A debugging DataSource artifically limiting the available bandwidth.

        ShoutcastSource.cpp       \

        StagefrightMediaScanner.cpp \

        StagefrightMetadataRetriever.cpp \

        ThrottledSource.cpp       \

        TimeSource.cpp            \

        TimedEventQueue.cpp       \

        WAVExtractor.cpp          \

/*

 * Copyright (C) 2010 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#include "include/ThrottledSource.h"

#include <media/stagefright/MediaDebug.h>

namespace android {

static int64_t getNowUs() {

    struct timeval tv;

    gettimeofday(&tv, NULL);

    return (int64_t)tv.tv_usec + tv.tv_sec * 1000000ll;

}

ThrottledSource::ThrottledSource(

        const sp<DataSource> &source,

        int32_t bandwidthLimitBytesPerSecond)

    : mSource(source),

      mBandwidthLimitBytesPerSecond(bandwidthLimitBytesPerSecond),

      mStartTimeUs(-1),

      mTotalTransferred(0) {

    CHECK(mBandwidthLimitBytesPerSecond > 0);

}

status_t ThrottledSource::initCheck() const {

    return mSource->initCheck();

}

ssize_t ThrottledSource::readAt(off_t offset, void *data, size_t size) {

    Mutex::Autolock autoLock(mLock);

    ssize_t n = mSource->readAt(offset, data, size);

    if (n <= 0) {

        return n;

    }

    mTotalTransferred += n;

    int64_t nowUs = getNowUs();

    if (mStartTimeUs < 0) {

        mStartTimeUs = nowUs;

    }

    // How long would it have taken to transfer everything we ever

    // transferred given the limited bandwidth.

    int64_t durationUs =

        mTotalTransferred * 1000000ll / mBandwidthLimitBytesPerSecond;

    int64_t whenUs = mStartTimeUs + durationUs;

    if (whenUs > nowUs) {

        usleep(whenUs - nowUs);

    }

    return n;

}

status_t ThrottledSource::getSize(off_t *size) {

    return mSource->getSize(size);

}

uint32_t ThrottledSource::flags() {

    return mSource->flags();

}

}  // namespace android

/*

 * Copyright (C) 2010 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#ifndef THROTTLED_SOURCE_H_

#define THROTTLED_SOURCE_H_

#include <media/stagefright/DataSource.h>

#include <utils/threads.h>

namespace android {

struct ThrottledSource : public DataSource {

    ThrottledSource(

            const sp<DataSource> &source,

            int32_t bandwidthLimitBytesPerSecond);

    virtual status_t initCheck() const;

    virtual ssize_t readAt(off_t offset, void *data, size_t size);

    virtual status_t getSize(off_t *size);

    virtual uint32_t flags();

private:

    Mutex mLock;

    sp<DataSource> mSource;

    int32_t mBandwidthLimitBytesPerSecond;

    int64_t mStartTimeUs;

    size_t mTotalTransferred;

    ThrottledSource(const ThrottledSource &);

    ThrottledSource &operator=(const ThrottledSource &);

};

}  // namespace android

#endif  // THROTTLED_SOURCE_H_