Replace boost by the standalone asio library

1 files changed, 2162 insertions, 0 deletions

diff --git a/lib/asio/buffer.hpp b/lib/asio/buffer.hpp
new file mode 100644
index 0000000..a9aa8aa
--- /dev/null
+++ b/lib/asio/buffer.hpp
@@ -0,0 +1,2162 @@
+//
+// buffer.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_BUFFER_HPP
+#define ASIO_BUFFER_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 <cstring>
+#include <limits>
+#include <stdexcept>
+#include <string>
+#include <vector>
+#include "asio/detail/array_fwd.hpp"
+#include "asio/detail/is_buffer_sequence.hpp"
+#include "asio/detail/string_view.hpp"
+#include "asio/detail/throw_exception.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#if defined(ASIO_MSVC) && (ASIO_MSVC >= 1700)
+# if defined(_HAS_ITERATOR_DEBUGGING) && (_HAS_ITERATOR_DEBUGGING != 0)
+#  if !defined(ASIO_DISABLE_BUFFER_DEBUGGING)
+#   define ASIO_ENABLE_BUFFER_DEBUGGING
+#  endif // !defined(ASIO_DISABLE_BUFFER_DEBUGGING)
+# endif // defined(_HAS_ITERATOR_DEBUGGING)
+#endif // defined(ASIO_MSVC) && (ASIO_MSVC >= 1700)
+
+#if defined(__GNUC__)
+# if defined(_GLIBCXX_DEBUG)
+#  if !defined(ASIO_DISABLE_BUFFER_DEBUGGING)
+#   define ASIO_ENABLE_BUFFER_DEBUGGING
+#  endif // !defined(ASIO_DISABLE_BUFFER_DEBUGGING)
+# endif // defined(_GLIBCXX_DEBUG)
+#endif // defined(__GNUC__)
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+# include "asio/detail/functional.hpp"
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+
+#if defined(ASIO_HAS_BOOST_WORKAROUND)
+# include <boost/detail/workaround.hpp>
+# if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x582)) \
+    || BOOST_WORKAROUND(__SUNPRO_CC, BOOST_TESTED_AT(0x590))
+#  define ASIO_ENABLE_ARRAY_BUFFER_WORKAROUND
+# endif // BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x582))
+        // || BOOST_WORKAROUND(__SUNPRO_CC, BOOST_TESTED_AT(0x590))
+#endif // defined(ASIO_HAS_BOOST_WORKAROUND)
+
+#if defined(ASIO_ENABLE_ARRAY_BUFFER_WORKAROUND)
+# include "asio/detail/type_traits.hpp"
+#endif // defined(ASIO_ENABLE_ARRAY_BUFFER_WORKAROUND)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+class mutable_buffer;
+class const_buffer;
+
+/// Holds a buffer that can be modified.
+/**
+ * The mutable_buffer class provides a safe representation of a buffer that can
+ * be modified. It does not own the underlying data, and so is cheap to copy or
+ * assign.
+ *
+ * @par Accessing Buffer Contents
+ *
+ * The contents of a buffer may be accessed using the @c data() and @c size()
+ * member functions:
+ *
+ * @code asio::mutable_buffer b1 = ...;
+ * std::size_t s1 = b1.size();
+ * unsigned char* p1 = static_cast<unsigned char*>(b1.data());
+ * @endcode
+ *
+ * The @c data() member function permits violations of type safety, so uses of
+ * it in application code should be carefully considered.
+ */
+class mutable_buffer
+{
+public:
+  /// Construct an empty buffer.
+  mutable_buffer() ASIO_NOEXCEPT
+    : data_(0),
+      size_(0)
+  {
+  }
+
+  /// Construct a buffer to represent a given memory range.
+  mutable_buffer(void* data, std::size_t size) ASIO_NOEXCEPT
+    : data_(data),
+      size_(size)
+  {
+  }
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+  mutable_buffer(void* data, std::size_t size,
+      asio::detail::function<void()> debug_check)
+    : data_(data),
+      size_(size),
+      debug_check_(debug_check)
+  {
+  }
+
+  const asio::detail::function<void()>& get_debug_check() const
+  {
+    return debug_check_;
+  }
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+
+  /// Get a pointer to the beginning of the memory range.
+  void* data() const ASIO_NOEXCEPT
+  {
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+    if (size_ && debug_check_)
+      debug_check_();
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+    return data_;
+  }
+
+  /// Get the size of the memory range.
+  std::size_t size() const ASIO_NOEXCEPT
+  {
+    return size_;
+  }
+
+  /// Move the start of the buffer by the specified number of bytes.
+  mutable_buffer& operator+=(std::size_t n) ASIO_NOEXCEPT
+  {
+    std::size_t offset = n < size_ ? n : size_;
+    data_ = static_cast<char*>(data_) + offset;
+    size_ -= offset;
+    return *this;
+  }
+
+private:
+  void* data_;
+  std::size_t size_;
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+  asio::detail::function<void()> debug_check_;
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+};
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+/// (Deprecated: Use mutable_buffer.) Adapts a single modifiable buffer so that
+/// it meets the requirements of the MutableBufferSequence concept.
+class mutable_buffers_1
+  : public mutable_buffer
+{
+public:
+  /// The type for each element in the list of buffers.
+  typedef mutable_buffer value_type;
+
+  /// A random-access iterator type that may be used to read elements.
+  typedef const mutable_buffer* const_iterator;
+
+  /// Construct to represent a given memory range.
+  mutable_buffers_1(void* data, std::size_t size) ASIO_NOEXCEPT
+    : mutable_buffer(data, size)
+  {
+  }
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+  mutable_buffers_1(void* data, std::size_t size,
+      asio::detail::function<void()> debug_check)
+    : mutable_buffer(data, size, debug_check)
+  {
+  }
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+
+  /// Construct to represent a single modifiable buffer.
+  explicit mutable_buffers_1(const mutable_buffer& b) ASIO_NOEXCEPT
+    : mutable_buffer(b)
+  {
+  }
+
+  /// Get a random-access iterator to the first element.
+  const_iterator begin() const ASIO_NOEXCEPT
+  {
+    return this;
+  }
+
+  /// Get a random-access iterator for one past the last element.
+  const_iterator end() const ASIO_NOEXCEPT
+  {
+    return begin() + 1;
+  }
+};
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+/// Holds a buffer that cannot be modified.
+/**
+ * The const_buffer class provides a safe representation of a buffer that cannot
+ * be modified. It does not own the underlying data, and so is cheap to copy or
+ * assign.
+ *
+ * @par Accessing Buffer Contents
+ *
+ * The contents of a buffer may be accessed using the @c data() and @c size()
+ * member functions:
+ *
+ * @code asio::const_buffer b1 = ...;
+ * std::size_t s1 = b1.size();
+ * const unsigned char* p1 = static_cast<const unsigned char*>(b1.data());
+ * @endcode
+ *
+ * The @c data() member function permits violations of type safety, so uses of
+ * it in application code should be carefully considered.
+ */
+class const_buffer
+{
+public:
+  /// Construct an empty buffer.
+  const_buffer() ASIO_NOEXCEPT
+    : data_(0),
+      size_(0)
+  {
+  }
+
+  /// Construct a buffer to represent a given memory range.
+  const_buffer(const void* data, std::size_t size) ASIO_NOEXCEPT
+    : data_(data),
+      size_(size)
+  {
+  }
+
+  /// Construct a non-modifiable buffer from a modifiable one.
+  const_buffer(const mutable_buffer& b) ASIO_NOEXCEPT
+    : data_(b.data()),
+      size_(b.size())
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , debug_check_(b.get_debug_check())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+  {
+  }
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+  const_buffer(const void* data, std::size_t size,
+      asio::detail::function<void()> debug_check)
+    : data_(data),
+      size_(size),
+      debug_check_(debug_check)
+  {
+  }
+
+  const asio::detail::function<void()>& get_debug_check() const
+  {
+    return debug_check_;
+  }
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+
+  /// Get a pointer to the beginning of the memory range.
+  const void* data() const ASIO_NOEXCEPT
+  {
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+    if (size_ && debug_check_)
+      debug_check_();
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+    return data_;
+  }
+
+  /// Get the size of the memory range.
+  std::size_t size() const ASIO_NOEXCEPT
+  {
+    return size_;
+  }
+
+  /// Move the start of the buffer by the specified number of bytes.
+  const_buffer& operator+=(std::size_t n) ASIO_NOEXCEPT
+  {
+    std::size_t offset = n < size_ ? n : size_;
+    data_ = static_cast<const char*>(data_) + offset;
+    size_ -= offset;
+    return *this;
+  }
+
+private:
+  const void* data_;
+  std::size_t size_;
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+  asio::detail::function<void()> debug_check_;
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+};
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+/// (Deprecated: Use const_buffer.) Adapts a single non-modifiable buffer so
+/// that it meets the requirements of the ConstBufferSequence concept.
+class const_buffers_1
+  : public const_buffer
+{
+public:
+  /// The type for each element in the list of buffers.
+  typedef const_buffer value_type;
+
+  /// A random-access iterator type that may be used to read elements.
+  typedef const const_buffer* const_iterator;
+
+  /// Construct to represent a given memory range.
+  const_buffers_1(const void* data, std::size_t size) ASIO_NOEXCEPT
+    : const_buffer(data, size)
+  {
+  }
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+  const_buffers_1(const void* data, std::size_t size,
+      asio::detail::function<void()> debug_check)
+    : const_buffer(data, size, debug_check)
+  {
+  }
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+
+  /// Construct to represent a single non-modifiable buffer.
+  explicit const_buffers_1(const const_buffer& b) ASIO_NOEXCEPT
+    : const_buffer(b)
+  {
+  }
+
+  /// Get a random-access iterator to the first element.
+  const_iterator begin() const ASIO_NOEXCEPT
+  {
+    return this;
+  }
+
+  /// Get a random-access iterator for one past the last element.
+  const_iterator end() const ASIO_NOEXCEPT
+  {
+    return begin() + 1;
+  }
+};
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+/// Trait to determine whether a type satisfies the MutableBufferSequence
+/// requirements.
+template <typename T>
+struct is_mutable_buffer_sequence
+#if defined(GENERATING_DOCUMENTATION)
+  : integral_constant<bool, automatically_determined>
+#else // defined(GENERATING_DOCUMENTATION)
+  : asio::detail::is_buffer_sequence<T, mutable_buffer>
+#endif // defined(GENERATING_DOCUMENTATION)
+{
+};
+
+/// Trait to determine whether a type satisfies the ConstBufferSequence
+/// requirements.
+template <typename T>
+struct is_const_buffer_sequence
+#if defined(GENERATING_DOCUMENTATION)
+  : integral_constant<bool, automatically_determined>
+#else // defined(GENERATING_DOCUMENTATION)
+  : asio::detail::is_buffer_sequence<T, const_buffer>
+#endif // defined(GENERATING_DOCUMENTATION)
+{
+};
+
+/// Trait to determine whether a type satisfies the DynamicBuffer requirements.
+template <typename T>
+struct is_dynamic_buffer
+#if defined(GENERATING_DOCUMENTATION)
+  : integral_constant<bool, automatically_determined>
+#else // defined(GENERATING_DOCUMENTATION)
+  : asio::detail::is_dynamic_buffer<T>
+#endif // defined(GENERATING_DOCUMENTATION)
+{
+};
+
+/// (Deprecated: Use the socket/descriptor wait() and async_wait() member
+/// functions.) An implementation of both the ConstBufferSequence and
+/// MutableBufferSequence concepts to represent a null buffer sequence.
+class null_buffers
+{
+public:
+  /// The type for each element in the list of buffers.
+  typedef mutable_buffer value_type;
+
+  /// A random-access iterator type that may be used to read elements.
+  typedef const mutable_buffer* const_iterator;
+
+  /// Get a random-access iterator to the first element.
+  const_iterator begin() const ASIO_NOEXCEPT
+  {
+    return &buf_;
+  }
+
+  /// Get a random-access iterator for one past the last element.
+  const_iterator end() const ASIO_NOEXCEPT
+  {
+    return &buf_;
+  }
+
+private:
+  mutable_buffer buf_;
+};
+
+/** @defgroup buffer_sequence_begin asio::buffer_sequence_begin
+ *
+ * @brief The asio::buffer_sequence_begin function returns an iterator
+ * pointing to the first element in a buffer sequence.
+ */
+/*@{*/
+
+/// Get an iterator to the first element in a buffer sequence.
+inline const mutable_buffer* buffer_sequence_begin(const mutable_buffer& b)
+{
+  return &b;
+}
+
+/// Get an iterator to the first element in a buffer sequence.
+inline const const_buffer* buffer_sequence_begin(const const_buffer& b)
+{
+  return &b;
+}
+
+#if defined(ASIO_HAS_DECLTYPE) || defined(GENERATING_DOCUMENTATION)
+
+/// Get an iterator to the first element in a buffer sequence.
+template <typename C>
+inline auto buffer_sequence_begin(C& c) -> decltype(c.begin())
+{
+  return c.begin();
+}
+
+/// Get an iterator to the first element in a buffer sequence.
+template <typename C>
+inline auto buffer_sequence_begin(const C& c) -> decltype(c.begin())
+{
+  return c.begin();
+}
+
+#else // defined(ASIO_HAS_DECLTYPE) || defined(GENERATING_DOCUMENTATION)
+
+template <typename C>
+inline typename C::iterator buffer_sequence_begin(C& c)
+{
+  return c.begin();
+}
+
+template <typename C>
+inline typename C::const_iterator buffer_sequence_begin(const C& c)
+{
+  return c.begin();
+}
+
+#endif // defined(ASIO_HAS_DECLTYPE) || defined(GENERATING_DOCUMENTATION)
+
+/*@}*/
+
+/** @defgroup buffer_sequence_end asio::buffer_sequence_end
+ *
+ * @brief The asio::buffer_sequence_end function returns an iterator
+ * pointing to one past the end element in a buffer sequence.
+ */
+/*@{*/
+
+/// Get an iterator to one past the end element in a buffer sequence.
+inline const mutable_buffer* buffer_sequence_end(const mutable_buffer& b)
+{
+  return &b + 1;
+}
+
+/// Get an iterator to one past the end element in a buffer sequence.
+inline const const_buffer* buffer_sequence_end(const const_buffer& b)
+{
+  return &b + 1;
+}
+
+#if defined(ASIO_HAS_DECLTYPE) || defined(GENERATING_DOCUMENTATION)
+
+/// Get an iterator to one past the end element in a buffer sequence.
+template <typename C>
+inline auto buffer_sequence_end(C& c) -> decltype(c.end())
+{
+  return c.end();
+}
+
+/// Get an iterator to one past the end element in a buffer sequence.
+template <typename C>
+inline auto buffer_sequence_end(const C& c) -> decltype(c.end())
+{
+  return c.end();
+}
+
+#else // defined(ASIO_HAS_DECLTYPE) || defined(GENERATING_DOCUMENTATION)
+
+template <typename C>
+inline typename C::iterator buffer_sequence_end(C& c)
+{
+  return c.end();
+}
+
+template <typename C>
+inline typename C::const_iterator buffer_sequence_end(const C& c)
+{
+  return c.end();
+}
+
+#endif // defined(ASIO_HAS_DECLTYPE) || defined(GENERATING_DOCUMENTATION)
+
+/*@}*/
+
+namespace detail {
+
+// Tag types used to select appropriately optimised overloads.
+struct one_buffer {};
+struct multiple_buffers {};
+
+// Helper trait to detect single buffers.
+template <typename BufferSequence>
+struct buffer_sequence_cardinality :
+  conditional<
+    is_same<BufferSequence, mutable_buffer>::value
+#if !defined(ASIO_NO_DEPRECATED)
+      || is_same<BufferSequence, mutable_buffers_1>::value
+      || is_same<BufferSequence, const_buffers_1>::value
+#endif // !defined(ASIO_NO_DEPRECATED)
+      || is_same<BufferSequence, const_buffer>::value,
+    one_buffer, multiple_buffers>::type {};
+
+template <typename Iterator>
+inline std::size_t buffer_size(one_buffer,
+    Iterator begin, Iterator) ASIO_NOEXCEPT
+{
+  return const_buffer(*begin).size();
+}
+
+template <typename Iterator>
+inline std::size_t buffer_size(multiple_buffers,
+    Iterator begin, Iterator end) ASIO_NOEXCEPT
+{
+  std::size_t total_buffer_size = 0;
+
+  Iterator iter = begin;
+  for (; iter != end; ++iter)
+  {
+    const_buffer b(*iter);
+    total_buffer_size += b.size();
+  }
+
+  return total_buffer_size;
+}
+
+} // namespace detail
+
+/// Get the total number of bytes in a buffer sequence.
+/**
+ * The @c buffer_size function determines the total size of all buffers in the
+ * buffer sequence, as if computed as follows:
+ *
+ * @code size_t total_size = 0;
+ * auto i = asio::buffer_sequence_begin(buffers);
+ * auto end = asio::buffer_sequence_end(buffers);
+ * for (; i != end; ++i)
+ * {
+ *   const_buffer b(*i);
+ *   total_size += b.size();
+ * }
+ * return total_size; @endcode
+ *
+ * The @c BufferSequence template parameter may meet either of the @c
+ * ConstBufferSequence or @c MutableBufferSequence type requirements.
+ */
+template <typename BufferSequence>
+inline std::size_t buffer_size(const BufferSequence& b) ASIO_NOEXCEPT
+{
+  return detail::buffer_size(
+      detail::buffer_sequence_cardinality<BufferSequence>(),
+      asio::buffer_sequence_begin(b),
+      asio::buffer_sequence_end(b));
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+/** @defgroup buffer_cast asio::buffer_cast
+ *
+ * @brief (Deprecated: Use the @c data() member function.) The
+ * asio::buffer_cast function is used to obtain a pointer to the
+ * underlying memory region associated with a buffer.
+ *
+ * @par Examples:
+ *
+ * To access the memory of a non-modifiable buffer, use:
+ * @code asio::const_buffer b1 = ...;
+ * const unsigned char* p1 = asio::buffer_cast<const unsigned char*>(b1);
+ * @endcode
+ *
+ * To access the memory of a modifiable buffer, use:
+ * @code asio::mutable_buffer b2 = ...;
+ * unsigned char* p2 = asio::buffer_cast<unsigned char*>(b2);
+ * @endcode
+ *
+ * The asio::buffer_cast function permits violations of type safety, so
+ * uses of it in application code should be carefully considered.
+ */
+/*@{*/
+
+/// Cast a non-modifiable buffer to a specified pointer to POD type.
+template <typename PointerToPodType>
+inline PointerToPodType buffer_cast(const mutable_buffer& b) ASIO_NOEXCEPT
+{
+  return static_cast<PointerToPodType>(b.data());
+}
+
+/// Cast a non-modifiable buffer to a specified pointer to POD type.
+template <typename PointerToPodType>
+inline PointerToPodType buffer_cast(const const_buffer& b) ASIO_NOEXCEPT
+{
+  return static_cast<PointerToPodType>(b.data());
+}
+
+/*@}*/
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+/// Create a new modifiable buffer that is offset from the start of another.
+/**
+ * @relates mutable_buffer
+ */
+inline mutable_buffer operator+(const mutable_buffer& b,
+    std::size_t n) ASIO_NOEXCEPT
+{
+  std::size_t offset = n < b.size() ? n : b.size();
+  char* new_data = static_cast<char*>(b.data()) + offset;
+  std::size_t new_size = b.size() - offset;
+  return mutable_buffer(new_data, new_size
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , b.get_debug_check()
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new modifiable buffer that is offset from the start of another.
+/**
+ * @relates mutable_buffer
+ */
+inline mutable_buffer operator+(std::size_t n,
+    const mutable_buffer& b) ASIO_NOEXCEPT
+{
+  return b + n;
+}
+
+/// Create a new non-modifiable buffer that is offset from the start of another.
+/**
+ * @relates const_buffer
+ */
+inline const_buffer operator+(const const_buffer& b,
+    std::size_t n) ASIO_NOEXCEPT
+{
+  std::size_t offset = n < b.size() ? n : b.size();
+  const char* new_data = static_cast<const char*>(b.data()) + offset;
+  std::size_t new_size = b.size() - offset;
+  return const_buffer(new_data, new_size
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , b.get_debug_check()
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new non-modifiable buffer that is offset from the start of another.
+/**
+ * @relates const_buffer
+ */
+inline const_buffer operator+(std::size_t n,
+    const const_buffer& b) ASIO_NOEXCEPT
+{
+  return b + n;
+}
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+namespace detail {
+
+template <typename Iterator>
+class buffer_debug_check
+{
+public:
+  buffer_debug_check(Iterator iter)
+    : iter_(iter)
+  {
+  }
+
+  ~buffer_debug_check()
+  {
+#if defined(ASIO_MSVC) && (ASIO_MSVC == 1400)
+    // MSVC 8's string iterator checking may crash in a std::string::iterator
+    // object's destructor when the iterator points to an already-destroyed
+    // std::string object, unless the iterator is cleared first.
+    iter_ = Iterator();
+#endif // defined(ASIO_MSVC) && (ASIO_MSVC == 1400)
+  }
+
+  void operator()()
+  {
+    (void)*iter_;
+  }
+
+private:
+  Iterator iter_;
+};
+
+} // namespace detail
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+
+/** @defgroup buffer asio::buffer
+ *
+ * @brief The asio::buffer function is used to create a buffer object to
+ * represent raw memory, an array of POD elements, a vector of POD elements,
+ * or a std::string.
+ *
+ * A buffer object represents a contiguous region of memory as a 2-tuple
+ * consisting of a pointer and size in bytes. A tuple of the form <tt>{void*,
+ * size_t}</tt> specifies a mutable (modifiable) region of memory. Similarly, a
+ * tuple of the form <tt>{const void*, size_t}</tt> specifies a const
+ * (non-modifiable) region of memory. These two forms correspond to the classes
+ * mutable_buffer and const_buffer, respectively. To mirror C++'s conversion
+ * rules, a mutable_buffer is implicitly convertible to a const_buffer, and the
+ * opposite conversion is not permitted.
+ *
+ * The simplest use case involves reading or writing a single buffer of a
+ * specified size:
+ *
+ * @code sock.send(asio::buffer(data, size)); @endcode
+ *
+ * In the above example, the return value of asio::buffer meets the
+ * requirements of the ConstBufferSequence concept so that it may be directly
+ * passed to the socket's write function. A buffer created for modifiable
+ * memory also meets the requirements of the MutableBufferSequence concept.
+ *
+ * An individual buffer may be created from a builtin array, std::vector,
+ * std::array or boost::array of POD elements. This helps prevent buffer
+ * overruns by automatically determining the size of the buffer:
+ *
+ * @code char d1[128];
+ * size_t bytes_transferred = sock.receive(asio::buffer(d1));
+ *
+ * std::vector<char> d2(128);
+ * bytes_transferred = sock.receive(asio::buffer(d2));
+ *
+ * std::array<char, 128> d3;
+ * bytes_transferred = sock.receive(asio::buffer(d3));
+ *
+ * boost::array<char, 128> d4;
+ * bytes_transferred = sock.receive(asio::buffer(d4)); @endcode
+ *
+ * In all three cases above, the buffers created are exactly 128 bytes long.
+ * Note that a vector is @e never automatically resized when creating or using
+ * a buffer. The buffer size is determined using the vector's <tt>size()</tt>
+ * member function, and not its capacity.
+ *
+ * @par Accessing Buffer Contents
+ *
+ * The contents of a buffer may be accessed using the @c data() and @c size()
+ * member functions:
+ *
+ * @code asio::mutable_buffer b1 = ...;
+ * std::size_t s1 = b1.size();
+ * unsigned char* p1 = static_cast<unsigned char*>(b1.data());
+ *
+ * asio::const_buffer b2 = ...;
+ * std::size_t s2 = b2.size();
+ * const void* p2 = b2.data(); @endcode
+ *
+ * The @c data() member function permits violations of type safety, so
+ * uses of it in application code should be carefully considered.
+ *
+ * For convenience, a @ref buffer_size function is provided that works with
+ * both buffers and buffer sequences (that is, types meeting the
+ * ConstBufferSequence or MutableBufferSequence type requirements). In this
+ * case, the function returns the total size of all buffers in the sequence.
+ *
+ * @par Buffer Copying
+ *
+ * The @ref buffer_copy function may be used to copy raw bytes between
+ * individual buffers and buffer sequences.
+*
+ * In particular, when used with the @ref buffer_size function, the @ref
+ * buffer_copy function can be used to linearise a sequence of buffers. For
+ * example:
+ *
+ * @code vector<const_buffer> buffers = ...;
+ *
+ * vector<unsigned char> data(asio::buffer_size(buffers));
+ * asio::buffer_copy(asio::buffer(data), buffers); @endcode
+ *
+ * Note that @ref buffer_copy is implemented in terms of @c memcpy, and
+ * consequently it cannot be used to copy between overlapping memory regions.
+ *
+ * @par Buffer Invalidation
+ *
+ * A buffer object does not have any ownership of the memory it refers to. It
+ * is the responsibility of the application to ensure the memory region remains
+ * valid until it is no longer required for an I/O operation. When the memory
+ * is no longer available, the buffer is said to have been invalidated.
+ *
+ * For the asio::buffer overloads that accept an argument of type
+ * std::vector, the buffer objects returned are invalidated by any vector
+ * operation that also invalidates all references, pointers and iterators
+ * referring to the elements in the sequence (C++ Std, 23.2.4)
+ *
+ * For the asio::buffer overloads that accept an argument of type
+ * std::basic_string, the buffer objects returned are invalidated according to
+ * the rules defined for invalidation of references, pointers and iterators
+ * referring to elements of the sequence (C++ Std, 21.3).
+ *
+ * @par Buffer Arithmetic
+ *
+ * Buffer objects may be manipulated using simple arithmetic in a safe way
+ * which helps prevent buffer overruns. Consider an array initialised as
+ * follows:
+ *
+ * @code boost::array<char, 6> a = { 'a', 'b', 'c', 'd', 'e' }; @endcode
+ *
+ * A buffer object @c b1 created using:
+ *
+ * @code b1 = asio::buffer(a); @endcode
+ *
+ * represents the entire array, <tt>{ 'a', 'b', 'c', 'd', 'e' }</tt>. An
+ * optional second argument to the asio::buffer function may be used to
+ * limit the size, in bytes, of the buffer:
+ *
+ * @code b2 = asio::buffer(a, 3); @endcode
+ *
+ * such that @c b2 represents the data <tt>{ 'a', 'b', 'c' }</tt>. Even if the
+ * size argument exceeds the actual size of the array, the size of the buffer
+ * object created will be limited to the array size.
+ *
+ * An offset may be applied to an existing buffer to create a new one:
+ *
+ * @code b3 = b1 + 2; @endcode
+ *
+ * where @c b3 will set to represent <tt>{ 'c', 'd', 'e' }</tt>. If the offset
+ * exceeds the size of the existing buffer, the newly created buffer will be
+ * empty.
+ *
+ * Both an offset and size may be specified to create a buffer that corresponds
+ * to a specific range of bytes within an existing buffer:
+ *
+ * @code b4 = asio::buffer(b1 + 1, 3); @endcode
+ *
+ * so that @c b4 will refer to the bytes <tt>{ 'b', 'c', 'd' }</tt>.
+ *
+ * @par Buffers and Scatter-Gather I/O
+ *
+ * To read or write using multiple buffers (i.e. scatter-gather I/O), multiple
+ * buffer objects may be assigned into a container that supports the
+ * MutableBufferSequence (for read) or ConstBufferSequence (for write) concepts:
+ *
+ * @code
+ * char d1[128];
+ * std::vector<char> d2(128);
+ * boost::array<char, 128> d3;
+ *
+ * boost::array<mutable_buffer, 3> bufs1 = {
+ *   asio::buffer(d1),
+ *   asio::buffer(d2),
+ *   asio::buffer(d3) };
+ * bytes_transferred = sock.receive(bufs1);
+ *
+ * std::vector<const_buffer> bufs2;
+ * bufs2.push_back(asio::buffer(d1));
+ * bufs2.push_back(asio::buffer(d2));
+ * bufs2.push_back(asio::buffer(d3));
+ * bytes_transferred = sock.send(bufs2); @endcode
+ */
+/*@{*/
+
+#if defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+# define ASIO_MUTABLE_BUFFER mutable_buffer
+# define ASIO_CONST_BUFFER const_buffer
+#else // defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+# define ASIO_MUTABLE_BUFFER mutable_buffers_1
+# define ASIO_CONST_BUFFER const_buffers_1
+#endif // defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+
+/// Create a new modifiable buffer from an existing buffer.
+/**
+ * @returns <tt>mutable_buffer(b)</tt>.
+ */
+inline ASIO_MUTABLE_BUFFER buffer(
+    const mutable_buffer& b) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(b);
+}
+
+/// Create a new modifiable buffer from an existing buffer.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     b.data(),
+ *     min(b.size(), max_size_in_bytes)); @endcode
+ */
+inline ASIO_MUTABLE_BUFFER buffer(const mutable_buffer& b,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(
+      mutable_buffer(b.data(),
+        b.size() < max_size_in_bytes
+        ? b.size() : max_size_in_bytes
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+        , b.get_debug_check()
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+        ));
+}
+
+/// Create a new non-modifiable buffer from an existing buffer.
+/**
+ * @returns <tt>const_buffer(b)</tt>.
+ */
+inline ASIO_CONST_BUFFER buffer(
+    const const_buffer& b) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(b);
+}
+
+/// Create a new non-modifiable buffer from an existing buffer.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     b.data(),
+ *     min(b.size(), max_size_in_bytes)); @endcode
+ */
+inline ASIO_CONST_BUFFER buffer(const const_buffer& b,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(b.data(),
+      b.size() < max_size_in_bytes
+      ? b.size() : max_size_in_bytes
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , b.get_debug_check()
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new modifiable buffer that represents the given memory range.
+/**
+ * @returns <tt>mutable_buffer(data, size_in_bytes)</tt>.
+ */
+inline ASIO_MUTABLE_BUFFER buffer(void* data,
+    std::size_t size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(data, size_in_bytes);
+}
+
+/// Create a new non-modifiable buffer that represents the given memory range.
+/**
+ * @returns <tt>const_buffer(data, size_in_bytes)</tt>.
+ */
+inline ASIO_CONST_BUFFER buffer(const void* data,
+    std::size_t size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data, size_in_bytes);
+}
+
+/// Create a new modifiable buffer that represents the given POD array.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     static_cast<void*>(data),
+ *     N * sizeof(PodType)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_MUTABLE_BUFFER buffer(PodType (&data)[N]) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(data, N * sizeof(PodType));
+}
+ 
+/// Create a new modifiable buffer that represents the given POD array.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     static_cast<void*>(data),
+ *     min(N * sizeof(PodType), max_size_in_bytes)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_MUTABLE_BUFFER buffer(PodType (&data)[N],
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(data,
+      N * sizeof(PodType) < max_size_in_bytes
+      ? N * sizeof(PodType) : max_size_in_bytes);
+}
+ 
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     static_cast<const void*>(data),
+ *     N * sizeof(PodType)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(
+    const PodType (&data)[N]) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data, N * sizeof(PodType));
+}
+
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     static_cast<const void*>(data),
+ *     min(N * sizeof(PodType), max_size_in_bytes)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(const PodType (&data)[N],
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data,
+      N * sizeof(PodType) < max_size_in_bytes
+      ? N * sizeof(PodType) : max_size_in_bytes);
+}
+
+#if defined(ASIO_ENABLE_ARRAY_BUFFER_WORKAROUND)
+
+// Borland C++ and Sun Studio think the overloads:
+//
+//   unspecified buffer(boost::array<PodType, N>& array ...);
+//
+// and
+//
+//   unspecified buffer(boost::array<const PodType, N>& array ...);
+//
+// are ambiguous. This will be worked around by using a buffer_types traits
+// class that contains typedefs for the appropriate buffer and container
+// classes, based on whether PodType is const or non-const.
+
+namespace detail {
+
+template <bool IsConst>
+struct buffer_types_base;
+
+template <>
+struct buffer_types_base<false>
+{
+  typedef mutable_buffer buffer_type;
+  typedef ASIO_MUTABLE_BUFFER container_type;
+};
+
+template <>
+struct buffer_types_base<true>
+{
+  typedef const_buffer buffer_type;
+  typedef ASIO_CONST_BUFFER container_type;
+};
+
+template <typename PodType>
+struct buffer_types
+  : public buffer_types_base<is_const<PodType>::value>
+{
+};
+
+} // namespace detail
+
+template <typename PodType, std::size_t N>
+inline typename detail::buffer_types<PodType>::container_type
+buffer(boost::array<PodType, N>& data) ASIO_NOEXCEPT
+{
+  typedef typename asio::detail::buffer_types<PodType>::buffer_type
+    buffer_type;
+  typedef typename asio::detail::buffer_types<PodType>::container_type
+    container_type;
+  return container_type(
+      buffer_type(data.c_array(), data.size() * sizeof(PodType)));
+}
+
+template <typename PodType, std::size_t N>
+inline typename detail::buffer_types<PodType>::container_type
+buffer(boost::array<PodType, N>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  typedef typename asio::detail::buffer_types<PodType>::buffer_type
+    buffer_type;
+  typedef typename asio::detail::buffer_types<PodType>::container_type
+    container_type;
+  return container_type(
+      buffer_type(data.c_array(),
+        data.size() * sizeof(PodType) < max_size_in_bytes
+        ? data.size() * sizeof(PodType) : max_size_in_bytes));
+}
+
+#else // defined(ASIO_ENABLE_ARRAY_BUFFER_WORKAROUND)
+
+/// Create a new modifiable buffer that represents the given POD array.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     data.data(),
+ *     data.size() * sizeof(PodType)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_MUTABLE_BUFFER buffer(
+    boost::array<PodType, N>& data) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(
+      data.c_array(), data.size() * sizeof(PodType));
+}
+
+/// Create a new modifiable buffer that represents the given POD array.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     data.data(),
+ *     min(data.size() * sizeof(PodType), max_size_in_bytes)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_MUTABLE_BUFFER buffer(boost::array<PodType, N>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(data.c_array(),
+      data.size() * sizeof(PodType) < max_size_in_bytes
+      ? data.size() * sizeof(PodType) : max_size_in_bytes);
+}
+
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.data(),
+ *     data.size() * sizeof(PodType)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(
+    boost::array<const PodType, N>& data) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(), data.size() * sizeof(PodType));
+}
+
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.data(),
+ *     min(data.size() * sizeof(PodType), max_size_in_bytes)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(boost::array<const PodType, N>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(),
+      data.size() * sizeof(PodType) < max_size_in_bytes
+      ? data.size() * sizeof(PodType) : max_size_in_bytes);
+}
+
+#endif // defined(ASIO_ENABLE_ARRAY_BUFFER_WORKAROUND)
+
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.data(),
+ *     data.size() * sizeof(PodType)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(
+    const boost::array<PodType, N>& data) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(), data.size() * sizeof(PodType));
+}
+
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.data(),
+ *     min(data.size() * sizeof(PodType), max_size_in_bytes)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(const boost::array<PodType, N>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(),
+      data.size() * sizeof(PodType) < max_size_in_bytes
+      ? data.size() * sizeof(PodType) : max_size_in_bytes);
+}
+
+#if defined(ASIO_HAS_STD_ARRAY) || defined(GENERATING_DOCUMENTATION)
+
+/// Create a new modifiable buffer that represents the given POD array.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     data.data(),
+ *     data.size() * sizeof(PodType)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_MUTABLE_BUFFER buffer(
+    std::array<PodType, N>& data) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(data.data(), data.size() * sizeof(PodType));
+}
+
+/// Create a new modifiable buffer that represents the given POD array.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     data.data(),
+ *     min(data.size() * sizeof(PodType), max_size_in_bytes)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_MUTABLE_BUFFER buffer(std::array<PodType, N>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(data.data(),
+      data.size() * sizeof(PodType) < max_size_in_bytes
+      ? data.size() * sizeof(PodType) : max_size_in_bytes);
+}
+
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.data(),
+ *     data.size() * sizeof(PodType)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(
+    std::array<const PodType, N>& data) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(), data.size() * sizeof(PodType));
+}
+
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.data(),
+ *     min(data.size() * sizeof(PodType), max_size_in_bytes)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(std::array<const PodType, N>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(),
+      data.size() * sizeof(PodType) < max_size_in_bytes
+      ? data.size() * sizeof(PodType) : max_size_in_bytes);
+}
+
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.data(),
+ *     data.size() * sizeof(PodType)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(
+    const std::array<PodType, N>& data) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(), data.size() * sizeof(PodType));
+}
+
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.data(),
+ *     min(data.size() * sizeof(PodType), max_size_in_bytes)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(const std::array<PodType, N>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(),
+      data.size() * sizeof(PodType) < max_size_in_bytes
+      ? data.size() * sizeof(PodType) : max_size_in_bytes);
+}
+
+#endif // defined(ASIO_HAS_STD_ARRAY) || defined(GENERATING_DOCUMENTATION)
+
+/// Create a new modifiable buffer that represents the given POD vector.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     data.size() ? &data[0] : 0,
+ *     data.size() * sizeof(PodType)); @endcode
+ *
+ * @note The buffer is invalidated by any vector operation that would also
+ * invalidate iterators.
+ */
+template <typename PodType, typename Allocator>
+inline ASIO_MUTABLE_BUFFER buffer(
+    std::vector<PodType, Allocator>& data) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(
+      data.size() ? &data[0] : 0, data.size() * sizeof(PodType)
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename std::vector<PodType, Allocator>::iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new modifiable buffer that represents the given POD vector.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     data.size() ? &data[0] : 0,
+ *     min(data.size() * sizeof(PodType), max_size_in_bytes)); @endcode
+ *
+ * @note The buffer is invalidated by any vector operation that would also
+ * invalidate iterators.
+ */
+template <typename PodType, typename Allocator>
+inline ASIO_MUTABLE_BUFFER buffer(std::vector<PodType, Allocator>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(data.size() ? &data[0] : 0,
+      data.size() * sizeof(PodType) < max_size_in_bytes
+      ? data.size() * sizeof(PodType) : max_size_in_bytes
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename std::vector<PodType, Allocator>::iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new non-modifiable buffer that represents the given POD vector.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.size() ? &data[0] : 0,
+ *     data.size() * sizeof(PodType)); @endcode
+ *
+ * @note The buffer is invalidated by any vector operation that would also
+ * invalidate iterators.
+ */
+template <typename PodType, typename Allocator>
+inline ASIO_CONST_BUFFER buffer(
+    const std::vector<PodType, Allocator>& data) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(
+      data.size() ? &data[0] : 0, data.size() * sizeof(PodType)
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename std::vector<PodType, Allocator>::const_iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new non-modifiable buffer that represents the given POD vector.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.size() ? &data[0] : 0,
+ *     min(data.size() * sizeof(PodType), max_size_in_bytes)); @endcode
+ *
+ * @note The buffer is invalidated by any vector operation that would also
+ * invalidate iterators.
+ */
+template <typename PodType, typename Allocator>
+inline ASIO_CONST_BUFFER buffer(
+    const std::vector<PodType, Allocator>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.size() ? &data[0] : 0,
+      data.size() * sizeof(PodType) < max_size_in_bytes
+      ? data.size() * sizeof(PodType) : max_size_in_bytes
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename std::vector<PodType, Allocator>::const_iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new modifiable buffer that represents the given string.
+/**
+ * @returns <tt>mutable_buffer(data.size() ? &data[0] : 0,
+ * data.size() * sizeof(Elem))</tt>.
+ *
+ * @note The buffer is invalidated by any non-const operation called on the
+ * given string object.
+ */
+template <typename Elem, typename Traits, typename Allocator>
+inline ASIO_MUTABLE_BUFFER buffer(
+    std::basic_string<Elem, Traits, Allocator>& data) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(data.size() ? &data[0] : 0,
+      data.size() * sizeof(Elem)
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename std::basic_string<Elem, Traits, Allocator>::iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new non-modifiable buffer that represents the given string.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     data.size() ? &data[0] : 0,
+ *     min(data.size() * sizeof(Elem), max_size_in_bytes)); @endcode
+ *
+ * @note The buffer is invalidated by any non-const operation called on the
+ * given string object.
+ */
+template <typename Elem, typename Traits, typename Allocator>
+inline ASIO_MUTABLE_BUFFER buffer(
+    std::basic_string<Elem, Traits, Allocator>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(data.size() ? &data[0] : 0,
+      data.size() * sizeof(Elem) < max_size_in_bytes
+      ? data.size() * sizeof(Elem) : max_size_in_bytes
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename std::basic_string<Elem, Traits, Allocator>::iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new non-modifiable buffer that represents the given string.
+/**
+ * @returns <tt>const_buffer(data.data(), data.size() * sizeof(Elem))</tt>.
+ *
+ * @note The buffer is invalidated by any non-const operation called on the
+ * given string object.
+ */
+template <typename Elem, typename Traits, typename Allocator>
+inline ASIO_CONST_BUFFER buffer(
+    const std::basic_string<Elem, Traits, Allocator>& data) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(), data.size() * sizeof(Elem)
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename std::basic_string<Elem, Traits, Allocator>::const_iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new non-modifiable buffer that represents the given string.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.data(),
+ *     min(data.size() * sizeof(Elem), max_size_in_bytes)); @endcode
+ *
+ * @note The buffer is invalidated by any non-const operation called on the
+ * given string object.
+ */
+template <typename Elem, typename Traits, typename Allocator>
+inline ASIO_CONST_BUFFER buffer(
+    const std::basic_string<Elem, Traits, Allocator>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(),
+      data.size() * sizeof(Elem) < max_size_in_bytes
+      ? data.size() * sizeof(Elem) : max_size_in_bytes
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename std::basic_string<Elem, Traits, Allocator>::const_iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+#if defined(ASIO_HAS_STRING_VIEW) \
+  || defined(GENERATING_DOCUMENTATION)
+
+/// Create a new modifiable buffer that represents the given string_view.
+/**
+ * @returns <tt>mutable_buffer(data.size() ? &data[0] : 0,
+ * data.size() * sizeof(Elem))</tt>.
+ */
+template <typename Elem, typename Traits>
+inline ASIO_CONST_BUFFER buffer(
+    basic_string_view<Elem, Traits> data) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.size() ? &data[0] : 0,
+      data.size() * sizeof(Elem)
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename basic_string_view<Elem, Traits>::iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new non-modifiable buffer that represents the given string.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     data.size() ? &data[0] : 0,
+ *     min(data.size() * sizeof(Elem), max_size_in_bytes)); @endcode
+ */
+template <typename Elem, typename Traits>
+inline ASIO_CONST_BUFFER buffer(
+    basic_string_view<Elem, Traits> data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.size() ? &data[0] : 0,
+      data.size() * sizeof(Elem) < max_size_in_bytes
+      ? data.size() * sizeof(Elem) : max_size_in_bytes
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename basic_string_view<Elem, Traits>::iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+#endif // defined(ASIO_HAS_STRING_VIEW)
+       //  || defined(GENERATING_DOCUMENTATION)
+
+/*@}*/
+
+/// Adapt a basic_string to the DynamicBuffer requirements.
+/**
+ * Requires that <tt>sizeof(Elem) == 1</tt>.
+ */
+template <typename Elem, typename Traits, typename Allocator>
+class dynamic_string_buffer
+{
+public:
+  /// The type used to represent the input sequence as a list of buffers.
+  typedef ASIO_CONST_BUFFER const_buffers_type;
+
+  /// The type used to represent the output sequence as a list of buffers.
+  typedef ASIO_MUTABLE_BUFFER mutable_buffers_type;
+
+  /// Construct a dynamic buffer from a string.
+  /**
+   * @param s The string to be used as backing storage for the dynamic buffer.
+   * Any existing data in the string is treated as the dynamic buffer's input
+   * sequence. The object stores a reference to the string and the user is
+   * responsible for ensuring that the string object remains valid until the
+   * dynamic_string_buffer object is destroyed.
+   *
+   * @param maximum_size Specifies a maximum size for the buffer, in bytes.
+   */
+  explicit dynamic_string_buffer(std::basic_string<Elem, Traits, Allocator>& s,
+      std::size_t maximum_size =
+        (std::numeric_limits<std::size_t>::max)()) ASIO_NOEXCEPT
+    : string_(s),
+      size_(string_.size()),
+      max_size_(maximum_size)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move construct a dynamic buffer.
+  dynamic_string_buffer(dynamic_string_buffer&& other) ASIO_NOEXCEPT
+    : string_(other.string_),
+      size_(other.size_),
+      max_size_(other.max_size_)
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Get the size of the input sequence.
+  std::size_t size() const ASIO_NOEXCEPT
+  {
+    return size_;
+  }
+
+  /// Get the maximum size of the dynamic buffer.
+  /**
+   * @returns The allowed maximum of the sum of the sizes of the input sequence
+   * and output sequence.
+   */
+  std::size_t max_size() const ASIO_NOEXCEPT
+  {
+    return max_size_;
+  }
+
+  /// Get the current capacity of the dynamic buffer.
+  /**
+   * @returns The current total capacity of the buffer, i.e. for both the input
+   * sequence and output sequence.
+   */
+  std::size_t capacity() const ASIO_NOEXCEPT
+  {
+    return string_.capacity();
+  }
+
+  /// Get a list of buffers that represents the input sequence.
+  /**
+   * @returns An object of type @c const_buffers_type that satisfies
+   * ConstBufferSequence requirements, representing the basic_string memory in
+   * input sequence.
+   *
+   * @note The returned object is invalidated by any @c dynamic_string_buffer
+   * or @c basic_string member function that modifies the input sequence or
+   * output sequence.
+   */
+  const_buffers_type data() const ASIO_NOEXCEPT
+  {
+    return const_buffers_type(asio::buffer(string_, size_));
+  }
+
+  /// Get a list of buffers that represents the output sequence, with the given
+  /// size.
+  /**
+   * Ensures that the output sequence can accommodate @c n bytes, resizing the
+   * basic_string object as necessary.
+   *
+   * @returns An object of type @c mutable_buffers_type that satisfies
+   * MutableBufferSequence requirements, representing basic_string memory
+   * at the start of the output sequence of size @c n.
+   *
+   * @throws std::length_error If <tt>size() + n > max_size()</tt>.
+   *
+   * @note The returned object is invalidated by any @c dynamic_string_buffer
+   * or @c basic_string member function that modifies the input sequence or
+   * output sequence.
+   */
+  mutable_buffers_type prepare(std::size_t n)
+  {
+    if (size () > max_size() || max_size() - size() < n)
+    {
+      std::length_error ex("dynamic_string_buffer too long");
+      asio::detail::throw_exception(ex);
+    }
+
+    string_.resize(size_ + n);
+
+    return asio::buffer(asio::buffer(string_) + size_, n);
+  }
+
+  /// Move bytes from the output sequence to the input sequence.
+  /**
+   * @param n The number of bytes to append from the start of the output
+   * sequence to the end of the input sequence. The remainder of the output
+   * sequence is discarded.
+   *
+   * Requires a preceding call <tt>prepare(x)</tt> where <tt>x >= n</tt>, and
+   * no intervening operations that modify the input or output sequence.
+   *
+   * @note If @c n is greater than the size of the output sequence, the entire
+   * output sequence is moved to the input sequence and no error is issued.
+   */
+  void commit(std::size_t n)
+  {
+    size_ += (std::min)(n, string_.size() - size_);
+    string_.resize(size_);
+  }
+
+  /// Remove characters from the input sequence.
+  /**
+   * Removes @c n characters from the beginning of the input sequence.
+   *
+   * @note If @c n is greater than the size of the input sequence, the entire
+   * input sequence is consumed and no error is issued.
+   */
+  void consume(std::size_t n)
+  {
+    std::size_t consume_length = (std::min)(n, size_);
+    string_.erase(0, consume_length);
+    size_ -= consume_length;
+  }
+
+private:
+  std::basic_string<Elem, Traits, Allocator>& string_;
+  std::size_t size_;
+  const std::size_t max_size_;
+};
+
+/// Adapt a vector to the DynamicBuffer requirements.
+/**
+ * Requires that <tt>sizeof(Elem) == 1</tt>.
+ */
+template <typename Elem, typename Allocator>
+class dynamic_vector_buffer
+{
+public:
+  /// The type used to represent the input sequence as a list of buffers.
+  typedef ASIO_CONST_BUFFER const_buffers_type;
+
+  /// The type used to represent the output sequence as a list of buffers.
+  typedef ASIO_MUTABLE_BUFFER mutable_buffers_type;
+
+  /// Construct a dynamic buffer from a string.
+  /**
+   * @param v The vector to be used as backing storage for the dynamic buffer.
+   * Any existing data in the vector is treated as the dynamic buffer's input
+   * sequence. The object stores a reference to the vector and the user is
+   * responsible for ensuring that the vector object remains valid until the
+   * dynamic_vector_buffer object is destroyed.
+   *
+   * @param maximum_size Specifies a maximum size for the buffer, in bytes.
+   */
+  explicit dynamic_vector_buffer(std::vector<Elem, Allocator>& v,
+      std::size_t maximum_size =
+        (std::numeric_limits<std::size_t>::max)()) ASIO_NOEXCEPT
+    : vector_(v),
+      size_(vector_.size()),
+      max_size_(maximum_size)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move construct a dynamic buffer.
+  dynamic_vector_buffer(dynamic_vector_buffer&& other) ASIO_NOEXCEPT
+    : vector_(other.vector_),
+      size_(other.size_),
+      max_size_(other.max_size_)
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Get the size of the input sequence.
+  std::size_t size() const ASIO_NOEXCEPT
+  {
+    return size_;
+  }
+
+  /// Get the maximum size of the dynamic buffer.
+  /**
+   * @returns The allowed maximum of the sum of the sizes of the input sequence
+   * and output sequence.
+   */
+  std::size_t max_size() const ASIO_NOEXCEPT
+  {
+    return max_size_;
+  }
+
+  /// Get the current capacity of the dynamic buffer.
+  /**
+   * @returns The current total capacity of the buffer, i.e. for both the input
+   * sequence and output sequence.
+   */
+  std::size_t capacity() const ASIO_NOEXCEPT
+  {
+    return vector_.capacity();
+  }
+
+  /// Get a list of buffers that represents the input sequence.
+  /**
+   * @returns An object of type @c const_buffers_type that satisfies
+   * ConstBufferSequence requirements, representing the basic_string memory in
+   * input sequence.
+   *
+   * @note The returned object is invalidated by any @c dynamic_vector_buffer
+   * or @c basic_string member function that modifies the input sequence or
+   * output sequence.
+   */
+  const_buffers_type data() const ASIO_NOEXCEPT
+  {
+    return const_buffers_type(asio::buffer(vector_, size_));
+  }
+
+  /// Get a list of buffers that represents the output sequence, with the given
+  /// size.
+  /**
+   * Ensures that the output sequence can accommodate @c n bytes, resizing the
+   * basic_string object as necessary.
+   *
+   * @returns An object of type @c mutable_buffers_type that satisfies
+   * MutableBufferSequence requirements, representing basic_string memory
+   * at the start of the output sequence of size @c n.
+   *
+   * @throws std::length_error If <tt>size() + n > max_size()</tt>.
+   *
+   * @note The returned object is invalidated by any @c dynamic_vector_buffer
+   * or @c basic_string member function that modifies the input sequence or
+   * output sequence.
+   */
+  mutable_buffers_type prepare(std::size_t n)
+  {
+    if (size () > max_size() || max_size() - size() < n)
+    {
+      std::length_error ex("dynamic_vector_buffer too long");
+      asio::detail::throw_exception(ex);
+    }
+
+    vector_.resize(size_ + n);
+
+    return asio::buffer(asio::buffer(vector_) + size_, n);
+  }
+
+  /// Move bytes from the output sequence to the input sequence.
+  /**
+   * @param n The number of bytes to append from the start of the output
+   * sequence to the end of the input sequence. The remainder of the output
+   * sequence is discarded.
+   *
+   * Requires a preceding call <tt>prepare(x)</tt> where <tt>x >= n</tt>, and
+   * no intervening operations that modify the input or output sequence.
+   *
+   * @note If @c n is greater than the size of the output sequence, the entire
+   * output sequence is moved to the input sequence and no error is issued.
+   */
+  void commit(std::size_t n)
+  {
+    size_ += (std::min)(n, vector_.size() - size_);
+    vector_.resize(size_);
+  }
+
+  /// Remove characters from the input sequence.
+  /**
+   * Removes @c n characters from the beginning of the input sequence.
+   *
+   * @note If @c n is greater than the size of the input sequence, the entire
+   * input sequence is consumed and no error is issued.
+   */
+  void consume(std::size_t n)
+  {
+    std::size_t consume_length = (std::min)(n, size_);
+    vector_.erase(vector_.begin(), vector_.begin() + consume_length);
+    size_ -= consume_length;
+  }
+
+private:
+  std::vector<Elem, Allocator>& vector_;
+  std::size_t size_;
+  const std::size_t max_size_;
+};
+
+/** @defgroup dynamic_buffer asio::dynamic_buffer
+ *
+ * @brief The asio::dynamic_buffer function is used to create a
+ * dynamically resized buffer from a @c std::basic_string or @c std::vector.
+ */
+/*@{*/
+
+/// Create a new dynamic buffer that represents the given string.
+/**
+ * @returns <tt>dynamic_string_buffer<Elem, Traits, Allocator>(data)</tt>.
+ */
+template <typename Elem, typename Traits, typename Allocator>
+inline dynamic_string_buffer<Elem, Traits, Allocator> dynamic_buffer(
+    std::basic_string<Elem, Traits, Allocator>& data) ASIO_NOEXCEPT
+{
+  return dynamic_string_buffer<Elem, Traits, Allocator>(data);
+}
+
+/// Create a new dynamic buffer that represents the given string.
+/**
+ * @returns <tt>dynamic_string_buffer<Elem, Traits, Allocator>(data,
+ * max_size)</tt>.
+ */
+template <typename Elem, typename Traits, typename Allocator>
+inline dynamic_string_buffer<Elem, Traits, Allocator> dynamic_buffer(
+    std::basic_string<Elem, Traits, Allocator>& data,
+    std::size_t max_size) ASIO_NOEXCEPT
+{
+  return dynamic_string_buffer<Elem, Traits, Allocator>(data, max_size);
+}
+
+/// Create a new dynamic buffer that represents the given vector.
+/**
+ * @returns <tt>dynamic_vector_buffer<Elem, Allocator>(data)</tt>.
+ */
+template <typename Elem, typename Allocator>
+inline dynamic_vector_buffer<Elem, Allocator> dynamic_buffer(
+    std::vector<Elem, Allocator>& data) ASIO_NOEXCEPT
+{
+  return dynamic_vector_buffer<Elem, Allocator>(data);
+}
+
+/// Create a new dynamic buffer that represents the given vector.
+/**
+ * @returns <tt>dynamic_vector_buffer<Elem, Allocator>(data, max_size)</tt>.
+ */
+template <typename Elem, typename Allocator>
+inline dynamic_vector_buffer<Elem, Allocator> dynamic_buffer(
+    std::vector<Elem, Allocator>& data,
+    std::size_t max_size) ASIO_NOEXCEPT
+{
+  return dynamic_vector_buffer<Elem, Allocator>(data, max_size);
+}
+
+/*@}*/
+
+/** @defgroup buffer_copy asio::buffer_copy
+ *
+ * @brief The asio::buffer_copy function is used to copy bytes from a
+ * source buffer (or buffer sequence) to a target buffer (or buffer sequence).
+ *
+ * The @c buffer_copy function is available in two forms:
+ *
+ * @li A 2-argument form: @c buffer_copy(target, source)
+ *
+ * @li A 3-argument form: @c buffer_copy(target, source, max_bytes_to_copy)
+ *
+ * Both forms return the number of bytes actually copied. The number of bytes
+ * copied is the lesser of:
+ *
+ * @li @c buffer_size(target)
+ *
+ * @li @c buffer_size(source)
+ *
+ * @li @c If specified, @c max_bytes_to_copy.
+ *
+ * This prevents buffer overflow, regardless of the buffer sizes used in the
+ * copy operation.
+ *
+ * Note that @ref buffer_copy is implemented in terms of @c memcpy, and
+ * consequently it cannot be used to copy between overlapping memory regions.
+ */
+/*@{*/
+
+namespace detail {
+
+inline std::size_t buffer_copy_1(const mutable_buffer& target,
+    const const_buffer& source)
+{
+  using namespace std; // For memcpy.
+  std::size_t target_size = target.size();
+  std::size_t source_size = source.size();
+  std::size_t n = target_size < source_size ? target_size : source_size;
+  if (n > 0)
+    memcpy(target.data(), source.data(), n);
+  return n;
+}
+
+template <typename TargetIterator, typename SourceIterator>
+inline std::size_t buffer_copy(one_buffer, one_buffer,
+    TargetIterator target_begin, TargetIterator,
+    SourceIterator source_begin, SourceIterator) ASIO_NOEXCEPT
+{
+  return (buffer_copy_1)(*target_begin, *source_begin);
+}
+
+template <typename TargetIterator, typename SourceIterator>
+inline std::size_t buffer_copy(one_buffer, one_buffer,
+    TargetIterator target_begin, TargetIterator,
+    SourceIterator source_begin, SourceIterator,
+    std::size_t max_bytes_to_copy) ASIO_NOEXCEPT
+{
+  return (buffer_copy_1)(*target_begin,
+      asio::buffer(*source_begin, max_bytes_to_copy));
+}
+
+template <typename TargetIterator, typename SourceIterator>
+std::size_t buffer_copy(one_buffer, multiple_buffers,
+    TargetIterator target_begin, TargetIterator,
+    SourceIterator source_begin, SourceIterator source_end,
+    std::size_t max_bytes_to_copy
+      = (std::numeric_limits<std::size_t>::max)()) ASIO_NOEXCEPT
+{
+  std::size_t total_bytes_copied = 0;
+  SourceIterator source_iter = source_begin;
+
+  for (mutable_buffer target_buffer(
+        asio::buffer(*target_begin, max_bytes_to_copy));
+      target_buffer.size() && source_iter != source_end; ++source_iter)
+  {
+    const_buffer source_buffer(*source_iter);
+    std::size_t bytes_copied = (buffer_copy_1)(target_buffer, source_buffer);
+    total_bytes_copied += bytes_copied;
+    target_buffer += bytes_copied;
+  }
+
+  return total_bytes_copied;
+}
+
+template <typename TargetIterator, typename SourceIterator>
+std::size_t buffer_copy(multiple_buffers, one_buffer,
+    TargetIterator target_begin, TargetIterator target_end,
+    SourceIterator source_begin, SourceIterator,
+    std::size_t max_bytes_to_copy
+      = (std::numeric_limits<std::size_t>::max)()) ASIO_NOEXCEPT
+{
+  std::size_t total_bytes_copied = 0;
+  TargetIterator target_iter = target_begin;
+
+  for (const_buffer source_buffer(
+        asio::buffer(*source_begin, max_bytes_to_copy));
+      source_buffer.size() && target_iter != target_end; ++target_iter)
+  {
+    mutable_buffer target_buffer(*target_iter);
+    std::size_t bytes_copied = (buffer_copy_1)(target_buffer, source_buffer);
+    total_bytes_copied += bytes_copied;
+    source_buffer += bytes_copied;
+  }
+
+  return total_bytes_copied;
+}
+
+template <typename TargetIterator, typename SourceIterator>
+std::size_t buffer_copy(multiple_buffers, multiple_buffers,
+    TargetIterator target_begin, TargetIterator target_end,
+    SourceIterator source_begin, SourceIterator source_end) ASIO_NOEXCEPT
+{
+  std::size_t total_bytes_copied = 0;
+
+  TargetIterator target_iter = target_begin;
+  std::size_t target_buffer_offset = 0;
+
+  SourceIterator source_iter = source_begin;
+  std::size_t source_buffer_offset = 0;
+
+  while (target_iter != target_end && source_iter != source_end)
+  {
+    mutable_buffer target_buffer =
+      mutable_buffer(*target_iter) + target_buffer_offset;
+
+    const_buffer source_buffer =
+      const_buffer(*source_iter) + source_buffer_offset;
+
+    std::size_t bytes_copied = (buffer_copy_1)(target_buffer, source_buffer);
+    total_bytes_copied += bytes_copied;
+
+    if (bytes_copied == target_buffer.size())
+    {
+      ++target_iter;
+      target_buffer_offset = 0;
+    }
+    else
+      target_buffer_offset += bytes_copied;
+
+    if (bytes_copied == source_buffer.size())
+    {
+      ++source_iter;
+      source_buffer_offset = 0;
+    }
+    else
+      source_buffer_offset += bytes_copied;
+  }
+
+  return total_bytes_copied;
+}
+
+template <typename TargetIterator, typename SourceIterator>
+std::size_t buffer_copy(multiple_buffers, multiple_buffers,
+    TargetIterator target_begin, TargetIterator target_end,
+    SourceIterator source_begin, SourceIterator source_end,
+    std::size_t max_bytes_to_copy) ASIO_NOEXCEPT
+{
+  std::size_t total_bytes_copied = 0;
+
+  TargetIterator target_iter = target_begin;
+  std::size_t target_buffer_offset = 0;
+
+  SourceIterator source_iter = source_begin;
+  std::size_t source_buffer_offset = 0;
+
+  while (total_bytes_copied != max_bytes_to_copy
+      && target_iter != target_end && source_iter != source_end)
+  {
+    mutable_buffer target_buffer =
+      mutable_buffer(*target_iter) + target_buffer_offset;
+
+    const_buffer source_buffer =
+      const_buffer(*source_iter) + source_buffer_offset;
+
+    std::size_t bytes_copied = (buffer_copy_1)(
+        target_buffer, asio::buffer(source_buffer,
+          max_bytes_to_copy - total_bytes_copied));
+    total_bytes_copied += bytes_copied;
+
+    if (bytes_copied == target_buffer.size())
+    {
+      ++target_iter;
+      target_buffer_offset = 0;
+    }
+    else
+      target_buffer_offset += bytes_copied;
+
+    if (bytes_copied == source_buffer.size())
+    {
+      ++source_iter;
+      source_buffer_offset = 0;
+    }
+    else
+      source_buffer_offset += bytes_copied;
+  }
+
+  return total_bytes_copied;
+}
+
+} // namespace detail
+
+/// Copies bytes from a source buffer sequence to a target buffer sequence.
+/**
+ * @param target A modifiable buffer sequence representing the memory regions to
+ * which the bytes will be copied.
+ *
+ * @param source A non-modifiable buffer sequence representing the memory
+ * regions from which the bytes will be copied.
+ *
+ * @returns The number of bytes copied.
+ *
+ * @note The number of bytes copied is the lesser of:
+ *
+ * @li @c buffer_size(target)
+ *
+ * @li @c buffer_size(source)
+ *
+ * This function is implemented in terms of @c memcpy, and consequently it
+ * cannot be used to copy between overlapping memory regions.
+ */
+template <typename MutableBufferSequence, typename ConstBufferSequence>
+inline std::size_t buffer_copy(const MutableBufferSequence& target,
+    const ConstBufferSequence& source) ASIO_NOEXCEPT
+{
+  return detail::buffer_copy(
+      detail::buffer_sequence_cardinality<MutableBufferSequence>(),
+      detail::buffer_sequence_cardinality<ConstBufferSequence>(),
+      asio::buffer_sequence_begin(target),
+      asio::buffer_sequence_end(target),
+      asio::buffer_sequence_begin(source),
+      asio::buffer_sequence_end(source));
+}
+
+/// Copies a limited number of bytes from a source buffer sequence to a target
+/// buffer sequence.
+/**
+ * @param target A modifiable buffer sequence representing the memory regions to
+ * which the bytes will be copied.
+ *
+ * @param source A non-modifiable buffer sequence representing the memory
+ * regions from which the bytes will be copied.
+ *
+ * @param max_bytes_to_copy The maximum number of bytes to be copied.
+ *
+ * @returns The number of bytes copied.
+ *
+ * @note The number of bytes copied is the lesser of:
+ *
+ * @li @c buffer_size(target)
+ *
+ * @li @c buffer_size(source)
+ *
+ * @li @c max_bytes_to_copy
+ *
+ * This function is implemented in terms of @c memcpy, and consequently it
+ * cannot be used to copy between overlapping memory regions.
+ */
+template <typename MutableBufferSequence, typename ConstBufferSequence>
+inline std::size_t buffer_copy(const MutableBufferSequence& target,
+    const ConstBufferSequence& source,
+    std::size_t max_bytes_to_copy) ASIO_NOEXCEPT
+{
+  return detail::buffer_copy(
+      detail::buffer_sequence_cardinality<MutableBufferSequence>(),
+      detail::buffer_sequence_cardinality<ConstBufferSequence>(),
+      asio::buffer_sequence_begin(target),
+      asio::buffer_sequence_end(target),
+      asio::buffer_sequence_begin(source),
+      asio::buffer_sequence_end(source), max_bytes_to_copy);
+}
+
+/*@}*/
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_BUFFER_HPP