--- gforth/blocks.fs 1995/02/09 17:49:54 1.3 +++ gforth/blocks.fs 1997/03/20 14:39:49 1.12 @@ -1,30 +1,84 @@ -\ A simple immplementation of the blocks wordset. +\ A less simple implementation of the blocks wordset. -\ This implementation uses only a single buffer and will therefore be a -\ little slow. An efficient implementation would use mmap on OSs that +\ Copyright (C) 1995 Free Software Foundation, Inc. + +\ This file is part of Gforth. + +\ Gforth is free software; you can redistribute it and/or +\ 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. + +\ This program is distributed in the hope that it will be useful, +\ 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. + + +\ A more efficient implementation would use mmap on OSs that \ provide it and many buffers on OSs that do not provide mmap. +\ Now, the replacement algorithm is "direct mapped"; change to LRU +\ if too slow. Using more buffers helps, too. + \ I think I avoid the assumption 1 char = 1 here, but I have not tested this \ 1024 constant chars/block \ mandated by the standard -create block-buffer chars/block chars allot +require struct.fs + +struct + 1 cells: field buffer-block \ the block number + 1 cells: field buffer-fid \ the block's fid + 1 cells: field buffer-dirty \ the block dirty flag + chars/block chars: field block-buffer \ the data + 0 cells: field next-buffer +end-struct buffer-struct + +Variable block-buffers +Variable last-block + +$20 Value buffers + +User block-fid + +: block-cold + defers 'cold block-fid off last-block off + buffers buffer-struct drop * allocate throw dup block-buffers ! + buffers buffer-struct drop * erase ; + +' block-cold IS 'cold -variable buffer-block 0 buffer-block ! \ the block currently in the buffer -variable block-fid 0 block-fid ! \ the file id of the current block file -variable buffer-dirty buffer-dirty off +block-cold +Defer flush-blocks + +: open-blocks ( addr u -- ) \ gforth + \g use the file, whose name is given by @var{addr u}, as blocks file + 2dup ['] open-path-file catch 0<> + if + 2drop r/w bin create-file throw + else + rot close-file throw 2dup file-status throw bin open-file throw + >r 2drop r> + then + block-fid @ IF flush-blocks block-fid @ close-file throw THEN + block-fid ! ; + +: use ( "file" -- ) \ gforth + \g use @var{file} as blocks file + name open-blocks ; \ the file is opened as binary file, since it either will contain text \ without newlines or binary data : get-block-fid ( -- fid ) block-fid @ 0= if - s" blocks.fb" r/w bin open-file 0<> - if - s" blocks.fb" r/w bin create-file throw - then - block-fid ! + s" blocks.fb" open-blocks then block-fid @ ; @@ -33,37 +87,52 @@ variable buffer-dirty buffer-dirty off 1- chars/block chars um* get-block-fid reposition-file throw ; : update ( -- ) - buffer-dirty on ; + last-block @ ?dup IF buffer-dirty on THEN ; -: save-buffers ( -- ) - buffer-dirty @ +: save-buffer ( buffer -- ) >r + r@ buffer-dirty @ r@ buffer-block @ 0<> and if - buffer-block @ block-position - block-buffer chars/block get-block-fid write-file throw - buffer-dirty off - endif ; + r@ buffer-block @ block-position + r@ block-buffer chars/block r@ buffer-fid @ write-file throw + r@ buffer-dirty off + endif + rdrop ; + +: empty-buffer ( buffer -- ) + buffer-block off ; + +: save-buffers ( -- ) block-buffers @ + buffers 0 ?DO dup save-buffer next-buffer LOOP drop ; -: empty-buffers ( -- ) - 0 buffer-block ! ; +: empty-buffers ( -- ) block-buffers @ + buffers 0 ?DO dup empty-buffer next-buffer LOOP drop ; : flush ( -- ) save-buffers empty-buffers ; +' flush IS flush-blocks + +: get-buffer ( n -- a-addr ) + buffers mod buffer-struct drop * block-buffers @ + ; + : block ( u -- a-addr ) dup 0= -35 and throw - dup buffer-block @ <> + dup get-buffer >r + dup r@ buffer-block @ <> + r@ buffer-fid @ block-fid @ <> or if - save-buffers + r@ save-buffer dup block-position - block-buffer chars/block get-block-fid read-file throw + r@ block-buffer chars/block get-block-fid read-file throw \ clear the rest of the buffer if the file is too short - block-buffer over chars + chars/block rot - blank - buffer-block ! + r@ block-buffer over chars + chars/block rot chars - blank + r@ buffer-block ! + get-block-fid r@ buffer-fid ! else drop then - block-buffer ; + r> dup last-block ! block-buffer ; : buffer ( u -- a-addr ) \ reading in the block is unnecessary, but simpler @@ -71,14 +140,18 @@ variable buffer-dirty buffer-dirty off User scr 0 scr ! +: updated? ( n -- f ) scr @ buffer + [ 0 buffer-dirty 0 block-buffer - ] Literal + @ ; + : list ( u -- ) \ calling block again and again looks inefficient but is necessary \ in a multitasking environment dup scr ! - ." Screen " u. cr + ." Screen " u. + updated? 0= IF ." not " THEN ." modified " cr 16 0 ?do - scr @ block i 64 * chars + 64 type cr + i 2 .r space scr @ block i 64 * chars + 64 type cr loop ; : (source) ( -- addr len ) @@ -101,3 +174,21 @@ User scr 0 scr ! : +thru ( i*x n1 n2 -- j*x ) 1+ swap 0 ?DO I +load LOOP ; + +: --> ( -- ) refill drop ; immediate + +: block-included ( addr u -- ) + block-fid @ >r block-fid off open-blocks + 1 load block-fid @ close-file throw flush + r> block-fid ! ; + +: include ( "name" -- ) + name 2dup dup 3 - /string s" .fb" compare + 0= IF block-included ELSE included THEN ; + +get-current environment-wordlist set-current +true constant block +true constant block-ext +set-current + +: bye ['] flush catch drop bye ; \ No newline at end of file