pair<void*,uint64_t> IOBufQueue::preallocateSlow(uint64_t min, uint64_t newAllocationSize, uint64_t max) { // Allocate a new buffer of the requested max size. unique_ptr<IOBuf> newBuf(IOBuf::create(std::max(min, newAllocationSize))); appendToChain(head_, std::move(newBuf), false); IOBuf* last = head_->prev(); return make_pair(last->writableTail(), std::min(max, last->tailroom())); }
void IOBufQueue::append(const void* buf, size_t len) { auto src = static_cast<const uint8_t*>(buf); while (len != 0) { if ((head_ == nullptr) || head_->prev()->isSharedOne() || (head_->prev()->tailroom() == 0)) { appendToChain(head_, IOBuf::create(std::max(MIN_ALLOC_SIZE, std::min(len, MAX_ALLOC_SIZE))), false); } IOBuf* last = head_->prev(); uint64_t copyLen = std::min(len, (size_t)last->tailroom()); memcpy(last->writableTail(), src, copyLen); src += copyLen; last->append(copyLen); chainLength_ += copyLen; len -= copyLen; } }