\ READ-LINE and WRITE-LINE
\ This file is in the public domain.
\ Unread one char from file FILEID.
: UNREAD ( fileid -- ior )
f file-position ( ud ior )
ELSE 1 s>d d- f reposition-file
\ Read the next available char from file FILEID and if it is a \n then
\ skip it; otherwise unread it. IOR is non-zero if an error occured.
\ C-ADDR is a buffer that can hold at least on char.
: SKIP-\n ( c-addr fileid -- ior )
a 1 f read-file ( u ior )
a c@ \n = ( is-it-a-\n? )
\ This is just s\" \n" but s\" isn't yet available.
create (LINE-TERMINATOR) \n c,
: LINE-TERMINATOR ( -- c-addr u ) (line-terminator) 1 ;
\ This treats \n, \r\n, and \r as line terminator. Reading is done
\ one char at a time with READ-FILE hence READ-FILE should probably do
\ some form of buffering for good efficiency.
: READ-LINE ( c-addr u1 fileid -- u2 flag ior )
a i chars + 1 f read-file ( u ior' )
?dup IF nip i false rot UNLOOP EXIT THEN \ Read error? ( u )
0= IF i i 0> 0 UNLOOP EXIT THEN \ End of file? ( )
\n OF i true 0 UNLOOP EXIT ENDOF
a i 1+ chars + f skip-\n ( ior )
?dup IF i false rot UNLOOP EXIT THEN \ IO Error? ( )
\ Line doesn't fit in buffer
: WRITE-LINE ( c-addr u fileid -- ior )
ELSE line-terminator f write-file