Imported existing code

libraries/include/boost/asio/buffers_iterator.hpp

@@ -0,0 +1,327 @@
+//
+// 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 BOOST_ASIO_BUFFERS_ITERATOR_HPP
+#define BOOST_ASIO_BUFFERS_ITERATOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include <boost/asio/detail/push_options.hpp>
+
+#include <boost/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 <boost/asio/detail/pop_options.hpp>
+
+#include <boost/asio/buffer.hpp>
+
+namespace boost {
+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 (boost::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_ += boost::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_ != boost::asio::buffer_size(current_buffer_))
+      return;
+
+    // Find the next non-empty buffer.
+    ++current_;
+    current_buffer_position_ = 0;
+    while (current_ != end_)
+    {
+      current_buffer_ = *current_;
+      if (boost::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 = boost::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
+          = boost::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 = boost::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
+} // namespace boost
+
+#include <boost/asio/detail/pop_options.hpp>
+
+#endif // BOOST_ASIO_BUFFERS_ITERATOR_HPP