src/cache/ftccache.h

   1 /***************************************************************************/
   2 /*                                                                         */
   3 /*  ftccache.h                                                             */
   4 /*                                                                         */
   5 /*    FreeType internal cache interface (specification).                   */
   6 /*                                                                         */
   7 /*  Copyright 2000-2001, 2002, 2003, 2004, 2005, 2006, 2007, 2009, 2010 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 #ifndef __FTCCACHE_H__
  20 #define __FTCCACHE_H__
  21
  22
  23 #include "ftcmru.h"
  24
  25 FT_BEGIN_HEADER
  26
  27   /* handle to cache object */
  28   typedef struct FTC_CacheRec_*  FTC_Cache;
  29
  30   /* handle to cache class */
  31   typedef const struct FTC_CacheClassRec_*  FTC_CacheClass;
  32
  33
  34   /*************************************************************************/
  35   /*************************************************************************/
  36   /*****                                                               *****/
  37   /*****                   CACHE NODE DEFINITIONS                      *****/
  38   /*****                                                               *****/
  39   /*************************************************************************/
  40   /*************************************************************************/
  41
  42   /*************************************************************************/
  43   /*                                                                       */
  44   /* Each cache controls one or more cache nodes.  Each node is part of    */
  45   /* the global_lru list of the manager.  Its `data' field however is used */
  46   /* as a reference count for now.                                         */
  47   /*                                                                       */
  48   /* A node can be anything, depending on the type of information held by  */
  49   /* the cache.  It can be an individual glyph image, a set of bitmaps     */
  50   /* glyphs for a given size, some metrics, etc.                           */
  51   /*                                                                       */
  52   /*************************************************************************/
  53
  54   /* structure size should be 20 bytes on 32-bits machines */
  55   typedef struct  FTC_NodeRec_
  56   {
  57     FTC_MruNodeRec  mru;          /* circular mru list pointer           */
  58     FTC_Node        link;         /* used for hashing                    */
  59     FT_UInt32       hash;         /* used for hashing too                */
  60     FT_UShort       cache_index;  /* index of cache the node belongs to  */
  61     FT_Short        ref_count;    /* reference count for this node       */
  62
  63   } FTC_NodeRec;
  64
  65
  66 #define FTC_NODE( x )    ( (FTC_Node)(x) )
  67 #define FTC_NODE_P( x )  ( (FTC_Node*)(x) )
  68
  69 #define FTC_NODE__NEXT( x )  FTC_NODE( (x)->mru.next )
  70 #define FTC_NODE__PREV( x )  FTC_NODE( (x)->mru.prev )
  71
  72
  73 #ifdef FT_CONFIG_OPTION_OLD_INTERNALS
  74   FT_BASE( void )
  75   ftc_node_destroy( FTC_Node     node,
  76                     FTC_Manager  manager );
  77 #endif
  78
  79
  80   /*************************************************************************/
  81   /*************************************************************************/
  82   /*****                                                               *****/
  83   /*****                       CACHE DEFINITIONS                       *****/
  84   /*****                                                               *****/
  85   /*************************************************************************/
  86   /*************************************************************************/
  87
  88   /* initialize a new cache node */
  89   typedef FT_Error
  90   (*FTC_Node_NewFunc)( FTC_Node    *pnode,
  91                        FT_Pointer   query,
  92                        FTC_Cache    cache );
  93
  94   typedef FT_Offset
  95   (*FTC_Node_WeightFunc)( FTC_Node   node,
  96                           FTC_Cache  cache );
  97
  98   /* compare a node to a given key pair */
  99   typedef FT_Bool
 100   (*FTC_Node_CompareFunc)( FTC_Node    node,
 101                            FT_Pointer  key,
 102                            FTC_Cache   cache );
 103
 104
 105   typedef void
 106   (*FTC_Node_FreeFunc)( FTC_Node   node,
 107                         FTC_Cache  cache );
 108
 109   typedef FT_Error
 110   (*FTC_Cache_InitFunc)( FTC_Cache  cache );
 111
 112   typedef void
 113   (*FTC_Cache_DoneFunc)( FTC_Cache  cache );
 114
 115
 116   typedef struct  FTC_CacheClassRec_
 117   {
 118     FTC_Node_NewFunc      node_new;
 119     FTC_Node_WeightFunc   node_weight;
 120     FTC_Node_CompareFunc  node_compare;
 121     FTC_Node_CompareFunc  node_remove_faceid;
 122     FTC_Node_FreeFunc     node_free;
 123
 124     FT_Offset             cache_size;
 125     FTC_Cache_InitFunc    cache_init;
 126     FTC_Cache_DoneFunc    cache_done;
 127
 128   } FTC_CacheClassRec;
 129
 130
 131   /* each cache really implements a dynamic hash table to manage its nodes */
 132   typedef struct  FTC_CacheRec_
 133   {
 134     FT_UFast           p;
 135     FT_UFast           mask;
 136     FT_Long            slack;
 137     FTC_Node*          buckets;
 138
 139     FTC_CacheClassRec  clazz;       /* local copy, for speed  */
 140
 141     FTC_Manager        manager;
 142     FT_Memory          memory;
 143     FT_UInt            index;       /* in manager's table     */
 144
 145     FTC_CacheClass     org_class;   /* original class pointer */
 146
 147   } FTC_CacheRec;
 148
 149
 150 #define FTC_CACHE( x )    ( (FTC_Cache)(x) )
 151 #define FTC_CACHE_P( x )  ( (FTC_Cache*)(x) )
 152
 153
 154   /* default cache initialize */
 155   FT_LOCAL( FT_Error )
 156   FTC_Cache_Init( FTC_Cache  cache );
 157
 158   /* default cache finalizer */
 159   FT_LOCAL( void )
 160   FTC_Cache_Done( FTC_Cache  cache );
 161
 162   /* Call this function to lookup the cache.  If no corresponding
 163    * node is found, a new one is automatically created.  This function
 164    * is capable of flushing the cache adequately to make room for the
 165    * new cache object.
 166    */
 167
 168 #ifndef FTC_INLINE
 169   FT_LOCAL( FT_Error )
 170   FTC_Cache_Lookup( FTC_Cache   cache,
 171                     FT_UInt32   hash,
 172                     FT_Pointer  query,
 173                     FTC_Node   *anode );
 174 #endif
 175
 176   FT_LOCAL( FT_Error )
 177   FTC_Cache_NewNode( FTC_Cache   cache,
 178                      FT_UInt32   hash,
 179                      FT_Pointer  query,
 180                      FTC_Node   *anode );
 181
 182   /* Remove all nodes that relate to a given face_id.  This is useful
 183    * when un-installing fonts.  Note that if a cache node relates to
 184    * the face_id, but is locked (i.e., has `ref_count > 0'), the node
 185    * will _not_ be destroyed, but its internal face_id reference will
 186    * be modified.
 187    *
 188    * The final result will be that the node will never come back
 189    * in further lookup requests, and will be flushed on demand from
 190    * the cache normally when its reference count reaches 0.
 191    */
 192   FT_LOCAL( void )
 193   FTC_Cache_RemoveFaceID( FTC_Cache   cache,
 194                           FTC_FaceID  face_id );
 195
 196
 197 #ifdef FTC_INLINE
 198
 199 #define FTC_CACHE_LOOKUP_CMP( cache, nodecmp, hash, query, node, error ) \
 200   FT_BEGIN_STMNT                                                         \
 201     FTC_Node             *_bucket, *_pnode, _node;                       \
 202     FTC_Cache             _cache   = FTC_CACHE(cache);                   \
 203     FT_UInt32             _hash    = (FT_UInt32)(hash);                  \
 204     FTC_Node_CompareFunc  _nodcomp = (FTC_Node_CompareFunc)(nodecmp);    \
 205     FT_UFast              _idx;                                          \
 206                                                                          \
 207                                                                          \
 208     error = FTC_Err_Ok;                                                  \
 209     node  = NULL;                                                        \
 210     _idx  = _hash & _cache->mask;                                        \
 211     if ( _idx < _cache->p )                                              \
 212       _idx = _hash & ( _cache->mask*2 + 1 );                             \
 213                                                                          \
 214     _bucket = _pnode = _cache->buckets + _idx;                           \
 215     for (;;)                                                             \
 216     {                                                                    \
 217       _node = *_pnode;                                                   \
 218       if ( _node == NULL )                                               \
 219         goto _NewNode;                                                   \
 220                                                                          \
 221       if ( _node->hash == _hash && _nodcomp( _node, query, _cache ) )    \
 222         break;                                                           \
 223                                                                          \
 224       _pnode = &_node->link;                                             \
 225     }                                                                    \
 226                                                                          \
 227     if ( _node != *_bucket )                                             \
 228     {                                                                    \
 229       *_pnode     = _node->link;                                         \
 230       _node->link = *_bucket;                                            \
 231       *_bucket    = _node;                                               \
 232     }                                                                    \
 233                                                                          \
 234     {                                                                    \
 235       FTC_Manager  _manager = _cache->manager;                           \
 236       void*        _nl      = &_manager->nodes_list;                     \
 237                                                                          \
 238                                                                          \
 239       if ( _node != _manager->nodes_list )                               \
 240         FTC_MruNode_Up( (FTC_MruNode*)_nl,                               \
 241                         (FTC_MruNode)_node );                            \
 242     }                                                                    \
 243     goto _Ok;                                                            \
 244                                                                          \
 245   _NewNode:                                                              \
 246     error = FTC_Cache_NewNode( _cache, _hash, query, &_node );           \
 247                                                                          \
 248   _Ok:                                                                   \
 249     node = _node;                                                        \
 250   FT_END_STMNT
 251
 252 #else /* !FTC_INLINE */
 253
 254 #define FTC_CACHE_LOOKUP_CMP( cache, nodecmp, hash, query, node, error ) \
 255   FT_BEGIN_STMNT                                                         \
 256     error = FTC_Cache_Lookup( FTC_CACHE( cache ), hash, query,           \
 257                               (FTC_Node*)&(node) );                      \
 258   FT_END_STMNT
 259
 260 #endif /* !FTC_INLINE */
 261
 262
 263   /*
 264    * This macro, together with FTC_CACHE_TRYLOOP_END, defines a retry
 265    * loop to flush the cache repeatedly in case of memory overflows.
 266    *
 267    * It is used when creating a new cache node, or within a lookup
 268    * that needs to allocate data (e.g., the sbit cache lookup).
 269    *
 270    * Example:
 271    *
 272    *   {
 273    *     FTC_CACHE_TRYLOOP( cache )
 274    *       error = load_data( ... );
 275    *     FTC_CACHE_TRYLOOP_END()
 276    *   }
 277    *
 278    */
 279 #define FTC_CACHE_TRYLOOP( cache )                           \
 280   {                                                          \
 281     FTC_Manager  _try_manager = FTC_CACHE( cache )->manager; \
 282     FT_UInt      _try_count   = 4;                           \
 283                                                              \
 284                                                              \
 285     for (;;)                                                 \
 286     {                                                        \
 287       FT_UInt  _try_done;
 288
 289
 290 #define FTC_CACHE_TRYLOOP_END()                                   \
 291       if ( !error || error != FTC_Err_Out_Of_Memory )             \
 292         break;                                                    \
 293                                                                   \
 294       _try_done = FTC_Manager_FlushN( _try_manager, _try_count ); \
 295       if ( _try_done == 0 )                                       \
 296         break;                                                    \
 297                                                                   \
 298       if ( _try_done == _try_count )                              \
 299       {                                                           \
 300         _try_count *= 2;                                          \
 301         if ( _try_count < _try_done              ||               \
 302             _try_count > _try_manager->num_nodes )                \
 303           _try_count = _try_manager->num_nodes;                   \
 304       }                                                           \
 305     }                                                             \
 306   }
 307
 308  /* */
 309
 310 FT_END_HEADER
 311
 312
 313 #endif /* __FTCCACHE_H__ */
 314
 315
 316 /* END */