re PR libfortran/16339 (Unformatted i/o on large arrays inefficient)

re PR libfortran/16339 (Unformatted i/o on large arrays inefficient)

2005-10-07  Janne Blomqvist <jblomqvi@cc.hut.fi>

	PR fortran/16339
	PR fortran/23363
	* io/io.h: Add read and write members to stream, define access
	macros.
	* io/transfer.c (read_block_direct): New function.
	(write_block_direct): New function.
	(unformatted_read): Change to use read_block_direct.
	(unformatted_write): Change to use write_block_direct.
	* io/unix.c: Remove mmap includes and defines.
	(writen): Remove.
	(readn): Remove.
	(reset_stream): New function.
	(do_read): New function.
	(do_write): New function.
	(fd_flush): Change to use do_write() instead of writen().
	(fd_alloc_r_at): Change to use do_read().
	(fd_seek): Change return type to try, as the prototype. Add check
	to avoid syscall overhead if possible.
	(fd_read): New function.
	(fd_write): New function.
	(fd_open): Set pointers for new functions.
	(mem_read): New function.
	(mem_write): New function.
	(open_internal): Set pointers for new functions.
	(is_seekable): Clean up comment.

From-SVN: r105101