1/* 2 * Copyright (C) 2010 Google 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#include "config.h" 27#include "DataView.h" 28 29#include "CheckedInt.h" 30#include "ExceptionCode.h" 31 32namespace { 33 34template<typename T> 35union Value { 36 T data; 37 char bytes[sizeof(T)]; 38}; 39 40} 41 42namespace WebCore { 43 44PassRefPtr<DataView> DataView::create(unsigned length) 45{ 46 RefPtr<ArrayBuffer> buffer = ArrayBuffer::create(length, sizeof(uint8_t)); 47 if (!buffer.get()) 48 return 0; 49 return create(buffer, 0, length); 50} 51 52PassRefPtr<DataView> DataView::create(PassRefPtr<ArrayBuffer> buffer, unsigned byteOffset, unsigned byteLength) 53{ 54 if (byteOffset > buffer->byteLength()) 55 return 0; 56 CheckedInt<uint32_t> checkedOffset(byteOffset); 57 CheckedInt<uint32_t> checkedLength(byteLength); 58 CheckedInt<uint32_t> checkedMax = checkedOffset + checkedLength; 59 if (!checkedMax.isValid() || checkedMax.value() > buffer->byteLength()) 60 return 0; 61 return adoptRef(new DataView(buffer, byteOffset, byteLength)); 62} 63 64DataView::DataView(PassRefPtr<ArrayBuffer> buffer, unsigned byteOffset, unsigned byteLength) 65 : ArrayBufferView(buffer, byteOffset) 66 , m_byteLength(byteLength) 67{ 68} 69 70static bool needToFlipBytes(bool littleEndian) 71{ 72#if CPU(BIG_ENDIAN) 73 return littleEndian; 74#else 75 return !littleEndian; 76#endif 77} 78 79inline void swapBytes(char* p, char* q) 80{ 81 char temp = *p; 82 *p = *q; 83 *q = temp; 84} 85 86static void flipBytesFor16Bits(char* p) 87{ 88 swapBytes(p, p + 1); 89} 90 91static void flipBytesFor32Bits(char* p) 92{ 93 swapBytes(p, p + 3); 94 swapBytes(p + 1, p + 2); 95} 96 97static void flipBytesFor64Bits(char* p) 98{ 99 swapBytes(p, p + 7); 100 swapBytes(p + 1, p + 6); 101 swapBytes(p + 2, p + 5); 102 swapBytes(p + 3, p + 4); 103} 104 105static void flipBytesIfNeeded(char* value, size_t size, bool littleEndian) 106{ 107 if (!needToFlipBytes(littleEndian)) 108 return; 109 110 switch (size) { 111 case 1: 112 // Nothing to do. 113 break; 114 case 2: 115 flipBytesFor16Bits(value); 116 break; 117 case 4: 118 flipBytesFor32Bits(value); 119 break; 120 case 8: 121 flipBytesFor64Bits(value); 122 break; 123 default: 124 ASSERT_NOT_REACHED(); 125 break; 126 } 127} 128 129template<typename T> 130T DataView::getData(unsigned byteOffset, bool littleEndian, ExceptionCode& ec) const 131{ 132 if (beyondRange<T>(byteOffset)) { 133 ec = INDEX_SIZE_ERR; 134 return 0; 135 } 136 137 // We do not want to load the data directly since it would cause a bus error on architectures that don't support unaligned loads. 138 Value<T> value; 139 memcpy(value.bytes, static_cast<const char*>(m_baseAddress) + byteOffset, sizeof(T)); 140 flipBytesIfNeeded(value.bytes, sizeof(T), littleEndian); 141 return value.data; 142} 143 144template<typename T> 145void DataView::setData(unsigned byteOffset, T value, bool littleEndian, ExceptionCode& ec) 146{ 147 if (beyondRange<T>(byteOffset)) { 148 ec = INDEX_SIZE_ERR; 149 return; 150 } 151 152 // We do not want to store the data directly since it would cause a bus error on architectures that don't support unaligned stores. 153 Value<T> tempValue; 154 tempValue.data = value; 155 flipBytesIfNeeded(tempValue.bytes, sizeof(T), littleEndian); 156 memcpy(static_cast<char*>(m_baseAddress) + byteOffset, tempValue.bytes, sizeof(T)); 157} 158 159int8_t DataView::getInt8(unsigned byteOffset, ExceptionCode& ec) 160{ 161 return getData<int8_t>(byteOffset, false, ec); 162} 163 164uint8_t DataView::getUint8(unsigned byteOffset, ExceptionCode& ec) 165{ 166 return getData<uint8_t>(byteOffset, false, ec); 167} 168 169int16_t DataView::getInt16(unsigned byteOffset, bool littleEndian, ExceptionCode& ec) 170{ 171 return getData<int16_t>(byteOffset, littleEndian, ec); 172} 173 174uint16_t DataView::getUint16(unsigned byteOffset, bool littleEndian, ExceptionCode& ec) 175{ 176 return getData<uint16_t>(byteOffset, littleEndian, ec); 177} 178 179int32_t DataView::getInt32(unsigned byteOffset, bool littleEndian, ExceptionCode& ec) 180{ 181 return getData<int32_t>(byteOffset, littleEndian, ec); 182} 183 184uint32_t DataView::getUint32(unsigned byteOffset, bool littleEndian, ExceptionCode& ec) 185{ 186 return getData<uint32_t>(byteOffset, littleEndian, ec); 187} 188 189float DataView::getFloat32(unsigned byteOffset, bool littleEndian, ExceptionCode& ec) 190{ 191 return getData<float>(byteOffset, littleEndian, ec); 192} 193 194double DataView::getFloat64(unsigned byteOffset, bool littleEndian, ExceptionCode& ec) 195{ 196 return getData<double>(byteOffset, littleEndian, ec); 197} 198 199void DataView::setInt8(unsigned byteOffset, int8_t value, ExceptionCode& ec) 200{ 201 setData<int8_t>(byteOffset, value, false, ec); 202} 203 204void DataView::setUint8(unsigned byteOffset, uint8_t value, ExceptionCode& ec) 205{ 206 setData<uint8_t>(byteOffset, value, false, ec); 207} 208 209void DataView::setInt16(unsigned byteOffset, short value, bool littleEndian, ExceptionCode& ec) 210{ 211 setData<int16_t>(byteOffset, value, littleEndian, ec); 212} 213 214void DataView::setUint16(unsigned byteOffset, uint16_t value, bool littleEndian, ExceptionCode& ec) 215{ 216 setData<uint16_t>(byteOffset, value, littleEndian, ec); 217} 218 219void DataView::setInt32(unsigned byteOffset, int32_t value, bool littleEndian, ExceptionCode& ec) 220{ 221 setData<int32_t>(byteOffset, value, littleEndian, ec); 222} 223 224void DataView::setUint32(unsigned byteOffset, uint32_t value, bool littleEndian, ExceptionCode& ec) 225{ 226 setData<uint32_t>(byteOffset, value, littleEndian, ec); 227} 228 229void DataView::setFloat32(unsigned byteOffset, float value, bool littleEndian, ExceptionCode& ec) 230{ 231 setData<float>(byteOffset, value, littleEndian, ec); 232} 233 234void DataView::setFloat64(unsigned byteOffset, double value, bool littleEndian, ExceptionCode& ec) 235{ 236 setData<double>(byteOffset, value, littleEndian, ec); 237} 238 239void DataView::neuter() 240{ 241 ArrayBufferView::neuter(); 242 m_byteLength = 0; 243} 244 245} 246