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      1 /*
      2  * Copyright (C) 2011 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 //#define LOG_NDEBUG 0
     18 #define LOG_TAG "HTTPBase"
     19 #include <utils/Log.h>
     20 
     21 #include "include/HTTPBase.h"
     22 
     23 #include <media/stagefright/foundation/ADebug.h>
     24 #include <media/stagefright/foundation/ALooper.h>
     25 
     26 #include <cutils/properties.h>
     27 #include <cutils/qtaguid.h>
     28 
     29 namespace android {
     30 
     31 HTTPBase::HTTPBase()
     32     : mNumBandwidthHistoryItems(0),
     33       mTotalTransferTimeUs(0),
     34       mTotalTransferBytes(0),
     35       mMaxBandwidthHistoryItems(100),
     36       mPrevBandwidthMeasureTimeUs(0),
     37       mPrevEstimatedBandWidthKbps(0),
     38       mBandWidthCollectFreqMs(5000) {
     39     mName = String8("HTTPBase(<disconnected>)");
     40 }
     41 
     42 void HTTPBase::addBandwidthMeasurement(
     43         size_t numBytes, int64_t delayUs) {
     44     Mutex::Autolock autoLock(mLock);
     45 
     46     BandwidthEntry entry;
     47     entry.mDelayUs = delayUs;
     48     entry.mNumBytes = numBytes;
     49     mTotalTransferTimeUs += delayUs;
     50     mTotalTransferBytes += numBytes;
     51 
     52     mBandwidthHistory.push_back(entry);
     53     if (++mNumBandwidthHistoryItems > mMaxBandwidthHistoryItems) {
     54         BandwidthEntry *entry = &*mBandwidthHistory.begin();
     55         mTotalTransferTimeUs -= entry->mDelayUs;
     56         mTotalTransferBytes -= entry->mNumBytes;
     57         mBandwidthHistory.erase(mBandwidthHistory.begin());
     58         --mNumBandwidthHistoryItems;
     59 
     60         int64_t timeNowUs = ALooper::GetNowUs();
     61         if (timeNowUs - mPrevBandwidthMeasureTimeUs >=
     62                 mBandWidthCollectFreqMs * 1000LL) {
     63 
     64             if (mPrevBandwidthMeasureTimeUs != 0) {
     65                 mPrevEstimatedBandWidthKbps =
     66                     (mTotalTransferBytes * 8E3 / mTotalTransferTimeUs);
     67             }
     68             mPrevBandwidthMeasureTimeUs = timeNowUs;
     69         }
     70     }
     71 
     72 }
     73 
     74 bool HTTPBase::estimateBandwidth(int32_t *bandwidth_bps) {
     75     Mutex::Autolock autoLock(mLock);
     76 
     77     // Do not do bandwidth estimation if we don't have enough samples, or
     78     // total bytes download are too small (<64K).
     79     // Bandwidth estimation from these samples can often shoot up and cause
     80     // unwanted bw adaption behaviors.
     81     if (mNumBandwidthHistoryItems < 2 || mTotalTransferBytes < 65536) {
     82         return false;
     83     }
     84 
     85     *bandwidth_bps = ((double)mTotalTransferBytes * 8E6 / mTotalTransferTimeUs);
     86 
     87     return true;
     88 }
     89 
     90 status_t HTTPBase::getEstimatedBandwidthKbps(int32_t *kbps) {
     91     Mutex::Autolock autoLock(mLock);
     92     *kbps = mPrevEstimatedBandWidthKbps;
     93     return OK;
     94 }
     95 
     96 status_t HTTPBase::setBandwidthStatCollectFreq(int32_t freqMs) {
     97     Mutex::Autolock autoLock(mLock);
     98 
     99     if (freqMs < kMinBandwidthCollectFreqMs
    100             || freqMs > kMaxBandwidthCollectFreqMs) {
    101 
    102         ALOGE("frequency (%d ms) is out of range [1000, 60000]", freqMs);
    103         return BAD_VALUE;
    104     }
    105 
    106     ALOGI("frequency set to %d ms", freqMs);
    107     mBandWidthCollectFreqMs = freqMs;
    108     return OK;
    109 }
    110 
    111 void HTTPBase::setBandwidthHistorySize(size_t numHistoryItems) {
    112     mMaxBandwidthHistoryItems = numHistoryItems;
    113 }
    114 
    115 }  // namespace android
    116