Avoid integer overflow

modules/demux/asf/libasf.c

@@ -1487,7 +1487,7 @@ static void ASF_ObjectDumpDebug( vlc_object_t *p_obj,
     psz_name = ASF_ObjectDumpDebugInfo[i].psz_name;
 
     char str[512];
-    if( i_level * 5 + 1 >= sizeof(str) )
+    if( i_level >= (sizeof(str) - 1)/5 )
         return;
 
     memset( str, ' ', sizeof( str ) );

modules/demux/avi/libavi.c

@@ -803,7 +803,7 @@ static void AVI_ChunkDumpDebug_level( vlc_object_t *p_obj,
     avi_chunk_t *p_child;
 
     char str[512];
-    if( i_level * 5 + 1 >= sizeof(str) )
+    if( i_level >= (sizeof(str) - 1)/5 )
         return;
 
     memset( str, ' ', sizeof( str ) );

modules/demux/mp4/libmp4.c

@@ -2895,7 +2895,7 @@ static void __MP4_BoxDumpStructure( stream_t *s,
         unsigned int i;
 
         char str[512];
-        if( i_level * 5 + 1 >= sizeof(str) )
+        if( i_level >= (sizeof(str) - 1)/5 )
             return;
 
         memset( str, ' ', sizeof(str) );