beast/core/read_size.hpp

0001 //
0002 // Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
0003 //
0004 // Distributed under the Boost Software License, Version 1.0. (See accompanying
0005 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 //
0007 // Official repository: https://github.com/boostorg/beast
0008 //
0009
0010 #ifndef BOOST_BEAST_READ_SIZE_HELPER_HPP
0011 #define BOOST_BEAST_READ_SIZE_HELPER_HPP
0012
0013 #include <boost/beast/core/detail/config.hpp>
0014 #include <boost/throw_exception.hpp>
0015
0016 namespace boost {
0017 namespace beast {
0018
0019 /** Returns a natural read size.
0020
0021     This function inspects the capacity, size, and maximum
0022     size of the dynamic buffer. Then it computes a natural
0023     read size given the passed-in upper limit. It favors
0024     a read size that does not require a reallocation, subject
0025     to a reasonable minimum to avoid tiny reads.
0026
0027     @param buffer The dynamic buffer to inspect.
0028
0029     @param max_size An upper limit on the returned value.
0030
0031     @note If the buffer is already at its maximum size, zero
0032     is returned.
0033 */
0034 template<class DynamicBuffer>
0035 std::size_t
0036 read_size(DynamicBuffer& buffer, std::size_t max_size);
0037
0038 /** Returns a natural read size or throw if the buffer is full.
0039
0040     This function inspects the capacity, size, and maximum
0041     size of the dynamic buffer. Then it computes a natural
0042     read size given the passed-in upper limit. It favors
0043     a read size that does not require a reallocation, subject
0044     to a reasonable minimum to avoid tiny reads.
0045
0046     @param buffer The dynamic buffer to inspect.
0047
0048     @param max_size An upper limit on the returned value.
0049
0050     @throws std::length_error if `max_size > 0` and the buffer
0051     is full.
0052 */
0053 template<class DynamicBuffer>
0054 std::size_t
0055 read_size_or_throw(DynamicBuffer& buffer,
0056     std::size_t max_size);
0057
0058 } // beast
0059 } // boost
0060
0061 #include <boost/beast/core/impl/read_size.hpp>
0062
0063 #endif