version 1.1, 1994/08/10 17:22:35
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version 1.7, 1995/11/07 18:06:32
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\ A simple immplementation of the blocks wordset. |
\ A less simple implementation of the blocks wordset. |
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\ This implementation uses only a single buffer and will therefore be a |
\ Copyright (C) 1995 Free Software Foundation, Inc. |
\ little slow. An efficient implementation would use mmap on OSs that |
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\ This file is part of Gforth. |
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\ Gforth is free software; you can redistribute it and/or |
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\ modify it under the terms of the GNU General Public License |
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\ as published by the Free Software Foundation; either version 2 |
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\ of the License, or (at your option) any later version. |
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\ This program is distributed in the hope that it will be useful, |
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\ but WITHOUT ANY WARRANTY; without even the implied warranty of |
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\ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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\ GNU General Public License for more details. |
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\ You should have received a copy of the GNU General Public License |
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\ along with this program; if not, write to the Free Software |
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\ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
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\ A more efficient implementation would use mmap on OSs that |
\ provide it and many buffers on OSs that do not provide mmap. |
\ provide it and many buffers on OSs that do not provide mmap. |
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\ Now, the replacement algorithm is "direct mapped"; change to LRU |
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\ if too slow. Using more buffers helps, too. |
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\ I think I avoid the assumption 1 char = 1 here, but I have not tested this |
\ I think I avoid the assumption 1 char = 1 here, but I have not tested this |
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1024 constant chars/block \ mandated by the standard |
\ 1024 constant chars/block \ mandated by the standard |
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require struct.fs |
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create block-buffer chars/block chars allot |
struct |
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1 cells: field buffer-block \ the block number |
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1 cells: field buffer-fid \ the block's fid |
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1 cells: field buffer-dirty \ the block dirty flag |
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chars/block chars: field block-buffer \ the data |
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0 cells: field next-buffer |
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end-struct buffer-struct |
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variable buffer-block 0 buffer-block ! \ the block currently in the buffer |
Variable block-buffers |
variable block-fid 0 block-fid ! \ the file id of the current block file |
Variable last-block |
variable buffer-dirty buffer-dirty off |
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$20 Value buffers |
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User block-fid |
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: block-cold |
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defers 'cold block-fid off last-block off |
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buffers buffer-struct drop * allocate throw dup block-buffers ! |
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buffers buffer-struct drop * erase ; |
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' block-cold IS 'cold |
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block-cold |
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Defer flush-file |
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: use-file ( addr u -- ) |
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2dup r/w bin open-file 0<> |
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if |
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drop r/w bin create-file throw |
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else |
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nip nip |
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then |
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block-fid @ IF flush-file block-fid @ close-file throw THEN |
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block-fid ! ; |
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\ the file is opened as binary file, since it either will contain text |
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\ without newlines or binary data |
: get-block-fid ( -- fid ) |
: get-block-fid ( -- fid ) |
block-fid @ 0= |
block-fid @ 0= |
if |
if |
s" blocks.fb" r/w open-file 0<> |
s" blocks.fb" use-file |
if |
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s" blocks.fb" r/w create-file .s throw |
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then |
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block-fid ! |
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then |
then |
block-fid @ ; |
block-fid @ ; |
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: block-position ( u -- ) |
: block-position ( u -- ) |
\ positions the block file to the start of block u |
\ positions the block file to the start of block u |
1- chars/block chars um* get-block-fid reposition-file .s throw ; |
1- chars/block chars um* get-block-fid reposition-file throw ; |
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: update ( -- ) |
: update ( -- ) |
buffer-dirty on ; |
last-block @ ?dup IF buffer-dirty on THEN ; |
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: save-buffers ( -- ) |
: save-buffer ( buffer -- ) >r |
buffer-dirty @ |
r@ buffer-dirty @ r@ buffer-block @ 0<> and |
if |
if |
buffer-block @ block-position |
r@ buffer-block @ block-position |
block-buffer chars/block get-block-fid write-file throw |
r@ block-buffer chars/block r@ buffer-fid @ write-file throw |
buffer-dirty off |
r@ buffer-dirty off |
endif ; |
endif |
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rdrop ; |
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: empty-buffer ( buffer -- ) |
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buffer-block off ; |
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: save-buffers ( -- ) block-buffers @ |
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buffers 0 ?DO dup save-buffer next-buffer LOOP drop ; |
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: empty-buffers ( -- ) |
: empty-buffers ( -- ) block-buffers @ |
0 buffer-block ! ; |
buffers 0 ?DO dup empty-buffer next-buffer LOOP drop ; |
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: flush ( -- ) |
: flush ( -- ) |
save-buffers |
save-buffers |
empty-buffers ; |
empty-buffers ; |
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' flush IS flush-file |
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: get-buffer ( n -- a-addr ) |
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buffers mod buffer-struct drop * block-buffers @ + ; |
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: block ( u -- a-addr ) |
: block ( u -- a-addr ) |
dup 0= -35 and throw |
dup 0= -35 and throw |
dup buffer-block @ <> |
dup get-buffer >r |
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dup r@ buffer-block @ <> |
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r@ buffer-fid @ block-fid @ <> and |
if |
if |
save-buffers |
r@ save-buffer |
dup block-position |
dup block-position |
block-buffer chars/block get-block-fid read-file .s throw |
r@ block-buffer chars/block get-block-fid read-file throw |
\ clear the rest of the buffer if the file is too short |
\ clear the rest of the buffer if the file is too short |
block-buffer over chars + chars/block rot - blank |
r@ block-buffer over chars + chars/block rot chars - blank |
buffer-block ! |
r@ buffer-block ! |
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get-block-fid r@ buffer-fid ! |
else |
else |
drop |
drop |
then |
then |
block-buffer ; |
r> dup last-block ! block-buffer ; |
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: buffer ( u -- a-addr ) |
: buffer ( u -- a-addr ) |
\ reading in the block is unnecessary, but simpler |
\ reading in the block is unnecessary, but simpler |
block ; |
block ; |
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variable scr 0 scr ! \ !! this should be a user var |
User scr 0 scr ! |
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: updated? ( n -- f ) scr @ buffer |
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[ 0 buffer-dirty 0 block-buffer - ] Literal + @ ; |
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: list ( u -- ) |
: list ( u -- ) |
\ calling block again and again looks inefficient but is necessary |
\ calling block again and again looks inefficient but is necessary |
\ in a multitasking environment |
\ in a multitasking environment |
dup scr ! |
dup scr ! |
." Screen " u. cr |
." Screen " u. |
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updated? 0= IF ." not " THEN ." modified " cr |
16 0 |
16 0 |
?do |
?do |
scr @ block i 64 * chars + 64 type cr |
i 2 .r space scr @ block i 64 * chars + 64 type cr |
loop ; |
loop ; |
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: (source) ( -- addr len ) |
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blk @ ?dup |
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IF block chars/block |
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ELSE tib #tib @ |
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THEN ; |
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' (source) IS source |
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: load ( i*x n -- j*x ) |
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push-file |
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dup loadline ! blk ! >in off ( ['] ) interpret ( catch ) |
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pop-file ( throw ) ; |
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: thru ( i*x n1 n2 -- j*x ) |
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1+ swap 0 ?DO I load LOOP ; |
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: +load ( i*x n -- j*x ) blk @ + load ; |
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: +thru ( i*x n1 n2 -- j*x ) |
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1+ swap 0 ?DO I +load LOOP ; |
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: --> ( -- ) refill drop ; immediate |
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: block-included ( addr u -- ) |
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block-fid @ >r block-fid off use-file |
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1 load block-fid @ close-file throw flush |
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r> block-fid ! ; |
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: include ( "name" -- ) |
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name 2dup dup 3 - /string s" .fb" compare |
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0= IF block-included ELSE included THEN ; |
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\ not yet implemented (with block semantics): |
get-current environment-wordlist set-current |
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true constant block |
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true constant block-ext |
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set-current |
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\ evaluate |
: bye ['] flush catch drop bye ; |
\ load |
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\ refill |
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\ thru |
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\ \ |
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