X-Git-Url: http://git.subgeniuskitty.com/pforth/.git/blobdiff_plain/406a0545a94f43e880e883da3673f705467ecab3..593eb738c871efd888f6c8652991dc2a413c8727:/fth/file.fth?ds=inline

diff --git a/fth/file.fth b/fth/file.fth
new file mode 100644
index 0000000..678a991
--- /dev/null
+++ b/fth/file.fth
@@ -0,0 +1,83 @@
+\ READ-LINE and WRITE-LINE
+\
+\ This file is in the public domain.
+\
+
+private{
+
+10 constant \n
+13 constant \r
+
+\ Unread one char from file FILEID.
+: UNREAD ( fileid -- ior )
+    { f }
+    f file-position          ( ud ior )
+    ?dup
+    IF   nip nip \ IO error
+    ELSE 1 s>d d- f reposition-file
+    THEN
+;
+
+\ 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 f }
+  a 1 f read-file               ( u ior )
+  ?dup
+  IF \ Read error?
+      nip
+  ELSE                          ( u )
+      0=
+      IF \ End of file?
+          0
+      ELSE
+          a c@ \n =             ( is-it-a-\n? )
+          IF   0
+          ELSE f unread
+          THEN
+      THEN
+  THEN
+;
+
+\ This is just s\" \n" but s\" isn't yet available.
+create (LINE-TERMINATOR) \n c,
+: LINE-TERMINATOR ( -- c-addr u ) (line-terminator) 1 ;
+
+}private
+
+
+\ 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 u f }
+  u 0 ?DO
+      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?    ( )
+      a i chars + c@
+      CASE
+          \n OF i true 0 UNLOOP EXIT ENDOF
+          \r OF
+              \ Detect \r\n
+              a i 1+ chars + f skip-\n                           ( ior )
+              ?dup IF i false rot UNLOOP EXIT THEN \ IO Error?   ( )
+              i true 0 UNLOOP EXIT
+	  ENDOF
+      ENDCASE
+  LOOP
+  \ Line doesn't fit in buffer
+  u true 0
+;
+
+: WRITE-LINE ( c-addr u fileid -- ior )
+  { f }
+  f write-file                  ( ior )
+  ?dup
+  IF \ IO error
+  ELSE line-terminator f write-file
+  THEN
+;
+
+privatize