void
scrolling_1 (struct frame *frame, int window_size, int unchanged_at_top,
int unchanged_at_bottom, int *draw_cost, int *old_draw_cost,
unsigned *old_hash, unsigned *new_hash, int free_at_end)
{
USE_SAFE_ALLOCA;
struct matrix_elt *matrix;
SAFE_NALLOCA (matrix, window_size + 1, window_size + 1);
if (FRAME_SCROLL_REGION_OK (frame))
{
calculate_direct_scrolling (frame, matrix, window_size,
unchanged_at_bottom,
draw_cost, old_draw_cost,
old_hash, new_hash, free_at_end);
do_direct_scrolling (frame, frame->current_matrix,
matrix, window_size, unchanged_at_top);
}
else
{
calculate_scrolling (frame, matrix, window_size, unchanged_at_bottom,
draw_cost, old_hash, new_hash,
free_at_end);
do_scrolling (frame,
frame->current_matrix, matrix, window_size,
unchanged_at_top);
}
SAFE_FREE ();
}
void
scrolling_1 (struct frame *frame, int window_size, int unchanged_at_top,
int unchanged_at_bottom, int *draw_cost, int *old_draw_cost,
int *old_hash, int *new_hash, int free_at_end)
{
struct matrix_elt *matrix
= alloca ((window_size + 1) * (window_size + 1) * sizeof *matrix);
if (FRAME_SCROLL_REGION_OK (frame))
{
calculate_direct_scrolling (frame, matrix, window_size,
unchanged_at_bottom,
draw_cost, old_draw_cost,
old_hash, new_hash, free_at_end);
do_direct_scrolling (frame, frame->current_matrix,
matrix, window_size, unchanged_at_top);
}
else
{
calculate_scrolling (frame, matrix, window_size, unchanged_at_bottom,
draw_cost, old_hash, new_hash,
free_at_end);
do_scrolling (frame,
frame->current_matrix, matrix, window_size,
unchanged_at_top);
}
}
static void
calculate_scrolling (struct frame *frame,
/* matrix is of size window_size + 1 on each side. */
struct matrix_elt *matrix,
int window_size, int lines_below,
int *draw_cost, unsigned *old_hash, unsigned *new_hash,
int free_at_end)
{
int i, j;
int frame_total_lines = FRAME_TOTAL_LINES (frame);
struct matrix_elt *p, *p1;
int cost, cost1;
int lines_moved = window_size
+ (FRAME_SCROLL_REGION_OK (frame) ? 0 : lines_below);
/* first_insert_cost[I] is the cost of doing the first insert-line
at the i'th line of the lines we are considering,
where I is origin 1 (as it is below). */
int *first_insert_cost
= &FRAME_INSERT_COST (frame)[frame_total_lines - 1 - lines_moved];
int *first_delete_cost
= &FRAME_DELETE_COST (frame)[frame_total_lines - 1 - lines_moved];
int *next_insert_cost
= &FRAME_INSERTN_COST (frame)[frame_total_lines - 1 - lines_moved];
int *next_delete_cost
= &FRAME_DELETEN_COST (frame)[frame_total_lines - 1 - lines_moved];
/* Discourage long scrolls on fast lines.
Don't scroll nearly a full frame height unless it saves
at least 1/4 second. */
int extra_cost
= clip_to_bounds (1, baud_rate / (10 * 4) / frame_total_lines, INT_MAX / 2);
/* initialize the top left corner of the matrix */
matrix->writecost = 0;
matrix->insertcost = SCROLL_INFINITY;
matrix->deletecost = SCROLL_INFINITY;
matrix->insertcount = 0;
matrix->deletecount = 0;
/* initialize the left edge of the matrix */
cost = first_insert_cost[1] - next_insert_cost[1];
for (i = 1; i <= window_size; i++)
{
p = matrix + i * (window_size + 1);
cost += draw_cost[i] + next_insert_cost[i] + extra_cost;
p->insertcost = cost;
p->writecost = SCROLL_INFINITY;
p->deletecost = SCROLL_INFINITY;
p->insertcount = i;
p->deletecount = 0;
}
/* initialize the top edge of the matrix */
cost = first_delete_cost[1] - next_delete_cost[1];
for (j = 1; j <= window_size; j++)
{
cost += next_delete_cost[j];
matrix[j].deletecost = cost;
matrix[j].writecost = SCROLL_INFINITY;
matrix[j].insertcost = SCROLL_INFINITY;
matrix[j].deletecount = j;
matrix[j].insertcount = 0;
}
/* `i' represents the vpos among new frame contents.
`j' represents the vpos among the old frame contents. */
p = matrix + window_size + 2; /* matrix [1, 1] */
for (i = 1; i <= window_size; i++, p++)
for (j = 1; j <= window_size; j++, p++)
{
/* p contains the address of matrix [i, j] */
/* First calculate the cost assuming we do
not insert or delete above this line.
That is, if we update through line i-1
based on old lines through j-1,
and then just change old line j to new line i. */
p1 = p - window_size - 2; /* matrix [i-1, j-1] */
cost = p1->writecost;
if (cost > p1->insertcost)
cost = p1->insertcost;
if (cost > p1->deletecost)
cost = p1->deletecost;
if (old_hash[j] != new_hash[i])
cost += draw_cost[i];
p->writecost = cost;
/* Calculate the cost if we do an insert-line
before outputting this line.
That is, we update through line i-1
based on old lines through j,
do an insert-line on line i,
and then output line i from scratch,
leaving old lines starting from j for reuse below. */
p1 = p - window_size - 1; /* matrix [i-1, j] */
/* No need to think about doing a delete followed
immediately by an insert. It cannot be as good
as not doing either of them. */
if (free_at_end == i)
{
cost = p1->writecost;
cost1 = p1->insertcost;
}
else
{
cost = p1->writecost + first_insert_cost[i];
if (p1->insertcount > i)
emacs_abort ();
cost1 = p1->insertcost + next_insert_cost[i - p1->insertcount];
}
p->insertcost = min (cost, cost1) + draw_cost[i] + extra_cost;
p->insertcount = (cost < cost1) ? 1 : p1->insertcount + 1;
if (p->insertcount > i)
emacs_abort ();
/* Calculate the cost if we do a delete line after
outputting this line.
That is, we update through line i
based on old lines through j-1,
and throw away old line j. */
p1 = p - 1; /* matrix [i, j-1] */
/* No need to think about doing an insert followed
immediately by a delete. */
if (free_at_end == i)
{
cost = p1->writecost;
cost1 = p1->deletecost;
}
else
{
cost = p1->writecost + first_delete_cost[i];
cost1 = p1->deletecost + next_delete_cost[i];
}
p->deletecost = min (cost, cost1);
p->deletecount = (cost < cost1) ? 1 : p1->deletecount + 1;
}
}
