/usr/include/asio/buffers_iterator.hpp is in libasio-dev 1.4.1-3ubuntu2.
This file is owned by root:root, with mode 0o644.
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// buffers_iterator.hpp
// ~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2008 Christopher M. Kohlhoff (chris at kohlhoff 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 ASIO_BUFFERS_ITERATOR_HPP
#define ASIO_BUFFERS_ITERATOR_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include "asio/detail/push_options.hpp"
#include "asio/detail/push_options.hpp"
#include <cstddef>
#include <boost/assert.hpp>
#include <boost/config.hpp>
#include <boost/detail/workaround.hpp>
#include <boost/iterator/iterator_facade.hpp>
#include <boost/type_traits/is_convertible.hpp>
#include <boost/type_traits/add_const.hpp>
#include "asio/detail/pop_options.hpp"
#include "asio/buffer.hpp"
namespace asio {
namespace detail
{
template <bool IsMutable>
struct buffers_iterator_types_helper;
template <>
struct buffers_iterator_types_helper<false>
{
typedef const_buffer buffer_type;
template <typename ByteType>
struct byte_type
{
typedef typename boost::add_const<ByteType>::type type;
};
};
template <>
struct buffers_iterator_types_helper<true>
{
typedef mutable_buffer buffer_type;
template <typename ByteType>
struct byte_type
{
typedef ByteType type;
};
};
template <typename BufferSequence, typename ByteType>
struct buffers_iterator_types
{
enum
{
is_mutable = boost::is_convertible<
typename BufferSequence::value_type, mutable_buffer>::value
};
typedef buffers_iterator_types_helper<is_mutable> helper;
typedef typename helper::buffer_type buffer_type;
typedef typename helper::template byte_type<ByteType>::type byte_type;
};
}
/// A random access iterator over the bytes in a buffer sequence.
template <typename BufferSequence, typename ByteType = char>
class buffers_iterator
: public boost::iterator_facade<
buffers_iterator<BufferSequence, ByteType>,
typename detail::buffers_iterator_types<
BufferSequence, ByteType>::byte_type,
boost::random_access_traversal_tag>
{
private:
typedef typename detail::buffers_iterator_types<
BufferSequence, ByteType>::buffer_type buffer_type;
typedef typename detail::buffers_iterator_types<
BufferSequence, ByteType>::byte_type byte_type;
public:
/// Default constructor. Creates an iterator in an undefined state.
buffers_iterator()
: current_buffer_(),
current_buffer_position_(0),
begin_(),
current_(),
end_(),
position_(0)
{
}
/// Construct an iterator representing the beginning of the buffers' data.
static buffers_iterator begin(const BufferSequence& buffers)
#if BOOST_WORKAROUND(__GNUC__, == 4) && BOOST_WORKAROUND(__GNUC_MINOR__, == 3)
__attribute__ ((noinline))
#endif
{
buffers_iterator new_iter;
new_iter.begin_ = buffers.begin();
new_iter.current_ = buffers.begin();
new_iter.end_ = buffers.end();
while (new_iter.current_ != new_iter.end_)
{
new_iter.current_buffer_ = *new_iter.current_;
if (asio::buffer_size(new_iter.current_buffer_) > 0)
break;
++new_iter.current_;
}
return new_iter;
}
/// Construct an iterator representing the end of the buffers' data.
static buffers_iterator end(const BufferSequence& buffers)
#if BOOST_WORKAROUND(__GNUC__, == 4) && BOOST_WORKAROUND(__GNUC_MINOR__, == 3)
__attribute__ ((noinline))
#endif
{
buffers_iterator new_iter;
new_iter.begin_ = buffers.begin();
new_iter.current_ = buffers.begin();
new_iter.end_ = buffers.end();
while (new_iter.current_ != new_iter.end_)
{
buffer_type buffer = *new_iter.current_;
new_iter.position_ += asio::buffer_size(buffer);
++new_iter.current_;
}
return new_iter;
}
private:
friend class boost::iterator_core_access;
// Dereference the iterator.
byte_type& dereference() const
{
return buffer_cast<byte_type*>(current_buffer_)[current_buffer_position_];
}
// Compare two iterators for equality.
bool equal(const buffers_iterator& other) const
{
return position_ == other.position_;
}
// Increment the iterator.
void increment()
{
BOOST_ASSERT(current_ != end_ && "iterator out of bounds");
++position_;
// Check if the increment can be satisfied by the current buffer.
++current_buffer_position_;
if (current_buffer_position_ != asio::buffer_size(current_buffer_))
return;
// Find the next non-empty buffer.
++current_;
current_buffer_position_ = 0;
while (current_ != end_)
{
current_buffer_ = *current_;
if (asio::buffer_size(current_buffer_) > 0)
return;
++current_;
}
}
// Decrement the iterator.
void decrement()
{
BOOST_ASSERT(position_ > 0 && "iterator out of bounds");
--position_;
// Check if the decrement can be satisfied by the current buffer.
if (current_buffer_position_ != 0)
{
--current_buffer_position_;
return;
}
// Find the previous non-empty buffer.
typename BufferSequence::const_iterator iter = current_;
while (iter != begin_)
{
--iter;
buffer_type buffer = *iter;
std::size_t buffer_size = asio::buffer_size(buffer);
if (buffer_size > 0)
{
current_ = iter;
current_buffer_ = buffer;
current_buffer_position_ = buffer_size - 1;
return;
}
}
}
// Advance the iterator by the specified distance.
void advance(std::ptrdiff_t n)
{
if (n > 0)
{
BOOST_ASSERT(current_ != end_ && "iterator out of bounds");
for (;;)
{
std::ptrdiff_t current_buffer_balance
= asio::buffer_size(current_buffer_)
- current_buffer_position_;
// Check if the advance can be satisfied by the current buffer.
if (current_buffer_balance > n)
{
position_ += n;
current_buffer_position_ += n;
return;
}
// Update position.
n -= current_buffer_balance;
position_ += current_buffer_balance;
// Move to next buffer. If it is empty then it will be skipped on the
// next iteration of this loop.
if (++current_ == end_)
{
BOOST_ASSERT(n == 0 && "iterator out of bounds");
current_buffer_ = buffer_type();
current_buffer_position_ = 0;
return;
}
current_buffer_ = *current_;
current_buffer_position_ = 0;
}
}
else if (n < 0)
{
std::size_t abs_n = -n;
BOOST_ASSERT(position_ >= abs_n && "iterator out of bounds");
for (;;)
{
// Check if the advance can be satisfied by the current buffer.
if (current_buffer_position_ >= abs_n)
{
position_ -= abs_n;
current_buffer_position_ -= abs_n;
return;
}
// Update position.
abs_n -= current_buffer_position_;
position_ -= current_buffer_position_;
// Check if we've reached the beginning of the buffers.
if (current_ == begin_)
{
BOOST_ASSERT(abs_n == 0 && "iterator out of bounds");
current_buffer_position_ = 0;
return;
}
// Find the previous non-empty buffer.
typename BufferSequence::const_iterator iter = current_;
while (iter != begin_)
{
--iter;
buffer_type buffer = *iter;
std::size_t buffer_size = asio::buffer_size(buffer);
if (buffer_size > 0)
{
current_ = iter;
current_buffer_ = buffer;
current_buffer_position_ = buffer_size;
break;
}
}
}
}
}
// Determine the distance between two iterators.
std::ptrdiff_t distance_to(const buffers_iterator& other) const
{
return other.position_ - position_;
}
buffer_type current_buffer_;
std::size_t current_buffer_position_;
typename BufferSequence::const_iterator begin_;
typename BufferSequence::const_iterator current_;
typename BufferSequence::const_iterator end_;
std::size_t position_;
};
/// Construct an iterator representing the beginning of the buffers' data.
template <typename BufferSequence>
inline buffers_iterator<BufferSequence> buffers_begin(
const BufferSequence& buffers)
{
return buffers_iterator<BufferSequence>::begin(buffers);
}
/// Construct an iterator representing the end of the buffers' data.
template <typename BufferSequence>
inline buffers_iterator<BufferSequence> buffers_end(
const BufferSequence& buffers)
{
return buffers_iterator<BufferSequence>::end(buffers);
}
} // namespace asio
#include "asio/detail/pop_options.hpp"
#endif // ASIO_BUFFERS_ITERATOR_HPP
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