diff options
Diffstat (limited to 'src/scroll.c')
| -rw-r--r-- | src/scroll.c | 55 |
1 files changed, 22 insertions, 33 deletions
diff --git a/src/scroll.c b/src/scroll.c index 8a53f9614f7..e6c058351ab 100644 --- a/src/scroll.c +++ b/src/scroll.c @@ -1,6 +1,6 @@ /* Calculate what line insertion or deletion to do, and do it -Copyright (C) 1985-1986, 1990, 1993-1994, 2001-2018 Free Software +Copyright (C) 1985-1986, 1990, 1993-1994, 2001-2019 Free Software Foundation, Inc. This file is part of GNU Emacs. @@ -20,7 +20,6 @@ along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>. */ #include <config.h> -#include <stdio.h> #include "lisp.h" #include "termchar.h" @@ -28,12 +27,6 @@ along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>. */ #include "frame.h" #include "termhooks.h" -/* All costs measured in characters. - So no cost can exceed the area of a frame, measured in characters. - Let's hope this is never more than 1000000 characters. */ - -#define INFINITY 1000000 - struct matrix_elt { /* Cost of outputting through this line @@ -47,13 +40,13 @@ struct matrix_elt int deletecost; /* Number of inserts so far in this run of inserts, for the cost in insertcost. */ - unsigned char insertcount; + int insertcount; /* Number of deletes so far in this run of deletes, for the cost in deletecost. */ - unsigned char deletecount; + int deletecount; /* Number of writes so far since the last insert or delete for the cost in writecost. */ - unsigned char writecount; + int writecount; }; static void do_direct_scrolling (struct frame *, @@ -113,15 +106,13 @@ calculate_scrolling (struct frame *frame, /* 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 = baud_rate / (10 * 4 * frame_total_lines); - - if (baud_rate <= 0) - extra_cost = 1; + 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 = INFINITY; - matrix->deletecost = INFINITY; + matrix->insertcost = SCROLL_INFINITY; + matrix->deletecost = SCROLL_INFINITY; matrix->insertcount = 0; matrix->deletecount = 0; @@ -132,8 +123,8 @@ calculate_scrolling (struct frame *frame, p = matrix + i * (window_size + 1); cost += draw_cost[i] + next_insert_cost[i] + extra_cost; p->insertcost = cost; - p->writecost = INFINITY; - p->deletecost = INFINITY; + p->writecost = SCROLL_INFINITY; + p->deletecost = SCROLL_INFINITY; p->insertcount = i; p->deletecount = 0; } @@ -144,8 +135,8 @@ calculate_scrolling (struct frame *frame, { cost += next_delete_cost[j]; matrix[j].deletecost = cost; - matrix[j].writecost = INFINITY; - matrix[j].insertcost = INFINITY; + matrix[j].writecost = SCROLL_INFINITY; + matrix[j].insertcost = SCROLL_INFINITY; matrix[j].deletecount = j; matrix[j].insertcount = 0; } @@ -192,13 +183,13 @@ calculate_scrolling (struct frame *frame, else { cost = p1->writecost + first_insert_cost[i]; - if ((int) p1->insertcount > 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 ((int) p->insertcount > i) + if (p->insertcount > i) emacs_abort (); /* Calculate the cost if we do a delete line after @@ -452,10 +443,8 @@ calculate_direct_scrolling (struct frame *frame, /* 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 = baud_rate / (10 * 4 * frame_total_lines); - - if (baud_rate <= 0) - extra_cost = 1; + int extra_cost + = clip_to_bounds (1, baud_rate / (10 * 4) / frame_total_lines, INT_MAX / 2); /* Overhead of setting the scroll window, plus the extra cost of scrolling by a distance of one. The extra cost is @@ -465,8 +454,8 @@ calculate_direct_scrolling (struct frame *frame, /* initialize the top left corner of the matrix */ matrix->writecost = 0; - matrix->insertcost = INFINITY; - matrix->deletecost = INFINITY; + matrix->insertcost = SCROLL_INFINITY; + matrix->deletecost = SCROLL_INFINITY; matrix->writecount = 0; matrix->insertcount = 0; matrix->deletecount = 0; @@ -478,8 +467,8 @@ calculate_direct_scrolling (struct frame *frame, p = matrix + i * (window_size + 1); cost += draw_cost[i]; p->insertcost = cost; - p->writecost = INFINITY; - p->deletecost = INFINITY; + p->writecost = SCROLL_INFINITY; + p->deletecost = SCROLL_INFINITY; p->insertcount = i; p->writecount = 0; p->deletecount = 0; @@ -489,8 +478,8 @@ calculate_direct_scrolling (struct frame *frame, for (j = 1; j <= window_size; j++) { matrix[j].deletecost = 0; - matrix[j].writecost = INFINITY; - matrix[j].insertcost = INFINITY; + matrix[j].writecost = SCROLL_INFINITY; + matrix[j].insertcost = SCROLL_INFINITY; matrix[j].deletecount = j; matrix[j].writecount = 0; matrix[j].insertcount = 0; |