[FFmpeg-cvslog] log: Fix an oob array read.

[Alex Converse]

ffmpeg | branch: master | Alex Converse <aconverse at google.com> | Thu May  5 22:33:31 2011 -0700| [847aaec682f2bbfaac55ee623364dd4527e0f341] | committer: Alex Converse

log: Fix an oob array read.

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=847aaec682f2bbfaac55ee623364dd4527e0f341
---

 libavutil/log.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/libavutil/log.c b/libavutil/log.c
index ddfd31f..c44130c 100644
--- a/libavutil/log.c
+++ b/libavutil/log.c
@@ -104,7 +104,7 @@ void av_log_default_callback(void* ptr, int level, const char* fmt, va_list vl)
 
     vsnprintf(line + strlen(line), sizeof(line) - strlen(line), fmt, vl);
 
-    print_prefix= line[strlen(line)-1] == '\n';
+    print_prefix = strlen(line) && line[strlen(line)-1] == '\n';
 
 #if HAVE_ISATTY
     if(!is_atty) is_atty= isatty(2) ? 1 : -1;