 53 } 54 55 // How long would it have taken to transfer everything we ever 56 // transferred given the limited bandwidth. 57 int64_t durationUs = 58 mTotalTransferred * 1000000ll / mBandwidthLimitBytesPerSecond; 59 60 int64_t whenUs = mStartTimeUs + durationUs; 61 62 if (whenUs > nowUs) { 63 usleep(whenUs - nowUs); 64 } 65 66 return n; 67} 68 69status_t ThrottledSource::getSize(off64_t *size) { 70 return mSource->getSize(size); 71} 72 73uint32_t ThrottledSource::flags() { 74 return mSource->flags(); 75} 76 77} // namespace android 78 79