misc/libfreetype/src/cache/ftcmanag.h
changeset 5172 88f2e05288ba
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/misc/libfreetype/src/cache/ftcmanag.h	Mon Apr 25 01:46:54 2011 +0200
@@ -0,0 +1,175 @@
+/***************************************************************************/
+/*                                                                         */
+/*  ftcmanag.h                                                             */
+/*                                                                         */
+/*    FreeType Cache Manager (specification).                              */
+/*                                                                         */
+/*  Copyright 2000-2001, 2003, 2004, 2006, 2010 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_ULong            max_weight;
+    FT_ULong            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 */