[Git][freetype/freetype][master] [smooth] Clean up the null cell usage.

[Alexei Podtelezhnikov (@apodtele)]

Alexei Podtelezhnikov pushed to branch master at FreeType / FreeType

Commits:

• d62d583d
  by Alexei Podtelezhnikov at 2021-08-20T23:40:49-04:00

  [smooth] Clean up the null cell usage.
  
  Put the null cell at the end of the pool and store it explicitly so that
  we can use it as both the limit and the dumpster.
  
  * src/smooth/ftgrays.c (gray_TWorker): Store the last `cell_null` and
  remove unnecesary fields.
  (NULL_CELL_PTR, CELL_IS_NULL): Remove in favor of explicit `cell_null`.
  (gray_dump_cells, gray_set_cell, gray_sweep{,_direct}): Update callers.
  (gray_convert_glyph_inner): Trace remaining cells (oh well).
  (gray_convert_glyph): Set up `cell_null` and slightly improve the pool
  management.
  

1 changed file:

• src/smooth/ftgrays.c

Changes:

src/smooth/ftgrays.c

---

...	...	@@ -479,14 +479,11 @@ typedef ptrdiff_t FT_PtrDist;
479	479
480	480	PCell cell; /* current cell */
481	481	PCell cell_free; /* call allocation next free slot */
482		- PCell cell_limit; /* cell allocation limit */
	482	+ PCell cell_null; /* last cell, used as dumpster and limit */
483	483
484	484	PCell* ycells; /* array of cell linked-lists; one per */
485	485	/* vertical coordinate in the current band */
486	486
487		- PCell cells; /* cell storage area */
488		- FT_PtrDist max_cells; /* cell storage capacity */
489		-
490	487	TPos x, y; /* last point position */
491	488
492	489	FT_Outline outline; /* input outline */
...	...	@@ -507,22 +504,10 @@ typedef ptrdiff_t FT_PtrDist;
507	504	static gray_TWorker ras;
508	505	#endif
509	506
510		- /*
511		- * Return a pointer to the 'null cell', used as a sentinel at the end of
512		- * all `ycells` linked lists. Its x coordinate should be maximal to
513		- * ensure no NULL checks are necessary when looking for an insertion point
514		- * in `gray_set_cell`. Other loops should check the cell pointer with
515		- * CELL_IS_NULL() to detect the end of the list.
516		- */
517		-#define NULL_CELL_PTR( ras ) (ras).cells
518		-
519	507	/* The |x| value of the null cell. Must be the largest possible */
520	508	/* integer value stored in a `TCell.x` field. */
521	509	#define CELL_MAX_X_VALUE INT_MAX
522	510
523		- /* Return true iff |cell| points to the null cell. */
524		-#define CELL_IS_NULL( cell ) ( (cell)->x == CELL_MAX_X_VALUE )
525		-
526	511
527	512	#define FT_INTEGRATE( ras, a, b ) \
528	513	ras.cell->cover = ADD_INT( ras.cell->cover, a ), \
...	...	@@ -553,7 +538,7 @@ typedef ptrdiff_t FT_PtrDist;
553	538
554	539	printf( "%3d:", y );
555	540
556		- for ( ; !CELL_IS_NULL( cell ); cell = cell->next )
	541	+ for ( ; cell != ras.cell_null; cell = cell->next )
557	542	printf( " (%3d, c:%4d, a:%6d)",
558	543	cell->x, cell->cover, cell->area );
559	544	printf( "\n" );
...	...	@@ -572,7 +557,7 @@ typedef ptrdiff_t FT_PtrDist;
572	557	TCoord ey )
573	558	{
574	559	/* Move the cell pointer to a new position in the linked list. We use */
575		- /* NULL to indicate that the cell is outside of the clipping region */
	560	+ /* a dumpster null cell for everything outside of the clipping region */
576	561	/* during the render phase. This means that: */
577	562	/* */
578	563	/* . the new vertical position must be within min_ey..max_ey-1. */
...	...	@@ -585,7 +570,7 @@ typedef ptrdiff_t FT_PtrDist;
585	570
586	571
587	572	if ( ey_index < 0 || ey_index >= ras.count_ey || ex >= ras.max_ex )
588		- ras.cell = NULL_CELL_PTR( ras );
	573	+ ras.cell = ras.cell_null;
589	574	else
590	575	{
591	576	PCell* pcell = ras.ycells + ey_index;
...	...	@@ -609,7 +594,7 @@ typedef ptrdiff_t FT_PtrDist;
609	594
610	595	/* insert new cell */
611	596	cell = ras.cell_free++;
612		- if ( cell >= ras.cell_limit )
	597	+ if ( cell >= ras.cell_null )
613	598	ft_longjmp( ras.jump_buffer, 1 );
614	599
615	600	cell->x = ex;
...	...	@@ -1483,7 +1468,7 @@ typedef ptrdiff_t FT_PtrDist;
1483	1468	unsigned char* line = ras.target.origin - ras.target.pitch * y;
1484	1469
1485	1470
1486		- for ( ; !CELL_IS_NULL( cell ); cell = cell->next )
	1471	+ for ( ; cell != ras.cell_null; cell = cell->next )
1487	1472	{
1488	1473	TArea area;
1489	1474
...	...	@@ -1534,7 +1519,7 @@ typedef ptrdiff_t FT_PtrDist;
1534	1519	TArea cover = 0;
1535	1520
1536	1521
1537		- for ( ; !CELL_IS_NULL( cell ); cell = cell->next )
	1522	+ for ( ; cell != ras.cell_null; cell = cell->next )
1538	1523	{
1539	1524	TArea area;
1540	1525
...	...	@@ -1914,11 +1899,11 @@ typedef ptrdiff_t FT_PtrDist;
1914	1899	if ( continued )
1915	1900	FT_Trace_Enable();
1916	1901
1917		- FT_TRACE7(( "band [%d..%d]: %ld cell%s\n",
	1902	+ FT_TRACE7(( "band [%d..%d]: %ld cell%s remaining/\n",
1918	1903	ras.min_ey,
1919	1904	ras.max_ey,
1920		- ras.cell_free - ras.cells,
1921		- ras.cell_free - ras.cells == 1 ? "" : "s" ));
	1905	+ ras.cell_null - ras.cell_free,
	1906	+ ras.cell_null - ras.cell_free == 1 ? "" : "s" ));
1922	1907	}
1923	1908	else
1924	1909	{
...	...	@@ -1948,7 +1933,16 @@ typedef ptrdiff_t FT_PtrDist;
1948	1933	int continued = 0;
1949	1934
1950	1935
	1936	+ /* Initialize the null cell at the end of the poll. */
	1937	+ ras.cell_null = buffer + FT_MAX_GRAY_POOL - 1;
	1938	+ ras.cell_null->x = CELL_MAX_X_VALUE;
	1939	+ ras.cell_null->area = 0;
	1940	+ ras.cell_null->cover = 0;
	1941	+ ras.cell_null->next = NULL;;
	1942	+
1951	1943	/* set up vertical bands */
	1944	+ ras.ycells = (PCell*)buffer;
	1945	+
1952	1946	if ( height > n )
1953	1947	{
1954	1948	/* two divisions rounded up */
...	...	@@ -1956,23 +1950,6 @@ typedef ptrdiff_t FT_PtrDist;
1956	1950	height = ( height + n - 1 ) / n;
1957	1951	}
1958	1952
1959		- /* memory management */
1960		- n = ( height * sizeof ( PCell ) + sizeof ( TCell ) - 1 ) / sizeof ( TCell );
1961		-
1962		- ras.cells = buffer + n;
1963		- ras.max_cells = (FT_PtrDist)( FT_MAX_GRAY_POOL - n );
1964		- ras.cell_limit = ras.cells + ras.max_cells;
1965		- ras.ycells = (PCell*)buffer;
1966		-
1967		- /* Initialize the null cell at the start of the `cells` array. */
1968		- /* Note that this requires `ras.cell_free` initialization to skip */
1969		- /* over the first entry in the array. */
1970		- PCell null_cell = NULL_CELL_PTR( ras );
1971		- null_cell->x = CELL_MAX_X_VALUE;
1972		- null_cell->area = 0;
1973		- null_cell->cover = 0;
1974		- null_cell->next = NULL;;
1975		-
1976	1953	for ( y = yMin; y < yMax; )
1977	1954	{
1978	1955	ras.min_ey = y;
...	...	@@ -1991,10 +1968,14 @@ typedef ptrdiff_t FT_PtrDist;
1991	1968
1992	1969
1993	1970	for ( w = 0; w < width; ++w )
1994		- ras.ycells[w] = null_cell;
	1971	+ ras.ycells[w] = ras.cell_null;
	1972	+
	1973	+ /* memory management: skip ycells */
	1974	+ n = ( width * sizeof ( PCell ) + sizeof ( TCell ) - 1 ) /
	1975	+ sizeof ( TCell );
1995	1976
1996		- ras.cell_free = ras.cells + 1; /* NOTE: Skip over the null cell. */
1997		- ras.cell = null_cell;
	1977	+ ras.cell_free = buffer + n;
	1978	+ ras.cell = ras.cell_null;
1998	1979	ras.min_ey = band[1];
1999	1980	ras.max_ey = band[0];
2000	1981	ras.count_ey = width;

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