scratch/long-lines-cleanup 0cc8d6826ad: Three final fixes to last changes

[Gregory Heytings]

branch: scratch/long-lines-cleanup
commit 0cc8d6826ad2717a3fd21240d0c97232536cab93
Author: Gregory Heytings <gregory@heytings.org>
Commit: Gregory Heytings <gregory@heytings.org>

    Three final fixes to last changes
    
    * src/xdisp.c (get_nearby_bol_pos): Initialize 'bol' to BEGV - 1
    instead of 0 (which fixes cursor motion commands in the presence
    of a narrowing), adapt the return condition accordingly, and do
    not restart the loop when BEGV has been reached.
    (get_small_narrowing_begv): Use correct type.
---
 src/xdisp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/xdisp.c b/src/xdisp.c
index 62dc3438117..940b8dc820e 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -3616,7 +3616,7 @@ get_medium_narrowing_zv (struct window *w, ptrdiff_t pos)
 static ptrdiff_t
 get_nearby_bol_pos (ptrdiff_t pos)
 {
-  ptrdiff_t start, pos_bytepos, cur, next, found, bol = 0;
+  ptrdiff_t start, pos_bytepos, cur, next, found, bol = BEGV - 1;
   int dist;
   for (dist = 500; dist <= 500000; dist *= 10)
     {
@@ -3632,7 +3632,7 @@ get_nearby_bol_pos (ptrdiff_t pos)
          else
            break;
        }
-      if (bol)
+      if (bol >= BEGV || start == BEGV)
        return bol;
       else
        pos = pos - dist < BEGV ? BEGV : pos - dist;
@@ -3644,7 +3644,7 @@ ptrdiff_t
 get_small_narrowing_begv (struct window *w, ptrdiff_t pos)
 {
   int len = get_narrowed_width (w);
-  int bol_pos = get_nearby_bol_pos (pos);
+  ptrdiff_t bol_pos = get_nearby_bol_pos (pos);
   return max (bol_pos + ((pos - bol_pos) / len - 1) * len, BEGV);
 }