0024534: Improve design of Image_PixMap class
[occt.git] / src / NCollection / NCollection_Buffer.hxx
diff --git a/src/NCollection/NCollection_Buffer.hxx b/src/NCollection/NCollection_Buffer.hxx
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+// Created on: 2014-04-01
+// Created by: Kirill Gavrilov
+// Copyright (c) 2014 OPEN CASCADE SAS
+//
+// This file is part of Open CASCADE Technology software library.
+//
+// This library is free software; you can redistribute it and/or modify it under
+// the terms of the GNU Lesser General Public License version 2.1 as published
+// by the Free Software Foundation, with special exception defined in the file
+// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
+// distribution for complete text of the license and disclaimer of any warranty.
+//
+// Alternatively, this file may be used under the terms of Open CASCADE
+// commercial license or contractual agreement.
+
+#ifndef _NCollection_Buffer_HeaderFile
+#define _NCollection_Buffer_HeaderFile
+
+#include <NCollection_BaseAllocator.hxx>
+#include <NCollection_Handle.hxx>
+
+//! Low-level buffer object.
+class NCollection_Buffer
+{
+
+public:
+
+  //! Default constructor.
+  //! When theData is NULL but theSize is not 0 than buffer of specified size will be allocated.
+  //! @param theAlloc memory allocator
+  //! @param theSize  buffer size
+  //! @param theData  buffer data allocated by theAlloc
+  NCollection_Buffer (const Handle(NCollection_BaseAllocator)& theAlloc,
+                      const Standard_Size                      theSize = 0,
+                      Standard_Byte*                           theData = NULL)
+  : myData (NULL),
+    mySize (0),
+    myAllocator (theAlloc)
+  {
+    if (theData != NULL)
+    {
+      myData = theData;
+      mySize = theSize;
+    }
+    else
+    {
+      Allocate (theSize);
+    }
+  }
+
+  //! Destructor.
+  virtual ~NCollection_Buffer()
+  {
+    Free();
+  }
+
+  //! @return buffer data
+  const Standard_Byte* Data() const
+  {
+    return myData;
+  }
+
+  //! @return buffer data
+  Standard_Byte* ChangeData()
+  {
+    return myData;
+  }
+
+  //! @return true if buffer is not allocated
+  bool IsEmpty() const
+  {
+    return myData == NULL;
+  }
+
+  //! Return buffer length in bytes.
+  Standard_Size Size() const
+  {
+    return mySize;
+  }
+
+  //! @return buffer allocator
+  const Handle(NCollection_BaseAllocator)& Allocator() const
+  {
+    return myAllocator;
+  }
+
+  //! Assign new buffer allocator with de-allocation of buffer.
+  void SetAllocator (const Handle(NCollection_BaseAllocator)& theAlloc)
+  {
+    Free();
+    myAllocator = theAlloc;
+  }
+
+  //! Allocate the buffer.
+  //! @param theSize buffer length in bytes
+  bool Allocate (const Standard_Size theSize)
+  {
+    Free();
+    mySize = theSize;
+    if (theSize != 0
+    || !myAllocator.IsNull())
+    {
+      myData = (Standard_Byte* )myAllocator->Allocate (theSize);
+    }
+
+    if (myData == NULL)
+    {
+      mySize = 0;
+      return false;
+    }
+    return true;
+  }
+
+  //! De-allocate buffer.
+  void Free()
+  {
+    if (!myAllocator.IsNull())
+    {
+      myAllocator->Free (myData);
+    }
+    myData = NULL;
+    mySize = 0;
+  }
+
+protected:
+
+  Standard_Byte*                    myData;      //!< data pointer
+  Standard_Size                     mySize;      //!< buffer length in bytes
+  Handle(NCollection_BaseAllocator) myAllocator; //!< buffer allocator
+
+};
+
+typedef NCollection_Handle<NCollection_Buffer> Handle(NCollection_Buffer);
+
+#endif // _NCollection_Buffer_HeaderFile