hopefully squash the history corruption bug once and for all

1 files changed, 5 insertions, 3 deletions

diff --git a/txt.c b/txt.c
index 45e6af4..07bd0bd 100644
--- a/txt.c
+++ b/txt.c
@@ -278,20 +278,22 @@ void txt_hist_push(Txt *t, TxtLoc cur) {
 		return;
 	}
 	if (t->hist.i + 1 < t->hist.n) t->hist.n = t->hist.i + 1;
-	if (t->hist.n == TXT_HIST_MAX) {
-		/* TODO: this is maybe still buggy? */
+	if (t->hist.n) t->hist.i++;
+	if (t->hist.i == TXT_HIST_MAX) {
 		free(t->hist.v[0].v);
 		MOVE(&t->hist.v[0], &t->hist.v[1], TXT_HIST_MAX - 1);
+		MOVE(&t->hist.cur[0], &t->hist.cur[1], TXT_HIST_MAX - 1);
+		memset(&t->hist.v[TXT_HIST_MAX - 1], 0, sizeof(*t->hist.v));
 		t->hist.i--;
 		t->hist.n--;
 	}
-	if (t->hist.i + 1 == t->hist.n) t->hist.i++;
 	DA_FIT(&t->hist.v[t->hist.i], t->ptbl.n);
 	memcpy(t->hist.v[t->hist.i].v, t->ptbl.v, sizeof(TxtPiece) * t->ptbl.n);
 	t->hist.v[t->hist.i].n = t->ptbl.n;
 	t->hist.v[t->hist.i].dirty = t->ptbl.dirty;
 	t->hist.cur[t->hist.i] = cur;
 	t->hist.n++;
+	ASSERT(t->hist.n == t->hist.i + 1);
 }
 
 int txt_hist_set(Txt *t, TxtLoc *cur) {