public int TryRead(VBufferInfo bufferInfo, out byte[] buffer, int offset, int count, int postion = 0)
{
buffer = new byte[count];
if (bufferInfo == null)
{
return(-1);
}
// 检测是否在范围之内
var len = buffer.Length - offset;
var size = len >= count ? count : len;
var trueTotal = size;
// 剩下的数量
var lastCount = bufferInfo.Count - postion;
trueTotal = lastCount >= trueTotal ? trueTotal : lastCount;
int currentSegmentOffset;
var index = SearchIndex(bufferInfo, postion, out currentSegmentOffset);
var segment = this[index];
size = segment.TryRead(offset, trueTotal, bufferInfo.Offset, ref buffer);
size = ReadNext(segment, buffer, trueTotal, size);
return(size);
}
public VBufferInfo ApplyFor(byte[] buffer, int segmentSize)
{
_segmentSize = segmentSize;
// 当前块索引
var index = _nextSegmentIndex;
var segment = QueryNext();
int offset;
var size = segment.TryWrite(buffer, out offset);
FillBuffer(segment, buffer, size);
return(VBufferInfo.Create(index, offset, buffer.Length));
}
public byte[] ReadBytes(VBufferInfo bufferInfo)
{
if (bufferInfo == null)
{
return(null);
}
var buffer = new byte[bufferInfo.Count];
var segment = this[bufferInfo.SegmentIndex];
var size = segment.TryRead(bufferInfo.Offset, buffer.Length, ref buffer);
ReadNext(segment, buffer, buffer.Length, size);
return(buffer);
}
private int SearchIndex(VBufferInfo bufferInfo, int postion, out int currentSegmentOffset)
{
currentSegmentOffset = 0;
var index = bufferInfo.SegmentIndex;
if (postion != 0)
{
postion += bufferInfo.Offset;
var segment = this[index];
while (postion > segment.Length && segment.NeedNext)
{
//剔除已经过去的
postion -= segment.Length;
segment = this[segment.NextIndex];
}
currentSegmentOffset = postion;
}
return(index);
}
public int TryWrite(VBufferInfo bufferInfo, byte[] buffer, int offset, int count, int postion = 0)
{
// 检测是否在范围之内
var len = buffer.Length - offset;
var size = len >= count ? count : len;
var tr = size;
// 剩下的数量
var lastCount = bufferInfo.Count - postion;
tr = lastCount >= tr ? tr : lastCount;
int currentSegmentOffset;
var index = SearchIndex(bufferInfo, postion, out currentSegmentOffset);
var segment = this[index];
var writeSize = segment.TryWrite(buffer, offset, tr, currentSegmentOffset);
int lastSize = -1;
if (tr != writeSize)
{
lastCount = tr - writeSize;
while (lastCount > 0 && segment.NeedNext)
{
segment = this[segment.NextIndex];
lastSize = segment.TryWrite(buffer, 0, lastCount);
lastCount -= lastSize;
}
}
// 将剩余的填入 0
if (lastCount > 0 && lastSize != -1)
{
var zBuffer = new byte[lastCount];
segment.TryWrite(zBuffer, 0, lastCount, lastSize);
}
return(tr);
}
