[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 1.19 \ Copyright (C) 1995,1996,1997,1998 Free Software Foundation, Inc.
4 : anton 1.7
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 1.30 User block-offset ( -- addr ) \ gforth
49 :     \G User variable containing the number of the first block (default
50 :     \G since 0.5.0: 0). Block files created with Gforth versions before
51 :     \G 0.5.0 have the offset 1. If you use these files you can: @code{1
52 :     \G offset !}; or add 1 to every block number used; or prepend 1024
53 :     \G characters to the file.
54 :     0 block-offset ! \ store 1 here fore 0.4.0 compatibility
55 :    
56 :     ' block-offset alias offset \ !! eliminate this?
57 : anton 1.1
58 : anton 1.17 : block-cold ( -- )
59 : jwilke 1.16 block-fid off last-block off
60 : anton 1.17 buffer-struct buffers * %alloc dup block-buffers ! ( addr )
61 :     buffer-struct %size buffers * erase ;
62 : anton 1.1
63 : jwilke 1.16 ' block-cold INIT8 chained
64 : pazsan 1.5
65 :     block-cold
66 :    
67 : crook 1.24 Defer flush-blocks ( -- ) \ gforth
68 : pazsan 1.5
69 : crook 1.24 : open-blocks ( c-addr u -- ) \ gforth
70 :     \g Use the file, whose name is given by @i{c-addr u}, as the blocks file.
71 : pazsan 1.18 2dup open-fpath-file 0<>
72 : pazsan 1.5 if
73 : pazsan 1.18 r/w bin create-file throw
74 : pazsan 1.5 else
75 : pazsan 1.8 rot close-file throw 2dup file-status throw bin open-file throw
76 :     >r 2drop r>
77 : pazsan 1.5 then
78 : anton 1.12 block-fid @ IF flush-blocks block-fid @ close-file throw THEN
79 : pazsan 1.5 block-fid ! ;
80 : pazsan 1.8
81 : anton 1.10 : use ( "file" -- ) \ gforth
82 : crook 1.24 \g Use @i{file} as the blocks file.
83 : anton 1.11 name open-blocks ;
84 : anton 1.1
85 : anton 1.3 \ the file is opened as binary file, since it either will contain text
86 :     \ without newlines or binary data
87 : crook 1.24 : get-block-fid ( -- wfileid ) \ gforth
88 :     \G Return the file-id of the current blocks file. If no blocks
89 :     \G file has been opened, use @file{blocks.fb} as the default
90 :     \G blocks file.
91 : anton 1.1 block-fid @ 0=
92 :     if
93 : anton 1.11 s" blocks.fb" open-blocks
94 : anton 1.1 then
95 :     block-fid @ ;
96 :    
97 : pazsan 1.20 : block-position ( u -- ) \ block
98 : crook 1.24 \G Position the block file to the start of block @i{u}.
99 : pazsan 1.26 offset @ - chars/block chars um* get-block-fid reposition-file throw ;
100 : anton 1.1
101 : pazsan 1.20 : update ( -- ) \ block
102 : crook 1.29 \G Mark the state of the current block buffer as assigned-dirty.
103 : pazsan 1.5 last-block @ ?dup IF buffer-dirty on THEN ;
104 : anton 1.1
105 : pazsan 1.20 : save-buffer ( buffer -- ) \ gforth
106 :     >r
107 : pazsan 1.5 r@ buffer-dirty @ r@ buffer-block @ 0<> and
108 : anton 1.1 if
109 : pazsan 1.5 r@ buffer-block @ block-position
110 :     r@ block-buffer chars/block r@ buffer-fid @ write-file throw
111 :     r@ buffer-dirty off
112 :     endif
113 :     rdrop ;
114 :    
115 : pazsan 1.20 : empty-buffer ( buffer -- ) \ gforth
116 : pazsan 1.5 buffer-block off ;
117 :    
118 : pazsan 1.20 : save-buffers ( -- ) \ block
119 : crook 1.24 \G Transfer the contents of each @code{update}d block buffer to
120 : anton 1.30 \G mass storage, then mark all block buffers as assigned-clean.
121 : pazsan 1.20 block-buffers @
122 : crook 1.24 buffers 0 ?DO dup save-buffer next-buffer LOOP drop ;
123 : anton 1.1
124 : crook 1.24 : empty-buffers ( -- ) \ block-ext
125 :     \G Mark all block buffers as unassigned; if any had been marked as
126 :     \G assigned-dirty (by @code{update}), the changes to those blocks
127 :     \G will be lost.
128 : pazsan 1.20 block-buffers @
129 : crook 1.24 buffers 0 ?DO dup empty-buffer next-buffer LOOP drop ;
130 : anton 1.1
131 : pazsan 1.20 : flush ( -- ) \ block
132 : crook 1.24 \G Perform the functions of @code{save-buffers} then
133 :     \G @code{empty-buffers}.
134 : anton 1.1 save-buffers
135 :     empty-buffers ;
136 :    
137 : anton 1.12 ' flush IS flush-blocks
138 : pazsan 1.5
139 : pazsan 1.26 : get-buffer ( u -- a-addr ) \ gforth
140 :     0 buffers um/mod drop buffer-struct %size * block-buffers @ + ;
141 : pazsan 1.5
142 : crook 1.28 : block ( u -- a-addr ) \ gforthman- block
143 : crook 1.24 \G If a block buffer is assigned for block @i{u}, return its
144 :     \G start address, @i{a-addr}. Otherwise, assign a block buffer
145 :     \G for block @i{u} (if the assigned block buffer has been
146 :     \G @code{update}d, transfer the contents to mass storage), read
147 :     \G the block into the block buffer and return its start address,
148 :     \G @i{a-addr}.
149 : pazsan 1.26 dup offset @ u< -35 and throw
150 : pazsan 1.5 dup get-buffer >r
151 :     dup r@ buffer-block @ <>
152 : pazsan 1.9 r@ buffer-fid @ block-fid @ <> or
153 : anton 1.1 if
154 : pazsan 1.5 r@ save-buffer
155 : anton 1.1 dup block-position
156 : pazsan 1.5 r@ block-buffer chars/block get-block-fid read-file throw
157 : anton 1.1 \ clear the rest of the buffer if the file is too short
158 : pazsan 1.5 r@ block-buffer over chars + chars/block rot chars - blank
159 :     r@ buffer-block !
160 :     get-block-fid r@ buffer-fid !
161 : anton 1.1 else
162 :     drop
163 :     then
164 : pazsan 1.5 r> dup last-block ! block-buffer ;
165 : anton 1.1
166 : pazsan 1.20 : buffer ( u -- a-addr ) \ block
167 : crook 1.24 \G If a block buffer is assigned for block @i{u}, return its
168 :     \G start address, @i{a-addr}. Otherwise, assign a block buffer
169 :     \G for block @i{u} (if the assigned block buffer has been
170 :     \G @code{update}d, transfer the contents to mass storage) and
171 :     \G return its start address, @i{a-addr}. The subtle difference
172 :     \G between @code{buffer} and @code{block} mean that you should
173 :     \G only use @code{buffer} if you don't care about the previous
174 :     \G contents of block @i{u}. In Gforth, this simply calls
175 :     \G @code{block}.
176 : anton 1.1 \ reading in the block is unnecessary, but simpler
177 :     block ;
178 :    
179 : crook 1.28 User scr ( -- a-addr ) \ block-ext s-c-r
180 : crook 1.27 \G @code{User} variable -- @i{a-addr} is the address of a cell containing
181 : crook 1.21 \G the block number of the block most recently processed by
182 : crook 1.24 \G @code{list}.
183 :     0 scr !
184 : anton 1.1
185 : crook 1.24 \ nac31Mar1999 moved "scr @" to list to make the stack comment correct
186 : pazsan 1.20 : updated? ( n -- f ) \ gforth
187 : crook 1.29 \G Return true if @code{updated} has been used to mark block @i{n}
188 :     \G as assigned-dirty.
189 : crook 1.24 buffer
190 : pazsan 1.5 [ 0 buffer-dirty 0 block-buffer - ] Literal + @ ;
191 :    
192 : crook 1.24 : list ( u -- ) \ block-ext
193 :     \G Display block @i{u}. In Gforth, the block is displayed as 16
194 :     \G numbered lines, each of 64 characters.
195 : anton 1.1 \ calling block again and again looks inefficient but is necessary
196 :     \ in a multitasking environment
197 :     dup scr !
198 : pazsan 1.5 ." Screen " u.
199 : crook 1.24 scr @ updated? 0= IF ." not " THEN ." modified " cr
200 : anton 1.1 16 0
201 :     ?do
202 : anton 1.4 i 2 .r space scr @ block i 64 * chars + 64 type cr
203 : anton 1.1 loop ;
204 :    
205 : crook 1.23 : (source) ( -- c-addr u )
206 : pazsan 1.2 blk @ ?dup
207 :     IF block chars/block
208 :     ELSE tib #tib @
209 :     THEN ;
210 :    
211 : crook 1.23 ' (source) IS source ( -- c-addr u ) \ core
212 : crook 1.24 \G @i{c-addr} is the address of the input buffer and @i{u} is the
213 : crook 1.23 \G number of characters in it.
214 : pazsan 1.2
215 : pazsan 1.20 : load ( i*x n -- j*x ) \ block
216 : crook 1.24 \G Save the current input source specification. Store @i{n} in
217 :     \G @code{BLK}, set @code{>IN} to 0 and interpret. When the parse
218 :     \G area is exhausted, restore the input source specification.
219 :     push-file
220 :     dup loadline ! blk ! >in off ['] interpret catch
221 :     pop-file throw ;
222 :    
223 :     : thru ( i*x n1 n2 -- j*x ) \ block-ext
224 :     \G @code{load} the blocks @i{n1} through @i{n2} in sequence.
225 :     1+ swap ?DO I load LOOP ;
226 :    
227 :     : +load ( i*x n -- j*x ) \ gforth
228 :     \G Used within a block to load the block specified as the
229 :     \G current block + @i{n}.
230 : pazsan 1.20 blk @ + load ;
231 : pazsan 1.2
232 : crook 1.24 : +thru ( i*x n1 n2 -- j*x ) \ gforth
233 :     \G Used within a block to load the range of blocks specified as the
234 :     \G current block + @i{n1} thru the current block + @i{n2}.
235 :     1+ swap ?DO I +load LOOP ;
236 :    
237 : crook 1.28 : --> ( -- ) \ gforthman- gforth chain
238 : crook 1.24 \G If this symbol is encountered whilst loading block @i{n},
239 :     \G discard the remainder of the block and load block @i{n+1}. Used
240 : anton 1.25 \G for chaining multiple blocks together as a single loadable
241 :     \G unit. Not recommended, because it destroys the independence of
242 :     \G loading. Use @code{thru} (which is standard) or @code{+thru}
243 :     \G instead.
244 : pazsan 1.20 refill drop ; immediate
245 : pazsan 1.5
246 : crook 1.24 : block-included ( a-addr u -- ) \ gforth
247 :     \G Use within a block that is to be processed by @code{load}. Save
248 :     \G the current blocks file specification, open the blocks file
249 :     \G specified by @i{a-addr u} and @code{load} block 1 from that
250 :     \G file (which may in turn chain or load other blocks). Finally,
251 :     \G close the blocks file and restore the original blocks file.
252 : anton 1.11 block-fid @ >r block-fid off open-blocks
253 : pazsan 1.5 1 load block-fid @ close-file throw flush
254 :     r> block-fid ! ;
255 :    
256 : anton 1.13 \ thrown out because it may provide unpleasant surprises - anton
257 :     \ : include ( "name" -- )
258 :     \ name 2dup dup 3 - /string s" .fb" compare
259 :     \ 0= IF block-included ELSE included THEN ;
260 : pazsan 1.5
261 : anton 1.4 get-current environment-wordlist set-current
262 :     true constant block
263 :     true constant block-ext
264 :     set-current
265 : pazsan 1.5
266 : crook 1.21 : bye ( -- ) \ tools-ext
267 :     \G Return control to the host operating system (if any).
268 :     ['] flush catch drop bye ;

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