int buffer_init(struct line_buffer *buf, const char *filename);
int buffer_fdinit(struct line_buffer *buf, int fd);
int buffer_deinit(struct line_buffer *buf);
-void buffer_reset(struct line_buffer *buf);
int buffer_tmpfile_init(struct line_buffer *buf);
FILE *buffer_tmpfile_rewind(struct line_buffer *buf); /* prepare to write. */