Chris@16: //
Chris@16: // completion_condition.hpp
Chris@16: // ~~~~~~~~~~~~~~~~~~~~~~~~
Chris@16: //
Chris@101: // Copyright (c) 2003-2015 Christopher M. Kohlhoff (chris at kohlhoff dot com)
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16: // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: 
Chris@16: #ifndef BOOST_ASIO_COMPLETION_CONDITION_HPP
Chris@16: #define BOOST_ASIO_COMPLETION_CONDITION_HPP
Chris@16: 
Chris@16: #if defined(_MSC_VER) && (_MSC_VER >= 1200)
Chris@16: # pragma once
Chris@16: #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
Chris@16: 
Chris@16: #include <boost/asio/detail/config.hpp>
Chris@16: #include <cstddef>
Chris@16: 
Chris@16: #include <boost/asio/detail/push_options.hpp>
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace asio {
Chris@16: 
Chris@16: namespace detail {
Chris@16: 
Chris@16: // The default maximum number of bytes to transfer in a single operation.
Chris@101: enum default_max_transfer_size_t { default_max_transfer_size = 65536 };
Chris@16: 
Chris@16: // Adapt result of old-style completion conditions (which had a bool result
Chris@16: // where true indicated that the operation was complete).
Chris@16: inline std::size_t adapt_completion_condition_result(bool result)
Chris@16: {
Chris@16:   return result ? 0 : default_max_transfer_size;
Chris@16: }
Chris@16: 
Chris@16: // Adapt result of current completion conditions (which have a size_t result
Chris@16: // where 0 means the operation is complete, and otherwise the result is the
Chris@16: // maximum number of bytes to transfer on the next underlying operation).
Chris@16: inline std::size_t adapt_completion_condition_result(std::size_t result)
Chris@16: {
Chris@16:   return result;
Chris@16: }
Chris@16: 
Chris@16: class transfer_all_t
Chris@16: {
Chris@16: public:
Chris@16:   typedef std::size_t result_type;
Chris@16: 
Chris@16:   template <typename Error>
Chris@16:   std::size_t operator()(const Error& err, std::size_t)
Chris@16:   {
Chris@16:     return !!err ? 0 : default_max_transfer_size;
Chris@16:   }
Chris@16: };
Chris@16: 
Chris@16: class transfer_at_least_t
Chris@16: {
Chris@16: public:
Chris@16:   typedef std::size_t result_type;
Chris@16: 
Chris@16:   explicit transfer_at_least_t(std::size_t minimum)
Chris@16:     : minimum_(minimum)
Chris@16:   {
Chris@16:   }
Chris@16: 
Chris@16:   template <typename Error>
Chris@16:   std::size_t operator()(const Error& err, std::size_t bytes_transferred)
Chris@16:   {
Chris@16:     return (!!err || bytes_transferred >= minimum_)
Chris@16:       ? 0 : default_max_transfer_size;
Chris@16:   }
Chris@16: 
Chris@16: private:
Chris@16:   std::size_t minimum_;
Chris@16: };
Chris@16: 
Chris@16: class transfer_exactly_t
Chris@16: {
Chris@16: public:
Chris@16:   typedef std::size_t result_type;
Chris@16: 
Chris@16:   explicit transfer_exactly_t(std::size_t size)
Chris@16:     : size_(size)
Chris@16:   {
Chris@16:   }
Chris@16: 
Chris@16:   template <typename Error>
Chris@16:   std::size_t operator()(const Error& err, std::size_t bytes_transferred)
Chris@16:   {
Chris@16:     return (!!err || bytes_transferred >= size_) ? 0 :
Chris@16:       (size_ - bytes_transferred < default_max_transfer_size
Chris@16:         ? size_ - bytes_transferred : std::size_t(default_max_transfer_size));
Chris@16:   }
Chris@16: 
Chris@16: private:
Chris@16:   std::size_t size_;
Chris@16: };
Chris@16: 
Chris@16: } // namespace detail
Chris@16: 
Chris@16: /**
Chris@16:  * @defgroup completion_condition Completion Condition Function Objects
Chris@16:  *
Chris@16:  * Function objects used for determining when a read or write operation should
Chris@16:  * complete.
Chris@16:  */
Chris@16: /*@{*/
Chris@16: 
Chris@16: /// Return a completion condition function object that indicates that a read or
Chris@16: /// write operation should continue until all of the data has been transferred,
Chris@16: /// or until an error occurs.
Chris@16: /**
Chris@16:  * This function is used to create an object, of unspecified type, that meets
Chris@16:  * CompletionCondition requirements.
Chris@16:  *
Chris@16:  * @par Example
Chris@16:  * Reading until a buffer is full:
Chris@16:  * @code
Chris@16:  * boost::array<char, 128> buf;
Chris@16:  * boost::system::error_code ec;
Chris@16:  * std::size_t n = boost::asio::read(
Chris@16:  *     sock, boost::asio::buffer(buf),
Chris@16:  *     boost::asio::transfer_all(), ec);
Chris@16:  * if (ec)
Chris@16:  * {
Chris@16:  *   // An error occurred.
Chris@16:  * }
Chris@16:  * else
Chris@16:  * {
Chris@16:  *   // n == 128
Chris@16:  * }
Chris@16:  * @endcode
Chris@16:  */
Chris@16: #if defined(GENERATING_DOCUMENTATION)
Chris@16: unspecified transfer_all();
Chris@16: #else
Chris@16: inline detail::transfer_all_t transfer_all()
Chris@16: {
Chris@16:   return detail::transfer_all_t();
Chris@16: }
Chris@16: #endif
Chris@16: 
Chris@16: /// Return a completion condition function object that indicates that a read or
Chris@16: /// write operation should continue until a minimum number of bytes has been
Chris@16: /// transferred, or until an error occurs.
Chris@16: /**
Chris@16:  * This function is used to create an object, of unspecified type, that meets
Chris@16:  * CompletionCondition requirements.
Chris@16:  *
Chris@16:  * @par Example
Chris@16:  * Reading until a buffer is full or contains at least 64 bytes:
Chris@16:  * @code
Chris@16:  * boost::array<char, 128> buf;
Chris@16:  * boost::system::error_code ec;
Chris@16:  * std::size_t n = boost::asio::read(
Chris@16:  *     sock, boost::asio::buffer(buf),
Chris@16:  *     boost::asio::transfer_at_least(64), ec);
Chris@16:  * if (ec)
Chris@16:  * {
Chris@16:  *   // An error occurred.
Chris@16:  * }
Chris@16:  * else
Chris@16:  * {
Chris@16:  *   // n >= 64 && n <= 128
Chris@16:  * }
Chris@16:  * @endcode
Chris@16:  */
Chris@16: #if defined(GENERATING_DOCUMENTATION)
Chris@16: unspecified transfer_at_least(std::size_t minimum);
Chris@16: #else
Chris@16: inline detail::transfer_at_least_t transfer_at_least(std::size_t minimum)
Chris@16: {
Chris@16:   return detail::transfer_at_least_t(minimum);
Chris@16: }
Chris@16: #endif
Chris@16: 
Chris@16: /// Return a completion condition function object that indicates that a read or
Chris@16: /// write operation should continue until an exact number of bytes has been
Chris@16: /// transferred, or until an error occurs.
Chris@16: /**
Chris@16:  * This function is used to create an object, of unspecified type, that meets
Chris@16:  * CompletionCondition requirements.
Chris@16:  *
Chris@16:  * @par Example
Chris@16:  * Reading until a buffer is full or contains exactly 64 bytes:
Chris@16:  * @code
Chris@16:  * boost::array<char, 128> buf;
Chris@16:  * boost::system::error_code ec;
Chris@16:  * std::size_t n = boost::asio::read(
Chris@16:  *     sock, boost::asio::buffer(buf),
Chris@16:  *     boost::asio::transfer_exactly(64), ec);
Chris@16:  * if (ec)
Chris@16:  * {
Chris@16:  *   // An error occurred.
Chris@16:  * }
Chris@16:  * else
Chris@16:  * {
Chris@16:  *   // n == 64
Chris@16:  * }
Chris@16:  * @endcode
Chris@16:  */
Chris@16: #if defined(GENERATING_DOCUMENTATION)
Chris@16: unspecified transfer_exactly(std::size_t size);
Chris@16: #else
Chris@16: inline detail::transfer_exactly_t transfer_exactly(std::size_t size)
Chris@16: {
Chris@16:   return detail::transfer_exactly_t(size);
Chris@16: }
Chris@16: #endif
Chris@16: 
Chris@16: /*@}*/
Chris@16: 
Chris@16: } // namespace asio
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #include <boost/asio/detail/pop_options.hpp>
Chris@16: 
Chris@16: #endif // BOOST_ASIO_COMPLETION_CONDITION_HPP