third_party/WebKit/Source/wtf/ArrayBufferView.h

   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 "wtf/ArrayBuffer.h"
  30
  31 #include "wtf/PassRefPtr.h"
  32 #include "wtf/RefCounted.h"
  33 #include "wtf/RefPtr.h"
  34 #include "wtf/WTFExport.h"
  35 #include <limits.h>
  36
  37 namespace WTF {
  38
  39 class WTF_EXPORT ArrayBufferView : public RefCounted<ArrayBufferView> {
  40   public:
  41     enum ViewType {
  42         TypeInt8,
  43         TypeUint8,
  44         TypeUint8Clamped,
  45         TypeInt16,
  46         TypeUint16,
  47         TypeInt32,
  48         TypeUint32,
  49         TypeFloat32,
  50         TypeFloat64,
  51         TypeDataView
  52     };
  53     virtual ViewType type() const = 0;
  54     const char* typeName();
  55
  56     PassRefPtr<ArrayBuffer> buffer() const
  57     {
  58         return m_buffer;
  59     }
  60
  61     void* baseAddress() const
  62     {
  63         return m_baseAddress;
  64     }
  65
  66     unsigned byteOffset() const
  67     {
  68         return m_byteOffset;
  69     }
  70
  71     virtual unsigned byteLength() const = 0;
  72
  73     void setNeuterable(bool flag) { m_isNeuterable = flag; }
  74     bool isNeuterable() const { return m_isNeuterable; }
  75     bool isShared() const { return m_buffer ? m_buffer->isShared() : false; }
  76
  77     virtual ~ArrayBufferView();
  78
  79   protected:
  80     ArrayBufferView(PassRefPtr<ArrayBuffer>, unsigned byteOffset);
  81
  82     inline bool setImpl(ArrayBufferView*, unsigned byteOffset);
  83
  84     // Helper to verify that a given sub-range of an ArrayBuffer is
  85     // within range.
  86     template <typename T>
  87     static bool verifySubRange(PassRefPtr<ArrayBuffer> buffer,
  88                                unsigned byteOffset,
  89                                unsigned numElements)
  90     {
  91         if (!buffer)
  92             return false;
  93         if (sizeof(T) > 1 && byteOffset % sizeof(T))
  94             return false;
  95         if (byteOffset > buffer->byteLength())
  96             return false;
  97         unsigned remainingElements = (buffer->byteLength() - byteOffset) / sizeof(T);
  98         if (numElements > remainingElements)
  99             return false;
 100         return true;
 101     }
 102
 103     virtual void neuter();
 104
 105     // This is the address of the ArrayBuffer's storage, plus the byte offset.
 106     void* m_baseAddress;
 107
 108     unsigned m_byteOffset : 31;
 109     bool m_isNeuterable : 1;
 110
 111   private:
 112     friend class ArrayBuffer;
 113     RefPtr<ArrayBuffer> m_buffer;
 114     ArrayBufferView* m_prevView;
 115     ArrayBufferView* m_nextView;
 116 };
 117
 118 bool ArrayBufferView::setImpl(ArrayBufferView* array, unsigned byteOffset)
 119 {
 120     if (byteOffset > byteLength()
 121         || byteOffset + array->byteLength() > byteLength()
 122         || byteOffset + array->byteLength() < byteOffset) {
 123         // Out of range offset or overflow
 124         return false;
 125     }
 126
 127     char* base = static_cast<char*>(baseAddress());
 128     memmove(base + byteOffset, array->baseAddress(), array->byteLength());
 129     return true;
 130 }
 131
 132 } // namespace WTF
 133
 134 using WTF::ArrayBufferView;
 135
 136 #endif // ArrayBufferView_h