From 6f0d40508286afc8cdd72a0b5f807d5c2a589cfc Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Fri, 4 Jun 2010 16:33:08 +0200
Subject: Initial implementation

---
 odb/shared-ptr/base.cxx | 63 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 odb/shared-ptr/base.cxx

(limited to 'odb/shared-ptr/base.cxx')

diff --git a/odb/shared-ptr/base.cxx b/odb/shared-ptr/base.cxx
new file mode 100644
index 0000000..11fa1c2
--- /dev/null
+++ b/odb/shared-ptr/base.cxx
@@ -0,0 +1,63 @@
+// file      : odb/shared-ptr/base.cxx
+// author    : Boris Kolpackov <boris@codesynthesis.com>
+// copyright : Copyright (c) 2009-2010 Code Synthesis Tools CC
+// license   : GNU GPL v2; see accompanying LICENSE file
+
+#include <odb/shared-ptr/base.hxx>
+
+using std::size_t;
+
+//
+//
+odb::share shared = odb::share (1);
+odb::share exclusive = odb::share (2);
+
+//
+//
+namespace odb
+{
+  char const* not_shared::
+  what () const throw ()
+  {
+    return "object is not shared";
+  }
+}
+
+//
+//
+void*
+operator new (size_t n, odb::share s) throw (std::bad_alloc)
+{
+  if (s == shared)
+  {
+    // Here we need to make sure we don't break the alignment of the
+    // returned block. For that we need to know the maximum alignment
+    // of this platform. Twice the pointer size is a good guess for
+    // most platforms.
+    //
+    size_t* p = static_cast<size_t*> (operator new (n + 2 * sizeof (size_t)));
+    *p++ = 1;          // Initial count.
+    *p++ = 0xDEADBEEF; // Signature.
+    return p;
+  }
+  else
+    return operator new (n);
+
+}
+
+void
+operator delete (void* p, odb::share s) throw ()
+{
+  // This version of operator delete is only called when the c-tor
+  // fails. In this case there is no object and we can just free the
+  // memory.
+  //
+  if (s == shared)
+  {
+    size_t* sp = static_cast<size_t*> (p);
+    sp -= 2;
+    operator delete (sp);
+  }
+  else
+    operator delete (p);
+}
-- 
cgit v1.1