ftccache.c

一个Xpdf应用的例子

/***************************************************************************/
/*                                                                         */
/*  ftccache.c                                                             */
/*                                                                         */
/*    The FreeType internal cache interface (body).                        */
/*                                                                         */
/*  Copyright 2000-2001 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.                                        */
/*                                                                         */
/***************************************************************************/


#include <ft2build.h>
#include FT_CACHE_MANAGER_H
#include FT_INTERNAL_OBJECTS_H
#include FT_INTERNAL_DEBUG_H

#include "ftcerror.h"


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                   CACHE NODE DEFINITIONS                      *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  FT_EXPORT_DEF( void )
  ftc_node_done( FTC_Node   node,
                 FTC_Cache  cache )
  {
    FTC_Family       family;
    FTC_FamilyEntry  entry;


    entry  = cache->manager->families.entries + node->fam_index;
    family = entry->family;

    /* remove from parent set table - eventually destroy the set */
    if ( --family->num_nodes == 0 )
      FT_LruList_Remove( cache->families, (FT_LruNode) family );
  }


  /* add a new node to the head of the manager's circular MRU list */
  static void
  ftc_node_mru_link( FTC_Node     node,
                     FTC_Manager  manager )
  {
    FTC_Node  first = manager->nodes_list;


    if ( first )
    {
      node->mru_prev = first->mru_prev;
      node->mru_next = first;

      first->mru_prev->mru_next = node;
      first->mru_prev           = node;
    }
    else
    {
      node->mru_next = node;
      node->mru_prev = node;
    }

    manager->nodes_list = node;
    manager->num_nodes++;
  }


  /* remove a node from the manager's MRU list */
  static void
  ftc_node_mru_unlink( FTC_Node     node,
                       FTC_Manager  manager )
  {
    FTC_Node  prev  = node->mru_prev;
    FTC_Node  next  = node->mru_next;
    FTC_Node  first = manager->nodes_list;


    prev->mru_next = next;
    next->mru_prev = prev;

    if ( node->mru_next == first )
    {
      /* this is the last node in the list; update its head pointer */
      if ( node == first )
        manager->nodes_list = NULL;
      else
        first->mru_prev = prev;
    }

    node->mru_next = NULL;
    node->mru_prev = NULL;
    manager->num_nodes--;
  }


  /* move a node to the head of the manager's MRU list */
  static void
  ftc_node_mru_up( FTC_Node     node,
                   FTC_Manager  manager )
  {
    FTC_Node  first = manager->nodes_list;


    if ( node != first )
    {
      ftc_node_mru_unlink( node, manager );
      ftc_node_mru_link( node, manager );
    }
  }


  /* remove a node from its cache's hash table */
  static void
  ftc_node_hash_unlink( FTC_Node   node,
                        FTC_Cache  cache )
  {
    FTC_Node  *pnode = cache->buckets + ( node->hash % cache->size );


    for (;;)
    {
      if ( *pnode == NULL )
      {
        FT_ERROR(( "FreeType.cache.hash_unlink: unknown node!\n" ));
        return;
      }

      if ( *pnode == node )
      {
        *pnode     = node->link;
        node->link = NULL;

        cache->nodes--;
        return;
      }

      pnode = &(*pnode)->link;
    }
  }


  /* add a node to the "top" of its cache's hash table */
  static void
  ftc_node_hash_link( FTC_Node   node,
                      FTC_Cache  cache )
  {
    FTC_Node  *pnode = cache->buckets + ( node->hash % cache->size );


    node->link = *pnode;
    *pnode     = node;

    cache->nodes++;
  }


  /* remove a node from the cache manager */
  FT_EXPORT_DEF( void )
  ftc_node_destroy( FTC_Node     node,
                    FTC_Manager  manager )
  {
    FT_Memory        memory  = manager->library->memory;
    FTC_Cache        cache;
    FTC_FamilyEntry  entry;
    FTC_Cache_Class  clazz;


#ifdef FT_DEBUG_ERROR
    /* find node's cache */
    if ( node->fam_index >= manager->families.count )
    {
      FT_ERROR(( "ftc_node_destroy: invalid node handle\n" ));
      return;
    }
#endif

    entry = manager->families.entries + node->fam_index;
    cache = entry->cache;

#ifdef FT_DEBUG_ERROR
    if ( cache == NULL )
    {
      FT_ERROR(( "ftc_node_destroy: invalid node handle\n" ));
      return;
    }
#endif

    clazz = cache->clazz;

    manager->cur_weight -= clazz->node_weight( node, cache );

    /* remove node from mru list */
    ftc_node_mru_unlink( node, manager );

    /* remove node from cache's hash table */
    ftc_node_hash_unlink( node, cache );

    /* now finalize it */
    if ( clazz->node_done )
      clazz->node_done( node, cache );

    FREE( node );

    /* check, just in case of general corruption :-) */
    if ( manager->num_nodes == 0 )
      FT_ERROR(( "ftc_node_destroy: invalid cache node count! = %d\n",
                  manager->num_nodes ));
  }


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                   CACHE FAMILY DEFINITIONS                    *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/


  FT_EXPORT_DEF( FT_Error )
  ftc_family_init( FTC_Family  family,
                   FTC_Query   query,
                   FTC_Cache   cache )
  {
    FT_Error         error;
    FTC_Manager      manager = cache->manager;
    FT_Memory        memory  = manager->library->memory;
    FTC_FamilyEntry  entry;


    family->cache     = cache;
    family->num_nodes = 0;

    /* now add to manager's family table */
    error = ftc_family_table_alloc( &manager->families, memory, &entry );
    if ( !error )
    {
      entry->cache      = cache;
      entry->family     = family;
      family->fam_index = entry->index;

      query->family = family;   /* save family in query */
    }

    return error;
  }


  FT_EXPORT_DEF( void )
  ftc_family_done( FTC_Family  family )
  {
    FTC_Manager  manager = family->cache->manager;


    /* remove from manager's family table */
    ftc_family_table_free( &manager->families, family->fam_index );
  }


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                    ABSTRACT CACHE CLASS                       *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

#define FTC_PRIMES_MIN  7
#define FTC_PRIMES_MAX  13845163

  static const FT_UInt  ftc_primes[] =
  {
    7,
    11,
    19,
    37,
    73,
    109,
    163,
    251,
    367,
    557,
    823,
    1237,
    1861,
    2777,
    4177,
    6247,
    9371,
    14057,
    21089,
    31627,
    47431,
    71143,
    106721,
    160073,
    240101,
    360163,
    540217,
    810343,
    1215497,
    1823231,