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Diffstat (limited to 'lib/asio/buffers_iterator.hpp')
| -rw-r--r-- | lib/asio/buffers_iterator.hpp | 521 |
1 files changed, 521 insertions, 0 deletions
diff --git a/lib/asio/buffers_iterator.hpp b/lib/asio/buffers_iterator.hpp new file mode 100644 index 0000000..f5c9d4c --- /dev/null +++ b/lib/asio/buffers_iterator.hpp @@ -0,0 +1,521 @@ +// +// buffers_iterator.hpp +// ~~~~~~~~~~~~~~~~~~~~ +// +// Copyright (c) 2003-2018 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/config.hpp" +#include <cstddef> +#include <iterator> +#include "asio/buffer.hpp" +#include "asio/detail/assert.hpp" +#include "asio/detail/type_traits.hpp" + +#include "asio/detail/push_options.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 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 = 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; + typedef typename BufferSequence::const_iterator const_iterator; + }; + + template <typename ByteType> + struct buffers_iterator_types<mutable_buffer, ByteType> + { + typedef mutable_buffer buffer_type; + typedef ByteType byte_type; + typedef const mutable_buffer* const_iterator; + }; + + template <typename ByteType> + struct buffers_iterator_types<const_buffer, ByteType> + { + typedef const_buffer buffer_type; + typedef typename add_const<ByteType>::type byte_type; + typedef const const_buffer* const_iterator; + }; + +#if !defined(ASIO_NO_DEPRECATED) + + template <typename ByteType> + struct buffers_iterator_types<mutable_buffers_1, ByteType> + { + typedef mutable_buffer buffer_type; + typedef ByteType byte_type; + typedef const mutable_buffer* const_iterator; + }; + + template <typename ByteType> + struct buffers_iterator_types<const_buffers_1, ByteType> + { + typedef const_buffer buffer_type; + typedef typename add_const<ByteType>::type byte_type; + typedef const const_buffer* const_iterator; + }; + +#endif // !defined(ASIO_NO_DEPRECATED) +} + +/// A random access iterator over the bytes in a buffer sequence. +template <typename BufferSequence, typename ByteType = char> +class buffers_iterator +{ +private: + typedef typename detail::buffers_iterator_types< + BufferSequence, ByteType>::buffer_type buffer_type; + + typedef typename detail::buffers_iterator_types<BufferSequence, + ByteType>::const_iterator buffer_sequence_iterator_type; + +public: + /// The type used for the distance between two iterators. + typedef std::ptrdiff_t difference_type; + + /// The type of the value pointed to by the iterator. + typedef ByteType value_type; + +#if defined(GENERATING_DOCUMENTATION) + /// The type of the result of applying operator->() to the iterator. + /** + * If the buffer sequence stores buffer objects that are convertible to + * mutable_buffer, this is a pointer to a non-const ByteType. Otherwise, a + * pointer to a const ByteType. + */ + typedef const_or_non_const_ByteType* pointer; +#else // defined(GENERATING_DOCUMENTATION) + typedef typename detail::buffers_iterator_types< + BufferSequence, ByteType>::byte_type* pointer; +#endif // defined(GENERATING_DOCUMENTATION) + +#if defined(GENERATING_DOCUMENTATION) + /// The type of the result of applying operator*() to the iterator. + /** + * If the buffer sequence stores buffer objects that are convertible to + * mutable_buffer, this is a reference to a non-const ByteType. Otherwise, a + * reference to a const ByteType. + */ + typedef const_or_non_const_ByteType& reference; +#else // defined(GENERATING_DOCUMENTATION) + typedef typename detail::buffers_iterator_types< + BufferSequence, ByteType>::byte_type& reference; +#endif // defined(GENERATING_DOCUMENTATION) + + /// The iterator category. + typedef std::random_access_iterator_tag iterator_category; + + /// 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 defined(__GNUC__) && (__GNUC__ == 4) && (__GNUC_MINOR__ == 3) + __attribute__ ((__noinline__)) +#endif // defined(__GNUC__) && (__GNUC__ == 4) && (__GNUC_MINOR__ == 3) + { + buffers_iterator new_iter; + new_iter.begin_ = asio::buffer_sequence_begin(buffers); + new_iter.current_ = asio::buffer_sequence_begin(buffers); + new_iter.end_ = asio::buffer_sequence_end(buffers); + while (new_iter.current_ != new_iter.end_) + { + new_iter.current_buffer_ = *new_iter.current_; + if (new_iter.current_buffer_.size() > 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 defined(__GNUC__) && (__GNUC__ == 4) && (__GNUC_MINOR__ == 3) + __attribute__ ((__noinline__)) +#endif // defined(__GNUC__) && (__GNUC__ == 4) && (__GNUC_MINOR__ == 3) + { + buffers_iterator new_iter; + new_iter.begin_ = asio::buffer_sequence_begin(buffers); + new_iter.current_ = asio::buffer_sequence_begin(buffers); + new_iter.end_ = asio::buffer_sequence_end(buffers); + while (new_iter.current_ != new_iter.end_) + { + buffer_type buffer = *new_iter.current_; + new_iter.position_ += buffer.size(); + ++new_iter.current_; + } + return new_iter; + } + + /// Dereference an iterator. + reference operator*() const + { + return dereference(); + } + + /// Dereference an iterator. + pointer operator->() const + { + return &dereference(); + } + + /// Access an individual element. + reference operator[](std::ptrdiff_t difference) const + { + buffers_iterator tmp(*this); + tmp.advance(difference); + return *tmp; + } + + /// Increment operator (prefix). + buffers_iterator& operator++() + { + increment(); + return *this; + } + + /// Increment operator (postfix). + buffers_iterator operator++(int) + { + buffers_iterator tmp(*this); + ++*this; + return tmp; + } + + /// Decrement operator (prefix). + buffers_iterator& operator--() + { + decrement(); + return *this; + } + + /// Decrement operator (postfix). + buffers_iterator operator--(int) + { + buffers_iterator tmp(*this); + --*this; + return tmp; + } + + /// Addition operator. + buffers_iterator& operator+=(std::ptrdiff_t difference) + { + advance(difference); + return *this; + } + + /// Subtraction operator. + buffers_iterator& operator-=(std::ptrdiff_t difference) + { + advance(-difference); + return *this; + } + + /// Addition operator. + friend buffers_iterator operator+(const buffers_iterator& iter, + std::ptrdiff_t difference) + { + buffers_iterator tmp(iter); + tmp.advance(difference); + return tmp; + } + + /// Addition operator. + friend buffers_iterator operator+(std::ptrdiff_t difference, + const buffers_iterator& iter) + { + buffers_iterator tmp(iter); + tmp.advance(difference); + return tmp; + } + + /// Subtraction operator. + friend buffers_iterator operator-(const buffers_iterator& iter, + std::ptrdiff_t difference) + { + buffers_iterator tmp(iter); + tmp.advance(-difference); + return tmp; + } + + /// Subtraction operator. + friend std::ptrdiff_t operator-(const buffers_iterator& a, + const buffers_iterator& b) + { + return b.distance_to(a); + } + + /// Test two iterators for equality. + friend bool operator==(const buffers_iterator& a, const buffers_iterator& b) + { + return a.equal(b); + } + + /// Test two iterators for inequality. + friend bool operator!=(const buffers_iterator& a, const buffers_iterator& b) + { + return !a.equal(b); + } + + /// Compare two iterators. + friend bool operator<(const buffers_iterator& a, const buffers_iterator& b) + { + return a.distance_to(b) > 0; + } + + /// Compare two iterators. + friend bool operator<=(const buffers_iterator& a, const buffers_iterator& b) + { + return !(b < a); + } + + /// Compare two iterators. + friend bool operator>(const buffers_iterator& a, const buffers_iterator& b) + { + return b < a; + } + + /// Compare two iterators. + friend bool operator>=(const buffers_iterator& a, const buffers_iterator& b) + { + return !(a < b); + } + +private: + // Dereference the iterator. + reference dereference() const + { + return static_cast<pointer>( + current_buffer_.data())[current_buffer_position_]; + } + + // Compare two iterators for equality. + bool equal(const buffers_iterator& other) const + { + return position_ == other.position_; + } + + // Increment the iterator. + void increment() + { + ASIO_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_ != current_buffer_.size()) + return; + + // Find the next non-empty buffer. + ++current_; + current_buffer_position_ = 0; + while (current_ != end_) + { + current_buffer_ = *current_; + if (current_buffer_.size() > 0) + return; + ++current_; + } + } + + // Decrement the iterator. + void decrement() + { + ASIO_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. + buffer_sequence_iterator_type iter = current_; + while (iter != begin_) + { + --iter; + buffer_type buffer = *iter; + std::size_t buffer_size = buffer.size(); + 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) + { + ASIO_ASSERT(current_ != end_ && "iterator out of bounds"); + for (;;) + { + std::ptrdiff_t current_buffer_balance + = current_buffer_.size() - 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_) + { + ASIO_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; + ASIO_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_) + { + ASIO_ASSERT(abs_n == 0 && "iterator out of bounds"); + current_buffer_position_ = 0; + return; + } + + // Find the previous non-empty buffer. + buffer_sequence_iterator_type iter = current_; + while (iter != begin_) + { + --iter; + buffer_type buffer = *iter; + std::size_t buffer_size = buffer.size(); + 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_; + buffer_sequence_iterator_type begin_; + buffer_sequence_iterator_type current_; + buffer_sequence_iterator_type 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 |