move the statically allocated tokens array into the skin buffer. this is done with a little bit of magic with the buffer... explanation in the comments but breifly, tokens + images are stored at the front of the buffer, everything else (constant sizes) are stored at the back, the 2 ends meet when the buffer is full.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@22418 a1c6a512-1295-4272-9138-f99709370657

apps/gui/skin_engine/skin_buffer.c

@@ -38,6 +38,15 @@
  * MAIN_ and REMOTE_BUFFER are just for reasonable size calibration,
  * both screens can use the whole buffer as they need; it's not split
  * between screens
+ * 
+ * Buffer can be allocated from either "end" of the global buffer.
+ * items with unknown sizes get allocated from the start (0->)      (data)
+ * items with known sizes get allocated from the end (<-buf_size)   (tokens)
+ * After loading 2 skins the buffer will look like this:
+ *  |tokens skin1|images skin2|---SPACE---|data skin2|data skin1|
+ * Make sure to never start allocating from the beginning before letting us know
+ * how much was used. and RESPECT THE buf_free RETURN VALUES!
+ * 
  */
 
 
@@ -55,63 +64,93 @@
 #define SKIN_BUFFER_SIZE (MAIN_BUFFER + REMOTE_BUFFER)
 
 
-static unsigned char buffer_start[SKIN_BUFFER_SIZE], *buffer_pos = NULL;
+static unsigned char buffer[SKIN_BUFFER_SIZE];
+static unsigned char *buffer_front = NULL; /* start of the free space,
+                                              increases with allocation*/
+static unsigned char *buffer_back  = NULL; /* end of the free space
+                                              decreases with allocation */
 static size_t buf_size = SKIN_BUFFER_SIZE;
 
 void skin_buffer_init(void)
 {
 #if 0 /* this will go in again later probably */
-    if (buffer_start == NULL)
+    if (buffer == NULL)
     {
         buf_size = SKIN_BUFFER_SIZE;/* global_settings.skin_buf_size */
             
-        buffer_start = buffer_alloc(buf_size);
-        buffer_pos = buffer_start;
+        buffer = buffer_alloc(buf_size);
+        buffer_front = buffer;
+        buffer_back = bufer + buf_size;
     }
     else
 #endif
     {
         /* reset the buffer.... */
-        buffer_pos = buffer_start;
+        buffer_front = buffer;
+        buffer_back = buffer + buf_size;
     }
 }
 
 /* get the number of bytes currently being used */
 size_t skin_buffer_usage(void)
 {
-    return buffer_pos-buffer_start;
+    return buf_size - (buffer_back-buffer_front);
 }
 
-/* Allocate size bytes from the buffer */
+size_t skin_buffer_freespace(void)
+{
+    return buffer_back-buffer_front;
+}
+
+/* Allocate size bytes from the buffer
+ * allocates from the back end (data end)
+ */
 void* skin_buffer_alloc(size_t size)
 {
-    void* retval = buffer_pos;
-    if (skin_buffer_usage()+size >= buf_size)
+    if (skin_buffer_freespace() <= size)
     {
         return NULL;
     }
-    buffer_pos += size;
+    buffer_back -= size;
     /* 32-bit aligned */
-    buffer_pos = (void *)(((unsigned long)buffer_pos + 3) & ~3);
-    return retval;
+    buffer_back = (void *)(((unsigned long)buffer_back) & ~3);
+    return buffer_back;
 }
 
 /* Get a pointer to the skin buffer and the count of how much is free
  * used to do your own buffer management. 
  * Any memory used will be overwritten next time wps_buffer_alloc()
  * is called unless skin_buffer_increment() is called first
+ * 
+ * This is from the start of the buffer, it is YOUR responsility to make
+ * sure you dont ever use more then *freespace, and bear in mind this will only
+ * be valid untill skin_buffer_alloc() is next called...
+ * so call skin_buffer_increment() and skin_buffer_freespace() regularly
  */
 void* skin_buffer_grab(size_t *freespace)
 {
     *freespace = buf_size - skin_buffer_usage();
-    return buffer_pos;
+    return buffer_front;
 }
 
 /* Use after skin_buffer_grab() to specify how much buffer was used */
-void skin_buffer_increment(size_t used)
+void skin_buffer_increment(size_t used, bool align)
 {
-    buffer_pos += used;
-    /* 32-bit aligned */
-    buffer_pos = (void *)(((unsigned long)buffer_pos + 3) & ~3);
+    buffer_front += used;
+    if (align)
+    {
+        /* 32-bit aligned */
+        buffer_front = (void *)(((unsigned long)buffer_front + 3) & ~3);
+    }
 }
 
+/* free previously skin_buffer_increment()'ed space. This just moves the pointer
+ * back 'used' bytes so make sure you actually want to do this */
+void skin_buffer_free_from_front(size_t used)
+{
+    buffer_front -= used;
+    /* 32-bit aligned */
+    buffer_front = (void *)(((unsigned long)buffer_front + 3) & ~3);
+}
+
+

apps/gui/skin_engine/skin_buffer.h

@@ -33,6 +33,7 @@ void skin_buffer_init(void);
 
 /* get the number of bytes currently being used */
 size_t skin_buffer_usage(void);
+size_t skin_buffer_freespace(void);
 
 /* Allocate size bytes from the buffer */
 void* skin_buffer_alloc(size_t size);
@@ -42,10 +43,22 @@ void* skin_buffer_alloc(size_t size);
  * used to do your own buffer management. 
  * Any memory used will be overwritten next time wps_buffer_alloc()
  * is called unless skin_buffer_increment() is called first
+ * 
+ * This is from the start of the buffer, it is YOUR responsility to make
+ * sure you dont ever use more then *freespace, and bear in mind this will only
+ * be valid untill skin_buffer_alloc() is next called...
+ * so call skin_buffer_increment() and skin_buffer_freespace() regularly
  */
 void* skin_buffer_grab(size_t *freespace);
 
-/* Use after skin_buffer_grab() to specify how much buffer was used */
-void skin_buffer_increment(size_t used);
+/* Use after skin_buffer_grab() to specify how much buffer was used.
+ * align should always be true unless there is a possibility that you will need
+ * more space *immediatly* after the previous allocation. (i.e in an array).
+ * NEVER leave the buffer unaligned */
+void skin_buffer_increment(size_t used, bool align);
+
+/* free previously skin_buffer_increment()'ed space. This just moves the pointer
+ * back 'used' bytes so make sure you actually want to do this */
+void skin_buffer_free_from_front(size_t used);
 
 #endif /* _SKIN_BUFFER_H_ */

apps/gui/skin_engine/skin_parser.c

@@ -1274,18 +1274,44 @@ static int parse_token(const char *wps_bufptr, struct wps_data *wps_data)
    data is the pointer to the structure where the parsed WPS should be stored.
         It is initialised.
    wps_bufptr points to the string containing the WPS tags */
+#define TOKEN_BLOCK_SIZE 128   
 static bool wps_parse(struct wps_data *data, const char *wps_bufptr)
 {
     if (!data || !wps_bufptr || !*wps_bufptr)
         return false;
     enum wps_parse_error fail = PARSE_OK;
     int ret;
+    int max_tokens = TOKEN_BLOCK_SIZE;
+    size_t buf_free = 0;
     line = 1;
     level = -1;
+    
+    /* allocate enough RAM for a reasonable skin, grow as needed. 
+     * Free any used RAM before loading the images to be 100% RAM efficient */
+    data->tokens = (struct wps_token *)skin_buffer_grab(&buf_free);
+    if (sizeof(struct wps_token)*max_tokens >= buf_free)
+        return false;
+    skin_buffer_increment(max_tokens * sizeof(struct wps_token), false);
+    data->num_tokens = 0;
 
-    while(*wps_bufptr && !fail && data->num_tokens < WPS_MAX_TOKENS - 1
+    while(*wps_bufptr && !fail
           && data->num_lines < WPS_MAX_LINES)
     {
+        /* first make sure there is enough room for tokens */
+        if (max_tokens -1 == data->num_tokens)
+        {
+            int extra_tokens = TOKEN_BLOCK_SIZE;
+            size_t needed = extra_tokens * sizeof(struct wps_token);
+            /* do some smarts here to grow the array a bit */
+            if (skin_buffer_freespace() < needed)
+            {
+                fail = PARSE_FAIL_LIMITS_EXCEEDED;
+                break;
+            }
+            skin_buffer_increment(needed, false);
+            max_tokens += extra_tokens;
+        }
+        
         switch(*wps_bufptr++)
         {
 
@@ -1482,6 +1508,10 @@ static bool wps_parse(struct wps_data *data, const char *wps_bufptr)
         /* one of the limits of the while loop was exceeded */
         fail = PARSE_FAIL_LIMITS_EXCEEDED;
 
+    /* Success! */
+    /* freeup unused tokens */
+    skin_buffer_free_from_front(sizeof(struct wps_token) 
+                                * (max_tokens - data->num_tokens));
     curr_vp->last_line = data->num_lines - 1;
 
 #if defined(DEBUG) || defined(SIMULATOR)
@@ -1528,7 +1558,7 @@ static bool load_skin_bmp(struct wps_data *wps_data, struct bitmap *bitmap, char
 
     if (ret > 0)
     {
-		skin_buffer_increment(ret);
+		skin_buffer_increment(ret, true);
         loaded = true;
     }
     else

apps/gui/skin_engine/wps_internals.h

@@ -276,7 +276,7 @@ struct wps_data
     /* Total number of tokens in the WPS. During WPS parsing, this is
        the index of the token being parsed. */
     int num_tokens;
-    struct wps_token tokens[WPS_MAX_TOKENS];
+    struct wps_token *tokens;
 
     struct skin_token_list *strings;