[692] | 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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