Annotation of gforth/blocks.fs, revision 1.55
1.5 pazsan 1: \ A less simple implementation of the blocks wordset.
1.1 anton 2:
1.55 ! anton 3: \ Copyright (C) 1995,1996,1997,1998,2000,2003,2006,2007,2008 Free Software Foundation, Inc.
1.7 anton 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
1.53 anton 9: \ as published by the Free Software Foundation, either version 3
1.7 anton 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
1.53 anton 18: \ along with this program. If not, see http://www.gnu.org/licenses/.
1.7 anton 19:
20:
21: \ A more efficient implementation would use mmap on OSs that
1.1 anton 22: \ provide it and many buffers on OSs that do not provide mmap.
23:
1.5 pazsan 24: \ Now, the replacement algorithm is "direct mapped"; change to LRU
25: \ if too slow. Using more buffers helps, too.
26:
1.1 anton 27: \ I think I avoid the assumption 1 char = 1 here, but I have not tested this
28:
1.2 pazsan 29: \ 1024 constant chars/block \ mandated by the standard
1.1 anton 30:
1.5 pazsan 31: require struct.fs
32:
33: struct
1.17 anton 34: cell% field buffer-block \ the block number
35: cell% field buffer-fid \ the block's fid
36: cell% field buffer-dirty \ the block dirty flag
37: char% chars/block * field block-buffer \ the data
38: cell% 0 * field next-buffer
1.5 pazsan 39: end-struct buffer-struct
40:
41: Variable block-buffers
42: Variable last-block
43:
44: $20 Value buffers
45:
1.36 anton 46: \ limit block files to 2GB; gforth <0.6.0 erases larger block files on
47: \ 32-bit systems
48: $200000 Value block-limit
49:
1.5 pazsan 50: User block-fid
1.30 anton 51: User block-offset ( -- addr ) \ gforth
52: \G User variable containing the number of the first block (default
53: \G since 0.5.0: 0). Block files created with Gforth versions before
54: \G 0.5.0 have the offset 1. If you use these files you can: @code{1
55: \G offset !}; or add 1 to every block number used; or prepend 1024
56: \G characters to the file.
57: 0 block-offset ! \ store 1 here fore 0.4.0 compatibility
58:
59: ' block-offset alias offset \ !! eliminate this?
1.1 anton 60:
1.17 anton 61: : block-cold ( -- )
1.16 jwilke 62: block-fid off last-block off
1.17 anton 63: buffer-struct buffers * %alloc dup block-buffers ! ( addr )
64: buffer-struct %size buffers * erase ;
1.1 anton 65:
1.43 anton 66: :noname ( -- )
67: defers 'cold
68: block-cold
69: ; is 'cold
1.5 pazsan 70:
71: block-cold
72:
1.24 crook 73: Defer flush-blocks ( -- ) \ gforth
1.5 pazsan 74:
1.24 crook 75: : open-blocks ( c-addr u -- ) \ gforth
1.36 anton 76: \g Use the file, whose name is given by @i{c-addr u}, as the blocks file.
77: try ( c-addr u )
78: 2dup open-fpath-file throw
1.8 pazsan 79: rot close-file throw 2dup file-status throw bin open-file throw
1.50 anton 80: >r 2drop r>
81: endtry-iferror ( c-addr u ior )
1.36 anton 82: >r 2dup file-status nip 0= r> and throw \ does it really not exist?
83: r/w bin create-file throw
1.48 anton 84: then
1.36 anton 85: block-fid @ IF
86: flush-blocks block-fid @ close-file throw
87: THEN
1.5 pazsan 88: block-fid ! ;
1.8 pazsan 89:
1.10 anton 90: : use ( "file" -- ) \ gforth
1.24 crook 91: \g Use @i{file} as the blocks file.
1.11 anton 92: name open-blocks ;
1.1 anton 93:
1.3 anton 94: \ the file is opened as binary file, since it either will contain text
95: \ without newlines or binary data
1.24 crook 96: : get-block-fid ( -- wfileid ) \ gforth
97: \G Return the file-id of the current blocks file. If no blocks
98: \G file has been opened, use @file{blocks.fb} as the default
99: \G blocks file.
1.1 anton 100: block-fid @ 0=
101: if
1.11 anton 102: s" blocks.fb" open-blocks
1.1 anton 103: then
104: block-fid @ ;
105:
1.20 pazsan 106: : block-position ( u -- ) \ block
1.36 anton 107: \G Position the block file to the start of block @i{u}.
108: dup block-limit u>= -35 and throw
1.26 pazsan 109: offset @ - chars/block chars um* get-block-fid reposition-file throw ;
1.1 anton 110:
1.20 pazsan 111: : update ( -- ) \ block
1.29 crook 112: \G Mark the state of the current block buffer as assigned-dirty.
1.5 pazsan 113: last-block @ ?dup IF buffer-dirty on THEN ;
1.1 anton 114:
1.20 pazsan 115: : save-buffer ( buffer -- ) \ gforth
116: >r
1.42 pazsan 117: r@ buffer-dirty @
1.1 anton 118: if
1.5 pazsan 119: r@ buffer-block @ block-position
120: r@ block-buffer chars/block r@ buffer-fid @ write-file throw
1.36 anton 121: r@ buffer-fid @ flush-file throw
122: r@ buffer-dirty off
1.5 pazsan 123: endif
124: rdrop ;
125:
1.20 pazsan 126: : empty-buffer ( buffer -- ) \ gforth
1.54 pazsan 127: dup buffer-block on buffer-dirty off ;
1.5 pazsan 128:
1.20 pazsan 129: : save-buffers ( -- ) \ block
1.24 crook 130: \G Transfer the contents of each @code{update}d block buffer to
1.30 anton 131: \G mass storage, then mark all block buffers as assigned-clean.
1.20 pazsan 132: block-buffers @
1.24 crook 133: buffers 0 ?DO dup save-buffer next-buffer LOOP drop ;
1.1 anton 134:
1.24 crook 135: : empty-buffers ( -- ) \ block-ext
136: \G Mark all block buffers as unassigned; if any had been marked as
137: \G assigned-dirty (by @code{update}), the changes to those blocks
138: \G will be lost.
1.20 pazsan 139: block-buffers @
1.24 crook 140: buffers 0 ?DO dup empty-buffer next-buffer LOOP drop ;
1.1 anton 141:
1.20 pazsan 142: : flush ( -- ) \ block
1.24 crook 143: \G Perform the functions of @code{save-buffers} then
144: \G @code{empty-buffers}.
1.1 anton 145: save-buffers
146: empty-buffers ;
147:
1.12 anton 148: ' flush IS flush-blocks
1.5 pazsan 149:
1.26 pazsan 150: : get-buffer ( u -- a-addr ) \ gforth
151: 0 buffers um/mod drop buffer-struct %size * block-buffers @ + ;
1.5 pazsan 152:
1.51 anton 153: : block ( u -- a-addr ) \ block
1.24 crook 154: \G If a block buffer is assigned for block @i{u}, return its
155: \G start address, @i{a-addr}. Otherwise, assign a block buffer
156: \G for block @i{u} (if the assigned block buffer has been
157: \G @code{update}d, transfer the contents to mass storage), read
158: \G the block into the block buffer and return its start address,
159: \G @i{a-addr}.
1.26 pazsan 160: dup offset @ u< -35 and throw
1.5 pazsan 161: dup get-buffer >r
162: dup r@ buffer-block @ <>
1.9 pazsan 163: r@ buffer-fid @ block-fid @ <> or
1.1 anton 164: if
1.5 pazsan 165: r@ save-buffer
1.1 anton 166: dup block-position
1.5 pazsan 167: r@ block-buffer chars/block get-block-fid read-file throw
1.1 anton 168: \ clear the rest of the buffer if the file is too short
1.5 pazsan 169: r@ block-buffer over chars + chars/block rot chars - blank
170: r@ buffer-block !
171: get-block-fid r@ buffer-fid !
1.1 anton 172: else
173: drop
174: then
1.5 pazsan 175: r> dup last-block ! block-buffer ;
1.1 anton 176:
1.20 pazsan 177: : buffer ( u -- a-addr ) \ block
1.24 crook 178: \G If a block buffer is assigned for block @i{u}, return its
179: \G start address, @i{a-addr}. Otherwise, assign a block buffer
180: \G for block @i{u} (if the assigned block buffer has been
181: \G @code{update}d, transfer the contents to mass storage) and
182: \G return its start address, @i{a-addr}. The subtle difference
183: \G between @code{buffer} and @code{block} mean that you should
184: \G only use @code{buffer} if you don't care about the previous
185: \G contents of block @i{u}. In Gforth, this simply calls
186: \G @code{block}.
1.1 anton 187: \ reading in the block is unnecessary, but simpler
188: block ;
189:
1.28 crook 190: User scr ( -- a-addr ) \ block-ext s-c-r
1.27 crook 191: \G @code{User} variable -- @i{a-addr} is the address of a cell containing
1.21 crook 192: \G the block number of the block most recently processed by
1.24 crook 193: \G @code{list}.
194: 0 scr !
1.1 anton 195:
1.24 crook 196: \ nac31Mar1999 moved "scr @" to list to make the stack comment correct
1.20 pazsan 197: : updated? ( n -- f ) \ gforth
1.29 crook 198: \G Return true if @code{updated} has been used to mark block @i{n}
199: \G as assigned-dirty.
1.24 crook 200: buffer
1.5 pazsan 201: [ 0 buffer-dirty 0 block-buffer - ] Literal + @ ;
202:
1.24 crook 203: : list ( u -- ) \ block-ext
204: \G Display block @i{u}. In Gforth, the block is displayed as 16
205: \G numbered lines, each of 64 characters.
1.1 anton 206: \ calling block again and again looks inefficient but is necessary
207: \ in a multitasking environment
208: dup scr !
1.5 pazsan 209: ." Screen " u.
1.24 crook 210: scr @ updated? 0= IF ." not " THEN ." modified " cr
1.1 anton 211: 16 0
212: ?do
1.4 anton 213: i 2 .r space scr @ block i 64 * chars + 64 type cr
1.1 anton 214: loop ;
215:
1.34 pazsan 216: [IFDEF] current-input
217: :noname 2 <> -12 and throw >in ! blk ! ;
218: \ restore-input
219: :noname blk @ >in @ 2 ; \ save-input
220: :noname 2 ; \ source-id "*a block*"
1.42 pazsan 221: :noname 1 blk +! 1 loadline +! >in off true ; \ refill
1.34 pazsan 222: :noname blk @ block chars/block ; \ source
223:
224: Create block-input A, A, A, A, A,
225:
226: : load ( i*x n -- j*x ) \ block
227: \G Save the current input source specification. Store @i{n} in
228: \G @code{BLK}, set @code{>IN} to 0 and interpret. When the parse
229: \G area is exhausted, restore the input source specification.
1.39 anton 230: block-input 0 new-tib dup loadline ! blk ! s" * a block*" loadfilename 2!
1.45 pazsan 231: ['] interpret catch pop-file throw ;
1.34 pazsan 232: [ELSE]
1.23 crook 233: : (source) ( -- c-addr u )
1.2 pazsan 234: blk @ ?dup
235: IF block chars/block
236: ELSE tib #tib @
237: THEN ;
238:
1.23 crook 239: ' (source) IS source ( -- c-addr u ) \ core
1.24 crook 240: \G @i{c-addr} is the address of the input buffer and @i{u} is the
1.23 crook 241: \G number of characters in it.
1.2 pazsan 242:
1.20 pazsan 243: : load ( i*x n -- j*x ) \ block
1.24 crook 244: \G Save the current input source specification. Store @i{n} in
245: \G @code{BLK}, set @code{>IN} to 0 and interpret. When the parse
246: \G area is exhausted, restore the input source specification.
1.40 anton 247: s" * a block*" loadfilename>r
1.24 crook 248: push-file
249: dup loadline ! blk ! >in off ['] interpret catch
1.31 anton 250: pop-file
1.40 anton 251: r>loadfilename
1.45 pazsan 252: throw ;
1.34 pazsan 253: [THEN]
1.24 crook 254:
255: : thru ( i*x n1 n2 -- j*x ) \ block-ext
256: \G @code{load} the blocks @i{n1} through @i{n2} in sequence.
257: 1+ swap ?DO I load LOOP ;
258:
259: : +load ( i*x n -- j*x ) \ gforth
260: \G Used within a block to load the block specified as the
261: \G current block + @i{n}.
1.20 pazsan 262: blk @ + load ;
1.2 pazsan 263:
1.24 crook 264: : +thru ( i*x n1 n2 -- j*x ) \ gforth
265: \G Used within a block to load the range of blocks specified as the
266: \G current block + @i{n1} thru the current block + @i{n2}.
267: 1+ swap ?DO I +load LOOP ;
268:
1.28 crook 269: : --> ( -- ) \ gforthman- gforth chain
1.24 crook 270: \G If this symbol is encountered whilst loading block @i{n},
271: \G discard the remainder of the block and load block @i{n+1}. Used
1.25 anton 272: \G for chaining multiple blocks together as a single loadable
273: \G unit. Not recommended, because it destroys the independence of
274: \G loading. Use @code{thru} (which is standard) or @code{+thru}
275: \G instead.
1.20 pazsan 276: refill drop ; immediate
1.5 pazsan 277:
1.24 crook 278: : block-included ( a-addr u -- ) \ gforth
279: \G Use within a block that is to be processed by @code{load}. Save
280: \G the current blocks file specification, open the blocks file
281: \G specified by @i{a-addr u} and @code{load} block 1 from that
282: \G file (which may in turn chain or load other blocks). Finally,
283: \G close the blocks file and restore the original blocks file.
1.11 anton 284: block-fid @ >r block-fid off open-blocks
1.5 pazsan 285: 1 load block-fid @ close-file throw flush
286: r> block-fid ! ;
287:
1.13 anton 288: \ thrown out because it may provide unpleasant surprises - anton
289: \ : include ( "name" -- )
290: \ name 2dup dup 3 - /string s" .fb" compare
291: \ 0= IF block-included ELSE included THEN ;
1.5 pazsan 292:
1.4 anton 293: get-current environment-wordlist set-current
1.51 anton 294: true constant block \ environment- environment
1.4 anton 295: true constant block-ext
296: set-current
1.5 pazsan 297:
1.21 crook 298: : bye ( -- ) \ tools-ext
299: \G Return control to the host operating system (if any).
300: ['] flush catch drop bye ;
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