Avoid memcpy if length is zero, the source can be NULL in this case.

diff --git a/libarchive/archive_read.c b/libarchive/archive_read.c
index d1fecebfd09f2929f981ed0216e192aa39932144..a642a336def6ff542aebd6392a069ac85eb8b7aa 100644 (file)
--- a/libarchive/archive_read.c
+++ b/libarchive/archive_read.c
@@ -881,7 +881,8 @@ archive_read_data(struct archive *_a, void *buff, size_t s)
                        len = a->read_data_remaining;
                        if (len > s)
                                len = s;
-                       memcpy(dest, a->read_data_block, len);
+                       if (len)
+                               memcpy(dest, a->read_data_block, len);
                        s -= len;
                        a->read_data_block += len;
                        a->read_data_remaining -= len;