Annotation of gforth/blocks.fs, revision 1.21
1.5 pazsan 1: \ A less simple implementation of the blocks wordset.
1.1 anton 2:
1.19 anton 3: \ Copyright (C) 1995,1996,1997,1998 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
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
1.1 anton 23: \ provide it and many buffers on OSs that do not provide mmap.
24:
1.5 pazsan 25: \ Now, the replacement algorithm is "direct mapped"; change to LRU
26: \ if too slow. Using more buffers helps, too.
27:
1.1 anton 28: \ I think I avoid the assumption 1 char = 1 here, but I have not tested this
29:
1.2 pazsan 30: \ 1024 constant chars/block \ mandated by the standard
1.1 anton 31:
1.5 pazsan 32: require struct.fs
33:
34: struct
1.17 anton 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
1.5 pazsan 40: end-struct buffer-struct
41:
42: Variable block-buffers
43: Variable last-block
44:
45: $20 Value buffers
46:
47: User block-fid
1.1 anton 48:
1.17 anton 49: : block-cold ( -- )
1.16 jwilke 50: block-fid off last-block off
1.17 anton 51: buffer-struct buffers * %alloc dup block-buffers ! ( addr )
52: buffer-struct %size buffers * erase ;
1.1 anton 53:
1.16 jwilke 54: ' block-cold INIT8 chained
1.5 pazsan 55:
56: block-cold
57:
1.12 anton 58: Defer flush-blocks
1.5 pazsan 59:
1.11 anton 60: : open-blocks ( addr u -- ) \ gforth
1.10 anton 61: \g use the file, whose name is given by @var{addr u}, as blocks file
1.18 pazsan 62: 2dup open-fpath-file 0<>
1.5 pazsan 63: if
1.18 pazsan 64: r/w bin create-file throw
1.5 pazsan 65: else
1.8 pazsan 66: rot close-file throw 2dup file-status throw bin open-file throw
67: >r 2drop r>
1.5 pazsan 68: then
1.12 anton 69: block-fid @ IF flush-blocks block-fid @ close-file throw THEN
1.5 pazsan 70: block-fid ! ;
1.8 pazsan 71:
1.10 anton 72: : use ( "file" -- ) \ gforth
73: \g use @var{file} as blocks file
1.11 anton 74: name open-blocks ;
1.1 anton 75:
1.3 anton 76: \ the file is opened as binary file, since it either will contain text
77: \ without newlines or binary data
1.20 pazsan 78: : get-block-fid ( -- fid ) \ gforth
1.1 anton 79: block-fid @ 0=
80: if
1.11 anton 81: s" blocks.fb" open-blocks
1.1 anton 82: then
83: block-fid @ ;
84:
1.20 pazsan 85: : block-position ( u -- ) \ block
1.21 ! crook 86: \G Position the block file to the start of block u.
1.3 anton 87: 1- chars/block chars um* get-block-fid reposition-file throw ;
1.1 anton 88:
1.20 pazsan 89: : update ( -- ) \ block
1.5 pazsan 90: last-block @ ?dup IF buffer-dirty on THEN ;
1.1 anton 91:
1.20 pazsan 92: : save-buffer ( buffer -- ) \ gforth
93: >r
1.5 pazsan 94: r@ buffer-dirty @ r@ buffer-block @ 0<> and
1.1 anton 95: if
1.5 pazsan 96: r@ buffer-block @ block-position
97: r@ block-buffer chars/block r@ buffer-fid @ write-file throw
98: r@ buffer-dirty off
99: endif
100: rdrop ;
101:
1.20 pazsan 102: : empty-buffer ( buffer -- ) \ gforth
1.5 pazsan 103: buffer-block off ;
104:
1.20 pazsan 105: : save-buffers ( -- ) \ block
106: block-buffers @
1.5 pazsan 107: buffers 0 ?DO dup save-buffer next-buffer LOOP drop ;
1.1 anton 108:
1.20 pazsan 109: : empty-buffers ( -- ) \ block
110: block-buffers @
1.5 pazsan 111: buffers 0 ?DO dup empty-buffer next-buffer LOOP drop ;
1.1 anton 112:
1.20 pazsan 113: : flush ( -- ) \ block
1.1 anton 114: save-buffers
115: empty-buffers ;
116:
1.12 anton 117: ' flush IS flush-blocks
1.5 pazsan 118:
1.20 pazsan 119: : get-buffer ( n -- a-addr ) \ gforth
1.17 anton 120: buffers mod buffer-struct %size * block-buffers @ + ;
1.5 pazsan 121:
1.21 ! crook 122: : block ( u -- a-addr ) \ block- block
! 123: \G u identifies a block number. Assign a block buffer to u,
! 124: \G make it the current block buffer and return its start
! 125: \G address, a-addr.
1.1 anton 126: dup 0= -35 and throw
1.5 pazsan 127: dup get-buffer >r
128: dup r@ buffer-block @ <>
1.9 pazsan 129: r@ buffer-fid @ block-fid @ <> or
1.1 anton 130: if
1.5 pazsan 131: r@ save-buffer
1.1 anton 132: dup block-position
1.5 pazsan 133: r@ block-buffer chars/block get-block-fid read-file throw
1.1 anton 134: \ clear the rest of the buffer if the file is too short
1.5 pazsan 135: r@ block-buffer over chars + chars/block rot chars - blank
136: r@ buffer-block !
137: get-block-fid r@ buffer-fid !
1.1 anton 138: else
139: drop
140: then
1.5 pazsan 141: r> dup last-block ! block-buffer ;
1.1 anton 142:
1.20 pazsan 143: : buffer ( u -- a-addr ) \ block
1.1 anton 144: \ reading in the block is unnecessary, but simpler
145: block ;
146:
1.21 ! crook 147: User scr ( -- a-addr ) \ block-ext
! 148: \G USER VARIABLE a-addr is the address of a cell containing
! 149: \G the block number of the block most recently processed by
! 150: \G @code{LIST}.
! 151: 0 scr !
1.1 anton 152:
1.20 pazsan 153: : updated? ( n -- f ) \ gforth
154: scr @ buffer
1.5 pazsan 155: [ 0 buffer-dirty 0 block-buffer - ] Literal + @ ;
156:
1.20 pazsan 157: : list ( u -- ) \ block
1.1 anton 158: \ calling block again and again looks inefficient but is necessary
159: \ in a multitasking environment
160: dup scr !
1.5 pazsan 161: ." Screen " u.
162: updated? 0= IF ." not " THEN ." modified " cr
1.1 anton 163: 16 0
164: ?do
1.4 anton 165: i 2 .r space scr @ block i 64 * chars + 64 type cr
1.1 anton 166: loop ;
167:
1.2 pazsan 168: : (source) ( -- addr len )
169: blk @ ?dup
170: IF block chars/block
171: ELSE tib #tib @
172: THEN ;
173:
174: ' (source) IS source
175:
1.20 pazsan 176: : load ( i*x n -- j*x ) \ block
1.2 pazsan 177: push-file
1.18 pazsan 178: dup loadline ! blk ! >in off ['] interpret catch
179: pop-file throw ;
1.1 anton 180:
1.20 pazsan 181: : thru ( i*x n1 n2 -- j*x ) \ block
1.15 pazsan 182: 1+ swap ?DO I load LOOP ;
1.1 anton 183:
1.20 pazsan 184: : +load ( i*x n -- j*x ) \ block
185: blk @ + load ;
1.2 pazsan 186:
1.20 pazsan 187: : +thru ( i*x n1 n2 -- j*x ) \ block
1.15 pazsan 188: 1+ swap ?DO I +load LOOP ;
1.4 anton 189:
1.20 pazsan 190: : --> ( -- ) \ block- block
1.21 ! crook 191: \G If this symbol is encountered whilst loading block @var{n},
! 192: \G discard the remainder of the block and load block @var{n+1}. Used
! 193: \G for chaining multiple blocks together as a single loadable unit.
1.20 pazsan 194: refill drop ; immediate
1.5 pazsan 195:
1.20 pazsan 196: : block-included ( addr u -- ) \ gforth
1.11 anton 197: block-fid @ >r block-fid off open-blocks
1.5 pazsan 198: 1 load block-fid @ close-file throw flush
199: r> block-fid ! ;
200:
1.13 anton 201: \ thrown out because it may provide unpleasant surprises - anton
202: \ : include ( "name" -- )
203: \ name 2dup dup 3 - /string s" .fb" compare
204: \ 0= IF block-included ELSE included THEN ;
1.5 pazsan 205:
1.4 anton 206: get-current environment-wordlist set-current
207: true constant block
208: true constant block-ext
209: set-current
1.5 pazsan 210:
1.21 ! crook 211: : bye ( -- ) \ tools-ext
! 212: \G Return control to the host operating system (if any).
! 213: ['] flush catch drop bye ;
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