From cb9ea47e7825b5073d4d645afb94f6326cb7cf4d Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Sun, 6 Sep 2009 12:52:53 +0200
Subject: Start the libcutl repository

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

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

diff --git a/cutl/shared-ptr/base.cxx b/cutl/shared-ptr/base.cxx
new file mode 100644
index 0000000..a74ed15
--- /dev/null
+++ b/cutl/shared-ptr/base.cxx
@@ -0,0 +1,63 @@
+// file      : cutl/shared-ptr/base.cxx
+// author    : Boris Kolpackov <boris@codesynthesis.com>
+// copyright : Copyright (c) 2009 Code Synthesis Tools CC
+// license   : MIT; see accompanying LICENSE file
+
+#include <cutl/shared-ptr/base.hxx>
+
+using std::size_t;
+
+//
+//
+cutl::share shared = cutl::share (1);
+cutl::share exclusive = cutl::share (2);
+
+//
+//
+namespace cutl
+{
+  char const* not_shared::
+  what () const throw ()
+  {
+    return "object is not shared";
+  }
+}
+
+//
+//
+void*
+operator new (size_t n, cutl::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, cutl::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);
+}
-- 
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