\ paths.fs path file handling                                    03may97jaw

\ Copyright (C) 1995-1997 Free Software Foundation, Inc.

\ This file is part of Gforth.

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\ modify it under the terms of the GNU General Public License
\ as published by the Free Software Foundation; either version 2
\ of the License, or (at your option) any later version.

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\ but WITHOUT ANY WARRANTY; without even the implied warranty of
\ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
\ GNU General Public License for more details.

\ You should have received a copy of the GNU General Public License
\ along with this program; if not, write to the Free Software
\ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

0 [IF]

-Changing the search-path:
fpath+ <path> 		adds a directory to the searchpath
fpath= <path>|<path>	makes complete now searchpath
			seperator is |
.fpath			displays the search path
remark I: 
a ~+ in the beginning of filename is expanded to the directory the
current file comes from. ~+ can also be included in the search-path!

remark II:
if there is no sufficient space for the search path increase it!


-Creating custom paths:

It is possible to use the search mechanism on yourself.

Make a buffer for the path:
create mypath	100 chars , 	\ maximum length (is checked)
		0 ,		\ real len
		100 chars allot \ space for path
use the same functions as above with:
mypath path+ 
mypath path=
mypath .path

do a open with the search path:
open-path-file ( adr len path -- fd adr len )
the file is opened read-only; if the file is not found an error is generated

\ questions to: wilke@jwdt.com
[THEN]

[IFUNDEF] +place
: +place ( adr len adr )
        2dup >r >r
        dup c@ char+ + swap move
        r> r> dup c@ rot + swap c! ;
[THEN]

[IFUNDEF] place
: place ( c-addr1 u c-addr2 )
        2dup c! char+ swap move ;
[THEN]

create sourcepath 256 chars , 0 , 256 chars allot
sourcepath avalue fpath

: also-path ( adr len path^ -- )
  >r
  \ len check
  r@ cell+ @ over + r@ @ u> ABORT" path buffer too small!"
  \ copy into
  tuck r@ cell+ dup @ cell+ + swap cmove
  \ make delemiter
  0 r@ cell+ dup @ cell+ + 2 pick + c! 1 + r> cell+ +!
  ;

: only-path ( adr len path^ -- )
  dup 0 swap cell+ ! also-path ;

: path+ ( path-addr  "dir" -- ) \ gforth
\G adds a directory to the search path path-addr
  name rot also-path ;

: fpath+ ( "dir" ) \ gforth
\G adds a directory to the forth search path
  fpath path+ ;

: path= ( path-addr "dir1|dir2|dir3" ) \ gforth
\G makes complete new searchpath, seperator is |
  name 2dup bounds ?DO i c@ '| = IF 0 i c! THEN LOOP
  rot only-path ;

: fpath= ( "dir1|dir2|dir3" ) \ gforth
\G makes complete new searchpath, serpeator is |
  fpath path= ;

: path>counted  cell+ dup cell+ swap @ ;

: next-path ( adr len -- adr2 len2 )
  2dup 0 scan
  dup 0= IF     2drop 0 -rot 0 -rot EXIT THEN
  >r 1+ -rot r@ 1- -rot
  r> - ;

: privous-path ( path^ -- )
  dup path>counted
  BEGIN tuck dup WHILE repeat ;

: .path ( path-addr -- ) \ gforth
\G displays the contents of the search path path-addr
  path>counted
  BEGIN next-path dup WHILE type space REPEAT 2drop 2drop ;

: .fpath ( ) \ gforth
\G displays the contents of the forth search patch
  fpath .path ;

: absolut-path? ( addr u -- flag ) \ gforth
    \G a path is absolute, if it starts with a / or a ~ (~ expansion),
    \G or if it is in the form ./* or ../*, extended regexp: ^[/~]|./|../
    \G Pathes simply containing a / are not absolute!
    2dup 2 u> swap 1+ c@ ': = and >r \ dos absoulte: c:/....
    over c@ '/ = >r
    over c@ '~ = >r
    2dup 2 min S" ./" compare 0= >r
         3 min S" ../" compare 0=
    r> r> r> r> or or or or ;

Create ofile 0 c, 255 chars allot
Create tfile 0 c, 255 chars allot

: pathsep? dup [char] / = swap [char] \ = or ;

: need/   ofile dup c@ + c@ pathsep? 0= IF s" /" ofile +place THEN ;

: extractpath ( adr len -- adr len2 )
  BEGIN dup WHILE 1-
        2dup + c@ pathsep? IF EXIT THEN
  REPEAT ;

: expandtopic
  ofile count 2 min s" ~+" compare 0=
  IF 	ofile count 2 /string tfile place
	0 ofile c! sourcefilename extractpath ofile place need/
	tfile count ofile +place
  THEN ;
	
: check-path ( adr1 len1 adr2 len2 -- fd 0 | 0 <>0 )
  0 ofile ! >r >r ofile place need/
  r> r> ofile +place
  expandtopic
  ofile count r/o open-file ;

: open-path-file ( adr len path-addr -- fd adr1 len2 0 | ior ) \ gforth
\G looks in path path-addr for the file specified by adr len
\G when found the resulting path and an open file descriptor
\G is returned. If the file is not found ior is non zero
  >r
  2dup absolut-path?
  IF    rdrop
        ofile place expandtopic ofile count r/o open-file throw
        ofile count 0 EXIT
  ELSE  r> path>counted
        BEGIN  next-path dup
        WHILE  5 pick 5 pick check-path
        0= IF >r 2drop 2drop r> ofile count 0 EXIT ELSE drop THEN
  REPEAT
        2drop 2drop 2drop -&38
  THEN ;

: open-fpath-file ( adr len -- fd adr1 len2 0 | ior ) \ gforth
\G looks in the forth search path for the file specified by adr len
\G when found the resulting path and an open file descriptor
\G is returned. If the file is not found ior is non zero
  fpath open-path-file ;