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/* Pango
* pango-fontcache.c: Cache of XFontStructs by XLFD
*
* Copyright (C) 2000 Red Hat Software
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include "pangox.h"
/* Font cache
*/
/* Number of fonts to retain after they are not otherwise referenced.
*/
#define CACHE_SIZE 16
typedef struct _CacheEntry CacheEntry;
struct _PangoXFontCache
{
Display *display;
GHashTable *forward;
GHashTable *back;
GList *mru;
GList *mru_tail;
int mru_count;
};
struct _CacheEntry
{
char *xlfd;
XFontStruct *fs;
gint ref_count;
GList *mru;
};
static void
free_cache_entry (char *xlfd G_GNUC_UNUSED,
CacheEntry *entry,
PangoXFontCache *cache)
{
g_free (entry->xlfd);
XFreeFont (cache->display, entry->fs);
g_slice_free (CacheEntry, entry);
}
/**
* pango_x_font_cache_free:
* @cache: a #PangoXFontCache
*
* Frees a #PangoXFontCache and all associated memory. All fonts loaded
* through this font cache will be freed along with the cache.
**/
void
pango_x_font_cache_free (PangoXFontCache *cache)
{
g_return_if_fail (cache != NULL);
g_hash_table_foreach (cache->forward, (GHFunc)free_cache_entry, cache);
g_hash_table_destroy (cache->forward);
g_hash_table_destroy (cache->back);
g_list_free (cache->mru);
g_slice_free (PangoXFontCache, cache);
}
/**
* pango_x_font_cache_new:
* @display: an X display.
*
* Creates a font cache for the specified display.
*
* Return value: The newly allocated #PangoXFontCache, which should be
* freed with pango_x_font_cache_free().
**/
PangoXFontCache *
pango_x_font_cache_new (Display *display)
{
PangoXFontCache *cache;
g_return_val_if_fail (display != NULL, NULL);
cache = g_slice_new (PangoXFontCache);
cache->display = display;
cache->forward = g_hash_table_new (g_str_hash, g_str_equal);
cache->back = g_hash_table_new (g_direct_hash, g_direct_equal);
cache->mru = NULL;
cache->mru_tail = NULL;
cache->mru_count = 0;
return cache;
}
static void
cache_entry_unref (PangoXFontCache *cache, CacheEntry *entry)
{
if (g_atomic_int_dec_and_test (&entry->ref_count))
{
g_hash_table_remove (cache->forward, entry->xlfd);
g_hash_table_remove (cache->back, entry->fs);
free_cache_entry (NULL, entry, cache);
}
}
/**
* pango_x_font_cache_load:
* @cache: a #PangoXFontCache
* @xlfd: the X Logical Font Description to load.
*
* Loads a #XFontStruct from a X Logical Font Description. The
* result may be newly loaded, or it may have been previously
* stored.
*
* Return value: The font structure, or %NULL if the font could
* not be loaded. In order to free this structure, you must call
* pango_x_font_cache_unload().
**/
XFontStruct *
pango_x_font_cache_load (PangoXFontCache *cache,
const char *xlfd)
{
CacheEntry *entry;
g_return_val_if_fail (cache != NULL, NULL);
g_return_val_if_fail (xlfd != NULL, NULL);
entry = g_hash_table_lookup (cache->forward, xlfd);
if (entry)
{
g_atomic_int_inc (&entry->ref_count);
}
else
{
XFontStruct *fs = XLoadQueryFont (cache->display, xlfd);
if (!fs)
return NULL;
entry = g_slice_new (CacheEntry);
entry->xlfd = g_strdup (xlfd);
entry->fs = fs;
entry->ref_count = 1;
entry->mru = NULL;
g_hash_table_insert (cache->forward, entry->xlfd, entry);
g_hash_table_insert (cache->back, entry->fs, entry);
}
if (entry->mru)
{
if (cache->mru_count > 1 && entry->mru->prev)
{
/* Move to the head of the mru list */
if (entry->mru == cache->mru_tail)
{
cache->mru_tail = cache->mru_tail->prev;
cache->mru_tail->next = NULL;
}
else
{
entry->mru->prev->next = entry->mru->next;
entry->mru->next->prev = entry->mru->prev;
}
entry->mru->next = cache->mru;
entry->mru->prev = NULL;
cache->mru->prev = entry->mru;
cache->mru = entry->mru;
}
}
else
{
g_atomic_int_inc (&entry->ref_count);
/* Insert into the mru list */
if (cache->mru_count == CACHE_SIZE)
{
CacheEntry *old_entry = cache->mru_tail->data;
cache->mru_tail = cache->mru_tail->prev;
cache->mru_tail->next = NULL;
g_list_free_1 (old_entry->mru);
old_entry->mru = NULL;
cache_entry_unref (cache, old_entry);
}
else
cache->mru_count++;
cache->mru = g_list_prepend (cache->mru, entry);
if (!cache->mru_tail)
cache->mru_tail = cache->mru;
entry->mru = cache->mru;
}
return entry->fs;
}
/**
* pango_x_font_cache_unload:
* @cache: a #PangoXFontCache
* @fs: the font structure to unload
*
* Frees a font structure previously loaded with pango_x_font_cache_load().
**/
void
pango_x_font_cache_unload (PangoXFontCache *cache,
XFontStruct *fs)
{
CacheEntry *entry;
g_return_if_fail (cache != NULL);
g_return_if_fail (fs != NULL);
entry = g_hash_table_lookup (cache->back, fs);
g_return_if_fail (entry != NULL);
cache_entry_unref (cache, entry);
}
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