(buf_*pos_to_*pos): Fix minor off-by one

* src/marker.c (buf_charpos_to_bytepos, buf_bytepos_to_charpos):
Slightly restructure the markers loop so we check `distance`
also before "consider"ing the first marker.

(cherry picked from commit 0385c0c0820361b71a74988f23d0445238f30473)

diff --git a/src/marker.c b/src/marker.c
index 9aaa2e7402cbf4fe56accff4779de570e216c7d0..16fa3bcef3e6c897c9564adcf1d693c4c19ee637 100644 (file)
--- a/src/marker.c
+++ b/src/marker.c
@@ -202,19 +202,15 @@ buf_charpos_to_bytepos (struct buffer *b, ptrdiff_t charpos)
   if (b == cached_buffer && BUF_MODIFF (b) == cached_modiff)
     CONSIDER (cached_charpos, cached_bytepos);
 
-  for (tail = BUF_MARKERS (b); tail; tail = tail->next)
-    {
-      CONSIDER (tail->charpos, tail->bytepos);
-
-      /* If we are down to a range of 50 chars,
-        don't bother checking any other markers;
-        scan the intervening chars directly now.  */
-      if (best_above - charpos < distance
-          || charpos - best_below < distance)
-       break;
-      else
-        distance += BYTECHAR_DISTANCE_INCREMENT;
-    }
+  for (tail = BUF_MARKERS (b);
+       /* If we are down to a range of DISTANCE chars,
+          don't bother checking any other markers;
+          scan the intervening chars directly now.  */
+       tail && !(best_above - charpos < distance
+                || charpos - best_below < distance);
+       tail = tail->next,
+       distance += BYTECHAR_DISTANCE_INCREMENT)
+    CONSIDER (tail->charpos, tail->bytepos);
 
   /* We get here if we did not exactly hit one of the known places.
      We have one known above and one known below.
@@ -354,19 +350,15 @@ buf_bytepos_to_charpos (struct buffer *b, ptrdiff_t bytepos)
   if (b == cached_buffer && BUF_MODIFF (b) == cached_modiff)
     CONSIDER (cached_bytepos, cached_charpos);
 
-  for (tail = BUF_MARKERS (b); tail; tail = tail->next)
-    {
-      CONSIDER (tail->bytepos, tail->charpos);
-
-      /* If we are down to a range of DISTANCE bytes,
-        don't bother checking any other markers;
-        scan the intervening chars directly now.  */
-      if (best_above_byte - bytepos < distance
-          || bytepos - best_below_byte < distance)
-       break;
-      else
-        distance += BYTECHAR_DISTANCE_INCREMENT;
-    }
+  for (tail = BUF_MARKERS (b);
+       /* If we are down to a range of DISTANCE bytes,
+          don't bother checking any other markers;
+          scan the intervening chars directly now.  */
+       tail && !(best_above_byte - bytepos < distance
+                || bytepos - best_below_byte < distance);
+       tail = tail->next,
+       distance += BYTECHAR_DISTANCE_INCREMENT)
+    CONSIDER (tail->bytepos, tail->charpos);
 
   /* We get here if we did not exactly hit one of the known places.
      We have one known above and one known below.