Move char_buffer into a separate file

Signed-off-by: Damian Jarek <damian.jarek93@gmail.com>

include/boost/beast/http/detail/basic_parser.hpp

@@ -11,6 +11,7 @@
 #define BOOST_BEAST_HTTP_DETAIL_BASIC_PARSER_HPP
 
 #include <boost/beast/core/string.hpp>
+#include <boost/beast/core/detail/char_buffer.hpp>
 #include <boost/beast/http/error.hpp>
 #include <boost/beast/http/detail/rfc7230.hpp>
 #include <boost/config.hpp>
@@ -23,59 +24,6 @@ namespace beast {
 namespace http {
 namespace detail {
 
-template <std::size_t N>
-class char_buffer
-{
-public:
-    bool try_push_back(char c)
-    {
-        if (size_ == N)
-            return false;
-        buf_[size_++] = c;
-        return true;
-    }
-
-    bool try_append(char const* first, char const* last)
-    {
-        std::size_t const n = last - first;
-        if (n > N - size_)
-            return false;
-        std::memmove(&buf_[size_], first, n);
-        size_ += n;
-        return true;
-    }
-
-    void clear() noexcept
-    {
-        size_ = 0;
-    }
-
-    char* data() noexcept
-    {
-        return buf_;
-    }
-
-    char const* data() const noexcept
-    {
-        return buf_;
-    }
-
-    std::size_t size() const noexcept
-    {
-        return size_;
-    }
-
-    bool empty() const noexcept
-    {
-        return size_ == 0;
-    }
-
-private:
-    std::size_t size_= 0;
-    char buf_[N];
-};
-
-
 struct basic_parser_base
 {
     // limit on the size of the obs-fold buffer
@@ -234,7 +182,7 @@ struct basic_parser_base
         char const* last,
         string_view& name,
         string_view& value,
-        char_buffer<max_obs_fold>& buf,
+        beast::detail::char_buffer<max_obs_fold>& buf,
         error_code& ec);
 
     BOOST_BEAST_DECL