boost/asio/impl/read_at.ipp
//
// read_at.ipp
// ~~~~~~~~~~~
//
// Copyright (c) 2003-2008 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#ifndef BOOST_ASIO_READ_AT_IPP
#define BOOST_ASIO_READ_AT_IPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include <boost/asio/detail/push_options.hpp>
#include <boost/asio/detail/push_options.hpp>
#include <algorithm>
#include <boost/asio/detail/pop_options.hpp>
#include <boost/asio/buffer.hpp>
#include <boost/asio/completion_condition.hpp>
#include <boost/asio/error.hpp>
#include <boost/asio/detail/bind_handler.hpp>
#include <boost/asio/detail/consuming_buffers.hpp>
#include <boost/asio/detail/handler_alloc_helpers.hpp>
#include <boost/asio/detail/handler_invoke_helpers.hpp>
#include <boost/asio/detail/throw_error.hpp>
namespace boost {
namespace asio {
template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence,
typename CompletionCondition>
std::size_t read_at(SyncRandomAccessReadDevice& d,
boost::uint64_t offset, const MutableBufferSequence& buffers,
CompletionCondition completion_condition, boost::system::error_code& ec)
{
ec = boost::system::error_code();
boost::asio::detail::consuming_buffers<
mutable_buffer, MutableBufferSequence> tmp(buffers);
std::size_t total_transferred = 0;
tmp.set_max_size(detail::adapt_completion_condition_result(
completion_condition(ec, total_transferred)));
while (tmp.begin() != tmp.end())
{
std::size_t bytes_transferred = d.read_some_at(
offset + total_transferred, tmp, ec);
tmp.consume(bytes_transferred);
total_transferred += bytes_transferred;
tmp.set_max_size(detail::adapt_completion_condition_result(
completion_condition(ec, total_transferred)));
}
return total_transferred;
}
template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence>
inline std::size_t read_at(SyncRandomAccessReadDevice& d,
boost::uint64_t offset, const MutableBufferSequence& buffers)
{
boost::system::error_code ec;
std::size_t bytes_transferred = read_at(
d, offset, buffers, transfer_all(), ec);
boost::asio::detail::throw_error(ec);
return bytes_transferred;
}
template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence,
typename CompletionCondition>
inline std::size_t read_at(SyncRandomAccessReadDevice& d,
boost::uint64_t offset, const MutableBufferSequence& buffers,
CompletionCondition completion_condition)
{
boost::system::error_code ec;
std::size_t bytes_transferred = read_at(
d, offset, buffers, completion_condition, ec);
boost::asio::detail::throw_error(ec);
return bytes_transferred;
}
template <typename SyncRandomAccessReadDevice, typename Allocator,
typename CompletionCondition>
std::size_t read_at(SyncRandomAccessReadDevice& d,
boost::uint64_t offset, boost::asio::basic_streambuf<Allocator>& b,
CompletionCondition completion_condition, boost::system::error_code& ec)
{
std::size_t total_transferred = 0;
for (;;)
{
std::size_t bytes_available =
std::min<std::size_t>(512, b.max_size() - b.size());
std::size_t bytes_transferred = d.read_some_at(
offset + total_transferred, b.prepare(bytes_available), ec);
b.commit(bytes_transferred);
total_transferred += bytes_transferred;
if (b.size() == b.max_size()
|| completion_condition(ec, total_transferred))
return total_transferred;
}
}
template <typename SyncRandomAccessReadDevice, typename Allocator>
inline std::size_t read_at(SyncRandomAccessReadDevice& d,
boost::uint64_t offset, boost::asio::basic_streambuf<Allocator>& b)
{
boost::system::error_code ec;
std::size_t bytes_transferred = read_at(
d, offset, b, transfer_all(), ec);
boost::asio::detail::throw_error(ec);
return bytes_transferred;
}
template <typename SyncRandomAccessReadDevice, typename Allocator,
typename CompletionCondition>
inline std::size_t read_at(SyncRandomAccessReadDevice& d,
boost::uint64_t offset, boost::asio::basic_streambuf<Allocator>& b,
CompletionCondition completion_condition)
{
boost::system::error_code ec;
std::size_t bytes_transferred = read_at(
d, offset, b, completion_condition, ec);
boost::asio::detail::throw_error(ec);
return bytes_transferred;
}
namespace detail
{
template <typename AsyncRandomAccessReadDevice,
typename MutableBufferSequence, typename CompletionCondition,
typename ReadHandler>
class read_at_handler
{
public:
typedef boost::asio::detail::consuming_buffers<
mutable_buffer, MutableBufferSequence> buffers_type;
read_at_handler(AsyncRandomAccessReadDevice& stream,
boost::uint64_t offset, const buffers_type& buffers,
CompletionCondition completion_condition, ReadHandler handler)
: stream_(stream),
offset_(offset),
buffers_(buffers),
total_transferred_(0),
completion_condition_(completion_condition),
handler_(handler)
{
}
void operator()(const boost::system::error_code& ec,
std::size_t bytes_transferred)
{
total_transferred_ += bytes_transferred;
buffers_.consume(bytes_transferred);
buffers_.set_max_size(detail::adapt_completion_condition_result(
completion_condition_(ec, total_transferred_)));
if (buffers_.begin() == buffers_.end())
{
handler_(ec, total_transferred_);
}
else
{
stream_.async_read_some_at(
offset_ + total_transferred_, buffers_, *this);
}
}
//private:
AsyncRandomAccessReadDevice& stream_;
boost::uint64_t offset_;
buffers_type buffers_;
std::size_t total_transferred_;
CompletionCondition completion_condition_;
ReadHandler handler_;
};
template <typename AsyncRandomAccessReadDevice,
typename MutableBufferSequence, typename CompletionCondition,
typename ReadHandler>
inline void* asio_handler_allocate(std::size_t size,
read_at_handler<AsyncRandomAccessReadDevice, MutableBufferSequence,
CompletionCondition, ReadHandler>* this_handler)
{
return boost_asio_handler_alloc_helpers::allocate(
size, &this_handler->handler_);
}
template <typename AsyncRandomAccessReadDevice,
typename MutableBufferSequence, typename CompletionCondition,
typename ReadHandler>
inline void asio_handler_deallocate(void* pointer, std::size_t size,
read_at_handler<AsyncRandomAccessReadDevice, MutableBufferSequence,
CompletionCondition, ReadHandler>* this_handler)
{
boost_asio_handler_alloc_helpers::deallocate(
pointer, size, &this_handler->handler_);
}
template <typename Function, typename AsyncRandomAccessReadDevice,
typename MutableBufferSequence, typename CompletionCondition,
typename ReadHandler>
inline void asio_handler_invoke(const Function& function,
read_at_handler<AsyncRandomAccessReadDevice, MutableBufferSequence,
CompletionCondition, ReadHandler>* this_handler)
{
boost_asio_handler_invoke_helpers::invoke(
function, &this_handler->handler_);
}
} // namespace detail
template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence,
typename CompletionCondition, typename ReadHandler>
inline void async_read_at(AsyncRandomAccessReadDevice& d,
boost::uint64_t offset, const MutableBufferSequence& buffers,
CompletionCondition completion_condition, ReadHandler handler)
{
boost::asio::detail::consuming_buffers<
mutable_buffer, MutableBufferSequence> tmp(buffers);
boost::system::error_code ec;
std::size_t total_transferred = 0;
tmp.set_max_size(detail::adapt_completion_condition_result(
completion_condition(ec, total_transferred)));
if (tmp.begin() == tmp.end())
{
d.get_io_service().post(detail::bind_handler(
handler, ec, total_transferred));
return;
}
d.async_read_some_at(offset, tmp,
detail::read_at_handler<AsyncRandomAccessReadDevice,
MutableBufferSequence, CompletionCondition, ReadHandler>(
d, offset, tmp, completion_condition, handler));
}
template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence,
typename ReadHandler>
inline void async_read_at(AsyncRandomAccessReadDevice& d,
boost::uint64_t offset, const MutableBufferSequence& buffers,
ReadHandler handler)
{
async_read_at(d, offset, buffers, transfer_all(), handler);
}
namespace detail
{
template <typename AsyncRandomAccessReadDevice, typename Allocator,
typename CompletionCondition, typename ReadHandler>
class read_at_streambuf_handler
{
public:
read_at_streambuf_handler(AsyncRandomAccessReadDevice& stream,
boost::uint64_t offset, basic_streambuf<Allocator>& streambuf,
CompletionCondition completion_condition, ReadHandler handler)
: stream_(stream),
offset_(offset),
streambuf_(streambuf),
total_transferred_(0),
completion_condition_(completion_condition),
handler_(handler)
{
}
void operator()(const boost::system::error_code& ec,
std::size_t bytes_transferred)
{
total_transferred_ += bytes_transferred;
streambuf_.commit(bytes_transferred);
std::size_t max_size = detail::adapt_completion_condition_result(
completion_condition_(ec, total_transferred_));
std::size_t bytes_available = std::min<std::size_t>(512,
std::min<std::size_t>(max_size,
streambuf_.max_size() - streambuf_.size()));
if (bytes_available == 0)
{
handler_(ec, total_transferred_);
}
else
{
stream_.async_read_some_at(offset_ + total_transferred_,
streambuf_.prepare(bytes_available), *this);
}
}
//private:
AsyncRandomAccessReadDevice& stream_;
boost::uint64_t offset_;
boost::asio::basic_streambuf<Allocator>& streambuf_;
std::size_t total_transferred_;
CompletionCondition completion_condition_;
ReadHandler handler_;
};
template <typename AsyncRandomAccessReadDevice, typename Allocator,
typename CompletionCondition, typename ReadHandler>
inline void* asio_handler_allocate(std::size_t size,
read_at_streambuf_handler<AsyncRandomAccessReadDevice, Allocator,
CompletionCondition, ReadHandler>* this_handler)
{
return boost_asio_handler_alloc_helpers::allocate(
size, &this_handler->handler_);
}
template <typename AsyncRandomAccessReadDevice, typename Allocator,
typename CompletionCondition, typename ReadHandler>
inline void asio_handler_deallocate(void* pointer, std::size_t size,
read_at_streambuf_handler<AsyncRandomAccessReadDevice, Allocator,
CompletionCondition, ReadHandler>* this_handler)
{
boost_asio_handler_alloc_helpers::deallocate(
pointer, size, &this_handler->handler_);
}
template <typename Function, typename AsyncRandomAccessReadDevice,
typename Allocator, typename CompletionCondition, typename ReadHandler>
inline void asio_handler_invoke(const Function& function,
read_at_streambuf_handler<AsyncRandomAccessReadDevice, Allocator,
CompletionCondition, ReadHandler>* this_handler)
{
boost_asio_handler_invoke_helpers::invoke(
function, &this_handler->handler_);
}
} // namespace detail
template <typename AsyncRandomAccessReadDevice, typename Allocator,
typename CompletionCondition, typename ReadHandler>
inline void async_read_at(AsyncRandomAccessReadDevice& d,
boost::uint64_t offset, boost::asio::basic_streambuf<Allocator>& b,
CompletionCondition completion_condition, ReadHandler handler)
{
boost::system::error_code ec;
std::size_t total_transferred = 0;
std::size_t max_size = detail::adapt_completion_condition_result(
completion_condition(ec, total_transferred));
std::size_t bytes_available = std::min<std::size_t>(512,
std::min<std::size_t>(max_size, b.max_size() - b.size()));
if (bytes_available == 0)
{
d.get_io_service().post(detail::bind_handler(
handler, ec, total_transferred));
return;
}
d.async_read_some_at(offset, b.prepare(bytes_available),
detail::read_at_streambuf_handler<AsyncRandomAccessReadDevice, Allocator,
CompletionCondition, ReadHandler>(
d, offset, b, completion_condition, handler));
}
template <typename AsyncRandomAccessReadDevice, typename Allocator,
typename ReadHandler>
inline void async_read_at(AsyncRandomAccessReadDevice& d,
boost::uint64_t offset, boost::asio::basic_streambuf<Allocator>& b,
ReadHandler handler)
{
async_read_at(d, offset, b, transfer_all(), handler);
}
} // namespace asio
} // namespace boost
#include <boost/asio/detail/pop_options.hpp>
#endif // BOOST_ASIO_READ_AT_IPP