[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 : anton 1.17 cell% field buffer-block \ the block number
36 :     cell% field buffer-fid \ the block's fid
37 :     cell% field buffer-dirty \ the block dirty flag
38 :     char% chars/block * field block-buffer \ the data
39 :     cell% 0 * field next-buffer
40 : pazsan 1.5 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 : anton 1.17 : block-cold ( -- )
50 : jwilke 1.16 block-fid off last-block off
51 : anton 1.17 buffer-struct buffers * %alloc dup block-buffers ! ( addr )
52 :     buffer-struct %size buffers * erase ;
53 : anton 1.1
54 : jwilke 1.16 ' block-cold INIT8 chained
55 : pazsan 1.5
56 :     block-cold
57 :    
58 : anton 1.12 Defer flush-blocks
59 : pazsan 1.5
60 : anton 1.11 : open-blocks ( addr u -- ) \ gforth
61 : anton 1.10 \g use the file, whose name is given by @var{addr u}, as blocks file
62 : anton 1.14 2dup ['] open-fpath-file catch 0<>
63 : pazsan 1.5 if
64 : pazsan 1.8 2drop r/w bin create-file throw
65 : pazsan 1.5 else
66 : pazsan 1.8 rot close-file throw 2dup file-status throw bin open-file throw
67 :     >r 2drop r>
68 : pazsan 1.5 then
69 : anton 1.12 block-fid @ IF flush-blocks block-fid @ close-file throw THEN
70 : pazsan 1.5 block-fid ! ;
71 : pazsan 1.8
72 : anton 1.10 : use ( "file" -- ) \ gforth
73 :     \g use @var{file} as blocks file
74 : anton 1.11 name open-blocks ;
75 : anton 1.1
76 : anton 1.3 \ the file is opened as binary file, since it either will contain text
77 :     \ without newlines or binary data
78 : anton 1.1 : get-block-fid ( -- fid )
79 :     block-fid @ 0=
80 :     if
81 : anton 1.11 s" blocks.fb" open-blocks
82 : anton 1.1 then
83 :     block-fid @ ;
84 :    
85 :     : block-position ( u -- )
86 :     \ positions the block file to the start of block u
87 : anton 1.3 1- chars/block chars um* get-block-fid reposition-file throw ;
88 : anton 1.1
89 :     : update ( -- )
90 : pazsan 1.5 last-block @ ?dup IF buffer-dirty on THEN ;
91 : anton 1.1
92 : pazsan 1.5 : save-buffer ( buffer -- ) >r
93 :     r@ buffer-dirty @ r@ buffer-block @ 0<> and
94 : anton 1.1 if
95 : pazsan 1.5 r@ buffer-block @ block-position
96 :     r@ block-buffer chars/block r@ buffer-fid @ write-file throw
97 :     r@ buffer-dirty off
98 :     endif
99 :     rdrop ;
100 :    
101 :     : empty-buffer ( buffer -- )
102 :     buffer-block off ;
103 :    
104 :     : save-buffers ( -- ) block-buffers @
105 :     buffers 0 ?DO dup save-buffer next-buffer LOOP drop ;
106 : anton 1.1
107 : pazsan 1.5 : empty-buffers ( -- ) block-buffers @
108 :     buffers 0 ?DO dup empty-buffer next-buffer LOOP drop ;
109 : anton 1.1
110 :     : flush ( -- )
111 :     save-buffers
112 :     empty-buffers ;
113 :    
114 : anton 1.12 ' flush IS flush-blocks
115 : pazsan 1.5
116 :     : get-buffer ( n -- a-addr )
117 : anton 1.17 buffers mod buffer-struct %size * block-buffers @ + ;
118 : pazsan 1.5
119 : anton 1.1 : block ( u -- a-addr )
120 :     dup 0= -35 and throw
121 : pazsan 1.5 dup get-buffer >r
122 :     dup r@ buffer-block @ <>
123 : pazsan 1.9 r@ buffer-fid @ block-fid @ <> or
124 : anton 1.1 if
125 : pazsan 1.5 r@ save-buffer
126 : anton 1.1 dup block-position
127 : pazsan 1.5 r@ block-buffer chars/block get-block-fid read-file throw
128 : anton 1.1 \ clear the rest of the buffer if the file is too short
129 : pazsan 1.5 r@ block-buffer over chars + chars/block rot chars - blank
130 :     r@ buffer-block !
131 :     get-block-fid r@ buffer-fid !
132 : anton 1.1 else
133 :     drop
134 :     then
135 : pazsan 1.5 r> dup last-block ! block-buffer ;
136 : anton 1.1
137 :     : buffer ( u -- a-addr )
138 :     \ reading in the block is unnecessary, but simpler
139 :     block ;
140 :    
141 : pazsan 1.2 User scr 0 scr !
142 : anton 1.1
143 : pazsan 1.5 : updated? ( n -- f ) scr @ buffer
144 :     [ 0 buffer-dirty 0 block-buffer - ] Literal + @ ;
145 :    
146 : anton 1.1 : list ( u -- )
147 :     \ calling block again and again looks inefficient but is necessary
148 :     \ in a multitasking environment
149 :     dup scr !
150 : pazsan 1.5 ." Screen " u.
151 :     updated? 0= IF ." not " THEN ." modified " cr
152 : anton 1.1 16 0
153 :     ?do
154 : anton 1.4 i 2 .r space scr @ block i 64 * chars + 64 type cr
155 : anton 1.1 loop ;
156 :    
157 : pazsan 1.2 : (source) ( -- addr len )
158 :     blk @ ?dup
159 :     IF block chars/block
160 :     ELSE tib #tib @
161 :     THEN ;
162 :    
163 :     ' (source) IS source
164 :    
165 :     : load ( i*x n -- j*x )
166 :     push-file
167 :     dup loadline ! blk ! >in off ( ['] ) interpret ( catch )
168 :     pop-file ( throw ) ;
169 : anton 1.1
170 : pazsan 1.2 : thru ( i*x n1 n2 -- j*x )
171 : pazsan 1.15 1+ swap ?DO I load LOOP ;
172 : anton 1.1
173 : pazsan 1.2 : +load ( i*x n -- j*x ) blk @ + load ;
174 :    
175 :     : +thru ( i*x n1 n2 -- j*x )
176 : pazsan 1.15 1+ swap ?DO I +load LOOP ;
177 : anton 1.4
178 : pazsan 1.5 : --> ( -- ) refill drop ; immediate
179 :    
180 :     : block-included ( addr u -- )
181 : anton 1.11 block-fid @ >r block-fid off open-blocks
182 : pazsan 1.5 1 load block-fid @ close-file throw flush
183 :     r> block-fid ! ;
184 :    
185 : anton 1.13 \ thrown out because it may provide unpleasant surprises - anton
186 :     \ : include ( "name" -- )
187 :     \ name 2dup dup 3 - /string s" .fb" compare
188 :     \ 0= IF block-included ELSE included THEN ;
189 : pazsan 1.5
190 : anton 1.4 get-current environment-wordlist set-current
191 :     true constant block
192 :     true constant block-ext
193 :     set-current
194 : pazsan 1.5
195 : jwilke 1.16 : bye ['] flush catch drop bye ;
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