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rippled/include/beast/basic_streambuf.hpp
2016-04-20 12:01:25 -04:00

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8.8 KiB
C++

//
// Copyright (c) 2013-2016 Vinnie Falco (vinnie dot falco at gmail 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 BEAST_BASIC_STREAMBUF_HPP
#define BEAST_BASIC_STREAMBUF_HPP
#include <beast/detail/empty_base_optimization.hpp>
#include <boost/asio/buffer.hpp>
#include <boost/intrusive/list.hpp>
#include <iterator>
#include <limits>
#include <memory>
#include <type_traits>
namespace beast {
/** A `Streambuf` that uses multiple buffers internally.
The implementation uses a sequence of one or more character arrays
of varying sizes. Additional character array objects are appended to
the sequence to accommodate changes in the size of the character
sequence.
@tparam Allocator The allocator to use for managing memory.
*/
template<class Allocator>
class basic_streambuf
#if ! GENERATING_DOCS
: private detail::empty_base_optimization<
typename std::allocator_traits<Allocator>::
template rebind_alloc<std::uint8_t>>
#endif
{
public:
using allocator_type = typename
std::allocator_traits<Allocator>::
template rebind_alloc<std::uint8_t>;
private:
class element;
using alloc_traits = std::allocator_traits<allocator_type>;
using list_type = typename boost::intrusive::make_list<element,
boost::intrusive::constant_time_size<true>>::type;
using iterator = typename list_type::iterator;
using const_iterator = typename list_type::const_iterator;
using size_type = typename std::allocator_traits<Allocator>::size_type;
using const_buffer = boost::asio::const_buffer;
using mutable_buffer = boost::asio::mutable_buffer;
static_assert(std::is_base_of<std::bidirectional_iterator_tag,
typename std::iterator_traits<iterator>::iterator_category>::value,
"BidirectionalIterator requirements not met");
static_assert(std::is_base_of<std::bidirectional_iterator_tag,
typename std::iterator_traits<const_iterator>::iterator_category>::value,
"BidirectionalIterator requirements not met");
list_type list_; // list of allocated buffers
iterator out_; // element that contains out_pos_
size_type alloc_size_; // min amount to allocate
size_type in_size_ = 0; // size of the input sequence
size_type in_pos_ = 0; // input offset in list_.front()
size_type out_pos_ = 0; // output offset in *out_
size_type out_end_ = 0; // output end offset in list_.back()
public:
class const_buffers_type;
class mutable_buffers_type;
/// Destructor.
~basic_streambuf();
/** Move constructor.
The output sequence of this object will be empty.
After the move, the moved-from object will have an
empty input and output sequence, with no internal
buffers allocated.
@param other The stream buffer to move from.
*/
basic_streambuf(basic_streambuf&& other);
/** Move constructor.
The output sequence of this object will be empty.
After the move, the moved-from object will have an
empty input and output sequence, with no internal
buffers allocated.
@param other The stream buffer to move from.
@param alloc The allocator to associate with the
stream buffer.
*/
basic_streambuf(basic_streambuf&& other,
allocator_type const& alloc);
/** Move assignment.
The output sequence of this object will be empty.
After the move, the moved-from object will have an
empty input and output sequence, with no internal
buffers allocated.
@param other The stream buffer to move from.
*/
basic_streambuf&
operator=(basic_streambuf&& other);
/// Copy constructor.
basic_streambuf(basic_streambuf const& other);
/** Copy constructor.
The output sequence of this object will be empty.
@param other The stream buffer to copy.
@param alloc The allocator to associate with the
stream buffer.
*/
basic_streambuf(basic_streambuf const& other,
allocator_type const& alloc);
/** Copy assignment.
The output sequence of this object will be empty.
@param other The stream buffer to copy.
*/
basic_streambuf& operator=(basic_streambuf const& other);
/** Copy constructor.
The output sequence of this object will be empty.
@param other The stream buffer to copy.
*/
template<class OtherAlloc>
basic_streambuf(basic_streambuf<OtherAlloc> const& other);
/** Copy constructor.
The output sequence of this object will be empty.
@param other The stream buffer to copy.
@param alloc The allocator to associate with the
stream buffer.
*/
template<class OtherAlloc>
basic_streambuf(basic_streambuf<OtherAlloc> const& other,
allocator_type const& alloc);
/** Copy assignment.
The output sequence of this object will be empty.
@param other The stream buffer to copy.
*/
template<class OtherAlloc>
basic_streambuf& operator=(basic_streambuf<OtherAlloc> const& other);
/** Construct a stream buffer.
@param alloc_size The size of buffer to allocate. This is a soft
limit, calls to prepare for buffers exceeding this size will allocate
the larger size.
@param alloc The allocator to use.
*/
explicit
basic_streambuf(std::size_t alloc_size = 1024,
Allocator const& alloc = allocator_type{});
/// Get the associated allocator
allocator_type
get_allocator() const
{
return this->member();
}
/// Get the maximum size of the basic_streambuf.
size_type
max_size() const
{
return std::numeric_limits<std::size_t>::max();
}
/// Get the size of the input sequence.
size_type
size() const
{
return in_size_;
}
/// Get a list of buffers that represents the output sequence, with the given size.
mutable_buffers_type
prepare(size_type n);
/// Move bytes from the output sequence to the input sequence.
void
commit(size_type n);
/// Get a list of buffers that represents the input sequence.
const_buffers_type
data() const;
/// Remove bytes from the input sequence.
void
consume(size_type n);
/// Clear everything.
void
clear();
// Helper for read_until
template<class OtherAllocator>
friend
std::size_t
read_size_helper(basic_streambuf<
OtherAllocator> const& streambuf, std::size_t max_size);
private:
void
move_assign(basic_streambuf& other, std::false_type);
void
move_assign(basic_streambuf& other, std::true_type);
void
copy_assign(basic_streambuf const& other, std::false_type);
void
copy_assign(basic_streambuf const& other, std::true_type);
void
delete_list();
std::size_t
prepare_size() const;
void
debug_check() const;
};
/// The type used to represent the input sequence as a list of buffers.
template<class Allocator>
class basic_streambuf<Allocator>::const_buffers_type
{
basic_streambuf const* sb_ = nullptr;
friend class basic_streambuf;
explicit
const_buffers_type(basic_streambuf const& sb);
public:
using value_type = boost::asio::const_buffer;
class const_iterator;
const_buffers_type() = default;
const_buffers_type(const_buffers_type const&) = default;
const_buffers_type& operator=(const_buffers_type const&) = default;
const_iterator
begin() const;
const_iterator
end() const;
};
/// The type used to represent the output sequence as a list of buffers.
template<class Allocator>
class basic_streambuf<Allocator>::mutable_buffers_type
{
basic_streambuf const* sb_;
friend class basic_streambuf;
explicit
mutable_buffers_type(basic_streambuf const& sb);
public:
using value_type = mutable_buffer;
class const_iterator;
mutable_buffers_type() = default;
mutable_buffers_type(mutable_buffers_type const&) = default;
mutable_buffers_type& operator=(mutable_buffers_type const&) = default;
const_iterator
begin() const;
const_iterator
end() const;
};
/** Format output to a stream buffer.
@param streambuf The streambuf to write to.
@param t The object to write.
@return The stream buffer.
*/
template<class Alloc, class T>
basic_streambuf<Alloc>&
operator<<(basic_streambuf<Alloc>& buf, T const& t);
/** Convert the entire basic_streambuf to a string.
@param streambuf The streambuf to convert.
@return A string representing the contents of the input sequence.
*/
template<class Allocator>
std::string
to_string(basic_streambuf<Allocator> const& streambuf);
} // beast
#include <beast/impl/basic_streambuf.ipp>
#endif