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[smooth] Clean up the null cell usage.

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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.
This commit is contained in:
Alexei Podtelezhnikov 2021-08-20 23:40:49 -04:00
parent 6e9d8d314f
commit d62d583d92
1 changed files with 26 additions and 45 deletions
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71
src/smooth/ftgrays.c
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@ -479,14 +479,11 @@ typedef ptrdiff_t FT_PtrDist;
PCell cell; /* current cell */
PCell cell_free; /* call allocation next free slot */
PCell cell_limit; /* cell allocation limit */
PCell cell_null; /* last cell, used as dumpster and limit */
PCell* ycells; /* array of cell linked-lists; one per */
/* vertical coordinate in the current band */
PCell cells; /* cell storage area */
FT_PtrDist max_cells; /* cell storage capacity */
TPos x, y; /* last point position */
FT_Outline outline; /* input outline */
@ -507,22 +504,10 @@ typedef ptrdiff_t FT_PtrDist;
static gray_TWorker ras;
#endif
/*
* Return a pointer to the 'null cell', used as a sentinel at the end of
* all `ycells` linked lists. Its x coordinate should be maximal to
* ensure no NULL checks are necessary when looking for an insertion point
* in `gray_set_cell`. Other loops should check the cell pointer with
* CELL_IS_NULL() to detect the end of the list.
*/
#define NULL_CELL_PTR( ras ) (ras).cells
/* The |x| value of the null cell. Must be the largest possible */
/* integer value stored in a `TCell.x` field. */
#define CELL_MAX_X_VALUE INT_MAX
/* Return true iff |cell| points to the null cell. */
#define CELL_IS_NULL( cell ) ( (cell)->x == CELL_MAX_X_VALUE )
#define FT_INTEGRATE( ras, a, b ) \
ras.cell->cover = ADD_INT( ras.cell->cover, a ), \
@ -553,7 +538,7 @@ typedef ptrdiff_t FT_PtrDist;
printf( "%3d:", y );
for ( ; !CELL_IS_NULL( cell ); cell = cell->next )
for ( ; cell != ras.cell_null; cell = cell->next )
printf( " (%3d, c:%4d, a:%6d)",
cell->x, cell->cover, cell->area );
printf( "\n" );
@ -572,7 +557,7 @@ typedef ptrdiff_t FT_PtrDist;
TCoord ey )
{
/* Move the cell pointer to a new position in the linked list. We use */
/* NULL to indicate that the cell is outside of the clipping region */
/* a dumpster null cell for everything outside of the clipping region */
/* during the render phase. This means that: */
/* */
/* . the new vertical position must be within min_ey..max_ey-1. */
@ -585,7 +570,7 @@ typedef ptrdiff_t FT_PtrDist;
if ( ey_index < 0 || ey_index >= ras.count_ey || ex >= ras.max_ex )
ras.cell = NULL_CELL_PTR( ras );
ras.cell = ras.cell_null;
else
{
PCell* pcell = ras.ycells + ey_index;
@ -609,7 +594,7 @@ typedef ptrdiff_t FT_PtrDist;
/* insert new cell */
cell = ras.cell_free++;
if ( cell >= ras.cell_limit )
if ( cell >= ras.cell_null )
ft_longjmp( ras.jump_buffer, 1 );
cell->x = ex;
@ -1483,7 +1468,7 @@ typedef ptrdiff_t FT_PtrDist;
unsigned char* line = ras.target.origin - ras.target.pitch * y;
for ( ; !CELL_IS_NULL( cell ); cell = cell->next )
for ( ; cell != ras.cell_null; cell = cell->next )
{
TArea area;
@ -1534,7 +1519,7 @@ typedef ptrdiff_t FT_PtrDist;
TArea cover = 0;
for ( ; !CELL_IS_NULL( cell ); cell = cell->next )
for ( ; cell != ras.cell_null; cell = cell->next )
{
TArea area;
@ -1914,11 +1899,11 @@ typedef ptrdiff_t FT_PtrDist;
if ( continued )
FT_Trace_Enable();
FT_TRACE7(( "band [%d..%d]: %ld cell%s\n",
FT_TRACE7(( "band [%d..%d]: %ld cell%s remaining/\n",
ras.min_ey,
ras.max_ey,
ras.cell_free - ras.cells,
ras.cell_free - ras.cells == 1 ? "" : "s" ));
ras.cell_null - ras.cell_free,
ras.cell_null - ras.cell_free == 1 ? "" : "s" ));
}
else
{
@ -1948,7 +1933,16 @@ typedef ptrdiff_t FT_PtrDist;
int continued = 0;
/* Initialize the null cell at the end of the poll. */
ras.cell_null = buffer + FT_MAX_GRAY_POOL - 1;
ras.cell_null->x = CELL_MAX_X_VALUE;
ras.cell_null->area = 0;
ras.cell_null->cover = 0;
ras.cell_null->next = NULL;;
/* set up vertical bands */
ras.ycells = (PCell*)buffer;
if ( height > n )
{
/* two divisions rounded up */
@ -1956,23 +1950,6 @@ typedef ptrdiff_t FT_PtrDist;
height = ( height + n - 1 ) / n;
}
/* memory management */
n = ( height * sizeof ( PCell ) + sizeof ( TCell ) - 1 ) / sizeof ( TCell );
ras.cells = buffer + n;
ras.max_cells = (FT_PtrDist)( FT_MAX_GRAY_POOL - n );
ras.cell_limit = ras.cells + ras.max_cells;
ras.ycells = (PCell*)buffer;
/* Initialize the null cell at the start of the `cells` array. */
/* Note that this requires `ras.cell_free` initialization to skip */
/* over the first entry in the array. */
PCell null_cell = NULL_CELL_PTR( ras );
null_cell->x = CELL_MAX_X_VALUE;
null_cell->area = 0;
null_cell->cover = 0;
null_cell->next = NULL;;
for ( y = yMin; y < yMax; )
{
ras.min_ey = y;
@ -1991,10 +1968,14 @@ typedef ptrdiff_t FT_PtrDist;
for ( w = 0; w < width; ++w )
ras.ycells[w] = null_cell;
ras.ycells[w] = ras.cell_null;
ras.cell_free = ras.cells + 1; /* NOTE: Skip over the null cell. */
ras.cell = null_cell;
/* memory management: skip ycells */
n = ( width * sizeof ( PCell ) + sizeof ( TCell ) - 1 ) /
sizeof ( TCell );
ras.cell_free = buffer + n;
ras.cell = ras.cell_null;
ras.min_ey = band[1];
ras.max_ey = band[0];
ras.count_ey = width;