1 | /***************************************************************************/
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2 | /* */
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3 | /* ftccache.h */
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4 | /* */
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5 | /* FreeType internal cache interface (specification). */
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6 | /* */
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7 | /* Copyright 2000-2001, 2002, 2003, 2004, 2005 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 | #ifndef __FTCCACHE_H__
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20 | #define __FTCCACHE_H__
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21 |
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22 |
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23 | #include FT_CACHE_INTERNAL_MRU_H
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24 |
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25 | FT_BEGIN_HEADER
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26 |
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27 | /* handle to cache object */
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28 | typedef struct FTC_CacheRec_* FTC_Cache;
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29 |
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30 | /* handle to cache class */
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31 | typedef const struct FTC_CacheClassRec_* FTC_CacheClass;
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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 | /***** *****/
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37 | /***** CACHE NODE DEFINITIONS *****/
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38 | /***** *****/
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39 | /*************************************************************************/
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40 | /*************************************************************************/
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41 |
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42 | /*************************************************************************/
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43 | /* */
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44 | /* Each cache controls one or more cache nodes. Each node is part of */
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45 | /* the global_lru list of the manager. Its `data' field however is used */
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46 | /* as a reference count for now. */
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47 | /* */
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48 | /* A node can be anything, depending on the type of information held by */
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49 | /* the cache. It can be an individual glyph image, a set of bitmaps */
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50 | /* glyphs for a given size, some metrics, etc. */
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51 | /* */
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52 | /*************************************************************************/
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53 |
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54 | /* structure size should be 20 bytes on 32-bits machines */
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55 | typedef struct FTC_NodeRec_
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56 | {
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57 | FTC_MruNodeRec mru; /* circular mru list pointer */
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58 | FTC_Node link; /* used for hashing */
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59 | FT_UInt32 hash; /* used for hashing too */
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60 | FT_UShort cache_index; /* index of cache the node belongs to */
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61 | FT_Short ref_count; /* reference count for this node */
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62 |
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63 | } FTC_NodeRec;
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64 |
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65 |
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66 | #define FTC_NODE( x ) ( (FTC_Node)(x) )
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67 | #define FTC_NODE_P( x ) ( (FTC_Node*)(x) )
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68 |
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69 | #define FTC_NODE__NEXT(x) FTC_NODE( (x)->mru.next )
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70 | #define FTC_NODE__PREV(x) FTC_NODE( (x)->mru.prev )
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71 |
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72 |
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73 | /*************************************************************************/
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74 | /* */
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75 | /* These functions are exported so that they can be called from */
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76 | /* user-provided cache classes; otherwise, they are really part of the */
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77 | /* cache sub-system internals. */
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78 | /* */
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79 |
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80 | /* reserved for manager's use */
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81 | FT_EXPORT( void )
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82 | ftc_node_destroy( FTC_Node node,
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83 | FTC_Manager manager );
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84 |
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85 |
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86 | /*************************************************************************/
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87 | /*************************************************************************/
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88 | /***** *****/
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89 | /***** CACHE DEFINITIONS *****/
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90 | /***** *****/
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91 | /*************************************************************************/
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92 | /*************************************************************************/
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93 |
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94 | /* initialize a new cache node */
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95 | typedef FT_Error
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96 | (*FTC_Node_NewFunc)( FTC_Node *pnode,
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97 | FT_Pointer query,
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98 | FTC_Cache cache );
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99 |
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100 | typedef FT_ULong
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101 | (*FTC_Node_WeightFunc)( FTC_Node node,
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102 | FTC_Cache cache );
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103 |
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104 | /* compare a node to a given key pair */
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105 | typedef FT_Bool
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106 | (*FTC_Node_CompareFunc)( FTC_Node node,
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107 | FT_Pointer key,
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108 | FTC_Cache cache );
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109 |
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110 |
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111 | typedef void
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112 | (*FTC_Node_FreeFunc)( FTC_Node node,
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113 | FTC_Cache cache );
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114 |
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115 | typedef FT_Error
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116 | (*FTC_Cache_InitFunc)( FTC_Cache cache );
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117 |
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118 | typedef void
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119 | (*FTC_Cache_DoneFunc)( FTC_Cache cache );
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120 |
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121 |
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122 | typedef struct FTC_CacheClassRec_
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123 | {
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124 | FTC_Node_NewFunc node_new;
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125 | FTC_Node_WeightFunc node_weight;
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126 | FTC_Node_CompareFunc node_compare;
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127 | FTC_Node_CompareFunc node_remove_faceid;
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128 | FTC_Node_FreeFunc node_free;
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129 |
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130 | FT_UInt cache_size;
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131 | FTC_Cache_InitFunc cache_init;
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132 | FTC_Cache_DoneFunc cache_done;
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133 |
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134 | } FTC_CacheClassRec;
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135 |
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136 |
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137 | /* each cache really implements a dynamic hash table to manage its nodes */
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138 | typedef struct FTC_CacheRec_
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139 | {
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140 | FT_UFast p;
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141 | FT_UFast mask;
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142 | FT_Long slack;
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143 | FTC_Node* buckets;
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144 |
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145 | FTC_CacheClassRec clazz; /* local copy, for speed */
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146 |
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147 | FTC_Manager manager;
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148 | FT_Memory memory;
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149 | FT_UInt index; /* in manager's table */
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150 |
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151 | FTC_CacheClass org_class; /* original class pointer */
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152 |
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153 | } FTC_CacheRec;
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154 |
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155 |
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156 | #define FTC_CACHE( x ) ( (FTC_Cache)(x) )
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157 | #define FTC_CACHE_P( x ) ( (FTC_Cache*)(x) )
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158 |
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159 |
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160 | /* default cache initialize */
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161 | FT_EXPORT( FT_Error )
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162 | FTC_Cache_Init( FTC_Cache cache );
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163 |
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164 | /* default cache finalizer */
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165 | FT_EXPORT( void )
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166 | FTC_Cache_Done( FTC_Cache cache );
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167 |
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168 | /* Call this function to lookup the cache. If no corresponding
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169 | * node is found, a new one is automatically created. This function
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170 | * is capable of flushing the cache adequately to make room for the
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171 | * new cache object.
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172 | */
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173 | FT_EXPORT( FT_Error )
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174 | FTC_Cache_Lookup( FTC_Cache cache,
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175 | FT_UInt32 hash,
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176 | FT_Pointer query,
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177 | FTC_Node *anode );
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178 |
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179 | FT_EXPORT( FT_Error )
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180 | FTC_Cache_NewNode( FTC_Cache cache,
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181 | FT_UInt32 hash,
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182 | FT_Pointer query,
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183 | FTC_Node *anode );
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184 |
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185 | /* Remove all nodes that relate to a given face_id. This is useful
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186 | * when un-installing fonts. Note that if a cache node relates to
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187 | * the face_id, but is locked (i.e., has 'ref_count > 0'), the node
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188 | * will _not_ be destroyed, but its internal face_id reference will
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189 | * be modified.
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190 | *
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191 | * The final result will be that the node will never come back
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192 | * in further lookup requests, and will be flushed on demand from
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193 | * the cache normally when its reference count reaches 0.
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194 | */
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195 | FT_EXPORT( void )
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196 | FTC_Cache_RemoveFaceID( FTC_Cache cache,
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197 | FTC_FaceID face_id );
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198 |
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199 |
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200 | #ifdef FTC_INLINE
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201 |
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202 | #define FTC_CACHE_LOOKUP_CMP( cache, nodecmp, hash, query, node, error ) \
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203 | FT_BEGIN_STMNT \
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204 | FTC_Node *_bucket, *_pnode, _node; \
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205 | FTC_Cache _cache = FTC_CACHE(cache); \
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206 | FT_UInt32 _hash = (FT_UInt32)(hash); \
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207 | FTC_Node_CompareFunc _nodcomp = (FTC_Node_CompareFunc)(nodecmp); \
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208 | FT_UInt _idx; \
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209 | \
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210 | \
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211 | error = 0; \
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212 | node = NULL; \
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213 | _idx = _hash & _cache->mask; \
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214 | if ( _idx < _cache->p ) \
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215 | _idx = _hash & ( _cache->mask*2 + 1 ); \
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216 | \
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217 | _bucket = _pnode = _cache->buckets + _idx; \
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218 | for (;;) \
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219 | { \
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220 | _node = *_pnode; \
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221 | if ( _node == NULL ) \
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222 | goto _NewNode; \
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223 | \
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224 | if ( _node->hash == _hash && _nodcomp( _node, query, _cache ) ) \
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225 | break; \
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226 | \
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227 | _pnode = &_node->link; \
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228 | } \
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229 | \
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230 | if ( _node != *_bucket ) \
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231 | { \
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232 | *_pnode = _node->link; \
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233 | _node->link = *_bucket; \
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234 | *_bucket = _node; \
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235 | } \
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236 | \
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237 | { \
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238 | FTC_Manager _manager = _cache->manager; \
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239 | \
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240 | \
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241 | if ( _node != _manager->nodes_list ) \
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242 | FTC_MruNode_Up( (FTC_MruNode*)&_manager->nodes_list, \
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243 | (FTC_MruNode)_node ); \
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244 | } \
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245 | goto _Ok; \
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246 | \
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247 | _NewNode: \
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248 | error = FTC_Cache_NewNode( _cache, _hash, query, &_node ); \
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249 | \
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250 | _Ok: \
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251 | _pnode = (FTC_Node*)(void*)&(node); \
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252 | *_pnode = _node; \
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253 | FT_END_STMNT
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254 |
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255 | #else /* !FTC_INLINE */
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256 |
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257 | #define FTC_CACHE_LOOKUP_CMP( cache, nodecmp, hash, query, node, error ) \
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258 | FT_BEGIN_STMNT \
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259 | error = FTC_Cache_Lookup( FTC_CACHE( cache ), hash, query, \
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260 | (FTC_Node*)&(node) ); \
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261 | FT_END_STMNT
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262 |
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263 | #endif /* !FTC_INLINE */
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264 |
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265 |
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266 | /*
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267 | * This macro, together with FTC_CACHE_TRYLOOP_END, defines a retry
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268 | * loop to flush the cache repeatedly in case of memory overflows.
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269 | *
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270 | * It is used when creating a new cache node, or within a lookup
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271 | * that needs to allocate data (e.g., the sbit cache lookup).
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272 | *
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273 | * Example:
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274 | *
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275 | * {
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276 | * FTC_CACHE_TRYLOOP( cache )
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277 | * error = load_data( ... );
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278 | * FTC_CACHE_TRYLOOP_END()
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279 | * }
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280 | *
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281 | */
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282 | #define FTC_CACHE_TRYLOOP( cache ) \
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283 | { \
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284 | FTC_Manager _try_manager = FTC_CACHE( cache )->manager; \
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285 | FT_UInt _try_count = 4; \
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286 | \
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287 | \
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288 | for (;;) \
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289 | { \
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290 | FT_UInt _try_done;
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291 |
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292 |
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293 | #define FTC_CACHE_TRYLOOP_END() \
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294 | if ( !error || error != FT_Err_Out_Of_Memory ) \
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295 | break; \
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296 | \
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297 | _try_done = FTC_Manager_FlushN( _try_manager, _try_count ); \
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298 | if ( _try_done == 0 ) \
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299 | break; \
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300 | \
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301 | if ( _try_done == _try_count ) \
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302 | { \
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303 | _try_count *= 2; \
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304 | if ( _try_count < _try_done || \
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305 | _try_count > _try_manager->num_nodes ) \
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306 | _try_count = _try_manager->num_nodes; \
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307 | } \
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308 | } \
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309 | }
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310 |
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311 | /* */
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312 |
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313 | FT_END_HEADER
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314 |
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315 |
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316 | #endif /* __FTCCACHE_H__ */
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317 |
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318 |
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319 | /* END */
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