Files
rippled/include/beast/impl/buffers_adapter.ipp
2016-04-25 05:08:47 -04:00

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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_IMPL_BUFFERS_ADAPTER_IPP
#define BEAST_IMPL_BUFFERS_ADAPTER_IPP
#include <boost/asio/buffer.hpp>
#include <algorithm>
#include <cstring>
#include <iterator>
#include <stdexcept>
#include <type_traits>
namespace beast {
template<class Buffers>
class buffers_adapter<Buffers>::const_buffers_type
{
buffers_adapter const* ba_;
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;
private:
friend class buffers_adapter;
const_buffers_type(buffers_adapter const& ba)
: ba_(&ba)
{
}
};
template<class Buffers>
class buffers_adapter<Buffers>::const_buffers_type::const_iterator
{
iter_type it_;
buffers_adapter const* ba_;
public:
using value_type = boost::asio::const_buffer;
using pointer = value_type const*;
using reference = value_type;
using difference_type = std::ptrdiff_t;
using iterator_category =
std::bidirectional_iterator_tag;
const_iterator() = default;
const_iterator(const_iterator&& other) = default;
const_iterator(const_iterator const& other) = default;
const_iterator& operator=(const_iterator&& other) = default;
const_iterator& operator=(const_iterator const& other) = default;
bool
operator==(const_iterator const& other) const
{
return ba_ == other.ba_ &&
it_ == other.it_;
}
bool
operator!=(const_iterator const& other) const
{
return !(*this == other);
}
reference
operator*() const
{
using boost::asio::buffer_cast;
using boost::asio::buffer_size;
return value_type{buffer_cast<void const*>(*it_),
(ba_->out_ == ba_->bs_.end() ||
it_ != ba_->out_) ? buffer_size(*it_) : ba_->out_pos_} +
(it_ == ba_->begin_ ? ba_->in_pos_ : 0);
}
pointer
operator->() const = delete;
const_iterator&
operator++()
{
++it_;
return *this;
}
const_iterator
operator++(int)
{
auto temp = *this;
++(*this);
return temp;
}
const_iterator&
operator--()
{
--it_;
return *this;
}
const_iterator
operator--(int)
{
auto temp = *this;
--(*this);
return temp;
}
private:
friend class const_buffers_type;
const_iterator(buffers_adapter const& ba,
iter_type iter)
: it_(iter)
, ba_(&ba)
{
}
};
template<class Buffers>
inline
auto
buffers_adapter<Buffers>::const_buffers_type::begin() const ->
const_iterator
{
return const_iterator{*ba_, ba_->begin_};
}
template<class Buffers>
inline
auto
buffers_adapter<Buffers>::const_buffers_type::end() const ->
const_iterator
{
return const_iterator{*ba_, ba_->out_ ==
ba_->end_ ? ba_->end_ : std::next(ba_->out_)};
}
//------------------------------------------------------------------------------
template<class Buffers>
class buffers_adapter<Buffers>::mutable_buffers_type
{
buffers_adapter const* ba_;
public:
using value_type = boost::asio::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;
private:
friend class buffers_adapter;
mutable_buffers_type(
buffers_adapter const& ba)
: ba_(&ba)
{
}
};
template<class Buffers>
class buffers_adapter<Buffers>::mutable_buffers_type::const_iterator
{
iter_type it_;
buffers_adapter const* ba_;
public:
using value_type = boost::asio::mutable_buffer;
using pointer = value_type const*;
using reference = value_type;
using difference_type = std::ptrdiff_t;
using iterator_category =
std::bidirectional_iterator_tag;
const_iterator() = default;
const_iterator(const_iterator&& other) = default;
const_iterator(const_iterator const& other) = default;
const_iterator& operator=(const_iterator&& other) = default;
const_iterator& operator=(const_iterator const& other) = default;
bool
operator==(const_iterator const& other) const
{
return ba_ == other.ba_ &&
it_ == other.it_;
}
bool
operator!=(const_iterator const& other) const
{
return !(*this == other);
}
reference
operator*() const
{
using boost::asio::buffer_cast;
using boost::asio::buffer_size;
return value_type{buffer_cast<void*>(*it_),
it_ == std::prev(ba_->end_) ?
ba_->out_end_ : buffer_size(*it_)} +
(it_ == ba_->out_ ? ba_->out_pos_ : 0);
}
pointer
operator->() const = delete;
const_iterator&
operator++()
{
++it_;
return *this;
}
const_iterator
operator++(int)
{
auto temp = *this;
++(*this);
return temp;
}
const_iterator&
operator--()
{
--it_;
return *this;
}
const_iterator
operator--(int)
{
auto temp = *this;
--(*this);
return temp;
}
private:
friend class mutable_buffers_type;
const_iterator(buffers_adapter const& ba,
iter_type iter)
: it_(iter)
, ba_(&ba)
{
}
};
template<class Buffers>
inline
auto
buffers_adapter<Buffers>::mutable_buffers_type::begin() const ->
const_iterator
{
return const_iterator{*ba_, ba_->out_};
}
template<class Buffers>
inline
auto
buffers_adapter<Buffers>::mutable_buffers_type::end() const ->
const_iterator
{
return const_iterator{*ba_, ba_->end_};
}
//------------------------------------------------------------------------------
template<class Buffers>
buffers_adapter<Buffers>::buffers_adapter(
buffers_adapter&& other)
: buffers_adapter(std::move(other),
std::distance<iter_type>(other.bs_.begin(), other.begin_),
std::distance<iter_type>(other.bs_.begin(), other.out_),
std::distance<iter_type>(other.bs_.begin(), other.end_))
{
}
template<class Buffers>
buffers_adapter<Buffers>::buffers_adapter(
buffers_adapter const& other)
: buffers_adapter(other,
std::distance<iter_type>(other.bs_.begin(), other.begin_),
std::distance<iter_type>(other.bs_.begin(), other.out_),
std::distance<iter_type>(other.bs_.begin(), other.end_))
{
}
template<class Buffers>
auto
buffers_adapter<Buffers>::operator=(
buffers_adapter&& other) -> buffers_adapter&
{
auto const nbegin = std::distance<iter_type>(
other.bs_.begin(), other.begin_);
auto const nout = std::distance<iter_type>(
other.bs_.begin(), other.out_);
auto const nend = std::distance<iter_type>(
other.bs_.begin(), other.end_);
bs_ = std::move(other.bs_);
begin_ = std::next(bs_.begin(), nbegin);
out_ = std::next(bs_.begin(), nout);
end_ = std::next(bs_.begin(), nend);
max_size_ = other.max_size_;
in_pos_ = other.in_pos_;
in_size_ = other.in_size_;
out_pos_ = other.out_pos_;
out_end_ = other.out_end_;
return *this;
}
template<class Buffers>
auto
buffers_adapter<Buffers>::operator=(
buffers_adapter const& other) -> buffers_adapter&
{
auto const nbegin = std::distance<iter_type>(
other.bs_.begin(), other.begin_);
auto const nout = std::distance<iter_type>(
other.bs_.begin(), other.out_);
auto const nend = std::distance<iter_type>(
other.bs_.begin(), other.end_);
bs_ = other.bs_;
begin_ = std::next(bs_.begin(), nbegin);
out_ = std::next(bs_.begin(), nout);
end_ = std::next(bs_.begin(), nend);
max_size_ = other.max_size_;
in_pos_ = other.in_pos_;
in_size_ = other.in_size_;
out_pos_ = other.out_pos_;
out_end_ = other.out_end_;
return *this;
}
template<class Buffers>
buffers_adapter<Buffers>::buffers_adapter(
Buffers const& bs)
: bs_(bs)
, begin_(bs_.begin())
, out_(bs_.begin())
, end_(bs_.begin())
, max_size_(boost::asio::buffer_size(bs_))
{
}
template<class Buffers>
auto
buffers_adapter<Buffers>::prepare(std::size_t n) ->
mutable_buffers_type
{
using boost::asio::buffer_size;
static_assert(is_mutable,
"Operation not valid for ConstBufferSequence");
end_ = out_;
if(end_ != bs_.end())
{
auto size = buffer_size(*end_) - out_pos_;
if(n > size)
{
n -= size;
while(++end_ != bs_.end())
{
size = buffer_size(*end_);
if(n < size)
{
out_end_ = n;
n = 0;
++end_;
break;
}
n -= size;
out_end_ = size;
}
}
else
{
++end_;
out_end_ = out_pos_ + n;
n = 0;
}
}
if(n > 0)
throw std::length_error(
"no space in buffers_adapter");
return mutable_buffers_type{*this};
}
template<class Buffers>
void
buffers_adapter<Buffers>::commit(std::size_t n)
{
using boost::asio::buffer_size;
static_assert(is_mutable,
"Operation not valid for ConstBufferSequence");
if(out_ == end_)
return;
auto const last = std::prev(end_);
while(out_ != last)
{
auto const avail =
buffer_size(*out_) - out_pos_;
if(n < avail)
{
out_pos_ += n;
in_size_ += n;
max_size_ -= n;
return;
}
++out_;
n -= avail;
out_pos_ = 0;
in_size_ += avail;
max_size_ -= avail;
}
n = std::min(n, out_end_ - out_pos_);
out_pos_ += n;
in_size_ += n;
max_size_ -= n;
if(out_pos_ == buffer_size(*out_))
{
++out_;
out_pos_ = 0;
out_end_ = 0;
}
}
template<class Buffers>
inline
auto
buffers_adapter<Buffers>::data() const ->
const_buffers_type
{
return const_buffers_type{*this};
}
template<class Buffers>
void
buffers_adapter<Buffers>::consume(std::size_t n)
{
for(;;)
{
if(begin_ != out_)
{
auto const avail =
buffer_size(*begin_) - in_pos_;
if(n < avail)
{
in_size_ -= n;
in_pos_ += n;
break;
}
n -= avail;
in_size_ -= avail;
in_pos_ = 0;
++begin_;
}
else
{
auto const avail = out_pos_ - in_pos_;
if(n < avail)
{
in_size_ -= n;
in_pos_ += n;
}
else
{
in_size_ -= avail;
if(out_pos_ != out_end_||
out_ != std::prev(bs_.end()))
{
in_pos_ = out_pos_;
}
else
{
// Use the whole buffer now.
in_pos_ = 0;
out_pos_ = 0;
out_end_ = 0;
}
}
break;
}
}
}
} // beast
#endif