diff-delta: set size out-parameter to 0 for NULL delta

diff --git a/xdiff/xemit.c b/xdiff/xemit.c
index 7778dc2b190f84fe2ab1e1539756a7e1f4254c3b..30713ae9a98ecfc9f764120d3a1d18b5a8ee11bf 100644 (file)
--- a/xdiff/xemit.c
+++ b/xdiff/xemit.c
@@ -210,7 +210,7 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
                        if (fs1 < 0)
                                fs1 = 0;
                        if (fs1 < s1) {
-                               s2 -= s1 - fs1;
+                               s2 = XDL_MAX(s2 - (s1 - fs1), 0);
                                s1 = fs1;
                        }
                }
@@ -232,7 +232,7 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
                        if (fe1 < 0)
                                fe1 = xe->xdf1.nrec;
                        if (fe1 > e1) {
-                               e2 += fe1 - e1;
+                               e2 = XDL_MIN(e2 + (fe1 - e1), xe->xdf2.nrec);
                                e1 = fe1;
                        }