1 /***************************************************************************/ |
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2 /* */ |
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3 /* otvgsub.c */ |
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4 /* */ |
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5 /* OpenType GSUB table validation (body). */ |
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6 /* */ |
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7 /* Copyright 2004, 2005, 2007 by */ |
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8 /* David Turner, Robert Wilhelm, and Werner Lemberg. */ |
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9 /* */ |
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10 /* This file is part of the FreeType project, and may only be used, */ |
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11 /* modified, and distributed under the terms of the FreeType project */ |
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12 /* license, LICENSE.TXT. By continuing to use, modify, or distribute */ |
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13 /* this file you indicate that you have read the license and */ |
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14 /* understand and accept it fully. */ |
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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 #include "otvalid.h" |
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20 #include "otvcommn.h" |
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21 |
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22 |
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23 /*************************************************************************/ |
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24 /* */ |
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25 /* The macro FT_COMPONENT is used in trace mode. It is an implicit */ |
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26 /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */ |
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27 /* messages during execution. */ |
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28 /* */ |
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29 #undef FT_COMPONENT |
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30 #define FT_COMPONENT trace_otvgsub |
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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 /***** *****/ |
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36 /***** GSUB LOOKUP TYPE 1 *****/ |
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37 /***** *****/ |
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38 /*************************************************************************/ |
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39 /*************************************************************************/ |
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40 |
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41 /* uses valid->glyph_count */ |
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42 |
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43 static void |
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44 otv_SingleSubst_validate( FT_Bytes table, |
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45 OTV_Validator valid ) |
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46 { |
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47 FT_Bytes p = table; |
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48 FT_UInt SubstFormat; |
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49 |
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50 |
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51 OTV_NAME_ENTER( "SingleSubst" ); |
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52 |
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53 OTV_LIMIT_CHECK( 2 ); |
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54 SubstFormat = FT_NEXT_USHORT( p ); |
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55 |
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56 OTV_TRACE(( " (format %d)\n", SubstFormat )); |
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57 |
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58 switch ( SubstFormat ) |
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59 { |
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60 case 1: /* SingleSubstFormat1 */ |
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61 { |
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62 FT_Bytes Coverage; |
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63 FT_Int DeltaGlyphID; |
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64 FT_Long idx; |
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65 |
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66 |
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67 OTV_LIMIT_CHECK( 4 ); |
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68 Coverage = table + FT_NEXT_USHORT( p ); |
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69 DeltaGlyphID = FT_NEXT_SHORT( p ); |
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70 |
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71 otv_Coverage_validate( Coverage, valid, -1 ); |
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72 |
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73 idx = otv_Coverage_get_first( Coverage ) + DeltaGlyphID; |
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74 if ( idx < 0 ) |
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75 FT_INVALID_DATA; |
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76 |
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77 idx = otv_Coverage_get_last( Coverage ) + DeltaGlyphID; |
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78 if ( (FT_UInt)idx >= valid->glyph_count ) |
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79 FT_INVALID_DATA; |
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80 } |
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81 break; |
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82 |
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83 case 2: /* SingleSubstFormat2 */ |
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84 { |
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85 FT_UInt Coverage, GlyphCount; |
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86 |
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87 |
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88 OTV_LIMIT_CHECK( 4 ); |
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89 Coverage = FT_NEXT_USHORT( p ); |
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90 GlyphCount = FT_NEXT_USHORT( p ); |
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91 |
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92 OTV_TRACE(( " (GlyphCount = %d)\n", GlyphCount )); |
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93 |
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94 otv_Coverage_validate( table + Coverage, valid, GlyphCount ); |
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95 |
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96 OTV_LIMIT_CHECK( GlyphCount * 2 ); |
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97 |
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98 /* Substitute */ |
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99 for ( ; GlyphCount > 0; GlyphCount-- ) |
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100 if ( FT_NEXT_USHORT( p ) >= valid->glyph_count ) |
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101 FT_INVALID_GLYPH_ID; |
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102 } |
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103 break; |
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104 |
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105 default: |
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106 FT_INVALID_FORMAT; |
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107 } |
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108 |
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109 OTV_EXIT; |
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110 } |
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111 |
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112 |
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113 /*************************************************************************/ |
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114 /*************************************************************************/ |
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115 /***** *****/ |
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116 /***** GSUB LOOKUP TYPE 2 *****/ |
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117 /***** *****/ |
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118 /*************************************************************************/ |
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119 /*************************************************************************/ |
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120 |
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121 /* sets valid->extra1 (glyph count) */ |
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122 |
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123 static void |
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124 otv_MultipleSubst_validate( FT_Bytes table, |
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125 OTV_Validator valid ) |
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126 { |
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127 FT_Bytes p = table; |
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128 FT_UInt SubstFormat; |
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129 |
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130 |
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131 OTV_NAME_ENTER( "MultipleSubst" ); |
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132 |
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133 OTV_LIMIT_CHECK( 2 ); |
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134 SubstFormat = FT_NEXT_USHORT( p ); |
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135 |
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136 OTV_TRACE(( " (format %d)\n", SubstFormat )); |
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137 |
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138 switch ( SubstFormat ) |
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139 { |
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140 case 1: |
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141 valid->extra1 = valid->glyph_count; |
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142 OTV_NEST2( MultipleSubstFormat1, Sequence ); |
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143 OTV_RUN( table, valid ); |
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144 break; |
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145 |
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146 default: |
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147 FT_INVALID_FORMAT; |
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148 } |
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149 |
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150 OTV_EXIT; |
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151 } |
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152 |
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153 |
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154 /*************************************************************************/ |
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155 /*************************************************************************/ |
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156 /***** *****/ |
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157 /***** GSUB LOOKUP TYPE 3 *****/ |
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158 /***** *****/ |
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159 /*************************************************************************/ |
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160 /*************************************************************************/ |
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161 |
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162 /* sets valid->extra1 (glyph count) */ |
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163 |
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164 static void |
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165 otv_AlternateSubst_validate( FT_Bytes table, |
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166 OTV_Validator valid ) |
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167 { |
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168 FT_Bytes p = table; |
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169 FT_UInt SubstFormat; |
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170 |
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171 |
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172 OTV_NAME_ENTER( "AlternateSubst" ); |
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173 |
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174 OTV_LIMIT_CHECK( 2 ); |
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175 SubstFormat = FT_NEXT_USHORT( p ); |
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176 |
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177 OTV_TRACE(( " (format %d)\n", SubstFormat )); |
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178 |
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179 switch ( SubstFormat ) |
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180 { |
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181 case 1: |
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182 valid->extra1 = valid->glyph_count; |
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183 OTV_NEST2( AlternateSubstFormat1, AlternateSet ); |
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184 OTV_RUN( table, valid ); |
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185 break; |
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186 |
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187 default: |
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188 FT_INVALID_FORMAT; |
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189 } |
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190 |
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191 OTV_EXIT; |
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192 } |
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193 |
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194 |
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195 /*************************************************************************/ |
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196 /*************************************************************************/ |
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197 /***** *****/ |
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198 /***** GSUB LOOKUP TYPE 4 *****/ |
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199 /***** *****/ |
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200 /*************************************************************************/ |
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201 /*************************************************************************/ |
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202 |
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203 #define LigatureFunc otv_Ligature_validate |
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204 |
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205 /* uses valid->glyph_count */ |
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206 |
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207 static void |
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208 otv_Ligature_validate( FT_Bytes table, |
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209 OTV_Validator valid ) |
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210 { |
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211 FT_Bytes p = table; |
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212 FT_UInt LigatureGlyph, CompCount; |
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213 |
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214 |
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215 OTV_ENTER; |
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216 |
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217 OTV_LIMIT_CHECK( 4 ); |
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218 LigatureGlyph = FT_NEXT_USHORT( p ); |
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219 if ( LigatureGlyph >= valid->glyph_count ) |
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220 FT_INVALID_DATA; |
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221 |
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222 CompCount = FT_NEXT_USHORT( p ); |
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223 |
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224 OTV_TRACE(( " (CompCount = %d)\n", CompCount )); |
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225 |
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226 if ( CompCount == 0 ) |
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227 FT_INVALID_DATA; |
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228 |
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229 CompCount--; |
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230 |
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231 OTV_LIMIT_CHECK( CompCount * 2 ); /* Component */ |
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232 |
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233 /* no need to check the Component glyph indices */ |
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234 |
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235 OTV_EXIT; |
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236 } |
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237 |
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238 |
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239 static void |
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240 otv_LigatureSubst_validate( FT_Bytes table, |
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241 OTV_Validator valid ) |
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242 { |
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243 FT_Bytes p = table; |
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244 FT_UInt SubstFormat; |
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245 |
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246 |
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247 OTV_NAME_ENTER( "LigatureSubst" ); |
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248 |
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249 OTV_LIMIT_CHECK( 2 ); |
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250 SubstFormat = FT_NEXT_USHORT( p ); |
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251 |
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252 OTV_TRACE(( " (format %d)\n", SubstFormat )); |
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253 |
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254 switch ( SubstFormat ) |
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255 { |
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256 case 1: |
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257 OTV_NEST3( LigatureSubstFormat1, LigatureSet, Ligature ); |
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258 OTV_RUN( table, valid ); |
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259 break; |
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260 |
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261 default: |
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262 FT_INVALID_FORMAT; |
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263 } |
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264 |
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265 OTV_EXIT; |
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266 } |
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267 |
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268 |
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269 /*************************************************************************/ |
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270 /*************************************************************************/ |
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271 /***** *****/ |
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272 /***** GSUB LOOKUP TYPE 5 *****/ |
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273 /***** *****/ |
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274 /*************************************************************************/ |
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275 /*************************************************************************/ |
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276 |
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277 /* sets valid->extra1 (lookup count) */ |
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278 |
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279 static void |
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280 otv_ContextSubst_validate( FT_Bytes table, |
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281 OTV_Validator valid ) |
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282 { |
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283 FT_Bytes p = table; |
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284 FT_UInt SubstFormat; |
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285 |
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286 |
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287 OTV_NAME_ENTER( "ContextSubst" ); |
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288 |
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289 OTV_LIMIT_CHECK( 2 ); |
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290 SubstFormat = FT_NEXT_USHORT( p ); |
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291 |
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292 OTV_TRACE(( " (format %d)\n", SubstFormat )); |
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293 |
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294 switch ( SubstFormat ) |
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295 { |
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296 case 1: |
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297 /* no need to check glyph indices/classes used as input for these */ |
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298 /* context rules since even invalid glyph indices/classes return */ |
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299 /* meaningful results */ |
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300 |
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301 valid->extra1 = valid->lookup_count; |
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302 OTV_NEST3( ContextSubstFormat1, SubRuleSet, SubRule ); |
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303 OTV_RUN( table, valid ); |
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304 break; |
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305 |
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306 case 2: |
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307 /* no need to check glyph indices/classes used as input for these */ |
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308 /* context rules since even invalid glyph indices/classes return */ |
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309 /* meaningful results */ |
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310 |
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311 OTV_NEST3( ContextSubstFormat2, SubClassSet, SubClassRule ); |
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312 OTV_RUN( table, valid ); |
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313 break; |
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314 |
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315 case 3: |
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316 OTV_NEST1( ContextSubstFormat3 ); |
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317 OTV_RUN( table, valid ); |
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318 break; |
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319 |
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320 default: |
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321 FT_INVALID_FORMAT; |
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322 } |
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323 |
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324 OTV_EXIT; |
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325 } |
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326 |
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327 |
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328 /*************************************************************************/ |
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329 /*************************************************************************/ |
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330 /***** *****/ |
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331 /***** GSUB LOOKUP TYPE 6 *****/ |
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332 /***** *****/ |
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333 /*************************************************************************/ |
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334 /*************************************************************************/ |
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335 |
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336 /* sets valid->extra1 (lookup count) */ |
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337 |
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338 static void |
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339 otv_ChainContextSubst_validate( FT_Bytes table, |
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340 OTV_Validator valid ) |
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341 { |
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342 FT_Bytes p = table; |
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343 FT_UInt SubstFormat; |
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344 |
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345 |
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346 OTV_NAME_ENTER( "ChainContextSubst" ); |
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347 |
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348 OTV_LIMIT_CHECK( 2 ); |
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349 SubstFormat = FT_NEXT_USHORT( p ); |
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350 |
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351 OTV_TRACE(( " (format %d)\n", SubstFormat )); |
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352 |
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353 switch ( SubstFormat ) |
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354 { |
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355 case 1: |
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356 /* no need to check glyph indices/classes used as input for these */ |
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357 /* context rules since even invalid glyph indices/classes return */ |
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358 /* meaningful results */ |
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359 |
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360 valid->extra1 = valid->lookup_count; |
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361 OTV_NEST3( ChainContextSubstFormat1, |
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362 ChainSubRuleSet, ChainSubRule ); |
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363 OTV_RUN( table, valid ); |
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364 break; |
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365 |
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366 case 2: |
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367 /* no need to check glyph indices/classes used as input for these */ |
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368 /* context rules since even invalid glyph indices/classes return */ |
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369 /* meaningful results */ |
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370 |
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371 OTV_NEST3( ChainContextSubstFormat2, |
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372 ChainSubClassSet, ChainSubClassRule ); |
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373 OTV_RUN( table, valid ); |
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374 break; |
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375 |
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376 case 3: |
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377 OTV_NEST1( ChainContextSubstFormat3 ); |
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378 OTV_RUN( table, valid ); |
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379 break; |
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380 |
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381 default: |
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382 FT_INVALID_FORMAT; |
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383 } |
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384 |
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385 OTV_EXIT; |
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386 } |
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387 |
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388 |
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389 /*************************************************************************/ |
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390 /*************************************************************************/ |
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391 /***** *****/ |
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392 /***** GSUB LOOKUP TYPE 7 *****/ |
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393 /***** *****/ |
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394 /*************************************************************************/ |
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395 /*************************************************************************/ |
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396 |
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397 /* uses valid->type_funcs */ |
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398 |
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399 static void |
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400 otv_ExtensionSubst_validate( FT_Bytes table, |
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401 OTV_Validator valid ) |
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402 { |
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403 FT_Bytes p = table; |
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404 FT_UInt SubstFormat; |
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405 |
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406 |
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407 OTV_NAME_ENTER( "ExtensionSubst" ); |
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408 |
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409 OTV_LIMIT_CHECK( 2 ); |
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410 SubstFormat = FT_NEXT_USHORT( p ); |
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411 |
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412 OTV_TRACE(( " (format %d)\n", SubstFormat )); |
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413 |
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414 switch ( SubstFormat ) |
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415 { |
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416 case 1: /* ExtensionSubstFormat1 */ |
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417 { |
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418 FT_UInt ExtensionLookupType; |
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419 FT_ULong ExtensionOffset; |
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420 OTV_Validate_Func validate; |
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421 |
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422 |
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423 OTV_LIMIT_CHECK( 6 ); |
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424 ExtensionLookupType = FT_NEXT_USHORT( p ); |
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425 ExtensionOffset = FT_NEXT_ULONG( p ); |
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426 |
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427 if ( ExtensionLookupType == 0 || |
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428 ExtensionLookupType == 7 || |
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429 ExtensionLookupType > 8 ) |
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430 FT_INVALID_DATA; |
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431 |
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432 validate = valid->type_funcs[ExtensionLookupType - 1]; |
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433 validate( table + ExtensionOffset, valid ); |
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434 } |
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435 break; |
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436 |
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437 default: |
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438 FT_INVALID_FORMAT; |
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439 } |
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440 |
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441 OTV_EXIT; |
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442 } |
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443 |
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444 |
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445 /*************************************************************************/ |
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446 /*************************************************************************/ |
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447 /***** *****/ |
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448 /***** GSUB LOOKUP TYPE 8 *****/ |
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449 /***** *****/ |
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450 /*************************************************************************/ |
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451 /*************************************************************************/ |
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452 |
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453 /* uses valid->glyph_count */ |
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454 |
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455 static void |
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456 otv_ReverseChainSingleSubst_validate( FT_Bytes table, |
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457 OTV_Validator valid ) |
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458 { |
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459 FT_Bytes p = table, Coverage; |
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460 FT_UInt SubstFormat; |
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461 FT_UInt BacktrackGlyphCount, LookaheadGlyphCount, GlyphCount; |
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462 |
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463 |
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464 OTV_NAME_ENTER( "ReverseChainSingleSubst" ); |
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465 |
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466 OTV_LIMIT_CHECK( 2 ); |
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467 SubstFormat = FT_NEXT_USHORT( p ); |
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468 |
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469 OTV_TRACE(( " (format %d)\n", SubstFormat )); |
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470 |
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471 switch ( SubstFormat ) |
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472 { |
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473 case 1: /* ReverseChainSingleSubstFormat1 */ |
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474 OTV_LIMIT_CHECK( 4 ); |
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475 Coverage = table + FT_NEXT_USHORT( p ); |
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476 BacktrackGlyphCount = FT_NEXT_USHORT( p ); |
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477 |
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478 OTV_TRACE(( " (BacktrackGlyphCount = %d)\n", BacktrackGlyphCount )); |
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479 |
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480 otv_Coverage_validate( Coverage, valid, -1 ); |
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481 |
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482 OTV_LIMIT_CHECK( BacktrackGlyphCount * 2 + 2 ); |
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483 |
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484 for ( ; BacktrackGlyphCount > 0; BacktrackGlyphCount-- ) |
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485 otv_Coverage_validate( table + FT_NEXT_USHORT( p ), valid, -1 ); |
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486 |
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487 LookaheadGlyphCount = FT_NEXT_USHORT( p ); |
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488 |
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489 OTV_TRACE(( " (LookaheadGlyphCount = %d)\n", LookaheadGlyphCount )); |
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490 |
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491 OTV_LIMIT_CHECK( LookaheadGlyphCount * 2 + 2 ); |
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492 |
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493 for ( ; LookaheadGlyphCount > 0; LookaheadGlyphCount-- ) |
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494 otv_Coverage_validate( table + FT_NEXT_USHORT( p ), valid, -1 ); |
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495 |
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496 GlyphCount = FT_NEXT_USHORT( p ); |
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497 |
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498 OTV_TRACE(( " (GlyphCount = %d)\n", GlyphCount )); |
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499 |
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500 if ( GlyphCount != otv_Coverage_get_count( Coverage ) ) |
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501 FT_INVALID_DATA; |
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502 |
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503 OTV_LIMIT_CHECK( GlyphCount * 2 ); |
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504 |
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505 /* Substitute */ |
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506 for ( ; GlyphCount > 0; GlyphCount-- ) |
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507 if ( FT_NEXT_USHORT( p ) >= valid->glyph_count ) |
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508 FT_INVALID_DATA; |
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509 |
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510 break; |
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511 |
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512 default: |
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513 FT_INVALID_FORMAT; |
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514 } |
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515 |
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516 OTV_EXIT; |
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517 } |
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518 |
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519 |
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520 static const OTV_Validate_Func otv_gsub_validate_funcs[8] = |
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521 { |
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522 otv_SingleSubst_validate, |
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523 otv_MultipleSubst_validate, |
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524 otv_AlternateSubst_validate, |
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525 otv_LigatureSubst_validate, |
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526 otv_ContextSubst_validate, |
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527 otv_ChainContextSubst_validate, |
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528 otv_ExtensionSubst_validate, |
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529 otv_ReverseChainSingleSubst_validate |
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530 }; |
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531 |
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532 |
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533 /*************************************************************************/ |
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534 /*************************************************************************/ |
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535 /***** *****/ |
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536 /***** GSUB TABLE *****/ |
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537 /***** *****/ |
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538 /*************************************************************************/ |
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539 /*************************************************************************/ |
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540 |
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541 /* sets valid->type_count */ |
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542 /* sets valid->type_funcs */ |
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543 /* sets valid->glyph_count */ |
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544 |
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545 FT_LOCAL_DEF( void ) |
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546 otv_GSUB_validate( FT_Bytes table, |
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547 FT_UInt glyph_count, |
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548 FT_Validator ftvalid ) |
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549 { |
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550 OTV_ValidatorRec validrec; |
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551 OTV_Validator valid = &validrec; |
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552 FT_Bytes p = table; |
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553 FT_UInt ScriptList, FeatureList, LookupList; |
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554 |
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555 |
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556 valid->root = ftvalid; |
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557 |
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558 FT_TRACE3(( "validating GSUB table\n" )); |
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559 OTV_INIT; |
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560 |
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561 OTV_LIMIT_CHECK( 10 ); |
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562 |
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563 if ( FT_NEXT_ULONG( p ) != 0x10000UL ) /* Version */ |
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564 FT_INVALID_FORMAT; |
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565 |
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566 ScriptList = FT_NEXT_USHORT( p ); |
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567 FeatureList = FT_NEXT_USHORT( p ); |
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568 LookupList = FT_NEXT_USHORT( p ); |
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569 |
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570 valid->type_count = 8; |
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571 valid->type_funcs = (OTV_Validate_Func*)otv_gsub_validate_funcs; |
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572 valid->glyph_count = glyph_count; |
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573 |
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574 otv_LookupList_validate( table + LookupList, |
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575 valid ); |
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576 otv_FeatureList_validate( table + FeatureList, table + LookupList, |
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577 valid ); |
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578 otv_ScriptList_validate( table + ScriptList, table + FeatureList, |
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579 valid ); |
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580 |
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581 FT_TRACE4(( "\n" )); |
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582 } |
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583 |
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584 |
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585 /* END */ |
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