libavformat/aviobuf: Forward error from avio_read in ffio_read_size()

Suggested-by: Andreas Rheinhardt
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/aviobuf.c

@@ -686,9 +686,11 @@ int avio_read(AVIOContext *s, unsigned char *buf, int size)
 int ffio_read_size(AVIOContext *s, unsigned char *buf, int size)
 {
     int ret = avio_read(s, buf, size);
-    if (ret != size)
+    if (ret == size)
-        return AVERROR_INVALIDDATA;
+        return ret;
-    return ret;
+    if (ret < 0 && ret != AVERROR_EOF)
+        return ret;
+    return AVERROR_INVALIDDATA;
 }
 
 int ffio_read_indirect(AVIOContext *s, unsigned char *buf, int size, const unsigned char **data)