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1 // Copyright (c) 2005-2009 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 // This file contains definitions of string used by |
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15 // XmlEngine's modules. |
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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 /** |
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21 @file |
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22 @publishedPartner |
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23 @released |
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24 */ |
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25 |
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26 #ifndef XESTRINGS_H |
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27 #define XESTRINGS_H |
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28 |
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29 #include <e32base.h> |
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30 |
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31 /** |
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32 Defines a constant string to be used as an argument value for arguments of type |
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33 TDOMString and TDOMStringArg. |
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34 |
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35 No '\0' character can appear in the string. |
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36 |
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37 Usage: |
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38 @code |
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39 _XMLLIT(KLitName, "<some ASCII literal to be used as UTF-8 string>"); |
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40 obj.SomeMethod(KLitName); // argument type is TXmlEngConstString or TDOMStringArg |
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41 @endcode |
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42 */ |
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43 #define _XMLLIT(LitName, utf8String) const TUint8* const LitName = (const TUint8*) utf8String; |
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44 |
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45 /** |
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46 Implements a constant string used within libxml2-based API's. |
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47 |
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48 TXmlEngConstString contains a pointer to a zero-terminated UTF-8 string. The |
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49 contents of the string is not supposed to be changed. From this point of view |
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50 TXmlEngConstString instances are close to the concept of immutable strings. |
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51 |
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52 Ownership of the string is not defined for TXmlEngConstString. Thus, in |
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53 different contexts (APIs), different string-handling policies may be applied. |
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54 For instance, in XML Engine SAX API all reported via callbacks strings of |
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55 TXmlEngConstString type are assumed owned by the parser. |
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56 |
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57 TXmlEngConstString is a base class for other specialized string classes in XML |
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58 Engine APIs. |
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59 */ |
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60 class TXmlEngConstString |
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61 { |
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62 friend class Libxml2_XmlAttributes; |
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63 |
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64 public: |
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65 /** Default constructor */ |
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66 inline TXmlEngConstString(); |
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67 |
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68 /** |
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69 Constructor |
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70 @param aString The string for initialization. Ownership is not transferred |
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71 and the string must stay in scope for the lifetime of this object. |
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72 */ |
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73 inline TXmlEngConstString(const char* aString); |
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74 |
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75 /** |
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76 Check if the string is not NULL |
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77 @return ETrue if the string is not null, EFalse otherwise |
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78 */ |
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79 inline TBool NotNull() const; |
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80 |
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81 /** |
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82 Check if the string is NULL |
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83 @return ETrue if the string is null, EFalse otherwise |
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84 */ |
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85 inline TBool IsNull() const; |
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86 |
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87 /** |
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88 Gets a c string |
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89 @return The string as a C string or NULL if null |
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90 */ |
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91 inline const char* Cstring() const; |
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92 |
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93 /** |
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94 Gets a c string or if NULL, return a default value. |
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95 @param aDefaultValue default value |
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96 @return If not NULL, the c string, otherwise aDefaultValue |
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97 */ |
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98 inline const char* CstringDef(const char* aDefaultValue) const; |
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99 |
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100 /** |
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101 Compares with another string. NULL and "" are considered equal. |
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102 |
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103 @param aString The string to compare |
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104 @return ETrue if equal, EFalse otherwise |
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105 */ |
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106 inline TBool Equals(TXmlEngConstString aString) const; |
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107 |
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108 /** |
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109 Compares with another string. NULL and "" are considered equal. |
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110 |
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111 @param aString The string to compare |
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112 @return 0 if equal, -1 otherwise |
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113 */ |
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114 IMPORT_C TInt Compare(TXmlEngConstString aString) const; |
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115 |
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116 /** |
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117 Allocates a HBufC from the string contents. Ownership is transferred to |
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118 the caller. |
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119 |
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120 Typical use: |
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121 @code |
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122 ... |
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123 HBufC* attrValue = attr.Value().AllocL(); |
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124 ... |
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125 @endcode |
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126 |
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127 @see AllocLC() |
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128 @leave KErrNoMemory Memory allocation failure |
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129 @leave KUriUtilsCannotConvert String cannot be converted |
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130 */ |
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131 IMPORT_C HBufC* AllocL() const; |
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132 |
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133 /** |
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134 Allocates a HBufC from the string contents and pushes the descriptor to |
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135 cleanup stack. Ownership is transferred to the caller. |
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136 |
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137 Typical use: |
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138 @code |
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139 ... |
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140 HBufC* attrValue = attr.Value().AllocLC(); |
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141 ... |
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142 @endcode |
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143 |
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144 @see AllocL() |
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145 @leave KErrNoMemory Memory allocation failure |
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146 @leave KUriUtilsCannotConvert String cannot be converted |
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147 */ |
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148 IMPORT_C HBufC* AllocLC() const; |
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149 |
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150 /** |
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151 Get a TPtrC8 that contains the string |
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152 @return A point descriptor that holds the string |
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153 */ |
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154 inline TPtrC8 PtrC8() const; |
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155 |
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156 /** |
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157 Creates a new copy of the string contents. Ownership for the new string is |
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158 transferred to the caller. |
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159 |
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160 @return A c string copy of the string contents |
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161 @leave KErrNoMemory Memory allocation failure |
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162 */ |
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163 IMPORT_C char* CopyL() const; |
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164 |
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165 /** |
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166 Returns the size of the string in bytes |
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167 @return The size |
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168 */ |
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169 IMPORT_C TUint Size() const; |
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170 |
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171 /** |
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172 Get the length of the string. For non-ASCII strings, Size() != Length() due |
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173 to the UTF-8 encoding used for non-ASCII characters. |
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174 @return The number of characters in the string |
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175 */ |
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176 IMPORT_C TUint Length() const; |
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177 |
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178 protected: |
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179 /** |
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180 Set a new string value. The old string is not freed. Ownership is not |
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181 transferred. |
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182 @param aString The new value |
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183 */ |
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184 inline void Set(char* aString); |
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185 |
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186 protected: |
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187 /** String value */ |
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188 char* iString; |
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189 }; |
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190 |
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191 /** |
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192 General-purpose string used in libxml2-based API's. |
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193 |
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194 This class holds a zero-terminated sequence of bytes (c-style string). It is |
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195 commonly used to represent a sequence of UTF-8 characters. |
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196 |
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197 TXmlEngString objects should be treated as if they were pointers. The |
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198 destructor for TXmlEngString does nothing. This means that the developer needs |
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199 to free the memory allocated by TXmlEngString by calling Free() or Close() |
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200 (Close() is an alias for Free()) and to do so only once. |
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201 |
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202 The reason for this design is that the goal is to have a string class that is |
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203 as small as a one-pointer sized object that is mostly stored on the stack, not |
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204 on the heap (and therefore no additional memory allocation is required). It is |
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205 also as flexible as possible to allow developers to create their own derived |
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206 classes which may provide auto_ptr-like or reference counting solutions. |
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207 |
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208 The contents of this class can be replaced, destroyed, copied and converted to |
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209 c strings and Symbian descriptor types. |
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210 |
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211 The contents of TXmlEngString may also be modified with AppendL(). |
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212 |
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213 When TXmlEngString is the return type in libxml2 based API's, this usually |
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214 indicates that a string has been newly allocated, which should be freed by the |
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215 method caller. |
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216 */ |
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217 class TXmlEngString: public TXmlEngConstString |
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218 { |
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219 public: |
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220 /** Default constructor */ |
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221 inline TXmlEngString(); |
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222 |
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223 /** |
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224 Constructs a new string from a given c string. Ownership is transferred |
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225 and the string must be freed with Free() or Close(). |
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226 |
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227 @param aString A heap-based c string |
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228 */ |
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229 inline TXmlEngString(char* aString); |
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230 |
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231 /** Frees the string */ |
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232 IMPORT_C void Free(); |
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233 |
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234 /** |
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235 Sets a new value. The old string is freed. Ownership is transferred and |
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236 the string must be freed with Free() or Close(). |
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237 |
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238 @param aStr The new string |
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239 */ |
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240 inline void Set(char* aStr); |
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241 |
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242 /** |
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243 Transfers a string and its ownership from another TXmlEngString object. If |
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244 this object currently stores a string it is freed. |
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245 |
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246 @param aSrc The source string |
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247 */ |
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248 IMPORT_C void Set(TXmlEngString& aSrc); |
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249 |
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250 /** Frees the string */ |
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251 inline void Close(); |
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252 |
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253 /** |
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254 Pushes this string to the cleanup stack. This must be matched with a |
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255 corresponding call to CleanupStack::Pop() or CleanupStack::PopAndDestroy(). |
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256 @return This object |
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257 @leave KErrNoMemory Memory allocation failure |
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258 */ |
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259 inline TXmlEngString PushL(); |
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260 |
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261 /** |
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262 Initializes the string, converting from a UTF-16 descriptor to |
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263 a UTF-8 zero-terminated string. |
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264 @param aDes The new value |
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265 @leave - One of the system-wide error codes |
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266 */ |
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267 IMPORT_C void SetL(const TDesC& aDes); |
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268 |
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269 /** |
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270 Initializes the string from a descriptor |
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271 @param aDes The new value |
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272 @leave - One of the system-wide error codes |
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273 */ |
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274 IMPORT_C void SetL(const TDesC8& aDes); |
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275 |
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276 /** |
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277 Creates a new UTF-16 HBufC from the UTF-8 string contents and transfers |
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278 ownership of the string. The string held by this object is freed. |
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279 |
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280 Typical use: |
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281 @code |
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282 ... |
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283 HBufC* attrValue = attr.WholeValueCopyL().AllocAndFreeL(); |
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284 ... |
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285 @endcode |
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286 |
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287 @see AllocAndFreeLC() |
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288 @return The copied string |
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289 @leave KErrNoMemory Memory allocation failure |
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290 @leave KUriUtilsCannotConvert String cannot be converted |
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291 */ |
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292 IMPORT_C HBufC* AllocAndFreeL(); |
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293 |
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294 /** |
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295 Creates a new UTF-16 HBufC from the UTF-8 string contents and transfers |
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296 ownership of the string. The result is placed on the cleanup stack. The |
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297 string held by this object is freed. |
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298 |
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299 Typical use: |
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300 @code |
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301 ... |
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302 HBufC* attrValue = attr.WholeValueCopyL().AllocAndFreeL(); |
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303 ... |
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304 @endcode |
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305 |
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306 @see AllocAndFreeL() |
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307 @return The copied string |
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308 @leave KErrNoMemory Memory allocation failure |
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309 @leave KUriUtilsCannotConvert String cannot be converted |
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310 */ |
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311 IMPORT_C HBufC* AllocAndFreeLC(); |
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312 |
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313 /** |
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314 Appends new text to the string |
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315 @param aStr The string to add |
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316 @leave KErrNoMemory Memory allocation failure |
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317 */ |
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318 IMPORT_C void AppendL(TXmlEngString aStr); |
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319 |
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320 /** |
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321 Appends new text to the string. |
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322 @param aStr1 The first string to append |
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323 @param aStr2 The second string to append |
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324 @leave KErrNoMemory Memory allocation failure |
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325 */ |
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326 IMPORT_C void AppendL(TXmlEngString aStr1, TXmlEngString aStr2); |
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327 |
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328 protected: |
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329 /** |
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330 Constructs the object from a TXmlEngConstString |
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331 @param aStr The string to initialize from |
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332 */ |
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333 inline TXmlEngString(const TXmlEngConstString& aStr): TXmlEngConstString(aStr.Cstring()) {} |
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334 }; |
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335 |
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336 #include <xml/utils/xmlengxestrings.inl> |
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337 |
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338 #endif // XESTRINGS_H |
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339 |