summaryrefslogtreecommitdiffstats
path: root/src/3rdparty/freetype/src/cache/ftcmanag.h
blob: c6787b72c51a975c1be68b024c89fc1863cb6e06 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
/***************************************************************************/
/*                                                                         */
/*  ftcmanag.h                                                             */
/*                                                                         */
/*    FreeType Cache Manager (specification).                              */
/*                                                                         */
/*  Copyright 2000-2015 by                                                 */
/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used,       */
/*  modified, and distributed under the terms of the FreeType project      */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/***************************************************************************/


  /*************************************************************************/
  /*                                                                       */
  /* A cache manager is in charge of the following:                        */
  /*                                                                       */
  /*  - Maintain a mapping between generic FTC_FaceIDs and live FT_Face    */
  /*    objects.  The mapping itself is performed through a user-provided  */
  /*    callback.  However, the manager maintains a small cache of FT_Face */
  /*    and FT_Size objects in order to speed up things considerably.      */
  /*                                                                       */
  /*  - Manage one or more cache objects.  Each cache is in charge of      */
  /*    holding a varying number of `cache nodes'.  Each cache node        */
  /*    represents a minimal amount of individually accessible cached      */
  /*    data.  For example, a cache node can be an FT_Glyph image          */
  /*    containing a vector outline, or some glyph metrics, or anything    */
  /*    else.                                                              */
  /*                                                                       */
  /*    Each cache node has a certain size in bytes that is added to the   */
  /*    total amount of `cache memory' within the manager.                 */
  /*                                                                       */
  /*    All cache nodes are located in a global LRU list, where the oldest */
  /*    node is at the tail of the list.                                   */
  /*                                                                       */
  /*    Each node belongs to a single cache, and includes a reference      */
  /*    count to avoid destroying it (due to caching).                     */
  /*                                                                       */
  /*************************************************************************/


  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /*********                                                       *********/
  /*********             WARNING, THIS IS BETA CODE.               *********/
  /*********                                                       *********/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/


#ifndef __FTCMANAG_H__
#define __FTCMANAG_H__


#include <ft2build.h>
#include FT_CACHE_H
#include "ftcmru.h"
#include "ftccache.h"


FT_BEGIN_HEADER


  /*************************************************************************/
  /*                                                                       */
  /* <Section>                                                             */
  /*    cache_subsystem                                                    */
  /*                                                                       */
  /*************************************************************************/


#define FTC_MAX_FACES_DEFAULT  2
#define FTC_MAX_SIZES_DEFAULT  4
#define FTC_MAX_BYTES_DEFAULT  200000L  /* ~200kByte by default */

  /* maximum number of caches registered in a single manager */
#define FTC_MAX_CACHES         16


  typedef struct  FTC_ManagerRec_
  {
    FT_Library          library;
    FT_Memory           memory;

    FTC_Node            nodes_list;
    FT_Offset           max_weight;
    FT_Offset           cur_weight;
    FT_UInt             num_nodes;

    FTC_Cache           caches[FTC_MAX_CACHES];
    FT_UInt             num_caches;

    FTC_MruListRec      faces;
    FTC_MruListRec      sizes;

    FT_Pointer          request_data;
    FTC_Face_Requester  request_face;

  } FTC_ManagerRec;


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FTC_Manager_Compress                                               */
  /*                                                                       */
  /* <Description>                                                         */
  /*    This function is used to check the state of the cache manager if   */
  /*    its `num_bytes' field is greater than its `max_bytes' field.  It   */
  /*    will flush as many old cache nodes as possible (ignoring cache     */
  /*    nodes with a non-zero reference count).                            */
  /*                                                                       */
  /* <InOut>                                                               */
  /*    manager :: A handle to the cache manager.                          */
  /*                                                                       */
  /* <Note>                                                                */
  /*    Client applications should not call this function directly.  It is */
  /*    normally invoked by specific cache implementations.                */
  /*                                                                       */
  /*    The reason this function is exported is to allow client-specific   */
  /*    cache classes.                                                     */
  /*                                                                       */
  FT_LOCAL( void )
  FTC_Manager_Compress( FTC_Manager  manager );


  /* try to flush `count' old nodes from the cache; return the number
   * of really flushed nodes
   */
  FT_LOCAL( FT_UInt )
  FTC_Manager_FlushN( FTC_Manager  manager,
                      FT_UInt      count );


  /* this must be used internally for the moment */
  FT_LOCAL( FT_Error )
  FTC_Manager_RegisterCache( FTC_Manager      manager,
                             FTC_CacheClass   clazz,
                             FTC_Cache       *acache );

 /* */

#define FTC_SCALER_COMPARE( a, b )                \
    ( (a)->face_id      == (b)->face_id      &&   \
      (a)->width        == (b)->width        &&   \
      (a)->height       == (b)->height       &&   \
      ((a)->pixel != 0) == ((b)->pixel != 0) &&   \
      ( (a)->pixel ||                             \
        ( (a)->x_res == (b)->x_res &&             \
          (a)->y_res == (b)->y_res ) ) )

#define FTC_SCALER_HASH( q )                                 \
    ( _FTC_FACE_ID_HASH( (q)->face_id ) +                     \
      (q)->width + (q)->height*7 +                           \
      ( (q)->pixel ? 0 : ( (q)->x_res*33 ^ (q)->y_res*61 ) ) )

 /* */

FT_END_HEADER

#endif /* __FTCMANAG_H__ */


/* END */