4
鉴于其通过TCP传送文件的内容的示例服务器 -升压ASIO transfer_exactly读取0字节
#include <vector>
#include <fstream>
#include <iostream>
#include <boost/asio.hpp>
using namespace boost::asio;
using namespace boost::system;
using namespace boost::asio::ip;
using std::cerr;
using std::endl;
using std::ifstream;
using std::vector;
using std::ios;
using stream_iter = std::istreambuf_iterator<char>;
int main()
{
ifstream input("movie.ogv", ios::in | ios::binary);
vector<uint8_t> stream((stream_iter(input)), stream_iter());
io_service ioservice;
tcp::acceptor acceptor(ioservice, tcp::endpoint(tcp::v4(), 8000));
tcp::socket socket(ioservice);
acceptor.accept(socket);
error_code ec;
write(socket, boost::asio::buffer(stream), ec);
if (ec) {
cerr << ec.message() << endl;
}
}
我写以下客户端提取开始文件的报头被传送 -
#include <vector>
#include <iostream>
#include <array>
#include <boost/asio.hpp>
using namespace boost::asio;
using namespace boost::system;
using namespace boost::asio::ip;
using std::cerr;
using std::endl;
using std::ifstream;
using std::vector;
using std::ios;
using stream_iter = std::istreambuf_iterator<char>;
int main()
{
int header_size_ = 30000;
error_code ec;
vector<char> headerBytesBuf;
headerBytesBuf.reserve(header_size_);
io_service ioservice;
tcp::socket socket(ioservice);
socket.connect(tcp::endpoint(tcp::v4(), 8000));
const auto bTransfer = read(socket, buffer(headerBytesBuf),
transfer_exactly(header_size_), ec);
if (ec) {
socket.close();
std::cerr << ec.message();
}
std::cout << headerBytesBuf.size();
}
相关的代码是 - const auto bTransfer = read(socket, buffer(headerBytesBuf), transfer_exactly(header_size_), ec);
,它将0字节读入向量中,但未记录错误:/
将该行更改为 -
std::array<char, 128> buf;
size_t total_transfer = 0;
while(total_transfer < header_size_) {
size_t len = socket.read_some(boost::asio::buffer(buf));
total_transfer += len;
if (len <= 0) break;
}
的total_transfer
报告30800
,我现在可以修剪和内环路追加到我的vector
。但为什么不是第一种在这里工作的方法?
不是100%确定,但我认为你想改变'headerBytesBuf.reserve(header_size _);'到'headerBytesBuf.resize(header_size _);',因为ASIO缓冲区在初始化后对原始数据起作用,他们没有办法调整大小矢量。您正在有效地传递一个0大小的缓冲区,它会立即触发'所提供的缓冲区已满。 – Frank