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 <algorithm>
32#include <limits.h>
33#include "wtf/PassRefPtr.h"
34#include "wtf/RefCounted.h"
35#include "wtf/RefPtr.h"
36#include "wtf/WTFExport.h"
37
38namespace WTF {
39
40class WTF_EXPORT ArrayBufferView : public RefCounted<ArrayBufferView> {
41  public:
42    enum ViewType {
43        TypeInt8,
44        TypeUint8,
45        TypeUint8Clamped,
46        TypeInt16,
47        TypeUint16,
48        TypeInt32,
49        TypeUint32,
50        TypeFloat32,
51        TypeFloat64,
52        TypeDataView
53    };
54    virtual ViewType type() const = 0;
55    const char* typeName();
56
57    PassRefPtr<ArrayBuffer> buffer() const
58    {
59        return m_buffer;
60    }
61
62    void* baseAddress() const
63    {
64        return m_baseAddress;
65    }
66
67    unsigned byteOffset() const
68    {
69        return m_byteOffset;
70    }
71
72    virtual unsigned byteLength() const = 0;
73
74    void setNeuterable(bool flag) { m_isNeuterable = flag; }
75    bool isNeuterable() const { return m_isNeuterable; }
76
77    virtual ~ArrayBufferView();
78
79  protected:
80    ArrayBufferView(PassRefPtr<ArrayBuffer>, unsigned byteOffset);
81
82    inline bool setImpl(ArrayBufferView*, unsigned byteOffset);
83
84    inline bool setRangeImpl(const char* data, size_t dataByteLength, unsigned byteOffset);
85
86    inline bool zeroRangeImpl(unsigned byteOffset, size_t rangeByteLength);
87
88    static inline void calculateOffsetAndLength(int start, int end, unsigned arraySize,
89                                         unsigned* offset, unsigned* length);
90
91    // Helper to verify that a given sub-range of an ArrayBuffer is
92    // within range.
93    template <typename T>
94    static bool verifySubRange(PassRefPtr<ArrayBuffer> buffer,
95                               unsigned byteOffset,
96                               unsigned numElements)
97    {
98        if (!buffer)
99            return false;
100        if (sizeof(T) > 1 && byteOffset % sizeof(T))
101            return false;
102        if (byteOffset > buffer->byteLength())
103            return false;
104        unsigned remainingElements = (buffer->byteLength() - byteOffset) / sizeof(T);
105        if (numElements > remainingElements)
106            return false;
107        return true;
108    }
109
110    // Input offset is in number of elements from this array's view;
111    // output offset is in number of bytes from the underlying buffer's view.
112    template <typename T>
113    static void clampOffsetAndNumElements(PassRefPtr<ArrayBuffer> buffer,
114                                          unsigned arrayByteOffset,
115                                          unsigned *offset,
116                                          unsigned *numElements)
117    {
118        unsigned maxOffset = (UINT_MAX - arrayByteOffset) / sizeof(T);
119        if (*offset > maxOffset) {
120            *offset = buffer->byteLength();
121            *numElements = 0;
122            return;
123        }
124        *offset = arrayByteOffset + *offset * sizeof(T);
125        *offset = std::min(buffer->byteLength(), *offset);
126        unsigned remainingElements = (buffer->byteLength() - *offset) / sizeof(T);
127        *numElements = std::min(remainingElements, *numElements);
128    }
129
130    virtual void neuter();
131
132    // This is the address of the ArrayBuffer's storage, plus the byte offset.
133    void* m_baseAddress;
134
135    unsigned m_byteOffset : 31;
136    bool m_isNeuterable : 1;
137
138  private:
139    friend class ArrayBuffer;
140    RefPtr<ArrayBuffer> m_buffer;
141    ArrayBufferView* m_prevView;
142    ArrayBufferView* m_nextView;
143};
144
145bool ArrayBufferView::setImpl(ArrayBufferView* array, unsigned byteOffset)
146{
147    if (byteOffset > byteLength()
148        || byteOffset + array->byteLength() > byteLength()
149        || byteOffset + array->byteLength() < byteOffset) {
150        // Out of range offset or overflow
151        return false;
152    }
153
154    char* base = static_cast<char*>(baseAddress());
155    memmove(base + byteOffset, array->baseAddress(), array->byteLength());
156    return true;
157}
158
159bool ArrayBufferView::setRangeImpl(const char* data, size_t dataByteLength, unsigned byteOffset)
160{
161    if (byteOffset > byteLength()
162        || byteOffset + dataByteLength > byteLength()
163        || byteOffset + dataByteLength < byteOffset) {
164        // Out of range offset or overflow
165        return false;
166    }
167
168    char* base = static_cast<char*>(baseAddress());
169    memmove(base + byteOffset, data, dataByteLength);
170    return true;
171}
172
173bool ArrayBufferView::zeroRangeImpl(unsigned byteOffset, size_t rangeByteLength)
174{
175    if (byteOffset > byteLength()
176        || byteOffset + rangeByteLength > byteLength()
177        || byteOffset + rangeByteLength < byteOffset) {
178        // Out of range offset or overflow
179        return false;
180    }
181
182    char* base = static_cast<char*>(baseAddress());
183    memset(base + byteOffset, 0, rangeByteLength);
184    return true;
185}
186
187void ArrayBufferView::calculateOffsetAndLength(int start, int end, unsigned arraySize,
188                                               unsigned* offset, unsigned* length)
189{
190    if (start < 0)
191        start += arraySize;
192    if (start < 0)
193        start = 0;
194    if (end < 0)
195        end += arraySize;
196    if (end < 0)
197        end = 0;
198    if (static_cast<unsigned>(end) > arraySize)
199        end = arraySize;
200    if (end < start)
201        end = start;
202    *offset = static_cast<unsigned>(start);
203    *length = static_cast<unsigned>(end - start);
204}
205
206} // namespace WTF
207
208using WTF::ArrayBufferView;
209
210#endif // ArrayBufferView_h
211