std::size_t read_some(const MutableBufferSequence& buffers,
boost::system::error_code& ec)
{
if (!file_)
{
ec = boost::asio::error::eof;
return 0;
}
typename MutableBufferSequence::const_iterator iter = buffers.begin();
typename MutableBufferSequence::const_iterator end = buffers.end();
for (; iter != end; ++iter)
{
boost::asio::mutable_buffer buffer(*iter);
size_t length = boost::asio::buffer_size(buffer);
if (length > 0)
{
file_.read(boost::asio::buffer_cast<char*>(buffer), length);
length = file_.gcount();
if (length == 0 && !file_)
ec = boost::asio::error::eof;
return length;
}
}
ec = boost::system::error_code();
return 0;
}
buffers_adapter(Deduced&& other,
std::size_t nbegin, std::size_t nout,
std::size_t nend)
: bs_(std::forward<Deduced>(other).bs_)
, begin_(std::next(bs_.begin(), nbegin))
, out_(std::next(bs_.begin(), nout))
, end_(std::next(bs_.begin(), nend))
, max_size_(other.max_size_)
, in_pos_(other.in_pos_)
, in_size_(other.in_size_)
, out_pos_(other.out_pos_)
, out_end_(other.out_end_)
{
}
std::size_t read_some(const MutableBufferSequence& buffers
, boost::system::error_code& ec)
{
ec = boost::system::error_code();
typename MutableBufferSequence::const_iterator iter = buffers.begin();
typename MutableBufferSequence::const_iterator end = buffers.end();
DWORD i = 0;
size_t buffer_size = 0;
size_t bytes_transferred = 0;
size_t total_bytes_transferred = 0;
for (; !ec && iter != end && i < max_buffers; ++iter, ++i)
{
boost::asio::mutable_buffer buffer(*iter);
buffer_size = boost::asio::buffer_size(buffer);
bytes_transferred = read_some(
boost::asio::buffer_cast<char*>(buffer), buffer_size , ec);
if (bytes_transferred < buffer_size)
return bytes_transferred;
total_bytes_transferred += buffer_size;
}
return total_bytes_transferred;
}
void async_read_some_at(implementation_type& impl, boost::uint64_t offset,
const MutableBufferSequence& buffers, Handler handler)
{
if (!is_open(impl))
{
this->get_io_service().post(bind_handler(handler,
boost::asio::error::bad_descriptor, 0));
return;
}
// Update the ID of the thread from which cancellation is safe.
if (impl.safe_cancellation_thread_id_ == 0)
impl.safe_cancellation_thread_id_ = ::GetCurrentThreadId();
else if (impl.safe_cancellation_thread_id_ != ::GetCurrentThreadId())
impl.safe_cancellation_thread_id_ = ~DWORD(0);
// Allocate and construct an operation to wrap the handler.
typedef read_operation<MutableBufferSequence, Handler> value_type;
typedef handler_alloc_traits<Handler, value_type> alloc_traits;
raw_handler_ptr<alloc_traits> raw_ptr(handler);
handler_ptr<alloc_traits> ptr(raw_ptr, iocp_service_, buffers, handler);
// Find first buffer of non-zero length.
boost::asio::mutable_buffer buffer;
typename MutableBufferSequence::const_iterator iter = buffers.begin();
typename MutableBufferSequence::const_iterator end = buffers.end();
for (DWORD i = 0; iter != end; ++iter, ++i)
{
buffer = boost::asio::mutable_buffer(*iter);
if (boost::asio::buffer_size(buffer) != 0)
break;
}
// A request to receive 0 bytes on a stream handle is a no-op.
if (boost::asio::buffer_size(buffer) == 0)
{
boost::asio::io_service::work work(this->get_io_service());
ptr.reset();
boost::system::error_code error;
iocp_service_.post(bind_handler(handler, error, 0));
return;
}
// Read some data.
DWORD bytes_transferred = 0;
ptr.get()->Offset = offset & 0xFFFFFFFF;
ptr.get()->OffsetHigh = (offset >> 32) & 0xFFFFFFFF;
BOOL ok = ::ReadFile(impl.handle_,
boost::asio::buffer_cast<LPVOID>(buffer),
static_cast<DWORD>(boost::asio::buffer_size(buffer)),
&bytes_transferred, ptr.get());
DWORD last_error = ::GetLastError();
if (!ok && last_error != ERROR_IO_PENDING && last_error != ERROR_MORE_DATA)
{
boost::asio::io_service::work work(this->get_io_service());
ptr.reset();
boost::system::error_code ec(last_error,
boost::asio::error::get_system_category());
iocp_service_.post(bind_handler(handler, ec, bytes_transferred));
}
else
{
ptr.release();
}
}
size_t read_some_at(implementation_type& impl, boost::uint64_t offset,
const MutableBufferSequence& buffers, boost::system::error_code& ec)
{
if (!is_open(impl))
{
ec = boost::asio::error::bad_descriptor;
return 0;
}
// Find first buffer of non-zero length.
boost::asio::mutable_buffer buffer;
typename MutableBufferSequence::const_iterator iter = buffers.begin();
typename MutableBufferSequence::const_iterator end = buffers.end();
for (DWORD i = 0; iter != end; ++iter, ++i)
{
buffer = boost::asio::mutable_buffer(*iter);
if (boost::asio::buffer_size(buffer) != 0)
break;
}
// A request to read 0 bytes on a stream handle is a no-op.
if (boost::asio::buffer_size(buffer) == 0)
{
ec = boost::system::error_code();
return 0;
}
overlapped_wrapper overlapped(ec);
if (ec)
{
return 0;
}
// Read some data.
overlapped.Offset = offset & 0xFFFFFFFF;
overlapped.OffsetHigh = (offset >> 32) & 0xFFFFFFFF;
BOOL ok = ::ReadFile(impl.handle_,
boost::asio::buffer_cast<LPVOID>(buffer),
static_cast<DWORD>(boost::asio::buffer_size(buffer)), 0, &overlapped);
if (!ok)
{
DWORD last_error = ::GetLastError();
if (last_error != ERROR_IO_PENDING && last_error != ERROR_MORE_DATA)
{
if (last_error == ERROR_HANDLE_EOF)
{
ec = boost::asio::error::eof;
}
else
{
ec = boost::system::error_code(last_error,
boost::asio::error::get_system_category());
}
return 0;
}
}
// Wait for the operation to complete.
DWORD bytes_transferred = 0;
ok = ::GetOverlappedResult(impl.handle_,
&overlapped, &bytes_transferred, TRUE);
if (!ok)
{
DWORD last_error = ::GetLastError();
if (last_error == ERROR_HANDLE_EOF)
{
ec = boost::asio::error::eof;
}
else
{
ec = boost::system::error_code(last_error,
boost::asio::error::get_system_category());
}
}
ec = boost::system::error_code();
return bytes_transferred;
}