Add buffer() overloads for basic_string_view.

asio/include/Makefile.am

@@ -217,6 +217,7 @@ nobase_include_HEADERS = \
 	asio/detail/std_thread.hpp \
 	asio/detail/strand_executor_service.hpp \
 	asio/detail/strand_service.hpp \
+	asio/detail/string_view.hpp \
 	asio/detail/thread_context.hpp \
 	asio/detail/thread_group.hpp \
 	asio/detail/thread.hpp \

asio/include/asio/buffer.hpp

@@ -24,6 +24,7 @@
 #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"
 
@@ -1474,6 +1475,54 @@ inline ASIO_CONST_BUFFER buffer(
       );
 }
 
+#if defined(ASIO_HAS_STD_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_STD_STRING_VIEW)
+       //  || defined(GENERATING_DOCUMENTATION)
+
 /*@}*/
 
 /// Adapt a basic_string to the DynamicBuffer requirements.

asio/include/asio/detail/config.hpp

@@ -703,6 +703,28 @@
 # endif // !defined(ASIO_DISABLE_STD_FUTURE)
 #endif // !defined(ASIO_HAS_STD_FUTURE)
 
+// Standard library support for experimental::string_view.
+#if !defined(ASIO_HAS_STD_STRING_VIEW)
+# if !defined(ASIO_DISABLE_STD_STRING_VIEW)
+#  if defined(__clang__)
+#   if (__cplusplus >= 201103)
+#    if __has_include(<experimental/string_view>)
+#     define ASIO_HAS_STD_STRING_VIEW 1
+#     define ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW 1
+#    endif // __has_include(<experimental/string_view>)
+#   endif // (__cplusplus >= 201103)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 9)) || (__GNUC__ > 4)
+#    if (__cplusplus >= 201300)
+#     define ASIO_HAS_STD_STRING_VIEW 1
+#     define ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW 1
+#    endif // (__cplusplus >= 201300)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+# endif // !defined(ASIO_DISABLE_STD_STRING_VIEW)
+#endif // !defined(ASIO_HAS_STD_STRING_VIEW)
+
 // Windows App target. Windows but with a limited API.
 #if !defined(ASIO_WINDOWS_APP)
 # if defined(_WIN32_WINNT) && (_WIN32_WINNT >= 0x0603)

asio/include/asio/detail/string_view.hpp

@@ -0,0 +1,42 @@
+//
+// detail/string_view.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2016 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_DETAIL_STRING_VIEW_HPP
+#define ASIO_DETAIL_STRING_VIEW_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#if defined(ASIO_HAS_STD_STRING_VIEW)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW)
+# include <experimental/string_view>
+#else // defined(ASIO_HAS_EXPERIMENTAL_STRING_VIEW)
+# include <string_view>
+#endif // defined(ASIO_HAS_EXPERIMENTAL_STRING_VIEW)
+
+namespace asio {
+
+#if defined(ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW)
+using std::experimental::basic_string_view;
+using std::experimental::string_view;
+#else // defined(ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW)
+using std::basic_string_view;
+using std::string_view;
+#endif // defined(ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW)
+
+} // namespace asio
+
+#endif // defined(ASIO_HAS_STD_STRING_VIEW)
+
+#endif // ASIO_DETAIL_STRING_VIEW_HPP

asio/src/tests/unit/buffer.cpp

@@ -61,6 +61,13 @@ void test()
     const std::string const_string_data(1024, ' ');
     std::vector<mutable_buffer> mutable_buffer_sequence;
     std::vector<const_buffer> const_buffer_sequence;
+#if defined(ASIO_HAS_STD_STRING_VIEW)
+# if defined(ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW)
+    std::experimental::string_view string_view_data(string_data);
+# else // defined(ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW)
+    std::string_view string_view_data(string_data);
+# endif // defined(ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW)
+#endif // defined(ASIO_HAS_STD_STRING_VIEW)
 
     // mutable_buffer constructors.
 
@@ -197,6 +204,10 @@ void test()
     mb1 = buffer(string_data, 1024);
     cb1 = buffer(const_string_data);
     cb1 = buffer(const_string_data, 1024);
+#if defined(ASIO_HAS_STD_STRING_VIEW)
+    cb1 = buffer(string_view_data);
+    cb1 = buffer(string_view_data, 1024);
+#endif // defined(ASIO_HAS_STD_STRING_VIEW)
 
     // buffer_copy function overloads.