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1 // Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies). |
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2 // All rights reserved. |
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3 // This component and the accompanying materials are made available |
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4 // under the terms of "Eclipse Public License v1.0" |
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5 // which accompanies this distribution, and is available |
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6 // at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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7 // |
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8 // Initial Contributors: |
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9 // Nokia Corporation - initial contribution. |
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10 // |
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11 // Contributors: |
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12 // |
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13 // Description: |
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14 // |
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15 |
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16 #include "readers.h" |
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17 |
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18 // |
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19 // Creates a new CReader object. |
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20 // |
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21 CReader::CReader(const TDesC8& aBuffer, TReaderType aType) |
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22 : iBuffer(aBuffer), |
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23 iType(aType) |
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24 { |
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25 } |
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26 |
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27 // |
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28 // Returns ETrue is aPattern is in the buffer, EFalse otherwise. |
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29 // |
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30 TBool CReader::Match(const TDesC8& aPattern) |
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31 { |
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32 return (iBuffer.Match(aPattern) != KErrNotFound); |
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33 } |
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34 |
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35 |
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36 // |
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37 // Reads aBuf.Length() bytes into a descriptor. |
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38 // |
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39 void CReader::ReadBytesL(TDes8& aBuf) |
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40 { |
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41 TInt bufLen = aBuf.Length(); |
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42 |
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43 if (!CheckEnoughData(bufLen)) |
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44 { |
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45 User::Leave(KErrEof); |
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46 } |
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47 |
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48 for (TInt i = 0; i < bufLen; i++) |
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49 { |
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50 aBuf[i] = iBuffer[iBufPos++]; |
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51 } |
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52 } |
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53 |
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54 |
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55 // |
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56 // Reads a byte from the buffer. |
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57 // |
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58 void CReader::ReadByteL(TUint8& aData) |
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59 { |
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60 if (!CheckEnoughData(sizeof(TUint8))) |
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61 { |
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62 User::Leave(KErrEof); |
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63 } |
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64 |
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65 aData = iBuffer[iBufPos++]; |
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66 } |
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67 |
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68 // |
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69 // Reads 16 bits of data at the current reader position. |
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70 // Some formats (mainly those developed by Microsoft) still use little-endian |
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71 // encoding of fields. The file format specifications will specify which |
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72 // byte-ordering scheme is used. |
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73 // |
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74 void CReader::Read16L(TUint16& aData, TBool aLittleEndian) |
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75 { |
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76 if (!CheckEnoughData(sizeof(TUint16))) |
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77 { |
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78 User::Leave(KErrEof); |
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79 } |
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80 |
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81 TUint8 a = iBuffer[iBufPos++]; |
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82 TUint8 b = iBuffer[iBufPos++]; |
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83 |
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84 if (aLittleEndian) |
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85 { |
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86 aData = (b << 8) | a; |
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87 } |
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88 else |
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89 { |
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90 aData = (a << 8) | b; |
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91 } |
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92 } |
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93 |
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94 |
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95 // |
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96 // Reads 32 bits of data at the current reader position. |
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97 // Some formats (mainly those developed by Microsoft) still use little-endian |
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98 // encoding of fields. The file format specifications will specify which |
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99 // byte-ordering scheme is used. |
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100 // |
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101 void CReader::Read32L(TUint32& aData, TBool aLittleEndian) |
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102 { |
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103 if (!CheckEnoughData(sizeof(TUint32))) |
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104 { |
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105 User::Leave(KErrEof); |
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106 } |
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107 |
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108 TUint8 a = iBuffer[iBufPos++]; |
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109 TUint8 b = iBuffer[iBufPos++]; |
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110 TUint8 c = iBuffer[iBufPos++]; |
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111 TUint8 d = iBuffer[iBufPos++]; |
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112 |
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113 if (aLittleEndian) |
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114 { |
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115 aData = MAKE_INT32(d, c, b, a); |
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116 } |
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117 else |
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118 { |
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119 aData = MAKE_INT32(a, b, c, d); |
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120 } |
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121 } |
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122 |
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123 |
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124 // |
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125 // Reads 64 bits of data at the current reader position. |
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126 // Some formats (mainly those developed by Microsoft) still use little-endian |
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127 // encoding of fields. The file format specifications will specify which |
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128 // byte-ordering scheme is used. |
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129 // |
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130 void CReader::Read64L(TInt64& aData, TBool aLittleEndian) |
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131 { |
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132 TUint32 high; |
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133 TUint32 low; |
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134 |
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135 Read32L(high, aLittleEndian); |
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136 Read32L(low, aLittleEndian); |
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137 |
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138 if (aLittleEndian) |
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139 { |
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140 aData = MAKE_TINT64(low, high); |
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141 } |
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142 else |
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143 { |
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144 aData = MAKE_TINT64(high, low); |
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145 } |
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146 } |
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147 |
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148 |
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149 // |
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150 // |
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151 // |
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152 TBool CReader::CheckEnoughData(TInt aNeeded) |
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153 { |
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154 return ((iBufPos + aNeeded) <= iBuffer.Length()); |
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155 } |
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156 |
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157 |
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158 // |
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159 // Skips forwards or backwards aOffset number of bytes. |
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160 // |
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161 TInt CReader::Seek(TInt aOffset) |
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162 { |
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163 TInt newBufPos = iBufPos + aOffset; |
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164 |
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165 if ((newBufPos < 0) || (newBufPos >= iBuffer.Length())) |
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166 { |
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167 // Trying to seek past the bounds of the buffer. |
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168 return KErrUnderflow; |
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169 } |
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170 |
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171 iBufPos += aOffset; |
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172 return KErrNone; |
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173 } |
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174 |
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175 |
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176 |
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177 |