Merge r1533104 from trunk:

it should really handle src==NULL 

Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/apr/apr/branches/1.5.x@1533105 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 9 insertions, 6 deletions

diff --git a/strings/apr_cpystrn.c b/strings/apr_cpystrn.c
index 6311c29f3..d6c98f7e9 100644
--- a/strings/apr_cpystrn.c
+++ b/strings/apr_cpystrn.c
@@ -38,6 +38,7 @@
  *   (3) Instead of returning the pointer to the beginning of
  *       the destination string, we return a pointer to the
  *       terminating '\0' to allow us to "check" for truncation
+ *   (4) If src is NULL, null terminate dst (empty string copy)
  *
  * apr_cpystrn() follows the same call structure as strncpy().
  */
@@ -51,13 +52,15 @@ APR_DECLARE(char *) apr_cpystrn(char *dst, const char *src, apr_size_t dst_size)
         return (dst);
     }
 
-    d = dst;
-    end = dst + dst_size - 1;
+    if (src) {
+        d = dst;
+        end = dst + dst_size - 1;
 
-    for (; d < end; ++d, ++src) {
-	if (!(*d = *src)) {
-	    return (d);
-	}
+        for (; d < end; ++d, ++src) {
+            if (!(*d = *src)) {
+                return (d);
+            }
+        }
     }
 
     *d = '\0';	/* always null terminate */