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      1 /*
      2  * Copyright (C) 2009 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #ifndef ArrayBufferView_h
     27 #define ArrayBufferView_h
     28 
     29 #include "ArrayBuffer.h"
     30 #include "ExceptionCode.h"
     31 
     32 #include <algorithm>
     33 #include <limits.h>
     34 #include <wtf/PassRefPtr.h>
     35 #include <wtf/RefCounted.h>
     36 #include <wtf/RefPtr.h>
     37 
     38 namespace WebCore {
     39 
     40 class ArrayBufferView : public RefCounted<ArrayBufferView> {
     41   public:
     42     virtual bool isByteArray() const { return false; }
     43     virtual bool isUnsignedByteArray() const { return false; }
     44     virtual bool isShortArray() const { return false; }
     45     virtual bool isUnsignedShortArray() const { return false; }
     46     virtual bool isIntArray() const { return false; }
     47     virtual bool isUnsignedIntArray() const { return false; }
     48     virtual bool isFloatArray() const { return false; }
     49     virtual bool isDoubleArray() const { return false; }
     50     virtual bool isDataView() const { return false; }
     51 
     52     PassRefPtr<ArrayBuffer> buffer() const
     53     {
     54         return m_buffer;
     55     }
     56 
     57     void* baseAddress() const
     58     {
     59         return m_baseAddress;
     60     }
     61 
     62     unsigned byteOffset() const
     63     {
     64         return m_byteOffset;
     65     }
     66 
     67     virtual unsigned byteLength() const = 0;
     68 
     69     virtual ~ArrayBufferView();
     70 
     71   protected:
     72     ArrayBufferView(PassRefPtr<ArrayBuffer> buffer, unsigned byteOffset);
     73 
     74     void setImpl(ArrayBufferView* array, unsigned byteOffset, ExceptionCode& ec);
     75 
     76     void setRangeImpl(const char* data, size_t dataByteLength, unsigned byteOffset, ExceptionCode& ec);
     77 
     78     void zeroRangeImpl(unsigned byteOffset, size_t rangeByteLength, ExceptionCode& ec);
     79 
     80     static void calculateOffsetAndLength(int start, int end, unsigned arraySize,
     81                                          unsigned* offset, unsigned* length);
     82 
     83     // Helper to verify that a given sub-range of an ArrayBuffer is
     84     // within range.
     85     template <typename T>
     86     static bool verifySubRange(PassRefPtr<ArrayBuffer> buffer,
     87                                unsigned byteOffset,
     88                                unsigned numElements)
     89     {
     90         if (!buffer)
     91             return false;
     92         if (sizeof(T) > 1 && byteOffset % sizeof(T))
     93             return false;
     94         if (byteOffset > buffer->byteLength())
     95             return false;
     96         unsigned remainingElements = (buffer->byteLength() - byteOffset) / sizeof(T);
     97         if (numElements > remainingElements)
     98             return false;
     99         return true;
    100     }
    101 
    102     // Input offset is in number of elements from this array's view;
    103     // output offset is in number of bytes from the underlying buffer's view.
    104     template <typename T>
    105     static void clampOffsetAndNumElements(PassRefPtr<ArrayBuffer> buffer,
    106                                           unsigned arrayByteOffset,
    107                                           unsigned *offset,
    108                                           unsigned *numElements)
    109     {
    110         unsigned maxOffset = (UINT_MAX - arrayByteOffset) / sizeof(T);
    111         if (*offset > maxOffset) {
    112             *offset = buffer->byteLength();
    113             *numElements = 0;
    114             return;
    115         }
    116         *offset = arrayByteOffset + *offset * sizeof(T);
    117         *offset = std::min(buffer->byteLength(), *offset);
    118         unsigned remainingElements = (buffer->byteLength() - *offset) / sizeof(T);
    119         *numElements = std::min(remainingElements, *numElements);
    120     }
    121 
    122     // This is the address of the ArrayBuffer's storage, plus the byte offset.
    123     void* m_baseAddress;
    124 
    125     unsigned m_byteOffset;
    126 
    127   private:
    128     RefPtr<ArrayBuffer> m_buffer;
    129 };
    130 
    131 } // namespace WebCore
    132 
    133 #endif // ArrayBufferView_h
    134