options: fix failure to parse trailing ',' in string list

A trailing separator in string list options was ignored after recent
commit e873d703e9 ("options: change option parsing to use bstr"),
which broke uses such as "-vo vdpau,". Fix.

2 files changed, 5 insertions, 4 deletions

diff --git a/bstr.c b/bstr.c
index a2a49cc371..219c136d7c 100644
--- a/bstr.c
+++ b/bstr.c
@@ -129,8 +129,7 @@ struct bstr bstr_splice(struct bstr str, int start, int end)
         end += str.len;
     end = FFMIN(end, str.len);
     start = FFMAX(start, 0);
-    if (start >= end)
-        return (struct bstr){NULL, 0};
+    end = FFMAX(end, start);
     str.start += start;
     str.len = end - start;
     return str;
diff --git a/m_option.c b/m_option.c
index 34b7cd7a99..a7321cb629 100644
--- a/m_option.c
+++ b/m_option.c
@@ -717,11 +717,13 @@ static int parse_str_list(const m_option_t *opt, struct bstr name,
     char *ptr = str.start;
     n = 0;
 
-    while (str.len) {
+    while (1) {
         struct bstr el = get_nextsep(&str, separator, 1);
         res[n] = bstrdup0(NULL, el);
-        str = bstr_cut(str, 1);
         n++;
+        if (!str.len)
+            break;
+        str = bstr_cut(str, 1);
     }
     res[n] = NULL;
     talloc_free(ptr);