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1 // Copyright (c) 1996-2009 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 the License "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 // f32\sfat32\inc\sl_cache.h |
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15 // |
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16 // |
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17 |
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18 /** |
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19 @file |
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20 @internalTechnology |
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21 */ |
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22 |
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23 #ifndef SL_CACHE_H |
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24 #define SL_CACHE_H |
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25 |
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26 |
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27 //--------------------------------------------------------------------------------------------------------------------------------- |
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28 //-- dedicated FAT directory cache related stuff |
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29 |
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30 //-- if defined, a dedicated cache will be used for FAT directories |
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31 #define ENABLE_DEDICATED_DIR_CACHE |
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32 |
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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 An abstract interface to the media Write-Through cache |
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38 */ |
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39 class MWTCacheInterface |
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40 { |
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41 public: |
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42 |
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43 /** Enums for control functions. See Control() */ |
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44 enum TControl |
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45 { |
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46 EDisableCache = 0, ///< disable/enable cache, can be used for debug purposes |
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47 EDumpCache = 1, ///< print full cache content, can be used for debug purposes |
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48 ECacheInfo = 2, ///< print cache info, can be used for debug purposes |
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49 }; |
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50 |
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51 virtual ~MWTCacheInterface() {} |
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52 |
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53 /** the same meaning and parameters as in CRawDisk::ReadL */ |
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54 virtual void ReadL(TInt64 aPos, TInt aLength, TDes8& aDes)=0; |
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55 |
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56 /** the same meaning and parameters as in CRawDisk::WriteL */ |
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57 virtual void WriteL(TInt64 aPos,const TDesC8& aDes)=0; |
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58 |
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59 /** Invalidates whole directory cache*/ |
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60 virtual void InvalidateCache(void)=0; |
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61 |
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62 /** invalidate a single cache page if the aPos is cached*/ |
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63 virtual void InvalidateCachePage(TUint64 aPos)=0; |
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64 |
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65 /** |
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66 Finds out if the media position "aPosToSearch" is in the cache and returns cache page information in this case. |
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67 |
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68 @param aPosToSearch linear media position to lookup in the cache |
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69 @param aCachedPosStart if "aPosToSearch" is cached, here will be media position of this page start |
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70 |
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71 @return 0 if aPosToSearch isn't cached, otherwise cache page size in bytes (see also aCachedPosStart). |
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72 */ |
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73 virtual TUint32 PosCached(const TInt64& aPosToSearch, TInt64& aCachedPosStart) = 0; |
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74 |
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75 /** |
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76 @return size of the cache in bytes. Can be 0. |
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77 */ |
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78 virtual TUint32 CacheSizeInBytes() const = 0; |
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79 |
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80 /** |
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81 Make the page indexed by aPos the MRU page in the cache. |
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82 Assumes cache evicts pages according to LRU algorithm. |
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83 */ |
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84 virtual void MakePageMRU(TInt64 aPos) = 0; |
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85 |
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86 /** |
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87 @return log2 number of the size of the cache in bytes. |
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88 */ |
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89 virtual TUint32 PageSizeInBytesLog2() const = 0; |
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90 |
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91 /** |
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92 Control method. |
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93 |
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94 @param aFunction control function |
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95 @param aParam1 just arbitrary parameter |
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96 @param aParam2 just arbitrary parameter |
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97 @return Standard error code. |
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98 */ |
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99 virtual TInt Control(TUint32 aFunction, TUint32 aParam1, TAny* aParam2)=0; |
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100 |
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101 /** |
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102 Set cache base position at aBasePos |
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103 @param aBasePos base position of the cache pages. Affects pages alignment. |
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104 */ |
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105 virtual void SetCacheBasePos(TInt64 aBasePos)=0; |
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106 |
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107 }; |
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108 |
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109 //--------------------------------------------------------------------------------------------------------------------------------- |
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110 |
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111 /** |
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112 This class represents the media Write-Through cache page |
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113 */ |
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114 class CWTCachePage |
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115 { |
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116 public: |
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117 |
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118 static CWTCachePage* NewL(TUint32 aPageSizeLog2); |
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119 void ConstructL(TUint32 aPageSizeLog2); |
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120 |
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121 ~CWTCachePage(); |
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122 |
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123 inline TBool PosCached(TInt64 aPos) const; |
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124 inline TUint32 PosInCachePage(TInt64 aPos) const; |
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125 inline TUint8* PtrInCachePage(TInt64 aPos) const; |
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126 inline TUint32 PageSize() const; |
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127 |
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128 protected: |
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129 |
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130 CWTCachePage(); |
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131 CWTCachePage(const CWTCachePage&); |
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132 CWTCachePage& operator=(const CWTCachePage&); |
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133 |
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134 public: |
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135 |
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136 TInt32 iValid; ///< 0 if the page doesn't contain valid data |
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137 TInt64 iStartPos; ///< cache page base media position |
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138 RBuf8 iData; ///< page Data |
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139 }; |
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140 |
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141 //--------------------------------------------------------------------------------------------------------------------------------- |
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142 |
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143 /** |
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144 Media Write-through cache. |
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145 */ |
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146 class CMediaWTCache : public CBase, public MWTCacheInterface |
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147 { |
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148 public: |
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149 ~CMediaWTCache(); |
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150 |
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151 static CMediaWTCache* NewL(TFatDriveInterface& aDrive, TUint32 aNumPages, TUint32 aPageSizeLog2); |
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152 |
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153 void ConstructL(TUint32 aNumPages, TUint32 aPageSizeLog2); |
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154 |
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155 //-- overloads from the base class |
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156 void ReadL (TInt64 aPos,TInt aLength,TDes8& aDes); |
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157 void WriteL(TInt64 aPos,const TDesC8& aDes); |
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158 void InvalidateCache(void); |
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159 void InvalidateCachePage(TUint64 aPos); |
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160 |
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161 |
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162 TUint32 PosCached(const TInt64& aPosToSearch, TInt64& aCachedPosStart); |
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163 TUint32 CacheSizeInBytes() const; |
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164 void MakePageMRU(TInt64 aPos); |
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165 TUint32 PageSizeInBytesLog2() const; |
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166 TInt Control(TUint32 aFunction, TUint32 aParam1, TAny* aParam2); |
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167 inline void SetCacheBasePos(TInt64 aBasePos); |
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168 //-- |
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169 |
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170 protected: |
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171 CMediaWTCache(); |
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172 CMediaWTCache(TFatDriveInterface& aDrive); |
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173 |
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174 inline TInt64 CalcPageStartPos(TInt64 aPos) const; |
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175 inline TUint32 PageSize() const; |
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176 |
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177 void MakePageLRU(TInt aPageNo); |
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178 |
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179 TInt FindPageByPos(TInt64 aPos) const; |
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180 TUint32 GrabPage() const; |
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181 TUint32 GrabReadPageL(TInt64 aPos); |
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182 TUint32 FindOrGrabReadPageL(TInt64 aPos); |
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183 |
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184 protected: |
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185 TFatDriveInterface& iDrive; ///< reference to the driver for media access |
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186 TUint32 iPageSizeLog2; ///< Log2 (cache page size) |
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187 mutable TBool iAllPagesValid;///< ETrue if all cache pages have valid data |
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188 TInt64 iCacheBasePos; ///< Cache pages base position, used to align them at cluster size |
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189 RPointerArray<CWTCachePage> iPages; ///< array of pointers to the cache pages. Used for organising LRU list |
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190 TUint32 iCacheDisabled :1; ///< if not 0 the cache is disabled totally and all reads and writes go via TFatDriveInterface directly |
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191 }; |
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192 |
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193 |
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194 |
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195 |
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196 #include"sl_cache.inl" |
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197 |
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198 #endif //SL_CACHE_H |
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199 |
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200 |
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201 |
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202 |