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xahaud/include/beast/core/streambuf.hpp
Vinnie Falco d8dea963fa Squashed 'src/beast/' changes from 1b9a714..6d5547a
6d5547a Set version to 1.0.0-b34
6fab138 Fix and tidy up CMake build scripts:
ccefa54 Set version to 1.0.0-b33
32afe41 Set internal state correctly when writing frames:
fe3e20b Add write_frames unit test
578dcd0 Add decorator unit test
aaa3733 Use fwrite return value in file_body
df66165 Require Visual Studio 2015 Update 3 or later
b8e5a21 Set version to 1.0.0-b32
ffb1758 Update CMake scripts for finding packages:
b893749 Remove http Writer suspend and resume feature (API Change):
27864fb Add io_service completion invariants tests
eba05a7 Set version to 1.0.0-b31
484bcef Fix badge markdown in README.md
5663bea Add missing dynabuf_readstream member
0d7a551 Tidy up build settings
0fd4030 Move the handler, don't copy it

git-subtree-dir: src/beast
git-subtree-split: 6d5547a32c50ec95832c4779311502555ab0ee1f
2017-04-20 13:40:52 -07:00

346 lines
10 KiB
C++

//
// Copyright (c) 2013-2017 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_STREAMBUF_HPP
#define BEAST_STREAMBUF_HPP
#include <beast/config.hpp>
#include <beast/core/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 @b `DynamicBuffer` 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.
@note Meets the requirements of @b DynamicBuffer.
@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<char>>
#endif
{
public:
#if GENERATING_DOCS
/// The type of allocator used.
using allocator_type = Allocator;
#else
using allocator_type = typename
std::allocator_traits<Allocator>::
template rebind_alloc<char>;
#endif
private:
// Storage for the list of buffers representing the input
// and output sequences. The allocation for each element
// contains `element` followed by raw storage bytes.
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:
#if GENERATING_DOCS
/// The type used to represent the input sequence as a list of buffers.
using const_buffers_type = implementation_defined;
/// The type used to represent the output sequence as a list of buffers.
using mutable_buffers_type = implementation_defined;
#else
class const_buffers_type;
class mutable_buffers_type;
#endif
/// Destructor.
~basic_streambuf();
/** Move constructor.
The new object will have the input sequence of
the other stream buffer, and an empty output sequence.
@note After the move, the moved-from object will have
an empty input and output sequence, with no internal
buffers allocated.
*/
basic_streambuf(basic_streambuf&&);
/** Move constructor.
The new object will have the input sequence of
the other stream buffer, and an empty output sequence.
@note After the move, the moved-from object will have
an empty input and output sequence, with no internal
buffers allocated.
@param alloc The allocator to associate with the
stream buffer.
*/
basic_streambuf(basic_streambuf&&,
allocator_type const& alloc);
/** Move assignment.
This object will have the input sequence of
the other stream buffer, and an empty output sequence.
@note After the move, the moved-from object will have
an empty input and output sequence, with no internal
buffers allocated.
*/
basic_streambuf&
operator=(basic_streambuf&&);
/** Copy constructor.
This object will have a copy of the other stream
buffer's input sequence, and an empty output sequence.
*/
basic_streambuf(basic_streambuf const&);
/** Copy constructor.
This object will have a copy of the other stream
buffer's input sequence, and an empty output sequence.
@param alloc The allocator to associate with the
stream buffer.
*/
basic_streambuf(basic_streambuf const&,
allocator_type const& alloc);
/** Copy assignment.
This object will have a copy of the other stream
buffer's input sequence, and an empty output sequence.
*/
basic_streambuf& operator=(basic_streambuf const&);
/** Copy constructor.
This object will have a copy of the other stream
buffer's input sequence, and an empty output sequence.
*/
template<class OtherAlloc>
basic_streambuf(basic_streambuf<OtherAlloc> const&);
/** Copy constructor.
This object will have a copy of the other stream
buffer's input sequence, and an empty output sequence.
@param alloc The allocator to associate with the
stream buffer.
*/
template<class OtherAlloc>
basic_streambuf(basic_streambuf<OtherAlloc> const&,
allocator_type const& alloc);
/** Copy assignment.
This object will have a copy of the other stream
buffer's input sequence, and an empty output sequence.
*/
template<class OtherAlloc>
basic_streambuf& operator=(basic_streambuf<OtherAlloc> const&);
/** 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. The default allocation size
is 1KB (1024 bytes).
@param alloc The allocator to use. If this parameter is
unspecified, a default constructed allocator will be used.
*/
explicit
basic_streambuf(std::size_t alloc_size = 1024,
Allocator const& alloc = allocator_type{});
/// Returns a copy of the associated allocator.
allocator_type
get_allocator() const
{
return this->member();
}
/** Returns the default allocation size.
This is the smallest size that the stream buffer will allocate.
The size of the allocation can influence capacity, which will
affect algorithms that use capacity to efficiently read from
streams.
*/
std::size_t
alloc_size() const
{
return alloc_size_;
}
/** Set the default allocation size.
This is the smallest size that the stream buffer will allocate.
The size of the allocation can influence capacity, which will
affect algorithms that use capacity to efficiently read from
streams.
@note This will not affect any already-existing allocations.
@param n The number of bytes.
*/
void
alloc_size(std::size_t n)
{
alloc_size_ = n;
}
/// Returns the size of the input sequence.
size_type
size() const
{
return in_size_;
}
/// Returns the permitted maximum sum of the sizes of the input and output sequence.
size_type
max_size() const
{
return (std::numeric_limits<std::size_t>::max)();
}
/// Returns the maximum sum of the sizes of the input sequence and output sequence the buffer can hold without requiring reallocation.
std::size_t
capacity() const;
/** Get a list of buffers that represents the input sequence.
@note These buffers remain valid across subsequent calls to `prepare`.
*/
const_buffers_type
data() const;
/** Get a list of buffers that represents the output sequence, with the given size.
@note Buffers representing the input sequence acquired prior to
this call remain valid.
*/
mutable_buffers_type
prepare(size_type n);
/** Move bytes from the output sequence to the input sequence.
@note Buffers representing the input sequence acquired prior to
this call remain valid.
*/
void
commit(size_type n);
/// Remove bytes from the input sequence.
void
consume(size_type n);
// Helper for boost::asio::read_until
template<class OtherAllocator>
friend
std::size_t
read_size_helper(basic_streambuf<
OtherAllocator> const& streambuf, std::size_t max_size);
private:
void
clear();
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();
void
debug_check() const;
};
/** A @b `DynamicBuffer` 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.
@note Meets the requirements of @b `DynamicBuffer`.
*/
using streambuf = basic_streambuf<std::allocator<char>>;
/** Format output to a @ref basic_streambuf.
@param streambuf The @ref basic_streambuf to write to.
@param t The object to write.
@return A reference to the @ref basic_streambuf.
*/
template<class Allocator, class T>
basic_streambuf<Allocator>&
operator<<(basic_streambuf<Allocator>& streambuf, T const& t);
} // beast
#include <beast/core/impl/streambuf.ipp>
#endif