unsigned int pos = (unsigned int)(nReadPos % vchBuf.size());
size_t nNow = nSize;
if (nNow + pos > vchBuf.size())
- nNow = (size_t)(vchBuf.size() - pos);
+ nNow = vchBuf.size() - pos;
if (nNow + nReadPos > nSrcPos)
nNow = (size_t)(nSrcPos - nReadPos);
memcpy(pch, &vchBuf[pos], nNow);