1: \ A less simple implementation of the blocks wordset.
2:
3: \ Copyright (C) 1995,1996,1997,1998,2000,2003 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., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
20:
21:
22: \ A more efficient implementation would use mmap on OSs that
23: \ provide it and many buffers on OSs that do not provide mmap.
24:
25: \ Now, the replacement algorithm is "direct mapped"; change to LRU
26: \ if too slow. Using more buffers helps, too.
27:
28: \ I think I avoid the assumption 1 char = 1 here, but I have not tested this
29:
30: \ 1024 constant chars/block \ mandated by the standard
31:
32: require struct.fs
33:
34: struct
35: 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: end-struct buffer-struct
41:
42: Variable block-buffers
43: Variable last-block
44:
45: $20 Value buffers
46:
47: \ limit block files to 2GB; gforth <0.6.0 erases larger block files on
48: \ 32-bit systems
49: $200000 Value block-limit
50:
51: User block-fid
52: User block-offset ( -- addr ) \ gforth
53: \G User variable containing the number of the first block (default
54: \G since 0.5.0: 0). Block files created with Gforth versions before
55: \G 0.5.0 have the offset 1. If you use these files you can: @code{1
56: \G offset !}; or add 1 to every block number used; or prepend 1024
57: \G characters to the file.
58: 0 block-offset ! \ store 1 here fore 0.4.0 compatibility
59:
60: ' block-offset alias offset \ !! eliminate this?
61:
62: : block-cold ( -- )
63: block-fid off last-block off
64: buffer-struct buffers * %alloc dup block-buffers ! ( addr )
65: buffer-struct %size buffers * erase ;
66:
67: :noname ( -- )
68: defers 'cold
69: block-cold
70: ; is 'cold
71:
72: block-cold
73:
74: Defer flush-blocks ( -- ) \ gforth
75:
76: : open-blocks ( c-addr u -- ) \ gforth
77: \g Use the file, whose name is given by @i{c-addr u}, as the blocks file.
78: try ( c-addr u )
79: 2dup open-fpath-file throw
80: rot close-file throw 2dup file-status throw bin open-file throw
81: >r 2drop r>
82: recover ( c-addr u ior )
83: >r 2dup file-status nip 0= r> and throw \ does it really not exist?
84: r/w bin create-file throw
85: endtry
86: block-fid @ IF
87: flush-blocks block-fid @ close-file throw
88: THEN
89: block-fid ! ;
90:
91: : use ( "file" -- ) \ gforth
92: \g Use @i{file} as the blocks file.
93: name open-blocks ;
94:
95: \ the file is opened as binary file, since it either will contain text
96: \ without newlines or binary data
97: : get-block-fid ( -- wfileid ) \ gforth
98: \G Return the file-id of the current blocks file. If no blocks
99: \G file has been opened, use @file{blocks.fb} as the default
100: \G blocks file.
101: block-fid @ 0=
102: if
103: s" blocks.fb" open-blocks
104: then
105: block-fid @ ;
106:
107: : block-position ( u -- ) \ block
108: \G Position the block file to the start of block @i{u}.
109: dup block-limit u>= -35 and throw
110: offset @ - chars/block chars um* get-block-fid reposition-file throw ;
111:
112: : update ( -- ) \ block
113: \G Mark the state of the current block buffer as assigned-dirty.
114: last-block @ ?dup IF buffer-dirty on THEN ;
115:
116: : save-buffer ( buffer -- ) \ gforth
117: >r
118: r@ buffer-dirty @
119: if
120: r@ buffer-block @ block-position
121: r@ block-buffer chars/block r@ buffer-fid @ write-file throw
122: r@ buffer-fid @ flush-file throw
123: r@ buffer-dirty off
124: endif
125: rdrop ;
126:
127: : empty-buffer ( buffer -- ) \ gforth
128: buffer-block off ;
129:
130: : save-buffers ( -- ) \ block
131: \G Transfer the contents of each @code{update}d block buffer to
132: \G mass storage, then mark all block buffers as assigned-clean.
133: block-buffers @
134: buffers 0 ?DO dup save-buffer next-buffer LOOP drop ;
135:
136: : empty-buffers ( -- ) \ block-ext
137: \G Mark all block buffers as unassigned; if any had been marked as
138: \G assigned-dirty (by @code{update}), the changes to those blocks
139: \G will be lost.
140: block-buffers @
141: buffers 0 ?DO dup empty-buffer next-buffer LOOP drop ;
142:
143: : flush ( -- ) \ block
144: \G Perform the functions of @code{save-buffers} then
145: \G @code{empty-buffers}.
146: save-buffers
147: empty-buffers ;
148:
149: ' flush IS flush-blocks
150:
151: : get-buffer ( u -- a-addr ) \ gforth
152: 0 buffers um/mod drop buffer-struct %size * block-buffers @ + ;
153:
154: : block ( u -- a-addr ) \ gforthman- block
155: \G If a block buffer is assigned for block @i{u}, return its
156: \G start address, @i{a-addr}. Otherwise, assign a block buffer
157: \G for block @i{u} (if the assigned block buffer has been
158: \G @code{update}d, transfer the contents to mass storage), read
159: \G the block into the block buffer and return its start address,
160: \G @i{a-addr}.
161: dup offset @ u< -35 and throw
162: dup get-buffer >r
163: dup r@ buffer-block @ <>
164: r@ buffer-fid @ block-fid @ <> or
165: if
166: r@ save-buffer
167: dup block-position
168: r@ block-buffer chars/block get-block-fid read-file throw
169: \ clear the rest of the buffer if the file is too short
170: r@ block-buffer over chars + chars/block rot chars - blank
171: r@ buffer-block !
172: get-block-fid r@ buffer-fid !
173: else
174: drop
175: then
176: r> dup last-block ! block-buffer ;
177:
178: : buffer ( u -- a-addr ) \ block
179: \G If a block buffer is assigned for block @i{u}, return its
180: \G start address, @i{a-addr}. Otherwise, assign a block buffer
181: \G for block @i{u} (if the assigned block buffer has been
182: \G @code{update}d, transfer the contents to mass storage) and
183: \G return its start address, @i{a-addr}. The subtle difference
184: \G between @code{buffer} and @code{block} mean that you should
185: \G only use @code{buffer} if you don't care about the previous
186: \G contents of block @i{u}. In Gforth, this simply calls
187: \G @code{block}.
188: \ reading in the block is unnecessary, but simpler
189: block ;
190:
191: User scr ( -- a-addr ) \ block-ext s-c-r
192: \G @code{User} variable -- @i{a-addr} is the address of a cell containing
193: \G the block number of the block most recently processed by
194: \G @code{list}.
195: 0 scr !
196:
197: \ nac31Mar1999 moved "scr @" to list to make the stack comment correct
198: : updated? ( n -- f ) \ gforth
199: \G Return true if @code{updated} has been used to mark block @i{n}
200: \G as assigned-dirty.
201: buffer
202: [ 0 buffer-dirty 0 block-buffer - ] Literal + @ ;
203:
204: : list ( u -- ) \ block-ext
205: \G Display block @i{u}. In Gforth, the block is displayed as 16
206: \G numbered lines, each of 64 characters.
207: \ calling block again and again looks inefficient but is necessary
208: \ in a multitasking environment
209: dup scr !
210: ." Screen " u.
211: scr @ updated? 0= IF ." not " THEN ." modified " cr
212: 16 0
213: ?do
214: i 2 .r space scr @ block i 64 * chars + 64 type cr
215: loop ;
216:
217: [IFDEF] current-input
218: :noname 2 <> -12 and throw >in ! blk ! ;
219: \ restore-input
220: :noname blk @ >in @ 2 ; \ save-input
221: :noname 2 ; \ source-id "*a block*"
222: :noname 1 blk +! 1 loadline +! >in off true ; \ refill
223: :noname blk @ block chars/block ; \ source
224:
225: Create block-input A, A, A, A, A,
226:
227: : load ( i*x n -- j*x ) \ block
228: \G Save the current input source specification. Store @i{n} in
229: \G @code{BLK}, set @code{>IN} to 0 and interpret. When the parse
230: \G area is exhausted, restore the input source specification.
231: block-input 0 new-tib dup loadline ! blk ! s" * a block*" loadfilename 2!
232: ['] interpret catch pop-file throw ;
233: [ELSE]
234: : (source) ( -- c-addr u )
235: blk @ ?dup
236: IF block chars/block
237: ELSE tib #tib @
238: THEN ;
239:
240: ' (source) IS source ( -- c-addr u ) \ core
241: \G @i{c-addr} is the address of the input buffer and @i{u} is the
242: \G number of characters in it.
243:
244: : load ( i*x n -- j*x ) \ block
245: \G Save the current input source specification. Store @i{n} in
246: \G @code{BLK}, set @code{>IN} to 0 and interpret. When the parse
247: \G area is exhausted, restore the input source specification.
248: s" * a block*" loadfilename>r
249: push-file
250: dup loadline ! blk ! >in off ['] interpret catch
251: pop-file
252: r>loadfilename
253: throw ;
254: [THEN]
255:
256: : thru ( i*x n1 n2 -- j*x ) \ block-ext
257: \G @code{load} the blocks @i{n1} through @i{n2} in sequence.
258: 1+ swap ?DO I load LOOP ;
259:
260: : +load ( i*x n -- j*x ) \ gforth
261: \G Used within a block to load the block specified as the
262: \G current block + @i{n}.
263: blk @ + load ;
264:
265: : +thru ( i*x n1 n2 -- j*x ) \ gforth
266: \G Used within a block to load the range of blocks specified as the
267: \G current block + @i{n1} thru the current block + @i{n2}.
268: 1+ swap ?DO I +load LOOP ;
269:
270: : --> ( -- ) \ gforthman- gforth chain
271: \G If this symbol is encountered whilst loading block @i{n},
272: \G discard the remainder of the block and load block @i{n+1}. Used
273: \G for chaining multiple blocks together as a single loadable
274: \G unit. Not recommended, because it destroys the independence of
275: \G loading. Use @code{thru} (which is standard) or @code{+thru}
276: \G instead.
277: refill drop ; immediate
278:
279: : block-included ( a-addr u -- ) \ gforth
280: \G Use within a block that is to be processed by @code{load}. Save
281: \G the current blocks file specification, open the blocks file
282: \G specified by @i{a-addr u} and @code{load} block 1 from that
283: \G file (which may in turn chain or load other blocks). Finally,
284: \G close the blocks file and restore the original blocks file.
285: block-fid @ >r block-fid off open-blocks
286: 1 load block-fid @ close-file throw flush
287: r> block-fid ! ;
288:
289: \ thrown out because it may provide unpleasant surprises - anton
290: \ : include ( "name" -- )
291: \ name 2dup dup 3 - /string s" .fb" compare
292: \ 0= IF block-included ELSE included THEN ;
293:
294: get-current environment-wordlist set-current
295: true constant block
296: true constant block-ext
297: set-current
298:
299: : bye ( -- ) \ tools-ext
300: \G Return control to the host operating system (if any).
301: ['] flush catch drop bye ;
FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>