1 /***************************************************************************/ 2 /* */ 3 /* ftcmanag.h */ 4 /* */ 5 /* FreeType Cache Manager (specification). */ 6 /* */ 7 /* Copyright 2000-2001 by */ 8 /* David Turner, Robert Wilhelm, and Werner Lemberg. */ 9 /* */ 10 /* This file is part of the FreeType project, and may only be used, */ 11 /* modified, and distributed under the terms of the FreeType project */ 12 /* license, LICENSE.TXT. By continuing to use, modify, or distribute */ 13 /* this file you indicate that you have read the license and */ 14 /* understand and accept it fully. */ 15 /* */ 16 /***************************************************************************/ 17 18 19 /*************************************************************************/ 20 /* */ 21 /* A cache manager is in charge of the following: */ 22 /* */ 23 /* - Maintain a mapping between generic FTC_FaceIDs and live FT_Face */ 24 /* objects. The mapping itself is performed through a user-provided */ 25 /* callback. However, the manager maintains a small cache of FT_Face */ 26 /* and FT_Size objects in order to speed up things considerably. */ 27 /* */ 28 /* - Manage one or more cache objects. Each cache is in charge of */ 29 /* holding a varying number of `cache nodes'. Each cache node */ 30 /* represents a minimal amount of individually accessible cached */ 31 /* data. For example, a cache node can be an FT_Glyph image */ 32 /* containing a vector outline, or some glyph metrics, or anything */ 33 /* else. */ 34 /* */ 35 /* Each cache node has a certain size in bytes that is added to the */ 36 /* total amount of `cache memory' within the manager. */ 37 /* */ 38 /* All cache nodes are located in a global LRU list, where the oldest */ 39 /* node is at the tail of the list. */ 40 /* */ 41 /* Each node belongs to a single cache, and includes a reference */ 42 /* count to avoid destroying it (due to caching). */ 43 /* */ 44 /*************************************************************************/ 45 46 47 /*************************************************************************/ 48 /*************************************************************************/ 49 /*************************************************************************/ 50 /*************************************************************************/ 51 /*************************************************************************/ 52 /********* *********/ 53 /********* WARNING, THIS IS BETA CODE. *********/ 54 /********* *********/ 55 /*************************************************************************/ 56 /*************************************************************************/ 57 /*************************************************************************/ 58 /*************************************************************************/ 59 /*************************************************************************/ 60 61 62 #ifndef __FTCMANAG_H__ 63 #define __FTCMANAG_H__ 64 65 66 #include <ft2build.h> 67 #include FT_CACHE_H 68 #include FT_CACHE_INTERNAL_LRU_H 69 #include FT_CACHE_INTERNAL_CACHE_H 70 71 72 FT_BEGIN_HEADER 73 74 75 /*************************************************************************/ 76 /* */ 77 /* <Section> */ 78 /* cache_subsystem */ 79 /* */ 80 /*************************************************************************/ 81 82 83 #define FTC_MAX_FACES_DEFAULT 2 84 #define FTC_MAX_SIZES_DEFAULT 4 85 #define FTC_MAX_BYTES_DEFAULT 200000L /* ~200kByte by default */ 86 87 /* maximum number of caches registered in a single manager */ 88 #define FTC_MAX_CACHES 16 89 90 91 typedef struct FTC_FamilyEntryRec_ 92 { 93 FTC_Family family; 94 FTC_Cache cache; 95 FT_UInt index; 96 FT_UInt link; 97 98 } FTC_FamilyEntryRec, *FTC_FamilyEntry; 99 100 101 #define FTC_FAMILY_ENTRY_NONE ( (FT_UInt)-1 ) 102 103 104 typedef struct FTC_FamilyTableRec_ 105 { 106 FT_UInt count; 107 FT_UInt size; 108 FTC_FamilyEntry entries; 109 FT_UInt free; 110 111 } FTC_FamilyTableRec, *FTC_FamilyTable; 112 113 114 FT_EXPORT( FT_Error ) 115 ftc_family_table_alloc( FTC_FamilyTable table, 116 FT_Memory memory, 117 FTC_FamilyEntry *aentry ); 118 119 FT_EXPORT( void ) 120 ftc_family_table_free( FTC_FamilyTable table, 121 FT_UInt idx ); 122 123 124 /*************************************************************************/ 125 /* */ 126 /* <Struct> */ 127 /* FTC_ManagerRec */ 128 /* */ 129 /* <Description> */ 130 /* The cache manager structure. */ 131 /* */ 132 /* <Fields> */ 133 /* library :: A handle to a FreeType library instance. */ 134 /* */ 135 /* faces_list :: The lru list of @FT_Face objects in the cache. */ 136 /* */ 137 /* sizes_list :: The lru list of @FT_Size objects in the cache. */ 138 /* */ 139 /* max_weight :: The maximum cache pool weight. */ 140 /* */ 141 /* cur_weight :: The current cache pool weight. */ 142 /* */ 143 /* num_nodes :: The current number of nodes in the manager. */ 144 /* */ 145 /* nodes_list :: The global lru list of all cache nodes. */ 146 /* */ 147 /* caches :: A table of installed/registered cache objects. */ 148 /* */ 149 /* request_data :: User-provided data passed to the requester. */ 150 /* */ 151 /* request_face :: User-provided function used to implement a mapping */ 152 /* between abstract @FTC_FaceID values and real */ 153 /* @FT_Face objects. */ 154 /* */ 155 /* families :: Global table of families. */ 156 /* */ 157 typedef struct FTC_ManagerRec_ 158 { 159 FT_Library library; 160 FT_LruList faces_list; 161 FT_LruList sizes_list; 162 163 FT_ULong max_weight; 164 FT_ULong cur_weight; 165 166 FT_UInt num_nodes; 167 FTC_Node nodes_list; 168 169 FTC_Cache caches[FTC_MAX_CACHES]; 170 171 FT_Pointer request_data; 172 FTC_Face_Requester request_face; 173 174 FTC_FamilyTableRec families; 175 176 } FTC_ManagerRec; 177 178 179 /*************************************************************************/ 180 /* */ 181 /* <Function> */ 182 /* FTC_Manager_Compress */ 183 /* */ 184 /* <Description> */ 185 /* This function is used to check the state of the cache manager if */ 186 /* its `num_bytes' field is greater than its `max_bytes' field. It */ 187 /* will flush as many old cache nodes as possible (ignoring cache */ 188 /* nodes with a non-zero reference count). */ 189 /* */ 190 /* <InOut> */ 191 /* manager :: A handle to the cache manager. */ 192 /* */ 193 /* <Note> */ 194 /* Client applications should not call this function directly. It is */ 195 /* normally invoked by specific cache implementations. */ 196 /* */ 197 /* The reason this function is exported is to allow client-specific */ 198 /* cache classes. */ 199 /* */ 200 FT_EXPORT( void ) 201 FTC_Manager_Compress( FTC_Manager manager ); 202 203 204 /* this must be used internally for the moment */ 205 FT_EXPORT( FT_Error ) 206 FTC_Manager_Register_Cache( FTC_Manager manager, 207 FTC_Cache_Class clazz, 208 FTC_Cache *acache ); 209 210 211 /* can be called to increment a node's reference count */ 212 FT_EXPORT( void ) 213 FTC_Node_Ref( FTC_Node node, 214 FTC_Manager manager ); 215 216 217 /*************************************************************************/ 218 /* */ 219 /* <Function> */ 220 /* FTC_Node_Unref */ 221 /* */ 222 /* <Description> */ 223 /* Decrement a cache node's internal reference count. When the count */ 224 /* reaches 0, it is not destroyed but becomes eligible for subsequent */ 225 /* cache flushes. */ 226 /* */ 227 /* <Input> */ 228 /* node :: The cache node handle. */ 229 /* */ 230 /* manager :: The cache manager handle. */ 231 /* */ 232 FT_EXPORT( void ) 233 FTC_Node_Unref( FTC_Node node, 234 FTC_Manager manager ); 235 236 /* */ 237 238 FT_END_HEADER 239 240 241 #endif /* __FTCMANAG_H__ */ 242 243 244 /* END */ 245