1 /***************************************************************************/ 2 /* */ 3 /* ftcmanag.h */ 4 /* */ 5 /* FreeType Cache Manager (specification). */ 6 /* */ 7 /* Copyright 2000-2018 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 "ftcmru.h" 69 #include "ftccache.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_ManagerRec_ 92 { 93 FT_Library library; 94 FT_Memory memory; 95 96 FTC_Node nodes_list; 97 FT_Offset max_weight; 98 FT_Offset cur_weight; 99 FT_UInt num_nodes; 100 101 FTC_Cache caches[FTC_MAX_CACHES]; 102 FT_UInt num_caches; 103 104 FTC_MruListRec faces; 105 FTC_MruListRec sizes; 106 107 FT_Pointer request_data; 108 FTC_Face_Requester request_face; 109 110 } FTC_ManagerRec; 111 112 113 /*************************************************************************/ 114 /* */ 115 /* <Function> */ 116 /* FTC_Manager_Compress */ 117 /* */ 118 /* <Description> */ 119 /* This function is used to check the state of the cache manager if */ 120 /* its `num_bytes' field is greater than its `max_bytes' field. It */ 121 /* will flush as many old cache nodes as possible (ignoring cache */ 122 /* nodes with a non-zero reference count). */ 123 /* */ 124 /* <InOut> */ 125 /* manager :: A handle to the cache manager. */ 126 /* */ 127 /* <Note> */ 128 /* Client applications should not call this function directly. It is */ 129 /* normally invoked by specific cache implementations. */ 130 /* */ 131 /* The reason this function is exported is to allow client-specific */ 132 /* cache classes. */ 133 /* */ 134 FT_LOCAL( void ) 135 FTC_Manager_Compress( FTC_Manager manager ); 136 137 138 /* try to flush `count' old nodes from the cache; return the number 139 * of really flushed nodes 140 */ 141 FT_LOCAL( FT_UInt ) 142 FTC_Manager_FlushN( FTC_Manager manager, 143 FT_UInt count ); 144 145 146 /* this must be used internally for the moment */ 147 FT_LOCAL( FT_Error ) 148 FTC_Manager_RegisterCache( FTC_Manager manager, 149 FTC_CacheClass clazz, 150 FTC_Cache *acache ); 151 152 /* */ 153 154 #define FTC_SCALER_COMPARE( a, b ) \ 155 ( (a)->face_id == (b)->face_id && \ 156 (a)->width == (b)->width && \ 157 (a)->height == (b)->height && \ 158 ((a)->pixel != 0) == ((b)->pixel != 0) && \ 159 ( (a)->pixel || \ 160 ( (a)->x_res == (b)->x_res && \ 161 (a)->y_res == (b)->y_res ) ) ) 162 163 #define FTC_SCALER_HASH( q ) \ 164 ( FTC_FACE_ID_HASH( (q)->face_id ) + \ 165 (q)->width + (q)->height*7 + \ 166 ( (q)->pixel ? 0 : ( (q)->x_res*33 ^ (q)->y_res*61 ) ) ) 167 168 /* */ 169 170 FT_END_HEADER 171 172 #endif /* FTCMANAG_H_ */ 173 174 175 /* END */ 176
