posix/fd: add read and write member functions

posix/fd.cpp

@@ -96,6 +96,27 @@ fd::stat (void) const
 }
 
 
+///////////////////////////////////////////////////////////////////////////////
+ssize_t
+fd::read (void *buffer, size_t count)
+{
+    auto res = ::read (m_fd, buffer, count);
+    if (res == -1)
+        errno_error::throw_code ();
+    return res;
+}
+
+//-----------------------------------------------------------------------------
+ssize_t
+fd::write (const void *buffer, size_t count)
+{
+    auto res = ::write (m_fd, buffer, count);
+    if (res == -1)
+        errno_error::throw_code ();
+    return res;
+}
+
+
 ///////////////////////////////////////////////////////////////////////////////
 fd::operator int (void) const
 {

posix/fd.hpp

@@ -53,6 +53,10 @@ namespace util::posix {
         ///////////////////////////////////////////////////////////////////////
         struct ::stat stat (void) const;
 
+        //---------------------------------------------------------------------
+        ssize_t read  (      void *buf, size_t count);
+        ssize_t write (const void *buf, size_t count);
+
         ///////////////////////////////////////////////////////////////////////
         operator int (void) const;