public async Task <IEnumerable <T> > Read(long resultNum)
{
if (resultNum > leftPoint)
{
resultNum = leftPoint;
}
T[] resultArray = new T[resultNum];
long resultIndex = 0;
for (int i = 0; i < JdbcCursor.Count();)
{
//有严重 bug review 这个循环变量i就没有用过，也没增加
var cursor = JdbcCursor[0];
List <SEPayload <T> > partialList = new List <SEPayload <T> >();
//review 下面这个代码也真是重复的厉害，，用do while不就完了吗
if (countIndex < count)
{
//读过了至少一次
partialList = cursor.Current.ToList();
readPartialPayload(partialList, resultArray, ref resultNum, ref resultIndex);
if (resultNum == 0)
{
if (countIndex == 0)
{
countIndex = count;
}
leftPoint = leftPoint - resultArray.Count();
return(resultArray);
}
}
while (await cursor.MoveNextAsync())
{
partialList = cursor.Current.ToList();
readPartialPayload(partialList, resultArray, ref resultNum, ref resultIndex);
if (resultNum == 0)
{
//readFlag = true;
if (countIndex == 0)
{
countIndex = count;
}
leftPoint = leftPoint - resultArray.Count();
return(resultArray);
}
}
countIndex = count;
}
leftPoint = leftPoint - resultArray.Count();
return(resultArray);
}
//review 这个方法太长了，十分不可读。。而且一条注释也没有。。。和理由重采样的代码吧，没法看。。变脸是干嘛的也没有注释解释一下，，，
private void readPartialPayload(List <SEPayload <T> > batch, T[] resultArray, ref long resultNum, ref long resultIndex)
{
long index;//review 啥index呀。。。。注释注释。很多变量都没有注释看不懂。。。我知道我以前写的时候业主是不全。。。我错了
bool lastReadIndexFlag = false;
bool removeFlag = false;
if (countIndex < count)
{
index = lastReadIndex;
}
else
{
index = startIndex;
}
long fetchnum = 0;
if (resultNum >= count)
{
if (countIndex < count)
{
fetchnum = countIndex;
}
else
{
fetchnum = count;
}
removeFlag = true;
lastReadIndexFlag = true;
}
else
{
if (resultNum >= countIndex)
{
fetchnum = countIndex;
removeFlag = true;
}
else
{
fetchnum = resultNum;
}
}
long factor = decimation;
for (int j = 0; j < batch.Count(); j++)
{
var item = batch[j];
if (index <= item.End && index >= item.Start)
{
long getnum = (fetchnum - 1) * factor + 1;
// long getnum = fetchnum * factor;
long pointer = index + getnum;
Int32 indexStart = (Int32)(index - item.Start);
Int32 realfetch = 0;
var restmp = new List <T>();
if ((pointer) <= item.End)
{
restmp = item.Samples.GetRange(indexStart, (Int32)getnum);
index = index + getnum;
realfetch = (Int32)fetchnum;
}
else
{
Int32 fetch = (Int32)(item.End - index + 1);
restmp = item.Samples.GetRange(indexStart, fetch);
realfetch = (Int32)((fetch - 1) / factor + 1);
fetchnum = fetchnum - realfetch;
index = index + fetch;
}
for (int k = 0; k < realfetch; k++)
{
resultArray[resultIndex++] = restmp[(Int32)factor * k];
}
resultNum -= realfetch;
countIndex -= realfetch;
if (removeFlag && countIndex == 0)
{
JdbcCursor.RemoveAt(0);
break;
}
}
}
if (!lastReadIndexFlag)
{
lastReadIndex = index;
}
}