vis: stop repeated motions as soon as resulting position remains the same

This improves responsiveness of {count}j for files with less than count
lines. For huge files this will still be slow because the code tries
to restore cursor position on every line before moving on to the next.
Also moving up will generally be slower than downwards. Use {count}%
(fastest) or or :count (slower) instead.

Close #267

1 files changed, 2 insertions, 1 deletions

diff --git a/vis.c b/vis.c
index 730763b..4926555 100644
--- a/vis.c
+++ b/vis.c
@@ -495,6 +495,7 @@ void action_do(Vis *vis, Action *a) {
 		if (a->movement) {
 			size_t start = pos;
 			for (int i = 0; i < count; i++) {
+				size_t pos_prev = pos;
 				if (a->movement->txt)
 					pos = a->movement->txt(txt, pos);
 				else if (a->movement->cur)
@@ -509,7 +510,7 @@ void action_do(Vis *vis, Action *a) {
 					pos = a->movement->win(vis, win, pos);
 				else if (a->movement->user)
 					pos = a->movement->user(vis, win, a->movement->data, pos);
-				if (pos == EPOS || a->movement->type & IDEMPOTENT)
+				if (pos == EPOS || a->movement->type & IDEMPOTENT || pos == pos_prev)
 					break;
 			}