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//
// Copyright (c) 2016-2017 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)
//
// Official repository: https://github.com/boostorg/beast
//
#ifndef BOOST_BEAST_IMPL_BUFFERS_PREFIX_IPP
#define BOOST_BEAST_IMPL_BUFFERS_PREFIX_IPP
#include <algorithm>
#include <cstdint>
#include <iterator>
#include <stdexcept>
#include <type_traits>
#include <utility>
namespace boost {
namespace beast {
namespace detail {
inline
boost::asio::const_buffer
buffers_prefix(std::size_t size,
boost::asio::const_buffer buffer)
{
return {buffer.data(),
(std::min)(size, buffer.size())};
}
inline
boost::asio::mutable_buffer
buffers_prefix(std::size_t size,
boost::asio::mutable_buffer buffer)
{
return {buffer.data(),
(std::min)(size, buffer.size())};
}
} // detail
template<class BufferSequence>
class buffers_prefix_view<BufferSequence>::const_iterator
{
friend class buffers_prefix_view<BufferSequence>;
buffers_prefix_view const* b_ = nullptr;
std::size_t remain_;
iter_type it_;
public:
using value_type = typename std::conditional<
boost::is_convertible<typename
std::iterator_traits<iter_type>::value_type,
boost::asio::mutable_buffer>::value,
boost::asio::mutable_buffer,
boost::asio::const_buffer>::type;
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
(b_ == nullptr) ?
(
other.b_ == nullptr ||
other.it_ == other.b_->end_
):(
(other.b_ == nullptr) ?
(
it_ == b_->end_
): (
b_ == other.b_ &&
it_ == other.it_
)
);
}
bool
operator!=(const_iterator const& other) const
{
return !(*this == other);
}
reference
operator*() const
{
return detail::buffers_prefix(remain_, *it_);
}
pointer
operator->() const = delete;
const_iterator&
operator++()
{
remain_ -= boost::asio::buffer_size(*it_++);
return *this;
}
const_iterator
operator++(int)
{
auto temp = *this;
remain_ -= boost::asio::buffer_size(*it_++);
return temp;
}
const_iterator&
operator--()
{
remain_ += boost::asio::buffer_size(*--it_);
return *this;
}
const_iterator
operator--(int)
{
auto temp = *this;
remain_ += boost::asio::buffer_size(*--it_);
return temp;
}
private:
const_iterator(buffers_prefix_view const& b,
std::true_type)
: b_(&b)
, remain_(b.remain_)
, it_(b_->end_)
{
}
const_iterator(buffers_prefix_view const& b,
std::false_type)
: b_(&b)
, remain_(b_->size_)
, it_(boost::asio::buffer_sequence_begin(b_->bs_))
{
}
};
//------------------------------------------------------------------------------
template<class BufferSequence>
void
buffers_prefix_view<BufferSequence>::
setup(std::size_t size)
{
size_ = 0;
remain_ = 0;
end_ = boost::asio::buffer_sequence_begin(bs_);
auto const last = bs_.end();
while(end_ != last)
{
auto const len =
boost::asio::buffer_size(*end_++);
if(len >= size)
{
size_ += size;
remain_ = size - len;
break;
}
size -= len;
size_ += len;
}
}
template<class BufferSequence>
buffers_prefix_view<BufferSequence>::
buffers_prefix_view(buffers_prefix_view&& other)
: buffers_prefix_view(std::move(other),
std::distance<iter_type>(
boost::asio::buffer_sequence_begin(other.bs_),
other.end_))
{
}
template<class BufferSequence>
buffers_prefix_view<BufferSequence>::
buffers_prefix_view(buffers_prefix_view const& other)
: buffers_prefix_view(other,
std::distance<iter_type>(
boost::asio::buffer_sequence_begin(other.bs_),
other.end_))
{
}
template<class BufferSequence>
auto
buffers_prefix_view<BufferSequence>::
operator=(buffers_prefix_view&& other) ->
buffers_prefix_view&
{
auto const dist = std::distance<iter_type>(
boost::asio::buffer_sequence_begin(other.bs_),
other.end_);
bs_ = std::move(other.bs_);
size_ = other.size_;
remain_ = other.remain_;
end_ = std::next(
boost::asio::buffer_sequence_begin(bs_),
dist);
return *this;
}
template<class BufferSequence>
auto
buffers_prefix_view<BufferSequence>::
operator=(buffers_prefix_view const& other) ->
buffers_prefix_view&
{
auto const dist = std::distance<iter_type>(
boost::asio::buffer_sequence_begin(other.bs_),
other.end_);
bs_ = other.bs_;
size_ = other.size_;
remain_ = other.remain_;
end_ = std::next(
boost::asio::buffer_sequence_begin(bs_),
dist);
return *this;
}
template<class BufferSequence>
buffers_prefix_view<BufferSequence>::
buffers_prefix_view(std::size_t size,
BufferSequence const& bs)
: bs_(bs)
{
setup(size);
}
template<class BufferSequence>
template<class... Args>
buffers_prefix_view<BufferSequence>::
buffers_prefix_view(std::size_t size,
boost::in_place_init_t, Args&&... args)
: bs_(std::forward<Args>(args)...)
{
setup(size);
}
template<class BufferSequence>
inline
auto
buffers_prefix_view<BufferSequence>::begin() const ->
const_iterator
{
return const_iterator{*this, std::false_type{}};
}
template<class BufferSequence>
inline
auto
buffers_prefix_view<BufferSequence>::end() const ->
const_iterator
{
return const_iterator{*this, std::true_type{}};
}
} // beast
} // boost
#endif
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