1 | /***************************************************************************/
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2 | /* */
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3 | /* ftcmanag.h */
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4 | /* */
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5 | /* FreeType Cache Manager (specification). */
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6 | /* */
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7 | /* Copyright 2000-2001, 2003, 2004 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 | /*************************************************************************/
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20 | /* */
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21 | /* A cache manager is in charge of the following: */
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22 | /* */
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23 | /* - Maintain a mapping between generic FTC_FaceIDs and live FT_Face */
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24 | /* objects. The mapping itself is performed through a user-provided */
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25 | /* callback. However, the manager maintains a small cache of FT_Face */
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26 | /* and FT_Size objects in order to speed up things considerably. */
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27 | /* */
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28 | /* - Manage one or more cache objects. Each cache is in charge of */
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29 | /* holding a varying number of `cache nodes'. Each cache node */
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30 | /* represents a minimal amount of individually accessible cached */
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31 | /* data. For example, a cache node can be an FT_Glyph image */
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32 | /* containing a vector outline, or some glyph metrics, or anything */
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33 | /* else. */
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34 | /* */
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35 | /* Each cache node has a certain size in bytes that is added to the */
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36 | /* total amount of `cache memory' within the manager. */
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37 | /* */
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38 | /* All cache nodes are located in a global LRU list, where the oldest */
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39 | /* node is at the tail of the list. */
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40 | /* */
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41 | /* Each node belongs to a single cache, and includes a reference */
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42 | /* count to avoid destroying it (due to caching). */
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43 | /* */
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44 | /*************************************************************************/
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45 |
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46 |
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47 | /*************************************************************************/
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48 | /*************************************************************************/
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49 | /*************************************************************************/
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50 | /*************************************************************************/
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51 | /*************************************************************************/
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52 | /********* *********/
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53 | /********* WARNING, THIS IS BETA CODE. *********/
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54 | /********* *********/
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55 | /*************************************************************************/
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56 | /*************************************************************************/
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57 | /*************************************************************************/
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58 | /*************************************************************************/
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59 | /*************************************************************************/
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60 |
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61 |
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62 | #ifndef __FTCMANAG_H__
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63 | #define __FTCMANAG_H__
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64 |
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65 |
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66 | #include <ft2build.h>
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67 | #include FT_CACHE_H
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68 | #include FT_CACHE_INTERNAL_MRU_H
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69 | #include FT_CACHE_INTERNAL_CACHE_H
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70 |
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71 |
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72 | FT_BEGIN_HEADER
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73 |
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74 |
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75 | /*************************************************************************/
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76 | /* */
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77 | /* <Section> */
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78 | /* cache_subsystem */
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79 | /* */
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80 | /*************************************************************************/
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81 |
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82 |
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83 | #define FTC_MAX_FACES_DEFAULT 2
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84 | #define FTC_MAX_SIZES_DEFAULT 4
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85 | #define FTC_MAX_BYTES_DEFAULT 200000L /* ~200kByte by default */
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86 |
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87 | /* maximum number of caches registered in a single manager */
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88 | #define FTC_MAX_CACHES 16
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89 |
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90 |
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91 | typedef struct FTC_ManagerRec_
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92 | {
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93 | FT_Library library;
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94 | FT_Memory memory;
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95 |
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96 | FTC_Node nodes_list;
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97 | FT_ULong max_weight;
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98 | FT_ULong cur_weight;
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99 | FT_UInt num_nodes;
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100 |
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101 | FTC_Cache caches[FTC_MAX_CACHES];
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102 | FT_UInt num_caches;
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103 |
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104 | FTC_MruListRec faces;
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105 | FTC_MruListRec sizes;
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106 |
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107 | FT_Pointer request_data;
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108 | FTC_Face_Requester request_face;
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109 |
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110 | } FTC_ManagerRec;
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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 | /* <Function> */
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116 | /* FTC_Manager_Compress */
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117 | /* */
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118 | /* <Description> */
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119 | /* This function is used to check the state of the cache manager if */
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120 | /* its `num_bytes' field is greater than its `max_bytes' field. It */
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121 | /* will flush as many old cache nodes as possible (ignoring cache */
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122 | /* nodes with a non-zero reference count). */
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123 | /* */
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124 | /* <InOut> */
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125 | /* manager :: A handle to the cache manager. */
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126 | /* */
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127 | /* <Note> */
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128 | /* Client applications should not call this function directly. It is */
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129 | /* normally invoked by specific cache implementations. */
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130 | /* */
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131 | /* The reason this function is exported is to allow client-specific */
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132 | /* cache classes. */
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133 | /* */
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134 | FT_EXPORT( void )
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135 | FTC_Manager_Compress( FTC_Manager manager );
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136 |
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137 |
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138 | /* try to flush `count' old nodes from the cache; return the number
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139 | * of really flushed nodes
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140 | */
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141 | FT_EXPORT( FT_UInt )
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142 | FTC_Manager_FlushN( FTC_Manager manager,
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143 | FT_UInt count );
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144 |
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145 |
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146 | /* this must be used internally for the moment */
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147 | FT_EXPORT( FT_Error )
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148 | FTC_Manager_RegisterCache( FTC_Manager manager,
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149 | FTC_CacheClass clazz,
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150 | FTC_Cache *acache );
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151 |
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152 | /* */
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153 |
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154 | #define FTC_SCALER_COMPARE( a, b ) \
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155 | ( (a)->face_id == (b)->face_id && \
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156 | (a)->width == (b)->width && \
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157 | (a)->height == (b)->height && \
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158 | ((a)->pixel != 0) == ((b)->pixel != 0) && \
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159 | ( (a)->pixel || \
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160 | ( (a)->x_res == (b)->x_res && \
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161 | (a)->y_res == (b)->y_res ) ) )
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162 |
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163 | #define FTC_SCALER_HASH( q ) \
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164 | ( FTC_FACE_ID_HASH( (q)->face_id ) + \
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165 | (q)->width + (q)->height*7 + \
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166 | ( (q)->pixel ? 0 : ( (q)->x_res*33 ^ (q)->y_res*61 ) ) )
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167 |
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168 | /* */
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169 |
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170 | FT_END_HEADER
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171 |
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172 | #endif /* __FTCMANAG_H__ */
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173 |
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174 |
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175 | /* END */
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