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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 #ifndef READERS_H |
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17 #define READERS_H |
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18 |
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19 #include "constants.h" |
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20 #include "mmruf.h" |
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21 |
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22 |
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23 static const TInt KAACFrameHeaderSize = 7; |
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24 static const TInt KMP3FrameHeaderSize = 4; |
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25 static const TInt KBufSize = 64; |
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26 |
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27 |
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28 // |
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29 // This class provides a level of abstraction that allows |
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30 // for parsing data. It is necessary because AppArc may |
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31 // only provide a buffer that contains a limited snapshot |
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32 // of the beginning of a file, or a file handle that allows |
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33 // the whole file to be parsed. |
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34 // |
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35 class CReader : public CBase |
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36 { |
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37 public: |
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38 |
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39 // |
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40 // Enums used so that CParsers can determine |
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41 // the type of reader they've been given. |
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42 // |
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43 typedef enum |
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44 { |
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45 EUnknown = 0, |
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46 EBuffer = 1, |
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47 EFile = 2 |
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48 } |
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49 TReaderType; |
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50 |
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51 // |
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52 // This function resets the reader such that the next |
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53 // read operation will be performed from the start of |
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54 // the source. |
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55 // For a CFileReader the buffer is filled from the start |
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56 // of the file, for a CBufferReader the position in the |
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57 // buffer is set to zero. |
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58 // |
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59 virtual void Reset() { iBufPos = 0; } |
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60 |
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61 // |
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62 // Seeks within the source. |
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63 // This function tries to support 64-bit compatible file |
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64 // formats as much as possible, but there may be some |
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65 // instances when the operation cannot be performed due to |
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66 // limitations of the file server. |
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67 // |
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68 virtual void SeekL(TInt64 aOffset) = 0; |
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69 |
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70 // |
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71 // Seeks within the source. |
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72 // |
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73 virtual void SeekL(TInt aOffset) = 0; |
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74 |
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75 // |
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76 // Returns the current position in the buffer. |
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77 // |
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78 virtual TInt Position() { return iBufPos; } |
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79 |
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80 // |
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81 // Data reading routines. |
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82 // |
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83 TBool Match(const TDesC8& aPattern); |
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84 void Read64L(TInt64& aData, TBool aLittleEndian = EFalse); |
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85 void Read32L(TUint32& aData, TBool aLittleEndian = EFalse); |
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86 void Read16L(TUint16& aData, TBool aLittleEndian = EFalse); |
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87 void ReadByteL(TUint8& aData); |
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88 void ReadBytesL(TDes8& aData); |
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89 |
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90 // |
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91 // Gets the type of Reader being used. |
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92 // |
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93 inline TReaderType Type() { return iType; } |
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94 |
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95 protected: |
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96 CReader(const TDesC8& aBuffer, CReader::TReaderType aType); |
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97 |
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98 // |
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99 // Returns ETrue if there is aAmount of unread bytes available, |
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100 // EFalse otherwise. |
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101 // |
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102 virtual TBool CheckEnoughData(TInt aAmount); |
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103 |
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104 // |
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105 // Non-leaving Seek |
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106 // |
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107 TInt Seek(TInt aOffset); |
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108 TInt Seek(TInt64 aOffset); |
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109 |
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110 private: |
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111 const TDesC8& iBuffer; // The buffer that contains the source data. |
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112 TInt iBufPos; // The current position in the data source. |
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113 CReader::TReaderType iType; // The type of reader it is. |
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114 }; |
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115 |
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116 |
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117 // |
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118 // This class allows reading and seeking operations to be |
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119 // performed on a data buffer. This is used when no file |
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120 // handle is available to the recogniser. |
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121 // |
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122 class CBufferReader : public CReader |
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123 { |
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124 public: |
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125 static CBufferReader* NewLC(const TDesC8& aBuffer); |
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126 virtual ~CBufferReader(); |
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127 void Reset(); |
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128 void SeekL(TInt aOffset); // CReader |
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129 void SeekL(TInt64 aOffset); // CReader |
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130 |
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131 protected: |
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132 CBufferReader(const TDesC8& aBuffer); |
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133 CBufferReader(const TDesC8& aBuffer, TReaderType aType); |
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134 void ConstructL(); |
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135 }; |
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136 |
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137 |
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138 // |
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139 // This class allows reading and seeking operations to be |
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140 // performed on a file handle. This is used when a file |
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141 // handle is available to the recogniser. |
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142 // |
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143 class CFileReader : public CBufferReader |
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144 { |
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145 public: |
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146 static CFileReader* NewLC(RFile* aFile); |
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147 virtual ~CFileReader(); |
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148 void Reset(); |
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149 |
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150 // |
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151 // CReader::Position() override. |
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152 // |
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153 TInt Position() { return CBufferReader::Position() + iFilePos; } |
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154 |
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155 void SeekL(TInt aOffset); // CReader |
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156 void SeekL(TInt64 aOffset); // CReader |
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157 |
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158 protected: |
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159 CFileReader(RFile* aFile); |
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160 void ConstructL(); |
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161 TBool CheckEnoughData(TInt aAmount); // CReader |
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162 |
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163 // |
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164 // Seeks to a new file location and fills the buffer from there. |
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165 // |
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166 TInt PhysicallySeekAndRead(TInt aAmount); |
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167 TInt PhysicallySeekAndRead(TInt64 aOffset); |
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168 private: |
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169 RFile* iFile; |
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170 TInt64 iFilePos; |
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171 TBuf8<KBufSize> iFileBuffer; |
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172 }; |
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173 |
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174 |
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175 #endif |
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176 |