core/impl/flat_static_buffer.ipp

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_IMPL_FLAT_STATIC_BUFFER_IPP
0011 #define BOOST_BEAST_IMPL_FLAT_STATIC_BUFFER_IPP
0012
0013 #include <boost/beast/core/flat_static_buffer.hpp>
0014 #include <boost/throw_exception.hpp>
0015 #include <algorithm>
0016 #include <cstring>
0017 #include <iterator>
0018 #include <memory>
0019 #include <stdexcept>
0020
0021 namespace boost {
0022 namespace beast {
0023
0024 /*  Layout:
0025
0026       begin_     in_          out_        last_      end_
0027         |<------->|<---------->|<---------->|<------->|
0028                   |  readable  |  writable  |
0029 */
0030
0031 void
0032 flat_static_buffer_base::
0033 clear() noexcept
0034 {
0035     in_ = begin_;
0036     out_ = begin_;
0037     last_ = begin_;
0038 }
0039
0040 auto
0041 flat_static_buffer_base::
0042 prepare(std::size_t n) ->
0043     mutable_buffers_type
0044 {
0045     if(n <= dist(out_, end_))
0046     {
0047         last_ = out_ + n;
0048         return {out_, n};
0049     }
0050     auto const len = size();
0051     if(n > capacity() - len)
0052         BOOST_THROW_EXCEPTION(std::length_error{
0053             "buffer overflow"});
0054     if(len > 0)
0055         std::memmove(begin_, in_, len);
0056     in_ = begin_;
0057     out_ = in_ + len;
0058     last_ = out_ + n;
0059     return {out_, n};
0060 }
0061
0062 void
0063 flat_static_buffer_base::
0064 consume(std::size_t n) noexcept
0065 {
0066     if(n >= size())
0067     {
0068         in_ = begin_;
0069         out_ = in_;
0070         return;
0071     }
0072     in_ += n;
0073 }
0074
0075 void
0076 flat_static_buffer_base::
0077 reset(void* p, std::size_t n) noexcept
0078 {
0079     begin_ = static_cast<char*>(p);
0080     in_ = begin_;
0081     out_ = begin_;
0082     last_ = begin_;
0083     end_ = begin_ + n;
0084 }
0085
0086 } // beast
0087 } // boost
0088
0089 #endif