xdiff: cleanup xdl_trim_ends()

This patch is best viewed with a before and after of the whole
function.

Rather than using 2 pointers and walking them. Use direct indexing with
local variables of what is being compared to make it easier to follow
along.

Signed-off-by: Ezekiel Newren <ezekielnewren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/xdiff/xprepare.c b/xdiff/xprepare.c
index 0acb3437d49a2a3f8a8ac38bb4499d7b80476e13..06b6a6f804e0e37f21c1f6e6d9d2a41bac409ef7 100644 (file)
--- a/xdiff/xprepare.c
+++ b/xdiff/xprepare.c
@@ -340,29 +340,29 @@ cleanup:
 /*
  * Early trim initial and terminal matching records.
  */
-static int xdl_trim_ends(xdfenv_t *xe) {
-       long i, lim;
-       xrecord_t *recs1, *recs2;
-
-       recs1 = xe->xdf1.recs;
-       recs2 = xe->xdf2.recs;
-       for (i = 0, lim = (long)XDL_MIN(xe->xdf1.nrec, xe->xdf2.nrec); i < lim;
-            i++, recs1++, recs2++)
-               if (recs1->minimal_perfect_hash != recs2->minimal_perfect_hash)
+static void xdl_trim_ends(xdfenv_t *xe)
+{
+       size_t lim = XDL_MIN(xe->xdf1.nrec, xe->xdf2.nrec);
+
+       for (size_t i = 0; i < lim; i++) {
+               size_t mph1 = xe->xdf1.recs[i].minimal_perfect_hash;
+               size_t mph2 = xe->xdf2.recs[i].minimal_perfect_hash;
+               if (mph1 != mph2) {
+                       xe->xdf1.dstart = xe->xdf2.dstart = (ssize_t)i;
+                       lim -= i;
                        break;
+               }
+       }
 
-       xe->xdf1.dstart = xe->xdf2.dstart = i;
-
-       recs1 = xe->xdf1.recs + xe->xdf1.nrec - 1;
-       recs2 = xe->xdf2.recs + xe->xdf2.nrec - 1;
-       for (lim -= i, i = 0; i < lim; i++, recs1--, recs2--)
-               if (recs1->minimal_perfect_hash != recs2->minimal_perfect_hash)
+       for (size_t i = 0; i < lim; i++) {
+               size_t mph1 = xe->xdf1.recs[xe->xdf1.nrec - 1 - i].minimal_perfect_hash;
+               size_t mph2 = xe->xdf2.recs[xe->xdf2.nrec - 1 - i].minimal_perfect_hash;
+               if (mph1 != mph2) {
+                       xe->xdf1.dend = xe->xdf1.nrec - 1 - i;
+                       xe->xdf2.dend = xe->xdf2.nrec - 1 - i;
                        break;
-
-       xe->xdf1.dend = (long)xe->xdf1.nrec - i - 1;
-       xe->xdf2.dend = (long)xe->xdf2.nrec - i - 1;
-
-       return 0;
+               }
+       }
 }