1/*
2 * Copyright (C) 2009, 2013 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 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 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 "TypedArrayType.h"
31#include <algorithm>
32#include <limits.h>
33#include <wtf/PassRefPtr.h>
34#include <wtf/RefCounted.h>
35#include <wtf/RefPtr.h>
36
37namespace JSC {
38
39class JSArrayBufferView;
40class JSGlobalObject;
41class ExecState;
42
43class ArrayBufferView : public RefCounted<ArrayBufferView> {
44public:
45    virtual TypedArrayType getType() const = 0;
46
47    bool isNeutered() const
48    {
49        return !m_buffer || m_buffer->isNeutered();
50    }
51
52    PassRefPtr<ArrayBuffer> buffer() const
53    {
54        if (isNeutered())
55            return 0;
56        return m_buffer;
57    }
58
59    void* baseAddress() const
60    {
61        if (isNeutered())
62            return 0;
63        return m_baseAddress;
64    }
65
66    unsigned byteOffset() const
67    {
68        if (isNeutered())
69            return 0;
70        return m_byteOffset;
71    }
72
73    virtual unsigned byteLength() const = 0;
74
75    JS_EXPORT_PRIVATE void setNeuterable(bool flag);
76    bool isNeuterable() const { return m_isNeuterable; }
77
78    JS_EXPORT_PRIVATE virtual ~ArrayBufferView();
79
80    // Helper to verify that a given sub-range of an ArrayBuffer is
81    // within range.
82    // FIXME: This should distinguish between alignment errors and bounds errors.
83    // https://bugs.webkit.org/show_bug.cgi?id=125391
84    template <typename T>
85    static bool verifySubRange(
86        PassRefPtr<ArrayBuffer> buffer,
87        unsigned byteOffset,
88        unsigned numElements)
89    {
90        unsigned byteLength = buffer->byteLength();
91        if (sizeof(T) > 1 && byteOffset % sizeof(T))
92            return false;
93        if (byteOffset > byteLength)
94            return false;
95        unsigned remainingElements = (byteLength - byteOffset) / sizeof(T);
96        if (numElements > remainingElements)
97            return false;
98        return true;
99    }
100
101    virtual JSArrayBufferView* wrap(ExecState*, JSGlobalObject*) = 0;
102
103protected:
104    JS_EXPORT_PRIVATE ArrayBufferView(PassRefPtr<ArrayBuffer>, unsigned byteOffset);
105
106    inline bool setImpl(ArrayBufferView*, unsigned byteOffset);
107
108    inline bool setRangeImpl(const char* data, size_t dataByteLength, unsigned byteOffset);
109
110    inline bool zeroRangeImpl(unsigned byteOffset, size_t rangeByteLength);
111
112    static inline void calculateOffsetAndLength(
113        int start, int end, unsigned arraySize,
114        unsigned* offset, unsigned* length);
115
116    // Input offset is in number of elements from this array's view;
117    // output offset is in number of bytes from the underlying buffer's view.
118    template <typename T>
119    static void clampOffsetAndNumElements(
120        PassRefPtr<ArrayBuffer> buffer,
121        unsigned arrayByteOffset,
122        unsigned *offset,
123        unsigned *numElements)
124    {
125        unsigned maxOffset = (UINT_MAX - arrayByteOffset) / sizeof(T);
126        if (*offset > maxOffset) {
127            *offset = buffer->byteLength();
128            *numElements = 0;
129            return;
130        }
131        *offset = arrayByteOffset + *offset * sizeof(T);
132        *offset = std::min(buffer->byteLength(), *offset);
133        unsigned remainingElements = (buffer->byteLength() - *offset) / sizeof(T);
134        *numElements = std::min(remainingElements, *numElements);
135    }
136
137    // This is the address of the ArrayBuffer's storage, plus the byte offset.
138    void* m_baseAddress;
139
140    unsigned m_byteOffset : 31;
141    bool m_isNeuterable : 1;
142
143private:
144    friend class ArrayBuffer;
145    RefPtr<ArrayBuffer> m_buffer;
146};
147
148bool ArrayBufferView::setImpl(ArrayBufferView* array, unsigned byteOffset)
149{
150    if (byteOffset > byteLength()
151        || byteOffset + array->byteLength() > byteLength()
152        || byteOffset + array->byteLength() < byteOffset) {
153        // Out of range offset or overflow
154        return false;
155    }
156
157    char* base = static_cast<char*>(baseAddress());
158    memmove(base + byteOffset, array->baseAddress(), array->byteLength());
159    return true;
160}
161
162bool ArrayBufferView::setRangeImpl(const char* data, size_t dataByteLength, unsigned byteOffset)
163{
164    if (byteOffset > byteLength()
165        || byteOffset + dataByteLength > byteLength()
166        || byteOffset + dataByteLength < byteOffset) {
167        // Out of range offset or overflow
168        return false;
169    }
170
171    char* base = static_cast<char*>(baseAddress());
172    memmove(base + byteOffset, data, dataByteLength);
173    return true;
174}
175
176bool ArrayBufferView::zeroRangeImpl(unsigned byteOffset, size_t rangeByteLength)
177{
178    if (byteOffset > byteLength()
179        || byteOffset + rangeByteLength > byteLength()
180        || byteOffset + rangeByteLength < byteOffset) {
181        // Out of range offset or overflow
182        return false;
183    }
184
185    char* base = static_cast<char*>(baseAddress());
186    memset(base + byteOffset, 0, rangeByteLength);
187    return true;
188}
189
190void ArrayBufferView::calculateOffsetAndLength(
191    int start, int end, unsigned arraySize, unsigned* offset, unsigned* length)
192{
193    if (start < 0)
194        start += arraySize;
195    if (start < 0)
196        start = 0;
197    if (end < 0)
198        end += arraySize;
199    if (end < 0)
200        end = 0;
201    if (static_cast<unsigned>(end) > arraySize)
202        end = arraySize;
203    if (end < start)
204        end = start;
205    *offset = static_cast<unsigned>(start);
206    *length = static_cast<unsigned>(end - start);
207}
208
209} // namespace JSC
210
211using JSC::ArrayBufferView;
212
213#endif // ArrayBufferView_h
214