apply: use COPY_ARRAY and MOVE_ARRAY in update_image()

Simplify the code by using the helper macros COPY_ARRAY and MOVE_ARRAY,
which also makes them more robust in the case we copy or move no lines,
as they allow using NULL points in that case, while memcpy(3) and
memmove(3) don't.

Found with Clang's UBSan.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/apply.c b/apply.c
index f2d599141d00c64d8c50b3f5519412ada94bcd6f..40707ca50c50331c392ab51375a83f4fb97edee1 100644 (file)
--- a/apply.c
+++ b/apply.c
@@ -2809,13 +2809,10 @@ static void update_image(struct apply_state *state,
                img->line_allocated = img->line;
        }
        if (preimage_limit != postimage->nr)
-               memmove(img->line + applied_pos + postimage->nr,
-                       img->line + applied_pos + preimage_limit,
-                       (img->nr - (applied_pos + preimage_limit)) *
-                       sizeof(*img->line));
-       memcpy(img->line + applied_pos,
-              postimage->line,
-              postimage->nr * sizeof(*img->line));
+               MOVE_ARRAY(img->line + applied_pos + postimage->nr,
+                          img->line + applied_pos + preimage_limit,
+                          img->nr - (applied_pos + preimage_limit));
+       COPY_ARRAY(img->line + applied_pos, postimage->line, postimage->nr);
        if (!state->allow_overlap)
                for (i = 0; i < postimage->nr; i++)
                        img->line[applied_pos + i].flag |= LINE_PATCHED;