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 "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 // |
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15 |
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16 #ifndef LINEBREAKIMP_H_ |
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17 #define LINEBREAKIMP_H_ |
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18 |
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19 #include <e32def.h> |
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20 |
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21 const TText KZeroWidthSpace = 0x200B; |
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22 const TText KWhiteSpace = 0x0020; |
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23 |
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24 // Forward delcarations. |
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25 GLREF_C void Panic(TInt aError); |
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26 class MLineBreaker; |
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27 |
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28 /** |
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29 Rule for which classes may be broken before. |
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30 @internalComponent |
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31 */ |
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32 struct TLineBreakRule |
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33 { |
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34 /** Classes that breaks are illegal before, even after spaces. */ |
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35 TUint iForbid; |
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36 /** Classes that breaks are legal before, even without spaces. */ |
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37 TUint iAllow; |
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38 }; |
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39 |
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40 /** |
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41 Range of characters which have a particular line breaking class. |
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42 @internalComponent |
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43 */ |
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44 struct TLineBreakRange |
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45 { |
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46 TUint iStart; |
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47 TUint iEnd; |
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48 TUint iClass; |
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49 }; |
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50 |
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51 /** |
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52 Single-entry line break cache. Saves asking the MLineBreaker for the classes |
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53 of multiple characters in the same run. |
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54 @internalComponent |
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55 */ |
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56 class TLineBreakClassCache |
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57 { |
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58 public: |
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59 TLineBreakClassCache(const MLineBreaker& aBreaker): iBreaker(aBreaker), iStart(0), iEnd(0), iClass(0) { } |
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60 TUint LineBreakClass(TUint aChar); |
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61 const MLineBreaker& Breaker() const { return iBreaker; } |
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62 |
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63 private: |
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64 const MLineBreaker& iBreaker; |
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65 TUint iStart; |
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66 TUint iEnd; |
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67 TUint iClass; |
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68 }; |
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69 |
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70 /** |
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71 @internalComponent |
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72 */ |
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73 void TestLineBreakTables(void); |
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74 |
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75 /** |
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76 @internalComponent |
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77 */ |
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78 class TLineBreakClassIterator |
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79 { |
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80 public: |
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81 void Set(const TText* aFirst, const TText* aText, TLineBreakClassCache& aBreaker); |
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82 void SetNull(); |
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83 /** Returns the pointer to the character that has the class returned by |
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84 Class(). */ |
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85 const TText* Ptr() const { return iCurrent; } |
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86 /** Returns the class of the current character. */ |
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87 TInt Class() const { return iClass; } |
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88 // Will not go beyond maximum of aLimit |
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89 // Should not be called with aLimit == Ptr() |
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90 // Will return EFalse if the limit has been exceeded |
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91 // aOffset must be 1 or -1 |
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92 TBool Move(const TText* aLimit, const TText* aLimitAfterSpaces, |
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93 TInt aOffset, TBool& aHasSpaces, TLineBreakClassCache& aBreaker); |
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94 private: |
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95 /** Addres of first character in the string to iterator through */ |
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96 const TText* iFirst; |
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97 /** Current position within the iteration. */ |
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98 const TText* iCurrent; |
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99 /** Class of the character at the currrent position. */ |
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100 TInt iClass; |
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101 }; |
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102 |
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103 |
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104 /** |
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105 @internalComponent |
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106 */ |
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107 TInt MoveTextPtr(const TText*& aPtr, const TText* aLimit, TInt aOffset); |
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108 |
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109 /** |
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110 Class for implementing the Unicode line breaking algorithm |
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111 @internalComponent |
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112 */ |
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113 class TLineBreakIterator |
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114 { |
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115 public: |
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116 TLineBreakIterator(TLineBreakClassCache& aBreaker, |
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117 const TText* aText, TInt aLength, TBool aForwards, |
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118 TInt aMinBreakPos, TInt aMaxBreakPos); |
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119 TBool IsBreak(TBool aForwards); |
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120 // Is one side of the potential line break CB class? |
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121 TBool HasContingentBreak() const; |
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122 // Get class before the break: useful for CB |
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123 TInt PreviousClass() const; |
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124 // Get class after the break: useful for CB |
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125 TInt NextClass() const; |
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126 // Are there spaces between the classes: useful for CB |
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127 TInt HasSpaces() const; |
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128 // go backwards |
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129 TBool Decrement(); |
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130 // go forwards |
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131 TBool Increment(); |
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132 // position of iterator at the break |
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133 TInt BreakPos() const; |
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134 // position of iterator after the break |
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135 TInt AfterBreakPos() const; |
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136 // position of iterator before the break |
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137 TInt BeforeBreakPos() const; |
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138 private: |
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139 TLineBreakClassCache iBreaker; |
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140 const TText* iText; |
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141 TInt iTextLength; |
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142 const TText* iLimit; |
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143 /** The limit that we are allowed to search beyond space characters. For |
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144 forwards this will be up to the end of the text, for backwards we may not |
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145 search beyond the minimum break position because that would mean that the |
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146 break position returned would be below the minimum. */ |
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147 const TText* iLimitAfterSpaces; |
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148 TLineBreakClassIterator iBeforeBreak; |
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149 TLineBreakClassIterator iAfterBreak; |
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150 TBool iHasSpaces; |
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151 /** Holds the address of the lowest point allowed to break at */ |
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152 const TText* iMinBreakPos; |
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153 /** Holds the address of the highest point allowed to break at */ |
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154 const TText* iMaxBreakPos; |
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155 }; |
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156 |
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157 /** |
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158 @internalComponent |
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159 */ |
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160 TBool HasContingentBreak(TLineBreakIterator& aIterator, TBool aForwards, |
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161 MContingentLineBreaker& aCbDelegate); |
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162 |
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163 /** |
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164 @internalComponent |
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165 */ |
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166 TBool HasContingentBreakL(TLineBreakIterator& aIterator, TBool aForwards, |
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167 MContingentLineBreakerL& aCbDelegate); |
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168 |
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169 /** |
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170 @internalComponent |
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171 */ |
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172 TBool FindBreak(TLineBreakIterator& aIterator, TBool aForwards, |
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173 MContingentLineBreaker* aCbDelegate); |
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174 |
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175 /** |
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176 @internalComponent |
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177 */ |
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178 TBool FindBreakL(TLineBreakIterator& aIterator, TBool aForwards, |
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179 MContingentLineBreakerL* aCbDelegate); |
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180 |
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181 #endif |
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