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1 // Copyright (c) 1998-2009 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_facache32.h |
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15 // FAT32 various cache classes definition |
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16 // |
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17 // |
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18 |
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19 /** |
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20 @file |
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21 @internalTechnology |
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22 */ |
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23 |
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24 #ifndef SL_FAT_CACHE_32_H |
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25 #define SL_FAT_CACHE_32_H |
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26 |
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27 #include "sl_fatcache.h" |
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28 |
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29 class CFat32LruCachePage; |
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30 |
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31 |
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32 //--------------------------------------------------------------------------------------------------------------------------------- |
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33 |
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34 /** |
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35 FAT32 LRU paged cache. Used for FAT32 only. |
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36 |
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37 Consists of LRU list of cache pages; Each page is logically divided to page sectors. The number of pages depends on the |
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38 maximal amount of memory this cache allowed to use. Usually, whole FAT32 can not be cached fully because of its large size. |
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39 So, this type caches the most receinlly used areas of the FAT32. This is the wriite-back cache. |
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40 |
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41 Read granularity: One page, which size is 2^aRdGranularityLog2 |
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42 Write granularity: cache's page sector; its size is 2^aWrGranularityLog2 |
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43 */ |
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44 class CFat32LruCache : public CFatPagedCacheBase |
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45 { |
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46 public: |
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47 |
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48 static CFat32LruCache* NewL(CFatMountCB* aOwner, TUint32 aMaxMemSize, TUint32 aRdGranularityLog2, TUint32 aWrGranularityLog2); |
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49 |
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50 //-- overrides from base class |
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51 virtual void Close(TBool aDiscardDirtyData); |
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52 virtual void FlushL(); |
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53 |
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54 virtual TUint32 ReadEntryL(TUint32 aIndex); |
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55 virtual void WriteEntryL(TUint32 aIndex, TUint32 aEntry); |
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56 |
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57 virtual TInt Invalidate(); |
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58 virtual TInt InvalidateRegion(TUint32 aStartEntry, TUint32 aNumEntries); |
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59 |
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60 |
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61 virtual CFatBitCache* BitCacheInterface(); |
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62 |
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63 public: |
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64 TBool FindFreeEntryInCacheSectorL(TUint32& aFatEntryIndex); |
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65 |
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66 private: |
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67 |
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68 void InitialiseL(CFatMountCB* aOwner, TUint32 aFatSize, TUint32 aRdGranularityLog2, TUint32 aWrGranularityLog2); |
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69 |
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70 CFat32LruCache(); |
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71 CFat32LruCache(const CFat32LruCache&); |
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72 CFat32LruCache& operator=(const CFat32LruCache&); |
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73 |
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74 TBool ReadCachedEntryL(TUint32 aFatIndex, TFat32Entry& aResult); |
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75 TBool WriteCachedEntryL(TUint32 aFatIndex, TFat32Entry aFatEntry); |
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76 |
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77 CFat32LruCachePage* DoGetSpareCachePageL(); |
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78 |
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79 void AssertCacheReallyClean() ; |
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80 |
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81 private: |
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82 |
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83 typedef TDblQue<CFat32LruCachePage> TPageList; |
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84 typedef TDblQueIter<CFat32LruCachePage> TPageIterator; |
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85 |
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86 TUint32 iMaxFatEntries; ///< maximal number of FAT entries in FAT table |
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87 TUint iNumPagesAllocated; ///< number of pages currently allocated |
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88 TUint iMaxPages; ///< maximal pages allowed to allocate |
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89 TPageList iPageList; ///< LRU list of cache pages. |
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90 |
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91 |
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92 CFatBitCache *iBitCache; ///< pointer to the FAT bit supercache |
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93 |
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94 }; |
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95 |
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96 |
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97 //--------------------------------------------------------------------------------------------------------------------------------- |
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98 |
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99 /** |
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100 FAT32 LRU cache page. Used only by CFat32LruCache. |
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101 */ |
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102 class CFat32LruCachePage : public CFatCachePageBase |
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103 { |
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104 public: |
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105 |
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106 static CFat32LruCachePage* NewL(CFatPagedCacheBase& aCache); |
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107 |
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108 //-- overrides |
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109 virtual TBool ReadCachedEntryL (TUint32 aFatIndex, TUint32& aResult); |
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110 virtual TBool WriteCachedEntryL(TUint32 aFatIndex, TUint32 aFatEntry); |
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111 virtual TUint32 ReadFromMediaL(TUint32 aFatIndex); |
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112 //---- |
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113 |
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114 private: |
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115 CFat32LruCachePage(CFatPagedCacheBase& aCache); |
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116 |
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117 //-- outlaws here |
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118 CFat32LruCachePage(); |
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119 CFat32LruCachePage(const CFat32LruCachePage&); |
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120 CFat32LruCachePage& operator=(const CFat32LruCachePage&); |
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121 |
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122 inline TFat32Entry* GetEntryPtr(TUint32 aFatIndex) const; |
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123 virtual void DoWriteSectorL(TUint32 aSector); |
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124 |
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125 private: |
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126 enum {KFat32EntryMask = 0x0FFFFFFF}; ///< FAT32 entry mask |
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127 |
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128 public: |
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129 TDblQueLink iLink; ///< list link object. See TPageList |
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130 }; |
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131 |
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132 //--------------------------------------------------------------------------------------------------------------------------------- |
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133 |
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134 /** |
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135 FAT32 bit supercache. This is a special cache above the CFat32LruCache. |
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136 Used for quick lookup for the free entries in FAT32 table without accessing media and thrashing FAT32 LRU cache. |
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137 |
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138 Logically consists of a bit vector, where each bit represents one FAT sector (one unit of read granularity within CFat32LruCachePage) |
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139 for the _whole_ FAT table. |
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140 |
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141 If some bit in the vector is set to '1' it means that the corresponding FAT cache sector (not necessarily currently cached) _may_ have |
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142 a at least one free FAT entry. If the bit is '0' it means that there is no free fat entries in this part of the FAT. |
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143 |
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144 The situation when bit set to '1' corresponds to the FAT cache sector without free entries is quite possible, but it is resolved by this cache. |
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145 The situation when '0' bit corresponds to the fat sector that _does_ contain free entries is extremely unlikely and can be |
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146 caused by direct raw writes to the FAT, for example. Nothing terribly wrong with this situation, the search for free entry will fall back |
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147 to the old algorithm CFatTable::FindClosestFreeClusterL() . |
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148 |
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149 The information in this cache is also updated on flushing dirty sectros by CFat32LruCachePage. |
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150 |
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151 |
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152 */ |
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153 class CFatBitCache : public CBase |
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154 { |
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155 public: |
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156 |
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157 ~CFatBitCache(); |
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158 |
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159 static CFatBitCache* New(CFat32LruCache& aOnwerFatCache); |
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160 |
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161 void Close(); |
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162 |
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163 TBool StartPopulating(); |
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164 TBool FinishPopulating(TBool aSuccess); |
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165 |
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166 |
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167 /** possible states of this cache */ |
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168 enum TState |
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169 { |
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170 EInvalid, ///< initial, invalid |
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171 ENotPopulated, ///< initialised, but not populated yet |
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172 EPopulating, ///< in the process of populating |
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173 EPopulated, ///< successfully populated; the only consistent state. |
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174 }; |
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175 |
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176 inline TState State() const; |
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177 inline TBool UsableState() const; |
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178 inline TBool FatSectorHasFreeEntry(TUint32 aFatSectorNum) const; |
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179 inline void SetFreeEntryInFatSector(TUint32 aFatSectorNum, TBool aHasFreeEntry); |
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180 |
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181 TBool SetFreeFatEntry(TUint32 aFatIndex); |
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182 TInt FindClosestFreeFatEntry(TUint32& aFatIndex); |
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183 void MarkFatRange(TUint32 aStartFatIndex, TUint32 aEndFatIndex, TBool aAsFree); |
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184 |
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185 |
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186 void Dump() const; |
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187 |
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188 private: |
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189 |
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190 //-- outlaws |
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191 CFatBitCache(); |
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192 CFatBitCache(const CFatBitCache&); |
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193 CFatBitCache& operator=(const CFatBitCache&); |
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194 |
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195 CFatBitCache(CFat32LruCache& aOnwerFatCache); |
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196 |
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197 TInt Initialise(); |
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198 |
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199 inline void SetState(TState aState); |
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200 inline TUint32 FatIndexToCacheSectorNumber(TUint32 aFatIndex) const; |
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201 inline TUint32 CacheSectorNumberToFatIndex(TUint32 aCacheSecNum) const; |
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202 |
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203 private: |
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204 |
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205 TState iState; ///< internal state of the cache |
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206 RBitVector iBitCache; ///< bit vector itself |
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207 TUint32 iFatIdxToSecCoeff; ///< Log2(FatCacheSectorSize/Sizeof(FAT32 entry)). Used to convert FAT32 index to FAT32 cache sector number and back. |
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208 CFat32LruCache& iOwnerFatCache; ///< reference to the owner FAT32 LRU cache |
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209 |
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210 DBG_STATEMENT(TUint iPopulatingThreadId;) ///< used in debug mode for checking multithreading issues |
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211 }; |
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212 |
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213 //--------------------------------------------------------------------------------------------------------------------------------- |
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214 |
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215 #include "sl_fatcache32.inl" |
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216 |
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217 #endif //SL_FAT_CACHE_32_H |
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