1 s32share.h |
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 "Symbian Foundation License v1.0" to Symbian Foundation members and "Symbian Foundation End User License Agreement v1.0" to non-members |
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5 // which accompanies this distribution, and is available |
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6 // at the URL "http://www.symbianfoundation.org/legal/licencesv10.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 __S32SHARE_H__ |
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17 #define __S32SHARE_H__ |
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18 |
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19 #include <s32buf.h> |
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20 #include <s32strm.h> |
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21 |
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22 class TStreamExchange; |
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23 /** |
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24 * @publishedAll |
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25 * @released |
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26 * Manages the position of a read mark or a write mark within a shared stream. |
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27 |
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28 A shared stream is one that shares its host with other streams. In practice, |
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29 the host is a stream buffer that is, itself, hosted by a file, an RFileBuf |
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30 object. |
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31 |
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32 TStreamMark objects are owned by RShareBuf, one for reading and one for writing. |
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33 They re-direct read/write operations through a TStreamExchange object to the |
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34 RFileBuf object, which handles the actual file read and write operations. |
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35 |
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36 @see RFileBuf |
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37 @see RShareBuf |
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38 @see TStreamExchange |
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39 */ |
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40 class TStreamMark |
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41 { |
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42 public: |
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43 inline TStreamMark(); |
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44 inline TStreamMark(TStreamPos aPos); |
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45 inline TStreamMark& operator=(TStreamPos aPos); |
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46 inline operator TStreamMark*(); |
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47 inline operator const TStreamMark*() const; |
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48 // |
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49 inline TBool operator==(const TStreamMark& aMark) const; |
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50 inline TBool operator==(const TStreamMark* aPtr) const; |
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51 inline TBool operator!=(const TStreamMark& aMark) const; |
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52 inline TBool operator!=(const TStreamMark* aPtr) const; |
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53 // |
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54 inline TBool IsEmpty() const; |
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55 inline void Clear(); |
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56 inline TStreamPos Position() const; |
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57 // |
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58 inline TBool IsWith(TStreamExchange& aHost) const; |
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59 inline TBool RelatesTo(TStreamExchange& aHost) const; |
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60 inline void Withdraw(TStreamExchange& aHost); |
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61 inline void ExtractL(TStreamExchange& aHost); |
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62 // |
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63 inline TInt ReadL(TStreamExchange& aHost,TAny* aPtr,TInt aMaxLength); |
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64 IMPORT_C TInt ReadL(TStreamExchange& aHost,TDes8& aDes,TRequestStatus& aStatus); |
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65 inline TInt ReadL(TStreamExchange& aHost,TDes8& aDes,TInt aMaxLength,TRequestStatus& aStatus); |
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66 inline TStreamTransfer ReadL(TStreamExchange& aHost,MStreamInput& anInput,TStreamTransfer aTransfer); |
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67 inline TInt ReadL(TStreamExchange& aHost,MStreamInput& anInput,TInt aMaxLength); |
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68 inline void ReadL(TStreamExchange& aHost,MStreamInput& anInput); |
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69 // |
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70 inline void WriteL(TStreamExchange& aHost,const TAny* aPtr,TInt aLength); |
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71 IMPORT_C TInt WriteL(TStreamExchange& aHost,const TDesC8& aDes,TRequestStatus& aStatus); |
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72 inline TInt WriteL(TStreamExchange& aHost,const TDesC8& aDes,TInt aMaxLength,TRequestStatus& aStatus); |
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73 inline TStreamTransfer WriteL(TStreamExchange& aHost,MStreamOutput& anOutput,TStreamTransfer aTransfer); |
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74 inline TInt WriteL(TStreamExchange& aHost,MStreamOutput& anOutput,TInt aMaxLength); |
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75 inline void WriteL(TStreamExchange& aHost,MStreamOutput& anOutput); |
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76 // |
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77 inline void SeekL(TStreamExchange& aHost,TStreamPos aPos); |
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78 inline TStreamPos SeekL(TStreamExchange& aHost,TStreamLocation aLocation,TInt anOffset=0); |
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79 inline TStreamPos SeekL(TStreamExchange& aHost,TInt anOffset); |
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80 // |
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81 inline TStreamPos TellL(TStreamExchange& aHost) const; |
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82 private: |
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83 /** Constructs a default shared stream mark object. |
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84 |
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85 The position for the mark is uninitialised. |
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86 |
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87 An uninitialised mark means that a call to IsEmpty() returns true. |
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88 |
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89 @see IsEmpty() */ |
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90 TStreamMark(const TStreamMark&); |
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91 TStreamMark& operator=(const TStreamMark&); |
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92 private: |
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93 TStreamPos iPos; |
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94 private: |
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95 inline TBool IsTracking(TStreamMark*const& aRef) const; |
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96 inline void Track(TStreamMark*const& aRef); |
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97 private: |
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98 friend class TStreamExchange; |
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99 private: |
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100 IMPORT_C static void __DbgChkPos(TStreamPos aPos); |
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101 }; |
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102 |
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103 /** |
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104 * @publishedAll |
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105 * @released |
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106 * Manages access to a shared host buffer for shared stream buffers. |
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107 |
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108 The class maintains independent markers for the shared stream buffer that |
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109 has most recently read or written to the shared host buffer. |
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110 |
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111 This is the way in which multiple requests from the same shared stream buffer |
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112 are handled without the need for repeated seeking. The shared host buffer |
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113 only needs to seek when a new shared buffer needs to use it |
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114 |
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115 @see RShareBuf |
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116 */ |
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117 class TStreamExchange |
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118 { |
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119 public: |
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120 inline TStreamExchange(); |
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121 inline TStreamExchange(MStreamBuf* aHost); |
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122 inline void Share(MStreamBuf* aHost); |
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123 inline TBool IsActive() const; |
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124 IMPORT_C MStreamBuf* Host(); |
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125 IMPORT_C MStreamBuf* HostL(); |
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126 IMPORT_C void Release(); |
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127 // |
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128 IMPORT_C TInt SizeL() const; |
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129 private: |
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130 /** Used to identify the type of mark in a stream. |
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131 |
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132 The type is used by functions of this class and derived classes that perform |
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133 seek operations to marks within a stream. |
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134 |
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135 The type uses the ERead and EWrite enumeration values, as bit flags, to identify |
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136 the read and write marks respectively. |
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137 |
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138 ERead is an MStreamBuf::TRead enumerator. EWrite is an MStreamBuf::EWrite |
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139 enumerator. |
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140 |
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141 @see MStreamBuf::TRead |
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142 @see MStreamBuf::TWrite */ |
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143 typedef MStreamBuf::TMark TMark; |
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144 private: |
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145 /** Constructs an empty object. |
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146 |
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147 Call Share() to prepare for access to a shared stream buffer. */ |
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148 TStreamExchange(const TStreamExchange&); |
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149 TStreamExchange& operator=(const TStreamExchange&); |
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150 // |
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151 IMPORT_C TBool RefersTo(const TStreamMark& aMark); |
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152 IMPORT_C void Drop(const TStreamMark& aMark); |
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153 IMPORT_C void GetL(TStreamMark& aMark); |
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154 IMPORT_C TInt DoReadL(TAny* aPtr,TInt aMaxLength,TStreamMark& aMark); |
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155 IMPORT_C TInt DoReadL(TDes8& aDes,TInt aMaxLength,TRequestStatus& aStatus,TStreamMark& aMark); |
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156 IMPORT_C TStreamTransfer DoReadL(MStreamInput& anInput,TStreamTransfer aTransfer,TStreamMark& aMark); |
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157 IMPORT_C void DoWriteL(const TAny* aPtr,TInt aLength,TStreamMark& aMark); |
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158 IMPORT_C TInt DoWriteL(const TDesC8& aDes,TInt aMaxLength,TRequestStatus& aStatus,TStreamMark& aMark); |
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159 IMPORT_C TStreamTransfer DoWriteL(MStreamOutput& anOutput,TStreamTransfer aTransfer,TStreamMark& aMark); |
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160 IMPORT_C TStreamPos DoSeekL(TStreamMark& aMark,TStreamLocation aLocation,TInt anOffset); |
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161 // |
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162 void PrepareForReadingL(TStreamMark& aMark); |
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163 void PrepareForWritingL(TStreamMark& aMark); |
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164 // |
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165 TInt PrepareAndReadL(TAny* aPtr,TInt aMaxLength,TStreamMark& aMark); |
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166 TInt PrepareAndReadL(TDes8& aDes,TInt aMaxLength,TRequestStatus& aStatus,TStreamMark& aMark); |
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167 TStreamTransfer PrepareAndReadL(MStreamInput& anInput,TStreamTransfer aTransfer,TStreamMark& aMark); |
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168 void PrepareAndWriteL(const TAny* aPtr,TInt aLength,TStreamMark& aMark); |
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169 TInt PrepareAndWriteL(const TDesC8& aDes,TInt aMaxLength,TRequestStatus& aStatus,TStreamMark& aMark); |
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170 TStreamTransfer PrepareAndWriteL(MStreamOutput& anOutput,TStreamTransfer aTransfer,TStreamMark& aMark); |
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171 TStreamPos MarkSeekL(TStreamMark& aMark,TStreamLocation aLocation,TInt anOffset); |
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172 // |
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173 inline MStreamBuf& BufL() const; |
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174 inline MStreamBuf& Buf() const; |
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175 private: |
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176 MStreamBuf* iHost; |
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177 TStreamMark* iRMrk; |
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178 TStreamMark* iWMrk; |
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179 private: |
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180 friend class TStreamMark; |
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181 }; |
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182 |
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183 /** |
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184 * @publishedAll |
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185 * @released |
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186 * A shared stream buffer. |
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187 |
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188 This class is part of the framework used by CFileStore that allows multiple |
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189 stream buffers to concurrently access the single hosting file buffer, an RFileBuf |
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190 object. |
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191 |
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192 Each shared stream buffer maintains its own read and write positions. |
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193 |
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194 Read and write operations to RShareBuf are directed through separate TStreamMark |
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195 objects, one for read and one for write. The TStreamMark objects re-direct |
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196 read/write operations through a TStreamExchange object to the RFileBuf object, |
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197 which handles the actual file read and write operations. |
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198 |
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199 This stream buffer can also be accessed through RShareReadStream and RShareWriteStream |
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200 objects. |
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201 |
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202 @see TStreamMark |
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203 @see TStreamExchange |
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204 @see RFileBuf |
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205 @see RShareReadStream |
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206 @see RShareWriteStream |
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207 */ |
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208 class RShareBuf : public MStreamBuf |
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209 { |
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210 public: |
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211 IMPORT_C RShareBuf(); |
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212 IMPORT_C void Open(TStreamExchange& aHost,TStreamPos aPos,TInt aMode=ERead|EWrite); |
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213 inline void Open(TStreamExchange& aHost,TInt aMode=ERead|EWrite); |
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214 protected: |
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215 IMPORT_C void DoRelease(); |
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216 IMPORT_C TInt DoReadL(TAny* aPtr,TInt aMaxLength); |
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217 IMPORT_C TInt DoReadL(TDes8& aDes,TInt aMaxLength,TRequestStatus& aStatus); |
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218 IMPORT_C TStreamTransfer DoReadL(MStreamInput& anInput,TStreamTransfer aTransfer); |
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219 IMPORT_C void DoWriteL(const TAny* aPtr,TInt aLength); |
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220 IMPORT_C TInt DoWriteL(const TDesC8& aDes,TInt aMaxLength,TRequestStatus& aStatus); |
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221 IMPORT_C TStreamTransfer DoWriteL(MStreamOutput& anOutput,TStreamTransfer aTransfer); |
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222 IMPORT_C TStreamPos DoSeekL(TMark aMark,TStreamLocation aLocation,TInt anOffset); |
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223 private: |
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224 inline TStreamExchange& Host() const; |
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225 private: |
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226 TStreamExchange* iHost; |
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227 TStreamMark iRMark; |
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228 TStreamMark iWMark; |
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229 }; |
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230 |
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231 /** |
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232 * @publishedAll |
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233 * @released |
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234 * Supports the opening, for reading, of a stream which shares its host with other |
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235 streams. |
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236 |
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237 This is also called a shared read stream. |
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238 |
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239 The class uses a RShareBuf stream buffer. |
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240 |
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241 @see RShareBuf |
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242 @see RFileBuf |
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243 */ |
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244 class RShareReadStream : public RReadStream |
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245 { |
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246 public: |
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247 /** Constructs an empty shared read stream object. |
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248 |
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249 Call Open() to prepare the shared stream for reading. |
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250 |
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251 @see RShareReadStream::Open() */ |
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252 RShareReadStream() {} |
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253 IMPORT_C RShareReadStream(TStreamExchange& aHost,TStreamPos aPos=KStreamBeginning); |
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254 IMPORT_C void Open(TStreamExchange& aHost,TStreamPos aPos=KStreamBeginning); |
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255 private: |
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256 RShareBuf iSource; |
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257 }; |
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258 |
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259 /** |
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260 * @publishedAll |
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261 * @released |
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262 * Supports the opening, for writing, of a stream which shares its host with other |
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263 streams. |
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264 |
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265 This is also called a shared write stream. |
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266 |
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267 The class uses a RShareBuf stream buffer. |
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268 |
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269 @see RShareBuf |
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270 @see RFileBuf |
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271 */ |
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272 class RShareWriteStream : public RWriteStream |
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273 { |
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274 public: |
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275 /** Constructs an empty shared write stream object. |
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276 |
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277 Call Open() to prepare the shared stream for writing. |
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278 |
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279 @see RShareWriteStream::Open() */ |
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280 RShareWriteStream() {} |
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281 inline RShareWriteStream(const MExternalizer<TStreamRef>& anExter); |
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282 IMPORT_C RShareWriteStream(TStreamExchange& aHost,TStreamPos aPos=KStreamBeginning); |
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283 IMPORT_C void Open(TStreamExchange& aHost,TStreamPos aPos=KStreamBeginning); |
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284 private: |
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285 RShareBuf iSink; |
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286 }; |
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287 |
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288 #include <s32share.inl> |
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289 #endif |