ssize_t ChromiumHTTPDataSource::readAt(off64_t offset, void *data, size_t size) {
Mutex::Autolock autoLock(mLock);
if (mState != CONNECTED) {
return INVALID_OPERATION;
}
#if 0
char value[PROPERTY_VALUE_MAX];
if (property_get("media.stagefright.disable-net", value, 0)
&& (!strcasecmp(value, "true") || !strcmp(value, "1"))) {
LOG_PRI(ANDROID_LOG_INFO, LOG_TAG, "Simulating that the network is down.");
disconnect_l();
return ERROR_IO;
}
#endif
if (offset != mCurrentOffset) {
AString tmp = mURI;
KeyedVector<String8, String8> tmpHeaders = mHeaders;
disconnect_l();
status_t err = connect_l(tmp.c_str(), &tmpHeaders, offset);
if (err != OK) {
return err;
}
}
mState = READING;
int64_t startTimeUs = ALooper::GetNowUs();
mDelegate->initiateRead(data, size);
int32_t bandwidth_bps;
estimateBandwidth(&bandwidth_bps);
int64_t readTimeoutUs = 0;
if(bandwidth_bps > 0) {
readTimeoutUs = (size * 8000000ll)/bandwidth_bps;
}
readTimeoutUs += mReadTimeoutUs;
while (mState == READING) {
//mCondition.wait(mLock);
status_t err = mCondition.waitRelative(mLock, readTimeoutUs *1000ll);
if(mForceDisconnect) {
LOG_PRI(ANDROID_LOG_INFO, LOG_TAG, "disconnected, read return");
return ERROR_IO;
}
if(err == -ETIMEDOUT) {
LOG_PRI(ANDROID_LOG_INFO, LOG_TAG, "Read data timeout,"
"maybe server didn't response us, return %d", err);
return err;
}
}
if (mIOResult < OK) {
return mIOResult;
}
if (mState == CONNECTED) {
int64_t delayUs = ALooper::GetNowUs() - startTimeUs;
// The read operation was successful, mIOResult contains
// the number of bytes read.
addBandwidthMeasurement(mIOResult, delayUs);
mCurrentOffset += mIOResult;
return mIOResult;
}
return ERROR_IO;
}
/**
* Computes the min, max, mean, and median values of an array
* T[0:n-1] of 'n' long doubles.
*/
static void printStats (FILE* fp, long double* T, size_t ntrials, size_t ncorrect, size_t nelements){
long double t_min, t_max, t_mean, t_median;
assert (ntrials > 0);
t_min = T[0];
t_max = T[0];
t_mean = T[0];
t_median = T[0];
for (size_t i = 1; i < ntrials; ++i) {
if (T[i] < t_min) t_min = T[i];
if (T[i] > t_max) t_max = T[i];
t_mean += T[i];
}
t_mean /= ntrials;
std::nth_element(T, T + ntrials/2, T + ntrials);
t_median = T[ntrials/2];
fprintf(fp,"{\"ntrials\": %lu, "
"\"ncorrect\": %lu, "
"\"nelements\": %lu, "
"\"min\": %Lf, "
"\"max\": %Lf, "
"\"mean\": %Lf, "
"\"median\": %Lf, "
"\"bandwidth\": %Lf}\n", ntrials, ncorrect, nelements, t_min, t_max, t_mean, t_median, estimateBandwidth(nelements, t_mean));
}
