Meet DynamicBuffer requirements for static_streambuf

include/beast/core/impl/static_streambuf.ipp

@@ -279,6 +279,16 @@ static_streambuf::mutable_buffers_type::end() const ->
 
 //------------------------------------------------------------------------------
 
+
+inline
+auto
+static_streambuf::data() const ->
+    const_buffers_type
+{
+    return const_buffers_type{in_,
+        static_cast<std::size_t>(out_ - in_)};
+}
+
 inline
 auto
 static_streambuf::prepare(std::size_t n) ->
@@ -290,15 +300,6 @@ static_streambuf::prepare(std::size_t n) ->
     return mutable_buffers_type{out_, n};
 }
 
-inline
-auto
-static_streambuf::data() const ->
-    const_buffers_type
-{
-    return const_buffers_type{in_,
-        static_cast<std::size_t>(out_ - in_)};
-}
-
 } // beast
 
 #endif

include/beast/core/static_streambuf.hpp

@@ -32,6 +32,7 @@ class static_streambuf
 #else
 protected:
 #endif
+    std::uint8_t* begin_;
     std::uint8_t* in_;
     std::uint8_t* out_;
     std::uint8_t* last_;
@@ -57,21 +58,35 @@ class static_streambuf
 
 #endif
 
-    /// Returns the largest size output sequence possible.
+    /// Return the size of the input sequence.
+    std::size_t
+    size() const
+    {
+        return out_ - in_;
+    }
+
+    /// Return the maximum sum of the input and output sequence sizes.
     std::size_t
     max_size() const
     {
-        return end_ - in_;
+        return end_ - begin_;
     }
 
-    /// Get the size of the input sequence.
+    /// Return the maximum sum of input and output sizes that can be held without an allocation.
     std::size_t
-    size() const
+    capacity() const
     {
-        return out_ - in_;
+        return end_ - in_;
     }
 
-    /** Get a list of buffers that represents the output sequence, with the given size.
+    /** Get a list of buffers that represent the input sequence.
+
+        @note These buffers remain valid across subsequent calls to `prepare`.
+    */
+    const_buffers_type
+    data() const;
+
+    /** Get a list of buffers that represent the output sequence, with the given size.
 
         @throws std::length_error if the size would exceed the limit
         imposed by the underlying mutable buffer sequence.
@@ -93,13 +108,6 @@ class static_streambuf
         out_ += std::min<std::size_t>(n, last_ - out_);
     }
 
-    /** Get a list of buffers that represents the input sequence.
-
-        @note These buffers remain valid across subsequent calls to `prepare`.
-    */
-    const_buffers_type
-    data() const;
-
     /// Remove bytes from the input sequence.
     void
     consume(std::size_t n)
@@ -120,6 +128,7 @@ class static_streambuf
     void
     reset(std::uint8_t* p, std::size_t n)
     {
+        begin_ = p;
         in_ = p;
         out_ = p;
         last_ = p;