(clear_cached_bitmap_slots): Remove.

(get_bitmap_with_cache): Check if CreateBitmap failed.
Adjust cache size dynamically so cache is never larger than the
system limit of GDI resources.
Do cache clearing inline.  Move global variables to local scope.

diff --git a/src/w32bdf.c b/src/w32bdf.c
index 5b51db8e012c48439e063e519e86ca817d075688..e287f499ec1e34ab5bae463819c24d10d5120aef 100644 (file)
--- a/src/w32bdf.c
+++ b/src/w32bdf.c
@@ -34,15 +34,15 @@ Boston, MA 02111-1307, USA.  */
 #define min(a, b) ((a) < (b) ? (a) : (b))
 #define max(a, b) ((a) > (b) ? (a) : (b))
 
+/* Portion of GDI Objects which the font cache is allowed to use. This
+   can be quite high, since the font cache is the only part of Emacs
+   that uses a large number of GDI objects, but there should still be
+   some GDI objects reserved for other uses.  */
+#define CACHE_GDI_ALLOWANCE 9 / 10
+
 void w32_free_bdf_font(bdffont *fontp);
 bdffont *w32_init_bdf_font(char *filename);
 
-cache_bitmap cached_bitmap_slots[BDF_FONT_CACHE_SIZE];
-cache_bitmap *pcached_bitmap_latest = cached_bitmap_slots;
-
-#define FONT_CACHE_SLOT_OVER_P(p) \
-   ((p) >= cached_bitmap_slots + BDF_FONT_CACHE_SIZE)
-
 static int 
 search_file_line(char *key, char *start, int len, char **val, char **next)
 {
@@ -368,27 +368,6 @@ seek_char(bdffont *fontp, int index)
   return result;
 }
 
-void
-clear_cached_bitmap_slots()
-{
-  int i;
-  cache_bitmap *p;
-
-  p = pcached_bitmap_latest;
-  for (i = 0;i < BDF_FONT_CLEAR_SIZE;i++)
-    {
-      if (p->psrc)
-       {
-         DeleteObject(p->hbmp);
-         p->psrc->pcbmp = NULL;
-         p->psrc = NULL;
-       }
-      p++;
-      if (FONT_CACHE_SLOT_OVER_P(p))
-       p = cached_bitmap_slots;
-    }
-}
-
 #define GET_HEX_VAL(x) ((isdigit(x)) ? ((x) - '0') : \
                        (((x) >= 'A') && ((x) <= 'Z')) ? ((x) - 'A' + 10) : \
                        (((x) >= 'a') && ((x) <= 'z')) ? ((x) - 'a' + 10) : \
@@ -474,6 +453,8 @@ w32_get_bdf_glyph(bdffont *fontp, int index, int size, glyph_struct *glyph)
   return 1;
 }
 
+#define NEXT_CACHE_SLOT(n) (((n) + 1 >= BDF_FONT_CACHE_SIZE) ? 0 : ((n) + 1))
+
 static
 cache_bitmap*
 get_bitmap_with_cache(bdffont *fontp, int index)
@@ -483,6 +464,11 @@ get_bitmap_with_cache(bdffont *fontp, int index)
   cache_bitmap* pcb;
   HBITMAP hbmp;
   glyph_struct glyph;
+  static cache_bitmap cached_bitmap_slots[BDF_FONT_CACHE_SIZE];
+  static int cache_in_slot = 0;                /* the next slot to use */
+  static int cache_out_slot = 0;       /* the last slot allocated */
+  static int cache_occupancy = 0;      /* current cache occupancy */
+  static int cache_limit = BDF_FONT_CACHE_SIZE; /* allowed maximum occupancy */
 
   pch = get_cached_font_char(fontp, index);
   if (pch)
@@ -503,9 +489,35 @@ get_bitmap_with_cache(bdffont *fontp, int index)
 
   hbmp = CreateBitmap(glyph.metric.bbw, glyph.metric.bbh, 1, 1, glyph.bitmap);
 
-  pcb = pcached_bitmap_latest;
-  if (pcb->psrc)
-    clear_cached_bitmap_slots();
+  /* if bitmap allocation fails reduce the limit of the occupancy so
+     that we can hope it will not happen again.  */
+  if (hbmp == NULL)
+    cache_limit = cache_occupancy * CACHE_GDI_ALLOWANCE;
+
+  /* if cache occupancy reaches at the limit release some cache slots */
+  if (cache_occupancy >= cache_limit)
+    {
+      register int size_to_clear = cache_limit * BDF_FONT_CLEAR_SIZE
+                                   / BDF_FONT_CACHE_SIZE;
+      for (; size_to_clear; size_to_clear--,
+                            cache_out_slot = NEXT_CACHE_SLOT(cache_out_slot))
+        {
+          register cache_bitmap *p = &cached_bitmap_slots[cache_out_slot];
+          if (p->psrc)
+            {
+              DeleteObject(p->hbmp);
+              p->psrc->pcbmp = NULL;
+              p->psrc = NULL;
+              cache_occupancy--;
+            }
+        }
+    }
+
+  if (hbmp == NULL)
+    hbmp = CreateBitmap (glyph.metric.bbw, glyph.metric.bbh,
+                         1, 1, glyph.bitmap);
+
+  pcb = &cached_bitmap_slots[cache_in_slot];
 
   pcb->psrc = pch;
   pcb->metric = glyph.metric;
@@ -513,9 +525,8 @@ get_bitmap_with_cache(bdffont *fontp, int index)
 
   pch->pcbmp = pcb;
   
-  pcached_bitmap_latest++;
-  if (FONT_CACHE_SLOT_OVER_P(pcached_bitmap_latest))
-    pcached_bitmap_latest = cached_bitmap_slots;
+  cache_in_slot = NEXT_CACHE_SLOT(cache_in_slot);
+  cache_occupancy++;
 
   return pcb;
 }