runtime/DataView.h

   1 /*
   2  * Copyright (C) 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  *
   8  * 1.  Redistributions of source code must retain the above copyright
   9  *     notice, this list of conditions and the following disclaimer.
  10  * 2.  Redistributions in binary form must reproduce the above copyright
  11  *     notice, this list of conditions and the following disclaimer in the
  12  *     documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  15  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  16  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  17  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  18  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  19  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  20  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  21  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #ifndef DataView_h
  27 #define DataView_h
  28
  29 #include "ArrayBufferView.h"
  30 #include <wtf/FlipBytes.h>
  31 #include <wtf/PassRefPtr.h>
  32
  33 namespace JSC {
  34
  35 class DataView : public ArrayBufferView {
  36 protected:
  37     DataView(PassRefPtr<ArrayBuffer>, unsigned byteOffset, unsigned byteLength);
  38
  39 public:
  40     JS_EXPORT_PRIVATE static Ref<DataView> create(PassRefPtr<ArrayBuffer>, unsigned byteOffset, unsigned length);
  41     static Ref<DataView> create(PassRefPtr<ArrayBuffer>);
  42
  43     virtual unsigned byteLength() const override
  44     {
  45         return m_byteLength;
  46     }
  47
  48     virtual TypedArrayType getType() const override
  49     {
  50         return TypeDataView;
  51     }
  52
  53     virtual JSArrayBufferView* wrap(ExecState*, JSGlobalObject*) override;
  54
  55     template<typename T>
  56     T get(unsigned offset, bool littleEndian, bool* status = 0)
  57     {
  58         if (status) {
  59             if (offset + sizeof(T) > byteLength()) {
  60                 *status = false;
  61                 return T();
  62             }
  63             *status = true;
  64         } else
  65             ASSERT_WITH_SECURITY_IMPLICATION(offset + sizeof(T) <= byteLength());
  66         return flipBytesIfLittleEndian(
  67             *reinterpret_cast<T*>(static_cast<uint8_t*>(m_baseAddress) + offset),
  68             littleEndian);
  69     }
  70
  71     template<typename T>
  72     T read(unsigned& offset, bool littleEndian, bool* status = 0)
  73     {
  74         T result = this->template get<T>(offset, littleEndian, status);
  75         if (!status || *status)
  76             offset += sizeof(T);
  77         return result;
  78     }
  79
  80     template<typename T>
  81     void set(unsigned offset, T value, bool littleEndian, bool* status = 0)
  82     {
  83         if (status) {
  84             if (offset + sizeof(T) > byteLength()) {
  85                 *status = false;
  86                 return;
  87             }
  88             *status = true;
  89         } else
  90             ASSERT_WITH_SECURITY_IMPLICATION(offset + sizeof(T) <= byteLength());
  91         *reinterpret_cast<T*>(static_cast<uint8_t*>(m_baseAddress) + offset) =
  92             flipBytesIfLittleEndian(value, littleEndian);
  93     }
  94
  95 private:
  96     unsigned m_byteLength;
  97 };
  98
  99 } // namespace JSC
 100
 101 #endif // DataView_h
 102