Font cache: Replace fixed-size array with variable size link list.

graphics/nxterm/nxterm_font.c

@@ -99,7 +99,7 @@ FAR const struct nxterm_bitmap_s *
 nxterm_addchar(FAR struct nxterm_state_s *priv, uint8_t ch)
 {
   FAR struct nxterm_bitmap_s *bm = NULL;
-  FAR struct nxfonts_glyph_s *glyph;
+  FAR const struct nxfonts_glyph_s *glyph;
 
   /* Is there space for another character on the display? */
 
@@ -275,7 +275,7 @@ void nxterm_fillchar(FAR struct nxterm_state_s *priv,
                      FAR const struct nxgl_rect_s *rect,
                      FAR const struct nxterm_bitmap_s *bm)
 {
-  FAR struct nxfonts_glyph_s *glyph;
+  FAR const struct nxfonts_glyph_s *glyph;
   struct nxgl_rect_s bounds;
   struct nxgl_rect_s intersection;
   struct nxgl_size_s fsize;

graphics/nxterm/nxterm_register.c

@@ -106,7 +106,8 @@ FAR struct nxterm_state_s *
   /* Connect to the font cache for the configured font characteristics */
 
   priv->fcache = nxf_cache_connect(wndo->fontid, wndo->fcolor[0],
-                                   wndo->wcolor[0], CONFIG_NXTERM_BPP);
+                                   wndo->wcolor[0], CONFIG_NXTERM_BPP,
+                                   CONFIG_NXTERM_CACHESIZE);
   if (priv->fcache == NULL)
     {
       gerr("ERROR: Failed to connect to font cache for font ID %d: %d\n",

include/nuttx/nx/nxfonts.h

@@ -203,11 +203,6 @@
 
 #endif
 
-/* Font Cache Definitions (**************************************************/
-/* Limit to range of font cache usage count */
-
-#define MAX_USECNT 255                     /* Limit to range of a uint8_t */
-
 /****************************************************************************
  * Public Types
  ****************************************************************************/
@@ -469,14 +464,16 @@ typedef FAR void *FCACHE;
 
 struct nxfonts_glyph_s
 {
+  FAR struct nxfonts_glyph_s *flink;   /* Implements a singly linked list */
   uint8_t code;                        /* Character code */
   uint8_t height;                      /* Height of this glyph (in rows) */
   uint8_t width;                       /* Width of this glyph (in pixels) */
   uint8_t stride;                      /* Width of the glyph row (in bytes) */
-  uint8_t usecnt;                      /* Use count */
-  FAR uint8_t *bitmap;                 /* Allocated bitmap memory */
+  FAR uint8_t bitmap[1];               /* Bitmap memory, actual size varies */
 };
 
+#define SIZEOF_NXFONTS_GLYPH_S(b) (sizeof(struct nxfonts_glyph_s) + (b) - 1)
+
 /****************************************************************************
  * Public Data
  ****************************************************************************/
@@ -596,11 +593,15 @@ int nxf_convert_32bpp(FAR uint32_t *dest, uint16_t height,
  *
  * Description:
  *   Create a new font cache for the provided 'fontid'.  If the cache
- *   already, then just increment a reference count return the handler for
+ *   already, then just increment a reference count return the handle for
  *   the existing font cache.
  *
  * Input Parameters:
- *   fontid - Identifies the font supported by this cache
+ *   fontid    - Identifies the font supported by this cache
+ *   fgcolor   - Foreground color
+ *   bgcolor   - Background color
+ *   bpp       - Bits per pixel
+ *   maxglyphs - Maximum number of glyphs permitted in the cache
  *
  * Returned value:
  *   On success a non-NULL handle is returned that then may sequently be
@@ -612,7 +613,7 @@ int nxf_convert_32bpp(FAR uint32_t *dest, uint16_t height,
 
 FCACHE nxf_cache_connect(enum nx_fontid_e fontid,
                          nxgl_mxpixel_t fgcolor, nxgl_mxpixel_t bgcolor,
-                         int bpp);
+                         int bpp, int maxglyph);
 
 /****************************************************************************
  * Name: nxf_cache_disconnect
@@ -666,7 +667,7 @@ NXHANDLE nxf_cache_getfonthandle(FCACHE fcache);
  *
  ****************************************************************************/
 
-FAR struct nxfonts_glyph_s *nxf_cache_getglyph(FCACHE fcache, uint8_t ch);
+FAR const struct nxfonts_glyph_s *nxf_cache_getglyph(FCACHE fcache, uint8_t ch);
 
 #undef EXTERN
 #if defined(__cplusplus)

libc/queue/sq_addfirst.c

@@ -58,5 +58,6 @@ void sq_addfirst(FAR sq_entry_t *node, sq_queue_t *queue)
     {
       queue->tail = node;
     }
+
   queue->head = node;
 }

libc/queue/sq_remafter.c

@@ -44,10 +44,10 @@
  ****************************************************************************/
 
 /****************************************************************************
- * Name:
+ * Name: sq_remafter
  *
  * Description:
- *   sq_remafter removes the entry following 'node; from the'queue'  Returns
+ *   sq_remafter removes the entry following 'node' from the'queue'  Returns
  *   a reference to the removed entry.
  *
  ****************************************************************************/
@@ -55,6 +55,7 @@
 FAR sq_entry_t *sq_remafter(FAR sq_entry_t *node, sq_queue_t *queue)
 {
   FAR sq_entry_t *ret = node->flink;
+
   if (queue->head && ret)
     {
       if (queue->tail == ret)