1 mmfdatabuffer.h |
1 // Copyright (c) 2002-2009 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 // include\mmf\server\mmfdatabuffer.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 #ifndef __MMF_SERVER_DATABUFFER_H__ |
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20 #define __MMF_SERVER_DATABUFFER_H__ |
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21 |
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22 #include <e32base.h> |
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23 |
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24 |
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25 #include <mmf/server/mmfbuffer.h> |
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26 |
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27 /** |
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28 @publishedAll |
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29 @released |
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30 |
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31 Default buffer size if none is specified. |
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32 */ |
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33 static const TInt KMMFDataBufferDefaultBufferSize = 32; |
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34 |
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35 /** |
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36 @publishedAll |
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37 @released |
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38 |
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39 This class is an abstract class for databuffers that can be presented in the form of a descriptor. |
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40 A constructor is provided which instantiates a CMMFDescriptorBuffer buffer by default. |
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41 |
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42 @see CMMFDescriptorBuffer |
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43 */ |
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44 class CMMFDataBuffer : public CMMFBuffer |
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45 { |
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46 public: |
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47 IMPORT_C static CMMFDataBuffer* NewL(); |
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48 IMPORT_C static CMMFDataBuffer* NewL(TInt aMaxBufferSize); |
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49 /** |
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50 Destructor. |
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51 */ |
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52 virtual ~CMMFDataBuffer() {}; |
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53 |
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54 /** |
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55 Returns a reference to the data contained in the buffer (non const version). |
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56 |
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57 This is a virtual function that each derived class must implement. |
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58 |
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59 @return A reference to the buffer. |
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60 */ |
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61 virtual TDes8& Data() = 0; |
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62 |
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63 /** |
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64 Returns a reference to the data contained in the buffer (const version). |
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65 |
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66 This is a virtual function that each derived class must implement. |
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67 |
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68 @return A reference to the buffer. |
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69 */ |
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70 virtual const TDesC8& Data() const = 0; |
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71 |
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72 /** |
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73 Returns the buffer size, in bytes. |
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74 |
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75 This is a virtual function that each derived class must implement. |
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76 |
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77 @return The buffer size in bytes. |
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78 */ |
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79 virtual TUint BufferSize() const = 0; |
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80 |
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81 /** |
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82 Sets the request size. |
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83 |
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84 Used where a component, such as a data source, |
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85 may not be able to write to the entire maximum length of the buffer |
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86 (variable bit rate codecs for example). |
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87 |
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88 This is a virtual function that each derived class must implement. |
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89 |
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90 @param aSize |
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91 The requested size, in bytes. |
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92 */ |
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93 virtual void SetRequestSizeL(TInt aSize) = 0; |
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94 protected: |
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95 /** |
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96 Protected constructor. |
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97 */ |
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98 CMMFDataBuffer(TUid aType): CMMFBuffer(aType) {}; |
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99 }; |
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100 |
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101 |
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102 /** |
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103 @publishedAll |
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104 @released |
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105 |
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106 This class is a wrapper class to give a descriptor the same API as a CMMFDataBuffer. |
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107 |
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108 The purpose of this class is that components such as codecs can use CMMFDataBuffers transparently |
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109 without having to be concerned with whether the buffer is a descriptor buffer |
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110 or a transfer buffer. |
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111 */ |
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112 class CMMFDescriptorBuffer : public CMMFDataBuffer |
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113 { |
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114 public: |
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115 IMPORT_C static CMMFDescriptorBuffer* NewL(); |
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116 IMPORT_C static CMMFDescriptorBuffer* NewL(TInt aMaxBufferSize); |
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117 IMPORT_C ~CMMFDescriptorBuffer(); |
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118 IMPORT_C void ReAllocBufferL(TInt aMaxBufferSize); |
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119 virtual TDes8& Data(); |
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120 virtual const TDesC8& Data() const; |
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121 virtual void SetStatus(TBufferStatus aStatus); |
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122 virtual void SetRequestSizeL(TInt aSize); |
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123 virtual TUint BufferSize() const; |
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124 virtual void SetPosition (TUint aPosition); |
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125 private: |
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126 CMMFDescriptorBuffer() : CMMFDataBuffer(KUidMmfDescriptorBuffer), iPtr(0,0,0) {}; |
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127 void ConstructL(TInt aMaxBufferSize); |
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128 private: |
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129 TUint8* iData; |
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130 TPtr8 iPtr; |
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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 @publishedAll |
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136 @released |
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137 |
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138 This class is a wrapper class to give a transfer buffer/window the same API as a CMMFDataBuffer. |
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139 The purpose of this class is so that components such as codecs can use CMMFDataBuffers transparently |
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140 without having to be concerned with whether the buffer is a descriptor buffer |
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141 or a transfer buffer. |
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142 |
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143 The class assumes that a valid RTransferWindow with a RTransferBuffer mapped in already exists. |
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144 |
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145 Note: |
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146 CMMFTransferBuffers are not supported in EKA2. |
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147 */ |
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148 |
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149 |
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150 class RTransferWindow |
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151 { |
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152 // dummy class |
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153 }; |
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154 |
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155 |
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156 class CMMFTransferBuffer : public CMMFDataBuffer |
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157 { |
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158 public: |
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159 |
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160 IMPORT_C static CMMFTransferBuffer* NewL(RTransferWindow& aTransferWindow, TUint aDataLength = 0); |
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161 IMPORT_C ~CMMFTransferBuffer(); |
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162 virtual TDes8& Data(); |
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163 virtual const TDesC8& Data() const; |
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164 virtual TUint BufferSize() const; |
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165 virtual void SetRequestSizeL(TInt aSize); |
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166 virtual void SetPosition (TUint aPosition); |
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167 IMPORT_C RTransferWindow& TransferWindow(); |
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168 IMPORT_C void MapOutBuffer(); |
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169 IMPORT_C TInt UpdateTransferWindow(RTransferWindow& aTransferWindow, TUint aDataLength = 0); |
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170 |
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171 private: |
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172 /** |
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173 Private constructor. |
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174 */ |
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175 CMMFTransferBuffer() : CMMFDataBuffer(KUidMmfTransferBuffer), iPtr(0,0,0){}; |
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176 void ConstructL(RTransferWindow& aTransferWindow, TUint aDataLength); |
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177 |
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178 private: |
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179 RTransferWindow iTransferWindow; |
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180 TBool iTransferWindowMappedInOK; |
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181 TPtr8 iPtr; |
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182 }; |
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183 |
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184 |
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185 /** |
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186 @publishedAll |
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187 @released |
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188 |
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189 This class is a wrapper class intended to provide support for shared I/O buffers under EKA2 |
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190 This class, unlike other data buffers does not own memory - rather it contains a pointer to already allocated memory |
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191 The purpose of this class is that components such as codecs can use CMMFDataBuffers transparently |
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192 without having to be concerned with whether the buffer is a standard buffer or memory residing in shared I/O |
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193 |
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194 Users of this class need to be very careful when using buffers of this type. |
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195 It cannot be assumed that a buffer of this type can be written/read by any process other than the current one - example - handing CMMFPtrBuffer to the file server may not work since the file server's process may not have access to write data buffer. |
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196 */ |
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197 class CMMFPtrBuffer : public CMMFDataBuffer |
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198 { |
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199 public: |
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200 IMPORT_C static CMMFPtrBuffer* NewL(); //unitialised, pointer will be set via SetPtr |
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201 IMPORT_C static CMMFPtrBuffer* NewL(const TPtr8& aPtr); |
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202 IMPORT_C ~CMMFPtrBuffer(); |
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203 IMPORT_C void SetPtr(const TPtr8& aPtr); |
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204 virtual TDes8& Data(); |
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205 virtual const TDesC8& Data() const; |
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206 virtual void SetStatus(TBufferStatus aStatus); |
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207 virtual void SetRequestSizeL(TInt aSize); |
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208 virtual TUint BufferSize() const; |
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209 virtual void SetPosition (TUint aPosition); |
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210 private: |
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211 CMMFPtrBuffer() : CMMFDataBuffer(KUidMmfPtrBuffer), iPtr(0,0,0) {}; |
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212 void ConstructL(const TPtr8& aPtr); |
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213 private: |
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214 TPtr8 iPtr; |
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215 }; |
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216 |
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217 #endif |