Ensure that numeric array storage is aligned to 256-byte boundary.

OpenCL devices require this else we would get a performance hit.

Change-Id: I6b1db6320fa84f933b6446022a0fd02ba267bf21

1 files changed, 60 insertions, 0 deletions

diff --git a/sc/inc/stlalgorithm.hxx b/sc/inc/stlalgorithm.hxx
index fb5509f50f9c..37d7ba85066a 100644
--- a/sc/inc/stlalgorithm.hxx
+++ b/sc/inc/stlalgorithm.hxx
@@ -11,6 +11,9 @@
 #define __SC_STLALGORITHM_HXX__
 
 #include <functional>
+#include <limits>
+
+#include <rtl/alloc.h>
 
 /**
  * Function object to allow deleting instances stored in STL containers as
@@ -25,6 +28,63 @@ struct ScDeleteObjectByPtr : public ::std::unary_function<T*, void>
     }
 };
 
+namespace sc {
+
+/**
+ * Custom allocator for STL container to ensure that the base address of
+ * allocated storage is aligned to a specified boundary.
+ */
+template<typename T, size_t _Alignment>
+class AlignedAllocator
+{
+public:
+    typedef T value_type;
+    typedef size_t size_type;
+    typedef std::ptrdiff_t difference_type;
+
+    typedef T* pointer;
+    typedef const T* const_pointer;
+    typedef T* void_pointer;
+
+    typedef T& reference;
+    typedef const T& const_reference;
+
+    template<typename _Type2>
+    struct rebind
+    {
+        typedef AlignedAllocator<_Type2,_Alignment> other;
+    };
+
+    AlignedAllocator() {}
+    ~AlignedAllocator() {}
+
+    template<typename _Type2>
+    AlignedAllocator(const AlignedAllocator<_Type2,_Alignment>&) {}
+
+    void construct(T* p, const value_type& val) { new(p) value_type(val); }
+    void destroy(T* p) { p->~value_type(); }
+
+    size_type max_size() const
+    {
+        return std::numeric_limits<size_type>::max() / sizeof(value_type);
+    }
+
+    bool operator== (const AlignedAllocator&) const { return true; }
+    bool operator!= (const AlignedAllocator&) const { return false; }
+
+    pointer allocate(size_type n)
+    {
+        return (pointer)rtl_allocateAlinedMemory(_Alignment, n*sizeof(value_type));
+    }
+
+    void deallocate(pointer p, size_type)
+    {
+        rtl_freeAlignedMemory(p);
+    }
+};
+
+}
+
 #endif
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */