uint64_t ffio_read_varlen(AVIOContext *bc);
+/**
+ * Read size bytes from AVIOContext into buf.
+ * Check that exactly size bytes have been read.
+ * @return number of bytes read or AVERROR
+ */
+int ffio_read_size(AVIOContext *s, unsigned char *buf, int size);
+
/** @warning must be called before any I/O */
int ffio_set_buf_size(AVIOContext *s, int buf_size);