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/MediaDebug.h> 20 21 namespace android { 22 23 static int64_t getNowUs() { 24 struct timeval tv; 25 gettimeofday(&tv, NULL); 26 27 return (int64_t)tv.tv_usec + tv.tv_sec * 1000000ll; 28 } 29 30 ThrottledSource::ThrottledSource( 31 const sp<DataSource> &source, 32 int32_t bandwidthLimitBytesPerSecond) 33 : mSource(source), 34 mBandwidthLimitBytesPerSecond(bandwidthLimitBytesPerSecond), 35 mStartTimeUs(-1), 36 mTotalTransferred(0) { 37 CHECK(mBandwidthLimitBytesPerSecond > 0); 38 } 39 40 status_t ThrottledSource::initCheck() const { 41 return mSource->initCheck(); 42 } 43 44 ssize_t ThrottledSource::readAt(off64_t offset, void *data, size_t size) { 45 Mutex::Autolock autoLock(mLock); 46 47 ssize_t n = mSource->readAt(offset, data, size); 48 49 if (n <= 0) { 50 return n; 51 } 52 53 mTotalTransferred += n; 54 55 int64_t nowUs = getNowUs(); 56 57 if (mStartTimeUs < 0) { 58 mStartTimeUs = nowUs; 59 } 60 61 // How long would it have taken to transfer everything we ever 62 // transferred given the limited bandwidth. 63 int64_t durationUs = 64 mTotalTransferred * 1000000ll / mBandwidthLimitBytesPerSecond; 65 66 int64_t whenUs = mStartTimeUs + durationUs; 67 68 if (whenUs > nowUs) { 69 usleep(whenUs - nowUs); 70 } 71 72 return n; 73 } 74 75 status_t ThrottledSource::getSize(off64_t *size) { 76 return mSource->getSize(size); 77 } 78 79 uint32_t ThrottledSource::flags() { 80 return mSource->flags(); 81 } 82 83 } // namespace android 84 85
