diff -r 000000000000 -r 4f2f89ce4247 WebCore/html/canvas/ArrayBufferView.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebCore/html/canvas/ArrayBufferView.h	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,128 @@
+/*
+ * Copyright (C) 2009 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#ifndef ArrayBufferView_h
+#define ArrayBufferView_h
+
+#include <algorithm>
+#include "ExceptionCode.h"
+#include <limits.h>
+#include <wtf/PassRefPtr.h>
+#include <wtf/RefCounted.h>
+#include <wtf/RefPtr.h>
+#include "ArrayBuffer.h"
+
+namespace WebCore {
+
+class ArrayBufferView : public RefCounted<ArrayBufferView> {
+  public:
+    virtual bool isByteArray() const { return false; }
+    virtual bool isUnsignedByteArray() const { return false; }
+    virtual bool isShortArray() const { return false; }
+    virtual bool isUnsignedShortArray() const { return false; }
+    virtual bool isIntArray() const { return false; }
+    virtual bool isUnsignedIntArray() const { return false; }
+    virtual bool isFloatArray() const { return false; }
+
+    PassRefPtr<ArrayBuffer> buffer() const
+    {
+        return m_buffer;
+    }
+
+    void* baseAddress() const
+    {
+        return m_baseAddress;
+    }
+
+    unsigned byteOffset() const
+    {
+        return m_byteOffset;
+    }
+
+    virtual unsigned length() const = 0;
+    virtual unsigned byteLength() const = 0;
+    virtual PassRefPtr<ArrayBufferView> slice(int start, int end) const = 0;
+
+    virtual ~ArrayBufferView();
+
+  protected:
+    ArrayBufferView(PassRefPtr<ArrayBuffer> buffer, unsigned byteOffset);
+
+    void setImpl(ArrayBufferView* array, unsigned byteOffset, ExceptionCode& ec);
+
+    static void calculateOffsetAndLength(int start, int end, unsigned arraySize,
+                                         unsigned* offset, unsigned* length);
+
+    // Helper to verify that a given sub-range of an ArrayBuffer is
+    // within range.
+    template <typename T>
+    static bool verifySubRange(PassRefPtr<ArrayBuffer> buffer,
+                               unsigned byteOffset,
+                               unsigned numElements)
+    {
+        if (!buffer)
+            return false;
+        if (sizeof(T) > 1 && byteOffset % sizeof(T))
+            return false;
+        if (byteOffset > buffer->byteLength())
+            return false;
+        unsigned remainingElements = (buffer->byteLength() - byteOffset) / sizeof(T);
+        if (numElements > remainingElements)
+            return false;
+        return true;
+    }
+
+    // Input offset is in number of elements from this array's view;
+    // output offset is in number of bytes from the underlying buffer's view.
+    template <typename T>
+    static void clampOffsetAndNumElements(PassRefPtr<ArrayBuffer> buffer,
+                                          unsigned arrayByteOffset,
+                                          unsigned *offset,
+                                          unsigned *numElements)
+    {
+        unsigned maxOffset = (UINT_MAX - arrayByteOffset) / sizeof(T);
+        if (*offset > maxOffset) {
+            *offset = buffer->byteLength();
+            *numElements = 0;
+            return;
+        }
+        *offset = arrayByteOffset + *offset * sizeof(T);
+        *offset = std::min(buffer->byteLength(), *offset);
+        unsigned remainingElements = (buffer->byteLength() - *offset) / sizeof(T);
+        *numElements = std::min(remainingElements, *numElements);
+    }
+
+    // This is the address of the ArrayBuffer's storage, plus the byte offset.
+    void* m_baseAddress;
+
+    unsigned m_byteOffset;
+
+  private:
+    RefPtr<ArrayBuffer> m_buffer;
+};
+
+} // namespace WebCore
+
+#endif // ArrayBufferView_h