[gforth] / gforth / blocks.fs  

gforth: gforth/blocks.fs


1 : pazsan 1.5 \ A less simple implementation of the blocks wordset.
2 : anton 1.1
3 : anton 1.7 \ Copyright (C) 1995 Free Software Foundation, Inc.
4 :    
5 :     \ This file is part of Gforth.
6 :    
7 :     \ Gforth is free software; you can redistribute it and/or
8 :     \ modify it under the terms of the GNU General Public License
9 :     \ as published by the Free Software Foundation; either version 2
10 :     \ of the License, or (at your option) any later version.
11 :    
12 :     \ This program is distributed in the hope that it will be useful,
13 :     \ but WITHOUT ANY WARRANTY; without even the implied warranty of
14 :     \ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 :     \ GNU General Public License for more details.
16 :    
17 :     \ You should have received a copy of the GNU General Public License
18 :     \ along with this program; if not, write to the Free Software
19 :     \ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 :    
21 :    
22 :     \ A more efficient implementation would use mmap on OSs that
23 : anton 1.1 \ provide it and many buffers on OSs that do not provide mmap.
24 :    
25 : pazsan 1.5 \ Now, the replacement algorithm is "direct mapped"; change to LRU
26 :     \ if too slow. Using more buffers helps, too.
27 :    
28 : anton 1.1 \ I think I avoid the assumption 1 char = 1 here, but I have not tested this
29 :    
30 : pazsan 1.2 \ 1024 constant chars/block \ mandated by the standard
31 : anton 1.1
32 : pazsan 1.5 require struct.fs
33 :    
34 :     struct
35 :     1 cells: field buffer-block \ the block number
36 :     1 cells: field buffer-fid \ the block's fid
37 :     1 cells: field buffer-dirty \ the block dirty flag
38 :     chars/block chars: field block-buffer \ the data
39 :     0 cells: field next-buffer
40 :     end-struct buffer-struct
41 :    
42 :     Variable block-buffers
43 :     Variable last-block
44 :    
45 :     $20 Value buffers
46 :    
47 :     User block-fid
48 : anton 1.1
49 : pazsan 1.5 : block-cold
50 :     defers 'cold block-fid off last-block off
51 :     buffers buffer-struct drop * allocate throw dup block-buffers !
52 :     buffers buffer-struct drop * erase ;
53 : anton 1.1
54 : pazsan 1.5 ' block-cold IS 'cold
55 :    
56 :     block-cold
57 :    
58 :     Defer flush-file
59 :    
60 :     : use-file ( addr u -- )
61 :     2dup r/w bin open-file 0<>
62 :     if
63 :     drop r/w bin create-file throw
64 :     else
65 :     nip nip
66 :     then
67 : pazsan 1.6 block-fid @ IF flush-file block-fid @ close-file throw THEN
68 : pazsan 1.5 block-fid ! ;
69 : anton 1.1
70 : anton 1.3 \ the file is opened as binary file, since it either will contain text
71 :     \ without newlines or binary data
72 : anton 1.1 : get-block-fid ( -- fid )
73 :     block-fid @ 0=
74 :     if
75 : pazsan 1.5 s" blocks.fb" use-file
76 : anton 1.1 then
77 :     block-fid @ ;
78 :    
79 :     : block-position ( u -- )
80 :     \ positions the block file to the start of block u
81 : anton 1.3 1- chars/block chars um* get-block-fid reposition-file throw ;
82 : anton 1.1
83 :     : update ( -- )
84 : pazsan 1.5 last-block @ ?dup IF buffer-dirty on THEN ;
85 : anton 1.1
86 : pazsan 1.5 : save-buffer ( buffer -- ) >r
87 :     r@ buffer-dirty @ r@ buffer-block @ 0<> and
88 : anton 1.1 if
89 : pazsan 1.5 r@ buffer-block @ block-position
90 :     r@ block-buffer chars/block r@ buffer-fid @ write-file throw
91 :     r@ buffer-dirty off
92 :     endif
93 :     rdrop ;
94 :    
95 :     : empty-buffer ( buffer -- )
96 :     buffer-block off ;
97 :    
98 :     : save-buffers ( -- ) block-buffers @
99 :     buffers 0 ?DO dup save-buffer next-buffer LOOP drop ;
100 : anton 1.1
101 : pazsan 1.5 : empty-buffers ( -- ) block-buffers @
102 :     buffers 0 ?DO dup empty-buffer next-buffer LOOP drop ;
103 : anton 1.1
104 :     : flush ( -- )
105 :     save-buffers
106 :     empty-buffers ;
107 :    
108 : pazsan 1.5 ' flush IS flush-file
109 :    
110 :     : get-buffer ( n -- a-addr )
111 :     buffers mod buffer-struct drop * block-buffers @ + ;
112 :    
113 : anton 1.1 : block ( u -- a-addr )
114 :     dup 0= -35 and throw
115 : pazsan 1.5 dup get-buffer >r
116 :     dup r@ buffer-block @ <>
117 :     r@ buffer-fid @ block-fid @ <> and
118 : anton 1.1 if
119 : pazsan 1.5 r@ save-buffer
120 : anton 1.1 dup block-position
121 : pazsan 1.5 r@ block-buffer chars/block get-block-fid read-file throw
122 : anton 1.1 \ clear the rest of the buffer if the file is too short
123 : pazsan 1.5 r@ block-buffer over chars + chars/block rot chars - blank
124 :     r@ buffer-block !
125 :     get-block-fid r@ buffer-fid !
126 : anton 1.1 else
127 :     drop
128 :     then
129 : pazsan 1.5 r> dup last-block ! block-buffer ;
130 : anton 1.1
131 :     : buffer ( u -- a-addr )
132 :     \ reading in the block is unnecessary, but simpler
133 :     block ;
134 :    
135 : pazsan 1.2 User scr 0 scr !
136 : anton 1.1
137 : pazsan 1.5 : updated? ( n -- f ) scr @ buffer
138 :     [ 0 buffer-dirty 0 block-buffer - ] Literal + @ ;
139 :    
140 : anton 1.1 : list ( u -- )
141 :     \ calling block again and again looks inefficient but is necessary
142 :     \ in a multitasking environment
143 :     dup scr !
144 : pazsan 1.5 ." Screen " u.
145 :     updated? 0= IF ." not " THEN ." modified " cr
146 : anton 1.1 16 0
147 :     ?do
148 : anton 1.4 i 2 .r space scr @ block i 64 * chars + 64 type cr
149 : anton 1.1 loop ;
150 :    
151 : pazsan 1.2 : (source) ( -- addr len )
152 :     blk @ ?dup
153 :     IF block chars/block
154 :     ELSE tib #tib @
155 :     THEN ;
156 :    
157 :     ' (source) IS source
158 :    
159 :     : load ( i*x n -- j*x )
160 :     push-file
161 :     dup loadline ! blk ! >in off ( ['] ) interpret ( catch )
162 :     pop-file ( throw ) ;
163 : anton 1.1
164 : pazsan 1.2 : thru ( i*x n1 n2 -- j*x )
165 :     1+ swap 0 ?DO I load LOOP ;
166 : anton 1.1
167 : pazsan 1.2 : +load ( i*x n -- j*x ) blk @ + load ;
168 :    
169 :     : +thru ( i*x n1 n2 -- j*x )
170 :     1+ swap 0 ?DO I +load LOOP ;
171 : anton 1.4
172 : pazsan 1.5 : --> ( -- ) refill drop ; immediate
173 :    
174 :     : block-included ( addr u -- )
175 :     block-fid @ >r block-fid off use-file
176 :     1 load block-fid @ close-file throw flush
177 :     r> block-fid ! ;
178 :    
179 :     : include ( "name" -- )
180 :     name 2dup dup 3 - /string s" .fb" compare
181 :     0= IF block-included ELSE included THEN ;
182 :    
183 : anton 1.4 get-current environment-wordlist set-current
184 :     true constant block
185 :     true constant block-ext
186 :     set-current
187 : pazsan 1.5
188 :     : bye ['] flush catch drop bye ;

CVS Admin

Powered by ViewCVS 1.0-dev
(Powered by ViewCVS)

ViewCVS and CVS Help